CN103226634A - Computing method for unsteady flow field of rotary jet pump based on three-dimensional dynamic mesh - Google Patents
Computing method for unsteady flow field of rotary jet pump based on three-dimensional dynamic mesh Download PDFInfo
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Abstract
The invention provides a computing method for an unsteady flow field of a rotary jet pump based on a three-dimensional dynamic mesh. The method is applied to the technical field of rotary jet pumps, is based on the technology of three-dimensional dynamic mesh, solves the technical problem of reconfiguration of mesh, and realizes the compute of the unsteady flow field of the rotary jet pump.
Description
Technical field
The present invention relates to the rotary-jet pump technical field, more particularly, relate to a kind of computing method that are used for the nonstationary flow field of rotary-jet pump.
Background technology
Small flow and high lift pump has a wide range of applications in all conglomeraties such as oil, chemical industry, urban construction, metallurgy, papermaking.The specific speed of such pump very low (ns≤30), therefore the problem of bringing is that water pump efficiency is on the low side, energy loss is extremely serious.Rotary-jet pump (claiming rotary jet pump, Pitot pump again) is based on a kind of low specific speed pump that Pitot tube converts fluid dynamic energy to the potential energy principle development.Fig. 1 is the flow model of rotary-jet pump, and it comprises inlet segment, impeller, rotor chamber and four main flow passage components of header, and wherein impeller and rotor chamber are fixed together and rotate synchronously with main shaft, and header then is the stationary element that inserts in the rotor chamber.During the rotary-jet pump operation, liquid enters impeller from inlet segment, be subjected to obtain after the effect of rotary blade blade energy and enter rotor chamber, enter header after rotating the higher kinetic energy of acquisition with rotor chamber again, the straight length that is converted to behind the potential energy by header through diffuser kinetic energy flows out.Compare with the high-pressure pump (as multistage pump, reciprocating pump etc.) of routine, characteristics such as that rotary-jet pump has is simple in structure, volume is little, in light weight, easy to use, reliable operation, become the main option of small flow and high lift pump gradually, bigger lifting potentiality are also arranged at aspect of performances such as pump efficiency.From application point of view, as shown in Figure 1, the radical length of header is suitable with the rotor chamber radius, and the cross-sectional diameter of header accounts for 1/4~1/3 of rotor chamber axial dimension.Can imagine, when impeller and rotor chamber rotation, the header of fixed static must produce serious disturbance to the impeller and the rotor chamber flow field of high speed rotating (part rotary-jet pump rotating speed is more than 4000rpm), also form pressure reduction around the header itself and produce the acting force bigger, cause unfavorable factors such as vibrating noise header.
From the angle of scientific research, for the UNSTEADY FLOW problem of common blade pump (as centrifugal pump, axial flow pump etc.), when impeller rotated, rotor (impeller) territory and stator (pump housing, pipeline) territory geometric configuration remained constant; Except the interface that is connected, rotor territory and stator territory are independent separately, mutually noninterfere, and therefore can adopt all is that the rotor territory of rigid grid and " sliding mesh method " that the stator territory does relative motion are carried out transient analysis.But in the rotary-jet pump flow field, when rotor (rotor chamber and impeller) territory rotated, rotor territory and static header entity clashed; If will avoid the interference of header entity, the rotor computational fields must be done significantly distortion in time, and computing grid also needs to do corresponding adjustment, therefore can not use " the sliding mesh method " of above-mentioned rigid grid.
Solve the large deformation problem of flow territory and grid, must take three-dimensional computations rotation territory and grid reconstruction technology thereof, just might realize the nonstationary flow field analysis of rotary-jet pump.Owing to the complicacy of 3D grid reconstruct, calculate consuming time and new and old grid and repeatedly shine upon interpolation and cause many-sided reasons such as error, up to the present the flow field analysis based on the 3D grid reconfiguration technique still is in the exploratory stage, does not more have ripe engineering application case.
Nineteen twenty-three Krogh is applied to the Pitot tube principle of work in the design of pump, after be developed into rotary-jet pump and be used for World War II.The eighties in 20th century, the theoretical research and the product development of rotary-jet pump are carried out in the infusion of financial resources of states such as Germany, Japan, at present existing a lot of products put goods on the market, but the rotary-jet pump data that can consult mostly is product introduction, and relevant research report and technical information are also rarely found.In the nineties, Sbom has done comprehensive introduction to the aspects such as principle of work, design feature and application thereof of rotary-jet pump.
Late 1980s, China introduced the rotary-jet pump product successively, the domestic research that has also begun about aspects such as rotary-jet pump principle of work, hydraulic performances.Yang Junhu, Qi Xueyi, Ma Xijin etc. have analyzed flow condition in the rotary-jet pump by development test, propose the alternate combined type impeller method for designing of deviated splitter vane, have provided the design formula and the range of choice of header; They also adopt any accurate ternary normal surface method to find the solution the interior quasi-three dimensional flow field of rotary-jet pump impeller, and the flow mechanism and the method for designing of rotary-jet pump have been carried out Primary Study.Wang Chengmu etc. have carried out the various combination test with three kinds of impellers and four kinds of headers of rotary-jet pump, find that the efficient of combined type common blade impeller does not have straight-vaned impeller adiabatic efficiency height; Section configuration, size and the roughness of also finding header are except influential to the resistance to flow size, and also the job stability to pump exerts an influence.
Along with the fast development of computing technique, some scholars have carried out the numerical simulation study in rotary-jet pump viscosity flow field in succession in recent years.Utilization such as Wang Yunyun, Chen Cichang, Yang Changming Fluent software adopts standard k-ε turbulence model and SIMPLEC algorithm, has analyzed the flowing law in the rotary-jet pump impeller.Cheng Yunzhang, Zhu Bing, Chen Hongxun etc. under relative reference system to rotary-jet pump impeller and rotor chamber, under absolute reference frame, flow in to header and carried out the three-dimensional numerical value simulation, analog result shows that header has tangible backflow and vortex around the corner with in the cross section.Zou Xuelian, Chen Hongxun have set up the flow mathematical model of rotary-jet pump prismatic blade impeller, have carried out three-dimensional computations and comparative analysis to flowing in the impeller.Xu Hongyuan, Tian Aimin, Wang Xiaodong etc. are furtherd investigate flowing in the header, have understood the regularity of distribution of header internal pressure, flow velocity and turbulent flow, learn that the shape of header diffuser has bigger influence to pump efficiency.Yu Huiqiong, Ji Quankai, Fu Jie etc. have carried out numerical simulation to the rotary-jet pump flow field, and having inquired into geometry parameter such as impeller and header influences pump performance.Yi Tongxiang, Wang Chunlin utilization ANSYS-CFX software have carried out big whirlpool numerical simulation to the rotary-jet pump flow field, analyzed the influence of header entry shape and aerofoil profile to pump performance, analyzed under the different operating modes solid particle to the abrasion condition of rotary-jet pump wall, disregarding under the condition of header to the rotational flow field interference, studied the fluctuation pressure in the pump.Song Huaide, Liu Yi have carried out numerical simulation of flow field to the header and the rotor chamber of rotary-jet pump, study at different header shapes, rotary-jet pump that inlet size constituted.People such as Huang Si, Su Lijuan uses the experiment of numerical simulation bonding properties, has inquired into the influence of parameters such as vertical rotary-jet pump impeller form (one-sided open type, unilaterally-closed and bilateral open type), blade shape (prismatic blade, camber blades and deviated splitter vane combination), the number of blade, header profile, header cross section of fluid channel, header radius of turn to pump performance.
Since before mention because of the header physical intervention, cause rotor computational fields and computing grid to do in time and significantly be out of shape the adjustment problem, therefore the Flow Field Calculation of above-mentioned rotary-jet pump can only be confined to permanent calculating, promptly rotor territory (impeller and rotor chamber) taked " rotor freezing process ": rotor territory and stator territory (header) all are rigidity, do not have relative motion between them.Obviously, permanent simulation is to reflect the instantaneous flow condition of rotary-jet pump, especially fixedly header also forms pressure reduction and produces the phenomenon that also may cause vibrating noise to the bigger acting force of header the impeller and the serious interference of rotor chamber flow field generation of high speed rotating around the header self.
About the non-permanent computing method of hydraulic, the UNSTEADY FLOW problem of hydraulic is broadly divided into following 3 classes: (1) object is static and mobile for non-permanent problem, as the separated flow of static leaf grating etc.; (2) single body is made the UNSTEADY FLOW problem of rigid motion, as rotor around rotation of axle etc.; (3) many bodies are made the non-permanent problem of relative motion or amoeboid movement, as the open and close of gear-type pump engagement, valve, piston to-and-fro movement in cylinder or the like.
For the non-permanent problem of (1) above-mentioned class, static rigid grid just can meet the demands.For the non-permanent problem of (2) class, still can adopt static rigid grid, but need choose noninertial system or many reference frames (inertial system+noninertial system) are carried out permanent or non-permanent calculating.For example, for the modal rotor flow field problem of hydraulic.Because rotor is periodically to skim over to find the solution the territory, say that for inertial system the right and wrong that flow are permanent.Yet under the situation of not considering stationary parts, get computational fields that rotary part moves together under rotary reference system (noninertial system), mobilely can be considered permanent, problem is simplified.If except rotary part, also to consider stationary parts, as the flow field problem of rotor and stator is arranged in turbine simultaneously, this situation just must adopt many reference frames (Multiple Reference Frame is called for short MRF) to analyze.Adopt static rigid grid, can save many troubles (as geometry conservation law, moving boundaries etc.) of using dynamic mesh calculating to be brought, many reference frames MRF technology that therefore most CFD softwares are all integrated.But it must be noted that MRF is that the position relation of lower rotor part and stator only is the mutual alignment of a certain moment between them, is referred to as " rotor freezing process " (Frozen Rotor Approach).Clearly, the rotor freezing process can not solve because of rotor and stator and make the caused UNSTEADY FLOW problem of relative motion.
For the non-permanent problem of (3) class, relate to the relative motion or the distortion of object, common solution has methods such as sliding mesh and dynamic mesh.The basic thought of sliding mesh is to mark a slippage subdomain around the movement locus of moving component in advance.At slippage subdomain and other regional interface places, utilize boundary condition to dock, thereby realize the calculating in whole flow field with other zones.The sliding mesh technology belongs to a kind of of rigid motion grid strictly speaking.In whole motion process, computing grid is done rigid motion with object by known mode of motion, and computing grid need not regenerate, so calculated amount is little, and can keep the quality of initial mesh.The sliding mesh technology is widely used in UNSTEADY FLOW problems such as the rotary blade machinery of routine, vehicle intersection, also integrated this gridding technique in the CFD softwares such as Ansys-CFX, Fluent.But the sliding mesh method can not solve challenges such as deformable body or the relative motion of many bodies, and rotary-jet pump rotor territory belongs to deformable body one class just.
Theoretically, the dynamic mesh method is the general way that solves the UNSTEADY FLOW problem, the general problem that changes in time owing to move in the border with solving flow field patterns.The mode of motion on border can be known in advance, also can be unknown in advance, i.e. the motion on border will be by the result of calculation decision of back, and the renewal of grid is then finished automatically according to the situation of change on border.The basic thought of dynamic mesh method is in each time step, grid by the convection cell territory upgrades to realize because the variation of finding the solution the territory that the border motion causes, adopt any Lagrange-Euler (ALE) method to describe the governing equation of fluid motion, the physical quantity of new grid obtains from old mesh mapping by interpolation arithmetic, and the physical quantity on each time step grid carried out iterative, with this dynamic evolution result who obtains to flow.
Common dynamic mesh method has following three kinds: based on the spring theory of adjustment (Spring-based smoothing) of spring theory, dynamic layered method (Dynamic layering) and grid reconstruction method (Remeshing).
(l) the spring theory of adjustment is that each grid limit is reduced to the spring that has certain rigidity and connect by node.With the boundary condition of boundary displacement amount as spring, obtain the displacement increment of node by the equilibrium equation of finding the solution spring system, finally obtain the node location of new grid.The topological relation of new and old grid node remains unchanged in the spring theory of adjustment, therefore can guarantee computational accuracy.But the spring theory of adjustment stretches by change grid node position or compresses grid, causes grid overstocked or thin excessively easily; When the computational fields distortion was big, the grid after the distortion can produce bigger degree of tilt made mesh quality worsen, influence computational accuracy; When serious even negative volume mesh occurs, make to calculate and make mistakes and stop.
(2) dynamic layered method is that displacement according to the border dynamically increases or reduce borderline clathrum, promptly on the border, suppose a desirable clathrum height earlier, when the border moves, if the clathrum height on next-door neighbour border is highly compared when being stretched to a certain degree with ideal, just it is divided into two clathrums; When if meshes is compressed to a certain degree, two clathrums that just will be close to the border are merged into a layer, make borderline clathrum keep certain density.Dynamic layered method speed when generating mesh is very fast, but it to require near the grid the moving boundaries be hexahedron (three-dimensional), this mobile territory for complex appearance is unaccommodated.
(3) the grid reconstruction method is that the elasticity theory of adjustment generally can only be handled small deformation flow field problem to the replenishing of elasticity theory of adjustment.For some problem of hydraulic, as problems such as gear-type pump engagement, valve switch processes, large deformation is inevitable.Therefore, need utilize grid reconstruction method stream field grid to repartition.The grid reconstruction method be with size of mesh opening and aberration rate etc. as judgment criteria, when the moving and be out of shape excessively of border, when serious distortion takes place local grid, then grid is repartitioned in these zones.Physical quantity on the new grid obtains from old grid by volume conservation law and interpolation mapping.Need to prove that the grid reconstruction method all needs to repartition grid when each distortion is mobile, thereby expends more computing time.
At present the dynamic mesh technology mainly is aspect three of the open and close processes, the to-and-fro movement of piston in cylinder etc. of rotation, the valve of eccentric pump or gear-type pump in the application of hydraulic.The common practices of these work is to use moving boundary file (Profile) or User-Defined Functions (User-Defined Function in the software that flows, be called for short UDF) define the mode of motion of moving boundaries such as known gear, spool or piston, adopt dynamic mesh technology (spring theory of adjustment, dynamic layered method and grid reconstruction method) that the UNSTEADY FLOW state in the computational fields is carried out analog computation, visual analyzing, draw flow field and stressed situation over time.But the dynamic mesh technology is when being generalized to the 3D grid distortion, not only algorithm complexity increases, distortion of the mesh efficient reduces, and the mesh quality after the distortion is often undesirable and cause calculate stopping, therefore above-mentioned dynamic mesh technology as fired basis originally is confined to two dimension and (as in the gear-type pump model, approximately thinks that flow parameter does not change in the turning axle direction; In valve opening and closing, cylinder, do rotational symmetry hypothesis in the reciprocating motion of the pistons) or the simplified model of accurate three-dimensional (becoming three-dimensional domain at axial tension) by the two-dimensional field calculate.
In sum and since the static header severe interference of rotary-jet pump the rotor territory, therefore the flow field analysis of all rotary-jet pumps can only be to be based upon on the permanent calculating basis of rotor freezing process at present, the Unsteady Flow Calculation of rotary-jet pump is still blank so far.
Summary of the invention
The objective of the invention is to overcome the deficiencies in the prior art, a kind of computing method of the rotary-jet pump nonstationary flow field based on three-dimensional dynamic mesh are provided, this method has solved the technical matters of grid reconstruction based on three-dimensional dynamic mesh technology, has realized the Unsteady Flow Calculation of rotary-jet pump.
In order to achieve the above object, the present invention adopts following technical scheme: the computing method based on the rotary-jet pump nonstationary flow field of three-dimensional dynamic mesh, it is characterized in that, and comprise the steps:
The first step is defined as computational fields with rotary-jet pump rotor chamber, impeller, inlet segment and header, and wherein, rotor chamber and impeller are defined as the rotation territory in the computational fields, uses the 3D solid of mechanical drawing software construction computational fields, forms the 3D solid file;
Second step, use grid dividing software to read the 3D solid file, computational fields is carried out grid dividing, obtain three-dimensional initial mesh, form grid file;
In the 3rd step, use computational fluid dynamics software to read grid file, and carry out the physical parameter setting; Described physical parameter setting comprises the setting of moving boundaries; The setting of described moving boundaries is meant, the layout setting of the moving boundaries surface that to be fluid contacted with impeller with rotor chamber, and the characteristics of motion is set to sway, and mode of motion is set to the Profile mode;
The 4th step, use computational fluid dynamics software, the numerical value to each time step in the computation period calculates successively; The numerical evaluation of each time step is finished after the numerical value convergence of calculating gained; After the numerical evaluation of a time step is finished, by upgrading rotation territory grid and closing on the grid node of rotation territory part, next time step grid of reconstruct, next time step grid of reconstruct adopts two kinds of schemes: (1) is the zone in permissible range to size of mesh opening and aberration rate, adopt the spring theory of adjustment to obtain the grid node of next time step earlier, obtain the physical quantity of next time step grid by interpolation arithmetic from existing grid then, thus the grid of next time step of reconstruct; (2) size of mesh opening and aberration rate are exceeded the zone of permissible range, repartition grid as next time step grid; Behind next time step grid reconstruction, calculate the numerical value of next time step, up to finishing the final time calculating in step.
Because the singularity of rotary-jet pump structure, at present can only adopt the permanent method of " rotor freezes " about the Flow Field Calculation of rotary-jet pump both at home and abroad, and be adopt " sliding mesh method " about the general way of rotary blade machinery Unsteady Flow Calculation, but this method still can not solve the non-permanent calculating in rotary-jet pump flow field; The calculative strategy that the inventive method has taked the rotation territory to combine with the rigidity territory, based on 3D grid, adopt the spring theory of adjustment to realize mesh reconstruction in conjunction with local grid reconstruction method, calculate the numerical value of each time step, realized the Unsteady Flow Calculation of rotary-jet pump, for the transient state analysis of flow characteristics of rotary-jet pump provides strong instrument.
Further scheme is: the grid node that the employing spring theory of adjustment in described the 4th step obtains next time step is meant, the zone in permissible range to size of mesh opening and aberration rate, take the spring theory of adjustment, the grid limit that this is regional is reduced to the spring that has certain rigidity and connect by grid node, stretches or compresses grid by changing the grid node position; With the border amount of movement is the boundary condition of spring, obtains the displacement increment of grid node by the equilibrium equation of finding the solution spring system, finally obtains the grid node position of next time step.
Computation period in described the 4th step is meant, rotation territory 360 ° of required times of rotation.
Numerical value convergent determination methods in described the 4th step has two kinds: (one) judges with the variation of residual values; (2) the coding logarithm value is monitored.
Further scheme is: the physical parameter setting in described the 3rd step also comprises: the computational fields inlet is set is the pressure boundary condition; The computational fields outlet is set is the mass rate boundary condition; UNSTEADY FLOW is set calculates employing standard k-ε turbulence model; Time step Δ t is set; The starting condition that UNSTEADY FLOW is calculated is set, and described starting condition adopts the moving convergence solution of steady flow in the rotary-jet pump.
The span of time step Δ t in described the 3rd step is:
Wherein, n is the tachometer value of rotary-jet pump, and Z is the number of blade, and k is>1 integer.
The permanent mobile convergence solution that starting condition in described the 3rd step adopts is to calculate by the rotor freezing process.
Grid dividing software in described second step adopts ICEM software.
Computational fluid dynamics software in described the 3rd step and the 4th step adopts Ansys-Fluent software.
The present invention possesses following outstanding advantage and effect with respect to prior art:
1, the inventive method has been taked the calculative strategy that the rotation territory combines with the rigidity territory, solved the technical matters of three-dimensional computations territory grid reconstruction, capture prior art and can not calculate these technological difficulties of rotary-jet pump nonstationary flow field, realized the Unsteady Flow Calculation of rotary-jet pump, for the transient state analysis of flow characteristics of rotary-jet pump provides strong instrument;
2, the inventive method effectively uses the spring theory of adjustment to realize mesh reconstruction in conjunction with local grid reconstruction method, need not expend too much computing time.
Description of drawings
Fig. 1 is the sectional view of rotary-jet pump;
Fig. 2 is the process flow diagram of the inventive method;
Fig. 3 (a) is computational fields surface mesh synoptic diagram when being t=0;
Computational fields surface mesh synoptic diagram when Fig. 3 (b) is t=5 Δ t;
Computational fields surface mesh synoptic diagram when Fig. 3 (c) is t=10 Δ t;
Computational fields surface mesh synoptic diagram when Fig. 3 (d) is t=15 Δ t;
Near Fig. 4 (a) grid synoptic diagram of the computational fields header inlet on the computational fields central cross-section when being t=0;
Near the grid synoptic diagram of the computational fields of header inlet on computational fields central cross-section when Fig. 4 (b) is t=5 Δ t;
Fig. 5 is the rotary-jet pump rate of discharge figure that utilizes the inventive method to draw;
Wherein, 1 is that rotor chamber, 2 is that impeller, 3 is that inlet segment, 4 is that header, 4.1 is the header outlet.
Embodiment
The present invention is described in further detail below in conjunction with embodiment, but embodiments of the present invention are not limited thereto.
Embodiment
The present invention calculates the method for nonstationary flow field, is applied to rotary-jet pump, and its process flow diagram is seen Fig. 2, comprises the steps:
The first step is defined as the computational fields of fluid with rotary-jet pump rotor chamber, impeller, inlet segment and header, and wherein, rotor chamber and impeller are the rotation territory, and inlet segment and header are the rigidity territory; Use the 3D solid of mechanical drawing software (as Pro/E software) structure computational fields, form the 3D solid file;
Second step, use grid dividing software (as ICEM software) to read the 3D solid file, computational fields is carried out grid dividing, obtain structure/non-structure hybrid grid initial cell, form grid file;
In the 3rd step, use computational fluid dynamics software (as Ansys-Fluent) to read grid file, and carry out the physical parameter setting;
The physical parameter setting comprises moving boundaries is set, and the setting of moving boundaries is meant, the layout setting of the moving boundaries surface that to be fluid contacted with impeller with rotor chamber, and the characteristics of motion is set to sway, and mode of motion is set to the Profile mode; The setting of moving boundaries and control are the emphasis that dynamic mesh calculates; For the moving boundaries of the known characteristics of motion, need the mode of motion of definition moving boundaries, generally can adopt Profile(moving boundary file) and the UDF(User-Defined Functions) dual mode controls; The Profile mode is fit to the comparatively simple characteristics of motion, as translation and rotation; Moving boundary motion for more complicated then needs to adopt the UDF mode to control; The surface that though the moving boundaries of this method is a fluid to be contacted with impeller with rotor chamber, curve form more complicated, the characteristics of motion but are simply to sway, so this method adopts the Profile mode to define the mode of motion of moving boundaries;
The physical parameter setting also comprises, the computational fields inlet is set is the pressure boundary condition; The computational fields outlet is set is the mass rate boundary condition, can be according to operating point flow set mass rate boundary condition; UNSTEADY FLOW is set calculates employing standard k-ε turbulence model; Time step Δ t is set, and Δ t is not more than the mistiming that adjacent impeller blade skims over same position, and time step Δ t is definite according to the tachometer value n and the number of blade Z of rotary-jet pump,
Wherein, n is the tachometer value of rotary-jet pump, and Z is the number of blade, and k is>1 integer; The starting condition that UNSTEADY FLOW is calculated is set, and the value of starting condition adopts the moving convergence solution of steady flow in the rotary-jet pump, and permanent mobile convergence solution can calculate by the rotor freezing process;
The 4th step, use computational fluid dynamics software (as Ansys-Fluent software), with the rotation of rotation territory is a computation period for 360 °, and the numerical value to each time step in the computation period calculates successively, and the numerical evaluation of each time step is finished after the numerical value convergence of calculating gained; After the numerical evaluation of a time step is finished, rebuild the 3D solid of next time step, rotate the territory grid and close on the grid node that rotates the territory part by upgrading, thereby rebuild the grid of next time step, calculate the numerical value of next time step, up to finishing the final time calculating in step; Numerical value convergent determination methods has two kinds: (one) judges with the variation of residual values; (2) the coding logarithm value is monitored; In different time steps, motion because of moving boundaries, distortion has taken place in computational fields, therefore before calculating, to obtain next time step grid, next time step grid of reconstruct adopts two kinds of schemes: (1) is the zone in permissible range to size of mesh opening and aberration rate, adopt earlier the spring theory of adjustment to obtain the grid node of next time step, obtain the physical quantity of next time step grid by interpolation arithmetic from existing grid then, thus the grid of next time step of reconstruct; (2) size of mesh opening and aberration rate are exceeded the zone of permissible range, repartition grid as next time step grid; Behind next time step grid reconstruction, calculate the numerical value of next time step, up to finishing the final time calculating in step;
The grid node that adopts the spring theory of adjustment to obtain next time step is meant, the zone in permissible range to size of mesh opening and aberration rate, take the spring theory of adjustment, the grid limit that this is regional is reduced to the spring that has certain rigidity and connect by grid node, stretches or compresses grid by changing the grid node position; With the border amount of movement is the boundary condition of spring, obtains the displacement increment of grid node by the equilibrium equation of finding the solution spring system, finally obtains the grid node position of next time step;
When rotor chamber and impeller when axle turns over a certain angle because the fixedly existence of header, rotary-jet pump rotation territory clashes with header and forces the appearance of rotation territory to be out of shape; The rotation area deformation is two parts, and promptly a part of original rotation territory has become header, and another part is to turn over the part that header stays after this angle space has become new rotation territory; Therefore, new rotation territory is that former rotation territory deducts and the new overlapping part of header entity, fills the part that original header entity stays again; In any moment, the boundary surface shape and the mode of motion in rotation territory all are known, and the boundary surface in rotation territory comprises two parts: a part is the stationary interface adjacent with header, and remainder is the rotation interface adjacent with rotor chamber with impeller; There have been the geometric configuration and the characteristics of motion on border just can upgrade computational fields and the reconstructed mesh that obtains any time;
After the 4th step, can also comprise for the 5th step, calculate aftertreatment; The calculating aftertreatment comprises, show rotary-jet pump Unsteady Flow Calculation result, the rotary-jet pump external characteristic curve of predict steady-state, obtain the pulsating quantity non-permanent results such as (comprising ripple frequency and pulsation amplitude) of pump internal pressure, obtain because of there being the size and Orientation of pressure reduction generation around the header to the header acting force.
Outstanding advantage of the present invention is: because the singularity of rotary-jet pump structure, at present can only adopt the permanent method of " rotor freezes " about the Flow Field Calculation of rotary-jet pump both at home and abroad, and be adopt " sliding mesh method " about the general way of rotary blade machinery Unsteady Flow Calculation, the sliding mesh method is to allow do relative motion between two rigidity territories (rotor and stationary part), but this method still can not solve the non-permanent calculating in rotary-jet pump flow field; The calculative strategy that the inventive method has taked rotation territory (rotating parts such as rotor chamber, impeller) to combine with rigidity territory (fixed parts such as inlet segment, header), wherein, the rotation territory will deform in time, the grid node position also changes; And the grid node position of closing on rotation territory part may change, and the computational fields remainder does not deform in time; Realized the Unsteady Flow Calculation of rotary-jet pump, for the transient state analysis of flow characteristics of rotary-jet pump provides strong instrument.Effectively utilization spring theory of adjustment obtains new grid node position, three-dimensional computations territory in conjunction with local grid reconstruction method simultaneously, need not expend too much computing time.
The Unsteady Flow Calculation of rotary-jet pump of the present invention, grasp rotary-jet pump flow field sound interference, understand fully the dynamic flow characteristic and the Unsteady Flow Mechanism thereof of rotary-jet pump, to improving the hydraulic performance and the unfavorable factors such as functional reliability, minimizing vibrating noise of rotary-jet pump, will have important scientific research value and engineering using value.
Choose a vertical small-sized rotary-jet pump as research object, rotary-jet pump design conditions parameter is: rotation speed n=2900r/min, flow Q=1.8m3/h, lift H=100m.Actuating medium is a water, density p=998.2kg/m3, kinetic viscosity μ=1.003 * 10-3Pas, the number of blade Z=6 of impeller.Use the computational fields that Pro-E sets up rotary-jet pump, use Gambit to carry out the division of computational fields grid, obtain grid cell.Wherein inlet segment Unit 23355, rotation Unit 220239, territory, header Unit 159237, grid cell adds up to 402831, and grid node adds up to 112104.
Calculate and use the mobile software of Fluent, the swing circle that is calculated impeller by revolution speed and impeller blade number is 2.069 * 10
-2S, the blade cycle of skimming over is 3.448 * 10
-3S chooses step delta t=2.0 computing time * 10
-4S.Use the Profile mode to define turning to of computational fields boundary surface and rotating speed.Calculate for simplifying, warp mesh only limits to rotate the territory.Adopt spring theory of adjustment and local grid reconstruction method to realize distortion of the mesh.The synoptic diagram of computational fields surface mesh when Fig. 3 (a)-(d) is t=0,5 Δ t, 10 Δ t, 15 Δ t respectively.By Fig. 3 (a)-(d) as seen, the rotation territory is except outside surface rotates with solid, and the inside surface that contacts with header is also constantly adjusted in time, thereby has realized the distortion and the grid reconstruction of computational fields.Near the grid synoptic diagram of the computational fields of header inlet on the computational fields central cross-section can contrast near the local grid of header inlet over time when Fig. 4 (a) and Fig. 4 (b) were t=0 and t=5 Δ t respectively.By Fig. 4 (a) and Fig. 4 (b) as seen, fixedly the computing grid in the header remains unchanged, but the rotation territory needs constantly to adjust in time the border adjacent with header, and therefore rotating the territory grid distortion and reconstruct (seeing arrow indication position) in various degree occurred.
Fig. 5 has provided the rotary-jet pump rate of discharge that calculates curve over time, and as seen from Figure 5, after having started a period of time (t ≈ 0.010s, about half swing circle), rotary-jet pump rate of discharge value tends to be steady and the cycle pulsation of intercropping rule at any time.In a swing circle, 6 pulsation appear in the rotary-jet pump rate of discharge, and promptly flow pulsation frequency is corresponding with the number of blade Z of impeller.
Fig. 6 and Fig. 7 have provided the dimensionless radial force that calculates respectively
With
Curve over time.The dimensionless radial force is defined as:
Wherein A is the stressed total area, F
xAnd F
yBe respectively x, y direction radial force, U
InBe the pump intake mean flow rate.By Fig. 6 and Fig. 7 as seen, the ripple amplitude of radial force is bigger, shows that the rotor intraluminal fluid stream and the interference phenomenon of header can not be ignored.After rotary-jet pump works well, the radial force of horizontal direction
Level off to negative value, longitudinally
Level off on the occasion of, promptly the radial force direction is to flow a side by the back of the body that header is pointed in the axle center.
Validity and applicability for checking the inventive method compare the performance curve of the inventive method gained and the results of property of actual measurement.Adopt the Microcomputer Test System for Motor of multi function parameter measuring instrument, the startup by the system controlled by computer external unit, stop and regulating realization data acquisition, analyzing and processing etc.Measurement is included in the parameters such as motor three-phase alternating voltage, electric current, power, mains frequency, rotating speed, rotary-jet pump inlet and outlet pressure and flow under the design speed, obtains the performance curve of rotary-jet pump at last.Unstable state pressure adopts 10ms high frequency dynamic pressure transducer to measure.The performance curve of test gained is identical with the performance curve of the inventive method gained.
The foregoing description is a preferred implementation of the present invention; but embodiments of the present invention are not restricted to the described embodiments; other any do not deviate from change, the modification done under spirit of the present invention and the principle, substitutes, combination, simplify; all should be the substitute mode of equivalence, be included within protection scope of the present invention.
Claims (9)
1. based on the computing method of the rotary-jet pump nonstationary flow field of three-dimensional dynamic mesh, it is characterized in that, comprise the steps:
The first step is defined as computational fields with rotary-jet pump rotor chamber, impeller, inlet segment and header, and wherein, rotor chamber and impeller are defined as the rotation territory in the computational fields, uses the 3D solid of mechanical drawing software construction computational fields, forms the 3D solid file;
Second step, use grid dividing software to read the 3D solid file, computational fields is carried out grid dividing, obtain three-dimensional initial mesh, form grid file;
In the 3rd step, use computational fluid dynamics software to read grid file, and carry out the physical parameter setting; Described physical parameter setting comprises the setting of moving boundaries; The setting of described moving boundaries is meant, the layout setting of the moving boundaries surface that to be fluid contacted with impeller with rotor chamber, and the characteristics of motion is set to sway, and mode of motion is set to the Profile mode;
The 4th step, use computational fluid dynamics software, the numerical value to each time step in the computation period calculates successively; The numerical evaluation of each time step is finished after the numerical value convergence of calculating gained; After the numerical evaluation of a time step is finished, by upgrading rotation territory grid and closing on the grid node of rotation territory part, next time step grid of reconstruct, next time step grid of reconstruct adopts two kinds of schemes: (1) is the zone in permissible range to size of mesh opening and aberration rate, adopt the spring theory of adjustment to obtain the grid node of next time step earlier, obtain the physical quantity of next time step grid by interpolation arithmetic from existing grid then, thus the grid of next time step of reconstruct; (2) size of mesh opening and aberration rate are exceeded the zone of permissible range, repartition grid, as next time step grid; Behind next time step grid reconstruction, calculate the numerical value of next time step, up to finishing the final time calculating in step.
2. the computing method of the rotary-jet pump nonstationary flow field based on three-dimensional dynamic mesh according to claim 1, it is characterized in that, the grid node that employing spring theory of adjustment in described the 4th step obtains next time step is meant, the zone in permissible range to size of mesh opening and aberration rate, take the spring theory of adjustment, the grid limit that this is regional is reduced to the spring that has certain rigidity and connect by grid node, stretches or compresses grid by changing the grid node position; With the border amount of movement is the boundary condition of spring, obtains the displacement increment of grid node by the equilibrium equation of finding the solution spring system, finally obtains the grid node position of next time step.
3. the computing method of the rotary-jet pump nonstationary flow field based on three-dimensional dynamic mesh according to claim 2 is characterized in that, the computation period in described the 4th step is meant, rotation territory 360 ° of required times of rotation.
4. the computing method of the rotary-jet pump nonstationary flow field based on three-dimensional dynamic mesh according to claim 3 is characterized in that, the numerical value convergent determination methods in described the 4th step has two kinds: (one) judges with the variation of residual values; (2) the coding logarithm value is monitored.
5. the computing method of the rotary-jet pump nonstationary flow field based on three-dimensional dynamic mesh according to claim 1, the physical parameter setting in described the 3rd step also comprises: the computational fields inlet is set is the pressure boundary condition; The computational fields outlet is set is the mass rate boundary condition; UNSTEADY FLOW is set calculates employing standard k-ε turbulence model; Time step Δ t is set; The starting condition that UNSTEADY FLOW is calculated is set, and described starting condition adopts the moving convergence solution of steady flow in the rotary-jet pump.
6. the computing method of the rotary-jet pump nonstationary flow field based on three-dimensional dynamic mesh according to claim 5 is characterized in that, the span of the time step Δ t in described the 3rd step is:
Wherein, n is the tachometer value of rotary-jet pump, and Z is the number of blade, and k is>1 integer.
7. the computing method of the rotary-jet pump nonstationary flow field based on three-dimensional dynamic mesh according to claim 5 is characterized in that, the permanent mobile convergence solution that the starting condition in described the 3rd step adopts is to calculate by the rotor freezing process.
8. according to the computing method of each described rotary-jet pump nonstationary flow field based on three-dimensional dynamic mesh among the claim 1-7, it is characterized in that the grid dividing software in described second step adopts ICEM software.
9. according to the computing method of each described rotary-jet pump nonstationary flow field based on three-dimensional dynamic mesh among the claim 1-7, it is characterized in that the computational fluid dynamics software employing Ansys-Fluent software in described the 3rd step and the 4th step.
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Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2008207607A1 (en) * | 2007-12-21 | 2009-07-09 | Weir Minerals Australia Ltd | A guard |
CN102332040A (en) * | 2011-07-25 | 2012-01-25 | 大连理工大学 | Three-dimensional numerical simulation method for influence of flexible net on water flow |
-
2013
- 2013-04-19 CN CN201310138337.4A patent/CN103226634B/en not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU2008207607A1 (en) * | 2007-12-21 | 2009-07-09 | Weir Minerals Australia Ltd | A guard |
CN102332040A (en) * | 2011-07-25 | 2012-01-25 | 大连理工大学 | Three-dimensional numerical simulation method for influence of flexible net on water flow |
Non-Patent Citations (3)
Title |
---|
江帆等: ""基于动网格的离心泵内部流场数值模拟"", 《流体机械》, vol. 35, no. 7, 30 July 2007 (2007-07-30), pages 20 - 24 * |
苏丽娟: ""基于CFD的旋转喷射泵数值模拟与优化研究"", 《中国优秀硕士学位论文全文数据库 工程科技II辑》, no. 12, 15 December 2011 (2011-12-15), pages 29 - 33 * |
赵有朋等: "《高速铁路隧道气动效应》", 30 September 2012, article ""动网格技术"", pages: 75-78 * |
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