CN101545489A - Method for designing wrap profile of scroll machinery - Google Patents

Abstract

The invention relates to a method for designing a wrap profile of scroll machinery. According to the requirement on the design of the wrap profile of the scroll machinery, the method comprises that: various profiles combined by different line types are selected preliminarily, the wrap profile is a profile with the same wall thickness, and a wrap end modification part can have variable wall thickness; the profile consists of a plurality of similar profile units, values of crank angles swept by unit profiles are the same, the unit profiles can be expressed by the same equations set, and each unit consists of a plurality of curved sections; and geometrical property values of the profile are calculated through quantitation, the integral performance of the profile is predicted, line type combination, profile structural parameters and the like are adjusted and optimized, analysis and calculation on the deformation of the profile and a bottom plate of a scroll pan are carried out by a finite element method, the profile structural parameters are finally determined through calculation results, and a novel profile with excellent performance can be obtained finally. The wrap profile designed by the method can improve air displacement and performance of a whole machine.

Description

A kind of method for designing wrap profile of scroll machinery

Affiliated technical field

The invention belongs to Machine Design and manufacture field, particularly a kind of method for designing wrap profile of scroll machinery.

Background technique

Scroll machine has many exclusive characteristics as a kind of novel rotary machine.Compare with reciprocating machine, scroll machine since have simple in structure, volume is little, in light weight, noise is low, frictional loss is little, characteristic such as mechanical efficiency height, frequency conversion performance are good, be widely used in refrigeration, air-conditioning and heat pump and the kinds of processes flow process, in the using scope of refrigerating capacity 5kW～70kW, become main force's type gradually.

In the design process of scroll machine, the design of wrap profile often determines the overall performance of machine on the scroll.From the developing history of domestic and international wrap profile, the formation of wrap profile commonly used mainly contains 2 classes at present: the 1st class is to be made of 1 analytic curve, comprises circle involute, regular polygon involute, algebraic spiral, Archimedes spiral, trigonometric function curve.The 2nd class is to be made of the combination molded lines.Combination molded lines as circle involute-general curve-circle involute combination molded lines and circle involute-high order curve-circular arc.

The 1st type line vortex ring wall thickness is a constant, and the fluctuation of the gas moment of bearing is less, and Design and Machining is also comparatively convenient, but sound disc area utilization ratio is abundant inadequately; The 2nd type line outermost part vortex ring is made of circular arc, improved the area utilization of whirlpool dish, under the situation of identical whirlpool dish outside dimension, the machine air displacement adopts the machine of the 1st type line to want big, but the vortex ring wall thickness is a variable, and the gas load amplitude of variation is bigger, the in-process measurement difficulty, the variation of wall thickness also can increase the complexity of diabatic process, causes higher thermal effect.

Summary of the invention

At above-mentioned wrap profile of scroll machinery designs situation, the objective of the invention is to, a kind of wrap profile of scroll machinery design new method is proposed, it is constant that this method wrap profile of scroll machinery has the vortex ring wall thickness, the fluctuation of the gas moment of bearing is little, and it is comparatively convenient that Design and Machining is measured, the area utilization height of whirlpool dish, characteristics such as air displacement is big, thus the machine overall performance improved.

In order to realize above-mentioned requirements, the present invention adopts following technological scheme.

A kind of method for designing wrap profile of scroll machinery comprises some similar molded lines unit, and the crank angle numerical value that described unit molded lines is inswept is identical, and each unit molded lines can represent that each unit is made of 3 curved sections again, specifically comprises the following steps: with same set of equation

According to designing requirement, wrap profile of scroll machinery comprises orthodrome part, little circular arc portion and straight section, and each line segment tie point must guarantee tangent, and promptly single order can be led, and to guarantee the smooth connection of vortex ring curve, the equation of employing is as follows:

A orthodrome part

Exhibition angle φ ∈ [(k-1) π, k π-α], central coordinate of circle (x _b, y _b)

Vortex ring outer wall parametric equation is

$\left\{\begin{array}{c}{x}_{\mathrm{ko}}=r_{\mathrm{bko}}\cos (-\mathrm{\φ})+x_b\\ y_{\mathrm{ko}}=r_{\mathrm{bko}}\sin (-\mathrm{\φ})\end{array}\right.$

Vortex ring inwall parametric equation is

$\left\{\begin{array}{c}{x}_{\mathrm{ki}}=r_{\mathrm{bki}}\cos (-\mathrm{\φ})+x_b\\ y_{\mathrm{ki}}=r_{\mathrm{bki}}\sin (-\mathrm{\φ})\end{array}\right.$

Wherein, r _Bko, r _BkiBe orthodrome part vortex ring inner-outer wall radius of curvature.

The little circular arc portion of b

Exhibition angle φ ∈ [k π-α, k π], central coordinate of circle (x _s, y _s)

Vortex ring outer wall parametric equation is

$\left\{\begin{array}{c}{x}_{\mathrm{ko}}=r_{\mathrm{sko}}\cos (-\mathrm{\φ})+x_s\\ y_{\mathrm{ko}}=r_{\mathrm{sko}}\sin (-\mathrm{\φ})+y_s\end{array}\right.$

Vortex ring inwall parametric equation is

$\left\{\begin{array}{c}{x}_{\mathrm{ki}}=r_{\mathrm{ski}}\cos (-\mathrm{\φ})+x_s\\ y_{\mathrm{ki}}=r_{\mathrm{ski}}\sin (-\mathrm{\φ})+y_s\end{array}\right.$

Wherein, r _Sko, r _SkiBe little circular arc portion vortex ring inner-outer wall radius of curvature.

The c straight section

Exhibition angle φ=k π

Vortex ring outer wall parametric equation is

$x_{\mathrm{ko}}=\frac{{(-1)}^k}{2}(D-\mathrm{\ρ}-{\mathrm{kP}}_t)$

Vortex ring inwall parametric equation is

$x_{\mathrm{ki}}=\frac{{(-1)}^k}{2}(D-\mathrm{\ρ}-2t-{\mathrm{kP}}_t)$

Wherein, D is that whirlpool disk center and vortex ring distal-most end distance, ρ are that the turning radius, t are vortex ring wall thickness, P _tBe pitch.

Vortex ring increment retouch adopts the circular arc modification model, wherein connects the circular arc parametric equation and is

$\left\{\begin{array}{c}x=(\frac{R+r}{2}\cos \mathrm{\γ}+r\cos \mathrm{\θ}){(-1)}^k\\ y=(\frac{R+r}{2}\sin \mathrm{\γ}+r\sin \mathrm{\θ}){(-1)}^k\end{array}\right.$ 　　　θ∈[γ-π，β]

Revising the circular arc parametric equation is

$\left\{\begin{array}{c}x=(-\frac{R+r}{2}\cos \mathrm{\γ}+R\cos \mathrm{\θ}){(-1)}^k\\ y=(-\frac{R+r}{2}\sin \mathrm{\γ}+R\sin \mathrm{\θ}){(-1)}^k\end{array}\right.$ θ∈[γ，β+π]

Another technological scheme of the present invention is that the above-mentioned inswept crank angle numerical value in each molded lines unit is in the 170-190 radian scope.

Another technological scheme of the present invention is that each above-mentioned molded lines unit is an arc section from the first molded lines section that outmost turns begins number.

Effectively utilize geometrical property values such as area coefficient, vent ports area, interior volume specific ratio by quantitative calculating whirlpool dish, and prediction scroll machine complete machine performance, adjust and section combination of optimization molded lines and structural parameter, can make the gas force of designed molded lines keep changing continuously; Analytical calculation is carried out in distortion to whole scroll molded line, determines the back lash, and then definite processing dimension.

Advantage of the present invention

Owing in wrap profile design of the present invention, adopted the method and the criterion of a series of novelties, obtained brand-new wrap profile design result, result of calculation shows, compare with existing general circle involute molded lines, at identical whirlpool dish outside dimension, under the prerequisite of vortex ring height and vent ports area, adopt the wrap profile of method for designing wrap profile design of the present invention can improve air displacement about 4%, COP improves about 2%, and the complete machine performance increases with rotating speed and improves, have better variable speed performance advantage, utilize the scroll compressor model machine performance of this method design to reach the like product international most advanced level.

Description of drawings

Fig. 1 utilizes the molded lines increment of method of the present invention design not adopt the molded lines of correction, is called the unit combination molded lines.

Fig. 2 utilizes the molded lines increment of method design of the present invention to adopt the molded lines of revising.

Fig. 3 adopts symmetrical circular arc modification model on a certain curve in vortex ring increment molded lines unit.

Fig. 4 adopts symmetrical circular arc modification model on another curve in vortex ring increment molded lines unit.

Embodiment

In order further to understand the present invention, below in conjunction with drawings and the specific embodiments, the present invention is described in further detail.

The technology used in the present invention principle and scheme are described in detail as follows:

1. when the design molded lines, at first will be according to the specific (special) requirements of the fitness for purpose and the actual use pattern of wrap profile of scroll machinery, the design method according to the present invention, earlier preliminary selected multiple by the molded lines of synteny combination not, then by passing through quantitatively to calculate its geometrical property value and its performance of prediction, adjustment and optimization such as line style make up and reach molded lines structural parameter etc., finally are the superior new molded lines of availability.The present invention is significantly improved than master curve at the build-up curve of scroll wrap profile, adopts multi-section circular arc in the design, helps improving the molded lines machining accuracy.

2. computational geometry characteristic value and primary election molded lines structural parameter

The geometrical property value of so-called scroll machine, be meant on the basis of wrap profile result of calculation, consider the application operating mode, further calculating the whirlpool dish and effectively utilize geometrical properties such as area coefficient, vortex ring height pitch ratio, vortex ring wall thickness pitch ratio, leaky line length, suction and discharge orifice area, interior volume specific ratio, element volume Changing Pattern, is the basis and the prerequisite of scroll machine operation process simulation and performance prediction.When designing or analyzing new molded lines, can come the quality of preliminary judgement molded lines or the structural parameter of initial shaping line by comparing the geometrical property value of molded lines.

3. the scroll machine overall performance is predicted and the molded lines parameter optimization

The prediction of scroll machine overall performance is exactly on the basis that aforementioned geometrical property value is calculated, utilize engineering thermodynamics, thermal conduction study and hydromechanical knowledge, consider the various leakages in the scroll machine comprehensively, losses such as flow resistance, set up scroll machine and enter the mathematical model of air cavity to the entire work process of discharging air cavity from gas, adopt suitable algorithm then, utilize computer to find the solution this model, obtain the element volume internal pressure, temperature, microscopic characteristics and air displacement that quality etc. change with angle of rotor, theoretical adiabatic power and efficient, indicated power and efficient, air horsepower and efficient, macro properties such as volumetric efficiency.Thereby the various performance index of the different molded lines of quantitative comparison realize the molded lines structure parameter optimizing.

Embodiment

1. theory shaped wire is determined

As an example, Fig. 1 is shown as unit combination molded lines of the present invention.Molded lines of the present invention is made up of the plurality of sections similar curves, and the crank angle numerical value that every section curve group is inswept is identical, is π in this example, and every section curve group comprises 3 parts in this example: orthodrome part, little circular arc portion and straight section.So corresponding molded lines parametric equation also is expressed as following 3 parts in this example respectively:

A orthodrome part

Exhibition angle φ ∈ [(k-1) π, k π-α], central coordinate of circle (x _b, y _b)

Vortex ring outer wall parametric equation is

$\left\{\begin{array}{c}{x}_{\mathrm{ko}}=r_{\mathrm{bko}}\cos (-\mathrm{\φ})+x_b\\ y_{\mathrm{ko}}=r_{\mathrm{bko}}\sin (-\mathrm{\φ})\end{array}\right.$

Vortex ring inwall parametric equation is

$\left\{\begin{array}{c}{x}_{\mathrm{ki}}=r_{\mathrm{bki}}\cos (-\mathrm{\φ})+x_b\\ y_{\mathrm{ki}}=r_{\mathrm{bki}}\sin (-\mathrm{\φ})\end{array}\right.$

Wherein, r _Bko, r _BkiBe orthodrome part vortex ring inner-outer wall radius of curvature.

The little circular arc portion of b

Exhibition angle φ ∈ [k π-α, k π], central coordinate of circle (x _s, y _s)

Vortex ring outer wall parametric equation is

$\left\{\begin{array}{c}{x}_{\mathrm{ko}}=r_{\mathrm{sko}}\cos (-\mathrm{\φ})+x_s\\ y_{\mathrm{ko}}=r_{\mathrm{sko}}\sin (-\mathrm{\φ})+y_s\end{array}\right.$

Vortex ring inwall parametric equation is

$\left\{\begin{array}{c}{x}_{\mathrm{ki}}=r_{\mathrm{ski}}\cos (-\mathrm{\φ})+x_s\\ y_{\mathrm{ki}}=r_{\mathrm{ski}}\sin (-\mathrm{\φ})+y_s\end{array}\right.$

Wherein, r _Sko, r _SkiBe little circular arc portion vortex ring inner-outer wall radius of curvature.

The c straight section

Exhibition angle φ=k π

Vortex ring outer wall parametric equation is

$x_{\mathrm{ko}}=\frac{{(-1)}^k}{2}(D-\mathrm{\ρ}-{\mathrm{kP}}_t)$

Vortex ring inwall parametric equation is

$x_{\mathrm{ki}}=\frac{{(-1)}^k}{2}(D-\mathrm{\ρ}-2t-{\mathrm{kP}}_t)$

Wherein, D is that whirlpool disk center and vortex ring distal-most end distance, ρ are that the turning radius, t are vortex ring wall thickness, P _tBe pitch.

Fig. 2 utilizes the molded lines increment of method design of the present invention to adopt the molded lines of revising, and vortex ring increment retouch adopts symmetrical circular arc modification model as shown in Figure 3, Figure 4, wherein connects the circular arc parametric equation to be

$\left\{\begin{array}{c}x=(\frac{R+r}{2}\cos \mathrm{\γ}+r\cos \mathrm{\θ}){(-1)}^k\\ y=(\frac{R+r}{2}\sin \mathrm{\γ}+r\sin \mathrm{\θ}){(-1)}^k\end{array}\right.$ θ∈[γ-π，β]

Revising the circular arc parametric equation is

$\left\{\begin{array}{c}x=(-\frac{R+r}{2}\cos \mathrm{\γ}+R\cos \mathrm{\θ}){(-1)}^k\\ y=(-\frac{R+r}{2}\sin \mathrm{\γ}+R\sin \mathrm{\θ}){(-1)}^k\end{array}\right.$ θ∈[γ，β+π]

2. computation of geometric property and molded lines structure parameter optimizing

By adjusting whirlpool disk center and vortex ring distal-most end distance D, crank up radius ρ, vortex ring wall thickness t, vortex ring number of turns characteristic parameter k, vortex ring number of turns characteristic angle α, tooth depth H, connect radius of arc r, revise radius of arc R, whirlpool dish when relatively adopting the different characteristic parameter effectively utilizes geometrical properties such as area coefficient, vortex ring height pitch ratio, vortex ring wall thickness pitch ratio, leaky line length, suction and discharge orifice area, interior volume specific ratio, element volume Changing Pattern, comes the quality of preliminary judgement molded lines or the structural parameter of initial shaping line.

3. gas force calculates

The size of gas force decision scroll machine driving force is the basis of all Cable Power Computation, and different wrap profiles has different gas force computational methods, and wrap profile gas force computational methods of the present invention are as follows:

Tangential force: $F_t\left(\mathrm{\θ}\right)=\underset{k=1}{\overset{N_c}{\mathrm{\Σ}}}{F}_{\mathrm{tk}}\left(\mathrm{\θ}\right)=\underset{k=1}{\overset{N_c}{\mathrm{\Σ}}}H(2L_k+\mathrm{\ρ})(p_{k+1}-p_k)$

Wherein N is the active chamber logarithm, and k is the active chamber sequence number, L _kBe k to active chamber perpendicular to gas force direction cross-sectional length, p is the active chamber internal pressure, H is a tooth depth.

Radial force: $F_r\left(\mathrm{\θ}\right)=L_{r}H(p_{N_c+1}-p_{N_c})+\mathrm{LH}(p_{N_c}-p_1)$

Axial force: $F_a\left(\mathrm{\θ}\right)=\underset{k=1}{\overset{N_c}{\mathrm{\Σ}}}{p}_{k+1}{S}_k$

S wherein _kIt is the lifting surface area of k active chamber.

4. between the vortex ring and vortex ring and the whirlpool setting in the gap between the plate of trying to get to the heart of a matter

In order to compensate stressed and expanded by heating distortion during work of machining error and whirlpool dish, molded lines of the present invention utilizes finite element method that the try to get to the heart of a matter distortion of plate of molded lines and whirlpool is analyzed and calculated, again by the final structural parameter of definite molded lines of result of calculation.Thereby can guarantee when scroll machine is worked, further improve the complete machine performance and reduce noise.

She Ji the present invention makes up molded lines as stated above, produces model machine under the prerequisite that does not change processing technology precision and manufacture cost.According to GB5773-86 " positive displacement refrigeration compressor method for testing performance " and JB/T6915-93 " refrigeration compressor used for automobile air conditioning test method ", through prototyping testing, about air displacement 4%, COP improves about 2%, and the complete machine performance increases with rotating speed and improves, have better variable speed performance advantage, reach the like product international most advanced level.

The foregoing description is a concrete example, can certainly utilize method of the present invention to constitute wrap profile with a plurality of circular arcs, circle involute, archimedes curve, algebraic spiral, trigonometric function curve, straight line, high order curve and conjugate curve thereof, the increment fair curve also can adopt above-mentioned curve to revise, it is tangent that the tie point of each curved section keeps, and can guarantee the smooth connection of this wrap profile.Designed wrap profile of scroll machinery all can reach purpose of the present invention.

Claims (3)

1. a method for designing wrap profile of scroll machinery comprises some similar molded lines unit, it is characterized in that, the crank angle numerical value that described unit molded lines is inswept is identical, each unit molded lines can represent that each unit is made of 3 curved sections again, specifically comprises the following steps: with same set of equation

According to designing requirement, wrap profile of scroll machinery comprises orthodrome part, little circular arc portion and straight section, and each line segment tie point must guarantee tangent, and promptly single order can be led, and to guarantee the smooth connection of vortex ring curve, the equation of employing is as follows:

A orthodrome part

Exhibition angle φ ∈ [(k-1) π, k π-α], central coordinate of circle (x _b, y _b)

Vortex ring outer wall parametric equation is

$\left\{\begin{array}{c}{x}_{\mathrm{ko}}=r_{\mathrm{bko}}\cos (-\mathrm{\φ})+x_b\\ y_{\mathrm{ko}}=r_{\mathrm{bko}}\sin (-\mathrm{\φ})\end{array}\right.$

Vortex ring inwall parametric equation is

$\left\{\begin{array}{c}{x}_{\mathrm{ki}}=r_{\mathrm{bki}}\cos (-\mathrm{\φ})+x_b\\ y_{\mathrm{ki}}=r_{\mathrm{bki}}\sin (-\mathrm{\φ})\end{array}\right.$

Wherein, r _Bko, r _BkiBe orthodrome part vortex ring inner-outer wall radius of curvature, k is a molded lines unit sequence number;

The little circular arc portion of b

Exhibition angle φ ∈ [k π-α, k π], central coordinate of circle (x _s, y _s)

Vortex ring outer wall parametric equation is

$\left\{\begin{array}{c}{x}_{\mathrm{ko}}=r_{\mathrm{sko}}\cos (-\mathrm{\φ})+x_s\\ y_{\mathrm{ko}}=r_{\mathrm{sko}}\sin (-\mathrm{\φ})+y_s\end{array}\right.$

Vortex ring inwall parametric equation is

$\left\{\begin{array}{c}{x}_{\mathrm{ki}}=r_{\mathrm{ski}}\cos (-\mathrm{\φ})+x_s\\ y_{\mathrm{ki}}=r_{\mathrm{ski}}\sin (-\mathrm{\φ})+y_s\end{array}\right.$

Wherein, r _Sko, r _SkiBe little circular arc portion vortex ring inner-outer wall radius of curvature;

The c straight section

Exhibition angle φ=k π

Vortex ring outer wall parametric equation is

$x_{\mathrm{ko}}=\frac{{(-1)}^k}{2}(D-\mathrm{\ρ}-{\mathrm{kP}}_t)$

Vortex ring inwall parametric equation is

$x_{\mathrm{ki}}=\frac{{(-1)}^k}{2}(D-\mathrm{\ρ}-2t-{\mathrm{kP}}_t)$

Wherein, D is that whirlpool disk center and vortex ring distal-most end distance, ρ are that the turning radius, t are vortex ring wall thickness, P _tBe pitch;

Vortex ring increment retouch adopts the circular arc modification model, wherein connects the circular arc parametric equation and is

$\left\{\begin{array}{cc}\begin{array}{c}x=(\frac{R+r}{2}\cos \mathrm{\γ}+r\cos \mathrm{\θ}){(-1)}^k\\ y=(\frac{R+r}{2}\sin \mathrm{\γ}+r\sin \mathrm{\θ}){(-1)}^k\end{array}& \mathrm{\θ}\∈[\mathrm{\γ}-\mathrm{\π},\mathrm{\β}]\end{array}\right.$

Revising the circular arc parametric equation is

$\left\{\begin{array}{cc}\begin{array}{c}x=(-\frac{R+r}{2}\cos \mathrm{\γ}+R\cos \mathrm{\θ}){(-1)}^k\\ y=(-\frac{R+r}{2}\sin \mathrm{\γ}+R\sin \mathrm{\θ}){(-1)}^k\end{array}& \mathrm{\θ}\∈[\mathrm{\γ},\mathrm{\β}+\mathrm{\π}]\end{array}\right..$

2. a kind of method for designing wrap profile of scroll machinery as claimed in claim 1 is characterized in that, the crank angle numerical value that described each molded lines unit is inswept is in the 170-190 radian scope.

3. as claim 1,2 described a kind of method for designing wrap profile of scroll machinery, it is characterized in that described each molded lines unit is an arc section from the first molded lines section that outmost turns begins number.

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