CN101571144A - Gas compressor circumferential direction vorticity through-flow design method - Google Patents

Abstract

The invention relates to a circumferential direction vorticity through-flow design method of an aero-engine gas compressor. The circumferential direction vorticity distribution has a significant influent on the overall performance of the gas compressor and acts as critical diagnostic parameters of vorticity dynamics; in the through-flow design stage, the important design parameter circulation distribution is optimized so as to control the circumferential direction vorticity in advance and realize the design of the gas compressor with high performance. The method obtains a circulation optimal iterative formula according to the optimal distribution criterion of the circumferential direction vorticity close to zero in the main flow area of a meridian plane and the close relation of the vorticity and the circulation on the basis of a Crocco equation, can conveniently and automatically optimize the circulation distribution from the initial circulation distribution, realizes the better distribution of the circumferential direction vorticity, increases the pressure ratio and efficiency of the gas compressor, and guides the air-powered design of the gas compressor.

Description

Gas compressor circumferential direction vorticity through-flow design method

Technical field

The present invention relates to a kind of aero-engine compressor Pneumatic design method, relating in particular to a kind of is the through-flow design method of gas compressor of Diagnostic parameters with circumferential vorticity.

Background technique

Gas compressor is one of three big parts of aeroengine, plays the effect to air-flow compression work done.The gas compressor internal flow is very complicated, there are various spiral structures, as trailing vortex, tip leakage whirlpool, passage whirlpool etc., it is the successful key of gas compressor design that various spiral structures have quantitative influence, the distribution of rationalization vorticity field to gas compressor overall performance parameter pressure ratio, efficient etc.

Through-flow design method is the essential step of gas compressor proposal plan.Through-flow design is under cylindrical coordinate axisymmetric hypothesis, carries out the mobile CALCULATION OF PARAMETERS of meridian plane, thereby obtains the required data of blade shape construction.It is pneumatic input parameter crucial in the through-flow design that circular rector distributes, and what circular rector distributed representative promptly is to add the merit amount to distribute, and given rational circular rector distribution form is the successful key of gas compressor design, and the circular rector distribution form directly has influence on the distribution of the inner vorticity of gas compressor field.Traditional circular rector distributes and often relies on artificer's experience to carry out given, and then carry out three-dimensional computations, obtain flow field and vorticity field information, whether estimate gas compressor adheres to specification, if deficiency is arranged, return distribution of through-flow Change In Design circular rector or runner, the preceding trailing edge curve of blade again, carry out repeatedly repeatedly up to obtaining satisfied design result.The through-flow design method of tradition requires very high to artificer's experience, and does not instruct circular rector to distribute from rationalization's vorticity rink corner degree as yet.

The through-flow design method of tradition can be replenished at least in the following areas:

(1) organizes the vorticity field in advance at given rational circular rector distribution form of through-flow design phase;

(2) pass through the given of crucial Vorticity Distribution parameter guidance and optimization circular rector distribution form.

Summary of the invention

As replenishing of the through-flow design method of gas compressor tradition, the invention provides a kind of circumferential vorticity and optimize the through-flow design method that circular rector distributes.

Because gas compressor inside is a high-intensity complicated vorticity field, all kinds of vortex vorticitys all have its positive and negative, big or small contribution to gas compressor overall performance parameter, by discovering that this novel whirling motion mechanics parameter of circumferential vorticity has material impact to gas compressor performance such as flow, pressure ratio, efficient, when circumferential vorticity positive peak is close to the casing surface more, when negative peak is close to hub surface more, be that positive and negative peak value does not spread to main flow area, it is strong more that gas compressor adds the merit boosting capability, and indexs such as flow, pressure ratio, efficient are high more.

The present invention be in order to control circumferential Vorticity Distribution in advance effectively in the gas compressor concept phase, with circumferential vorticity diagnostic application in through-flow design.Derive and Analysis on Mechanism according to theory, propose circumferential vorticity and in the distribution criterion of through-flow design meridian plane optimum be: the circumferential vorticity of meridian plane main flow area approaches zero.According to this design criterion, from turbine axisymmetric Crocco equation, and utilize the substantial connection of vorticity and circular rector, obtained the optimization iterative formula of circular rector.

Under the axisymmetric hypothesis, each component of vorticity is as follows, and with circular rector following relation is arranged:

${\mathrm{\ω}}_r=\frac{\∂V_z}{r\∂\mathrm{\θ}}-\frac{\∂V_{\mathrm{\θ}}}{\∂z}=-\frac{1}{r}\frac{\∂\mathrm{\Γ}}{\∂z}---\left(1\right)$

${\mathrm{\ω}}_{\mathrm{\θ}}=\frac{\∂V_r}{\∂z}-\frac{{\∂V}_z}{\∂r}---\left(2\right)$

${\mathrm{\ω}}_z=\frac{1}{r}\frac{\∂\left(V_{\mathrm{\θ}}r\right)}{\∂r}-\frac{1}{r}\frac{{\∂V}_r}{\∂\mathrm{\θ}}=\frac{1}{r}\frac{\∂\mathrm{\Γ}}{\∂r}---\left(3\right)$

Wherein V is an absolute velocity, and ω is a vorticity, and (r, θ z) are each component under the cylindrical coordinates to subscript.The Crocco equation is

$\mathrm{\ω}\×V=-\▿H+T\▿s+F---\left(4\right)$

Wherein H is the stagnation total enthalpy, and s is an entropy, and F is that volumetric force comprises two-part, BLADE FORCE and viscosity volumetric force.Under the axisymmetric hypothesis prerequisite of through-flow design, Crocco equation three fractions under cylindrical coordinates are:

$V_z{\mathrm{\ω}}_{\mathrm{\θ}}=\frac{1}{{2r}^2}\frac{\∂\left({\mathrm{\Γ}}^2\right)}{\∂r}-\frac{\∂H}{\∂r}+T\frac{\∂s}{\∂r}+F_r---\left(5\right)$

$V\·\▿\mathrm{\Γ}=r{F}_{\mathrm{\θ}}---\left(6\right)$

$V_r{\mathrm{\ω}}_{\mathrm{\θ}}=\frac{1}{{2r}^2}\frac{\∂\left({\mathrm{\Γ}}^2\right)}{\∂z}+\frac{\∂H}{\∂z}-T\frac{\∂H}{\∂z}-F_z---\left(7\right)$

Approach zero Optimal Distribution criterion according to the circumferential vorticity of meridian plane main flow area, should satisfy (5) and (7) formula left side item is 0, thereby obtains the axial and gradient of corresponding circular rector square, promptly

$\frac{\∂\left({\mathrm{\Γ}}^2\right)}{\∂r}={2r}^2(\frac{\∂H}{\∂r}-T\frac{\∂s}{\∂t}-F_r)---\left(8\right)$

$\frac{\∂\left({\mathrm{\Γ}}^2\right)}{\∂z}={2r}^2(-\frac{\∂H}{\∂z}+T\frac{\∂s}{\∂z}+F_z)---\left(9\right)$

Distribute according to the circular rector both direction gradient updating circular rector of trying to achieve, in through-flow design, be used for carrying out the optimizing iteration that circular rector distributes.

Characteristics of the present invention are with circumferential vorticity as Diagnostic parameters, optimizing iterative formula according to circular rector in circumferential vorticity Optimal Distribution criterion and whirlpool, the through-flow design of circular rector relation derivation, be used for the circular rector distribution optimization, circumferential vorticity can also be optimized before passage curve and the blade trailing edge curve etc. as Diagnostic parameters in addition, this circumferential direction vorticity through-flow design method can instruct the gas compressor design, and help reducing to experimental requirement, realize the high-performance designs of gas compressor.

Content of the present invention comprises the through-flow design method with circumferential vorticity diagnostic function, and has the through-flow design method that circumferential vorticity is optimized the function of circular rector distribution.The present invention also comprises circumferential vorticity optimized other design parameters such as runner form as Diagnostic parameters, function such as trailing edge curve before the blade.

Description of drawings

Fig. 1 is a gas compressor circumferential direction vorticity through-flow design method flow chart of the present invention;

Fig. 2 is for contrasting with the rotor characteristics of striding before and after this design method optimization

Embodiment

Its embodiment of gas compressor circumferential direction vorticity through-flow design method of the present invention comprises as shown in Figure 1:

Geometric datas such as the passage curve that step 1, given through-flow design need, the preceding trailing edge curve of blade, generate the meridian plane computing grid, and given initial pneumatic design parameter circular rector distributes, and comprises radially and axial distribution form, uses through-flow program to carry out the meridian plane flow field and calculates;

Step 2, find the solution the vorticity field by velocity field, obtain of the distribution of circumferential vorticity at meridian plane according to vorticity definition;

Whether step 3, the circumferential Vorticity Distribution that obtains according to circumferential vorticity Optimal Distribution criterion judgement meet the requirements, promptly check at the positive negative peak of the circumferential vorticity of meridian plane and whether be confined to wheel hub casing zone, whether spread to main flow area, if it is more serious to the main flow area diffusion, need carry out the optimization of circular rector distribution form, enter step 4, otherwise, then can carry out blade shape construction and three-dimensional computations if circumferentially Vorticity Distribution is more satisfactory;

Step 4, utilize circular rector iterative formula (8) and (9) derived according to vorticity and circular rector substantial connection, carry out the circular rector distribution optimization, and then return step 1 and carry out through-flow calculating, until reaching satisfied result.

The present invention can begin to carry out iteration from better simply circular rector distribution form such as linear distribution, just carry out can obtaining more excellent circular rector distribution form after 3～4 iteration, corresponding circumferentially Vorticity Distribution is better, and peak value dies down to the main flow area diffusion.Can weaken requirement like this, help the artificer to search out more excellent circular rector distribution form automatically by circumferential vorticity diagnosis to artificer's experience.

Final design result will be carried out the verification that three-dimensional viscosity is analyzed, and check can obtain high-performance really according to the gas compressor of the circular rector distribution form design of optimizing.

Be the rotor three-dimensional computations characteristic curve contrast of striding before and after this novel design method optimization of utilization as Fig. 2, a left side is flow-pressure ratio characteristic curve, and the right side is flow-efficiency characteristic curve, and the black hollow dots is characteristic before optimizing, and red solid dot is for optimizing the back characteristic.Can find to optimize all raisings greatly of back rotor pressure ratio, efficient.Peak efficiencies point pressure ratio has improved 1.9%, and efficient has improved 1.36%.

The invention has the advantages that and caught the crucial whirling motion mechanics parameter-circumferential vorticity that influences the gas compressor overall performance, is to control circumferential Vorticity Distribution in the through-flow design in advance in the gas compressor concept phase; Distribute according to circumferential vorticity Optimal Distribution design criterion auto-optimization circular rector, reduced high request, improved design efficiency artificer's experience.

The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.

Claims (5)

1, gas compressor circumferential direction vorticity through-flow design method is characterized in that, comprises step:

(1) before the passage curve that needs of given through-flow design, the blade, geometric data such as trailing edge curve and initial circular rector distribute, use through-flow program to carry out the meridian plane flow field and calculate;

(2) carry out circumferential vorticity diagnosis, obtain of the distribution of circumferential vorticity at meridian plane;

(3) judge according to circumferential vorticity Optimal Distribution criterion whether the circumferential Vorticity Distribution that obtains meets the requirements, promptly check at the positive negative peak of the circumferential vorticity of meridian plane and whether be confined to wheel hub casing zone, whether spread to main flow area, if it is more serious to the main flow area diffusion, then need carry out the optimization of circular rector distribution form, enter step (4); If circumferentially more satisfactory blade shape construction and the three dimensional analysis of then can carrying out of Vorticity Distribution calculates;

(4) according to the circular rector iterative formula that goes out from vorticity, circular rector relation and Crocco equation inference, carry out the circular rector distribution optimization; And then return step 1 and carry out through-flow calculating, until reaching satisfied result.

2, gas compressor circumferential direction vorticity through-flow design method as claimed in claim 1 is characterized in that, in through-flow design with circumferential vorticity as Diagnostic parameters.

3, gas compressor circumferential direction vorticity through-flow design method as claimed in claim 1 is characterized in that, more excellent circumferential Vorticity Distribution form is: positive peak is pressed close to casing, and negative peak is pressed close to wheel hub, and peak value does not spread to main flow area as far as possible; The circumferential vorticity Optimal Distribution of through-flow design meridian plane criterion is: the circumferential vorticity of main flow area is near zero.

4, gas compressor circumferential direction vorticity through-flow design method as claimed in claim 1, it is characterized in that, according to circumferential vorticity Optimal Distribution criterion and with the substantial connection of circular rector, obtain the iterative formula that circular rector is optimized from the Crocco equation, put into the auto-optimization that circular rector is carried out in through-flow design.

5, gas compressor circumferential direction vorticity through-flow design method as claimed in claim 1 is characterized in that, also has circumferential vorticity is optimized the runner form as Diagnostic parameters the function of trailing edge curve before the blade.

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