CN111581870B - Design method for fixed guide vane of axial-flow propeller turbine - Google Patents

Design method for fixed guide vane of axial-flow propeller turbine Download PDF

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CN111581870B
CN111581870B CN202010498191.4A CN202010498191A CN111581870B CN 111581870 B CN111581870 B CN 111581870B CN 202010498191 A CN202010498191 A CN 202010498191A CN 111581870 B CN111581870 B CN 111581870B
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guide vane
fixed guide
volute
streamline
flow
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CN111581870A (en
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陈柱
王建明
罗定旗
赖吕海
陈瑶
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Chongqing Water Turbine Works Co Ltd
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Chongqing Water Turbine Works Co Ltd
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    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00Computer-aided design [CAD]
    • G06F30/20Design optimisation, verification or simulation
    • G06F30/23Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00Computer-aided design [CAD]
    • G06F30/10Geometric CAD
    • G06F30/17Mechanical parametric or variational design
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract

The invention discloses a method for designing a fixed guide vane of an axial-flow propeller turbine, which comprises the following steps: 1) Obtaining the streamline distribution condition of a non-volute region, and finding out a fixed guide vane causing flow shedding and a blade path vortex; 2) Removing the fixed guide vane to obtain the streamline distribution of the non-volute area; 3) Determining the mounting positions and the number of the new fixed guide vanes according to the streamline distribution of the non-volute region and by combining the distribution condition of the movable guide vanes; 4) Drawing a new fixed guide vane bone line according to the streamline of the new fixed guide vane mounting position area, and thickening the new fixed guide vane bone line into a streamline leaf shape according to the strength requirement to obtain a new fixed guide vane; 5) And adding the new fixed guide vane into the flow channel for verification. The method has the advantages of simplicity and convenience in operation, and by adopting the method, the abnormal hydraulic problems of guide vane region flow shedding, blade channel vortex and the like caused by mismatching of non-volute fixed guide vanes and a flow channel due to great increase of flow are well solved, and the problems of abnormal sound and unit vibration of a unit are eliminated.

Description

Design method for fixed guide vane of axial-flow propeller turbine
Technical Field
The invention relates to an axial-flow Kaplan turbine, in particular to a design method for a fixed guide vane of the axial-flow Kaplan turbine.
Background
In some power stations which are provided with the axial-flow paddle water turbine before the 90 s in the 20 th century, when the capacity increasing and efficiency improving are achieved by replacing the water distributor and the runner, the rated flow is required to be greatly increased under the condition that the rated water head is kept unchanged, and the purpose of increasing the capacity of the unit by about 20% is achieved. With the great increase of rated flow, the non-volute fixed guide vane wing profile and the distribution position deviate from the ideal condition, the conditions of flow shedding, blade channel vortex and the like occur, the periodic symmetrical inflow condition of the inlet of the rotating wheel is damaged, the vibration and noise of the unit are caused, and the safe and stable operation of the unit is influenced, so that the non-volute fixed guide vane needs to be designed and replaced. The design of a non-volute fixed guide vane is that the traditional method is to lead the inlet peripheral speed V from the tail part of a volute to the non-volute area of the inlet section of the volute U The design and arrangement of fixed guide vanes are designed according to the linear rule, while the embedded parts such as the capacity-increasing efficiency-improving project and the seat ring of the axial-flow Kaplan turbine can not move greatly in principle, only a few fixed guide vanes (mainly non-volute areas) can be modified and replaced, and the coexistence of new and old fixed guide vanes can destroy the peripheral speed V U The straight line change rule of the guide vane can bring new problems if the original guide vane cannot be designed according to the traditional method.
Disclosure of Invention
The invention aims to provide a fixed guide vane design method for an axial-flow Kaplan turbine, which can effectively enable new and old fixed guide vanes to coexist.
The invention aims to realize the technical scheme that the method for designing the fixed guide vane of the axial-flow Kaplan turbine comprises the following steps:
1) Utilizing CFD simulation software to obtain the streamline distribution condition of a non-volute area, and finding out the fixed guide vane causing flow shedding and a blade path vortex;
2) Removing fixed guide vanes causing flow separation and blade vortex, and obtaining the streamline distribution of the non-volute area by using CFD simulation software again;
3) Determining the mounting positions and the number of the new fixed guide vanes according to the streamline distribution of the non-volute region and by combining the distribution condition of the movable guide vanes;
4) Drawing a new fixed guide vane bone line according to the streamline of the new fixed guide vane mounting position area, and thickening the new fixed guide vane bone line into a streamline leaf shape according to the strength requirement to obtain a new fixed guide vane;
5) And adding the new fixed guide vane into the flow channel, and verifying by using CFD simulation software again.
In the step 1), CFD simulation software is used for carrying out three-dimensional geometric modeling on the water turbine under the full-flow-channel rated working condition, wherein the flow passage component comprises a volute, a fixed guide vane, a movable guide vane, a rotating wheel and a draft tube; using ANSYS ICEM software to perform grid division on the geometric model, and performing independence test on each flow passage component grid; the CFD software adopts ANSYS CFX, the numerical calculation adopts a Segregated separation type solver, a Steady constant flow and SST turbulence model, the solving conditions are that a flow inlet, an average static pressure outlet, a non-slip wall surface and a static and dynamic interface are in a Frozen Rotor, and the numerical simulation result of the water turbine under the rated working condition is obtained.
In the step 2), intercepting middle horizontal cross-sections of the volute, the fixed guide vane and the movable guide vane from ANSYS CFX software to obtain streamline distribution on the cross-sections, including streamline distribution conditions of non-volute regions;
and when the non-volute region has a blade vortex, deleting the fixed guide vane from the model, recalculating and intercepting the section to obtain a new streamline distribution condition of the non-volute region.
Wherein, in the step 3), the method further comprises the following steps:
(1) Determining the installation position-the installation position of the fixed guide vane is that the outlet edge of the fixed guide vane is staggered with the water inlet edge of the movable guide vane by 2.5-4 degrees, and the fixed guide vane is positioned in the back direction of the movable guide vane;
(2) Determining the number of the fixed guide vanes, namely determining the number of the fixed guide vanes according to the principle that one fixed guide vane corresponds to one movable guide vane and the original fixed guide vane is not replaced.
Wherein, in the step 4), the method further comprises the following steps:
airfoil determination-new stator blade excircle D a And inner circle D b Keeping the original shape unchanged; novel fixed guide vane inlet mounting angle alpha i The determination method comprises the following steps: taking the streamline inflow angle delta at the corresponding position of the non-volute area and the attack angle delta as the inlet mounting angle alpha of the fixed guide vane i Namely, it is
α i =δ+△
Fixed guide vane exit angle alpha o Taking the inflow angle alpha of the movable guide vane under the rated working condition c Are identical, i.e. that
α oc
Fixed guide vane inlet placement angle alpha i And the outlet angle alpha o And after the determination, drawing the fixed guide vane bone line by taking the streamline at the corresponding position of the non-volute region as a reference line.
By adopting the technical scheme, the method has the advantages of simplicity, convenience in operation and low cost, the abnormal hydraulic problems of guide vane regional flow shedding, blade path vortex and the like caused by mismatching of the non-volute fixed guide vanes and the flow channel due to great increase of the flow are well solved, the problems of abnormal sound and unit vibration of a unit are eliminated, and theoretical support is provided for the hydraulic design of the non-volute fixed guide vanes during the capacity increasing and efficiency improving of the axial flow propeller turbine.
Drawings
The drawings of the invention are illustrated as follows:
FIG. 1 is a streamline distribution for a non-volute region of the invention;
FIG. 2 is a schematic view of the invention showing the distribution of flow lines in the non-volute region where the stay vanes are deleted;
FIG. 3 is a schematic view of the determination of the installation position and number of the new stay vanes of the present invention;
FIG. 4 is a schematic view of the new stay vane profile of the present invention;
FIG. 5 is a schematic view of the streamline distribution of the non-volute region after the new stay vanes are added.
Detailed Description
The following detailed description of the embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to these embodiments, and any modifications or substitutions in the basic spirit of the embodiments will still fall within the scope of the present invention claimed in the claims.
Example 1: as shown in fig. 1, 2, 3, 4 and 5, a method for designing a stay vane of a turbine of the axial-flow propeller type, the method comprising the steps of:
1) Utilizing CFD simulation software to obtain the streamline distribution condition of a non-volute area, and finding out a fixed guide vane 2 which causes the flow shedding and the blade path vortex 1;
2) Removing the fixed guide vane 2 which causes the defluidization and the blade vortex, and obtaining the streamline distribution 3 of the non-volute area by using CFD simulation software again;
3) Determining the mounting positions 5 and the number of the new fixed guide vanes according to the streamline distribution 3 of the non-volute region and in combination with the distribution 4 of the movable guide vanes;
4) Drawing a new fixed guide vane bone line 6 according to the streamline of the new fixed guide vane mounting position area, and thickening the new fixed guide vane bone line into a streamline leaf shape according to the strength requirement to obtain a new fixed guide vane 7;
5) And adding the new fixed guide vane 7 into the flow channel, and verifying by using CFD simulation software again.
Further, in the step 1), CFD simulation software is used for carrying out three-dimensional geometric modeling on the water turbine under the full-flow-channel rated working condition, wherein the flow passage component comprises a volute, a fixed guide vane, a movable guide vane, a rotating wheel and a draft tube; using ANSYS ICEM software to perform grid division on the geometric model, and performing independence test on each flow passage component grid; the CFD software adopts ANSYS CFX, the numerical calculation adopts a Segregated separation type solver, a Steady constant flow and SST turbulence model, the solving conditions are that a flow inlet, an average static pressure outlet, a non-slip wall surface and a static and dynamic interface are in a Frozen Rotor, and the numerical simulation result of the water turbine under the rated working condition is obtained.
Further describing, in the step 2), cutting the middle cross-sectional planes of the volute, the fixed guide vane and the movable guide vane in ANSYS CFX software, and performing horizontal cross-sectional cutting to obtain the streamline distribution condition of the non-volute region;
and when the non-volute region generates a blade vortex, deleting the fixed guide vane from the model, and intercepting the section again to obtain a new streamline distribution condition of the non-volute region.
Further, in the step 3), the following steps are further included:
(1) Determining the mounting position-the mounting position of the fixed guide vane is that the outlet edge of the fixed guide vane is staggered with the water inlet edge of the movable guide vane by 2.5-4 degrees, and the fixed guide vane is positioned in the back direction of the movable guide vane;
(2) Determining the number of fixed guide vanes, namely determining the number of the fixed guide vanes according to the principle that one fixed guide vane corresponds to one movable guide vane and the original fixed guide vane is not replaced;
wherein, in the step 4), the method further comprises the following steps:
airfoil determination-new stator blade excircle D a And inner circle D b Keeping the original shape unchanged; novel fixed guide vane inlet mounting angle alpha i The determination method comprises the following steps:taking a streamline inflow angle delta at the corresponding position of the non-volute region and an attack angle delta as a fixed guide vane inlet installation angle alpha i Namely, it is
α i =δ+△
Fixed vane exit angle alpha o Taking the inflow angle alpha of the movable guide vane under the rated working condition c Are identical, i.e. that
α oc
Fixed guide vane inlet placement angle alpha i And the outlet angle alpha o And after the determination, drawing the fixed guide vane bone line by taking the streamline at the corresponding position of the non-volute region as a reference line.

Claims (1)

1. A design method for a fixed guide vane of a turbine with a rotating propeller shaft is characterized by comprising the following steps:
1) Utilizing CFD simulation software to obtain the streamline distribution condition of a non-volute area, and finding out the fixed guide vane causing flow shedding and a blade path vortex; carrying out three-dimensional geometric modeling on the water turbine under the full-flow-channel rated working condition by using CFD simulation software, wherein the flow passage component comprises a volute, a fixed guide vane, a movable guide vane, a rotating wheel and a draft tube; the method comprises the following steps of (1) carrying out mesh division on a geometric model by utilizing ANSYS ICEM software, and carrying out independence test on meshes of all flow passage components; the CFD software adopts ANSYS CFX, the numerical calculation adopts a Segregated separation type solver, a Steady constant flow and SST turbulence model, the solving conditions are that a flow inlet, an average static pressure outlet, a non-slip wall surface and a static and dynamic interface are in a Frozen Rotor, and the numerical simulation result of the water turbine under the rated working condition is obtained;
2) Removing fixed guide vanes causing flow separation and blade vortex, and obtaining the streamline distribution of the non-volute area by using CFD simulation software again; intercepting middle horizontal cross-sectional planes of the volute, the fixed guide vane and the movable guide vane in ANSYS CFX software to obtain streamline distribution on the cross-sectional planes, including streamline distribution conditions of non-volute areas;
when the non-volute region has a blade vortex, deleting the fixed guide vane from the model, recalculating and intercepting the section to obtain a new streamline distribution condition of the non-volute region;
3) Determining the mounting positions and the number of the new fixed guide vanes according to the streamline distribution of the non-volute region and by combining the distribution condition of the movable guide vanes; the method comprises the following steps:
(1) Determining the mounting position-the mounting position of the fixed guide vane is that the outlet edge of the fixed guide vane is staggered with the water inlet edge of the movable guide vane by 2.5-4 degrees, and the fixed guide vane is positioned in the back direction of the movable guide vane;
(2) Determining the number of fixed guide vanes, namely determining the number of the fixed guide vanes according to the principle that one fixed guide vane corresponds to one movable guide vane and the original fixed guide vane is not replaced;
4) Drawing a new fixed guide vane bone line according to the streamline of the new fixed guide vane mounting position area, and thickening the new fixed guide vane bone line into a streamline leaf shape according to the strength requirement to obtain a new fixed guide vane; the method comprises the following steps:
airfoil determination-new stator blade excircle D a And inner circle D b Keeping the original shape unchanged; novel fixed guide vane inlet mounting angle alpha i The determination method comprises the following steps: taking the streamline inflow angle delta at the corresponding position of the non-volute area and the attack angle delta as the inlet mounting angle alpha of the fixed guide vane i Namely, it is
α i =δ+△
Fixed guide vane exit angle alpha o Taking the inflow angle alpha of the movable guide vane under the rated working condition c Are identical, i.e. that
α oc
Fixed guide vane inlet placement angle alpha i And the outlet angle alpha o After the determination, the streamline on the corresponding position of the non-volute region is taken as a reference line, so that the fixed guide vane skeleton line is drawn;
5) And adding the new fixed guide vane into the flow channel, and verifying by using CFD simulation software again.
CN202010498191.4A 2020-06-04 2020-06-04 Design method for fixed guide vane of axial-flow propeller turbine Active CN111581870B (en)

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