A method for evaluating the impact weights of key flow factors in the compressor end area

Abstract

The present invention relates to a method for evaluating the influence weights of key flow factors in the compressor end region, and belongs to the field of compressor end region flow control technology. First, based on the geometric parameters of the compressor blades, the B coefficient that can characterize the influence of boundary layer intersection in the corner region under the conditions of constant / variable dihedral angle is calculated. m factor and E, which can characterize the influence of the lateral secondary flow in the end area m Factor. Then according to B m Factor and E m The parameter variation range of the factor is obtained respectively. m 、E m The relative numerical size of the factors. Finally, by comparing B m 、E m The relative magnitude of these factors determines the weight of key flow factors in the end zone of the compressor blade passage. This method can be used to identify the primary controlling factors affecting end zone flow, deepening understanding of complex flow in this region, and also as a basis for selecting control measures.

Description

Technical Field

[0001] The invention relates to a method for evaluating the influence weights of key flow factors in a compressor end region, and belongs to the technical field of compressor end region flow control. Background Art

[0002] In compressor blade passages, boundary layer convergence at the corners and transverse secondary flow at the tip are key factors influencing flow in these corners. The relative strength of these two factors directly influences the flow state in these corners. Regardless of the driving mechanism, they ultimately lead to accumulation of low-energy fluid in the corners, making it more likely to cause separation and even stall in the corners, severely degrading the compressor's aerodynamic performance.

[0003] To this end, researchers at home and abroad have attempted to use end zone flow control technology to further explore the potential for improving compressor blade performance. Although there are a variety of end zone flow control measures, the failure to quantitatively evaluate the main controlling factors driving end zone flow has led to a vague understanding of the end zone flow mechanism and a blind selection of flow control measures. Therefore, it is very necessary to evaluate the influence weights of key flow factors in the compressor end zone. On the one hand, it can be used to identify the main controlling factors affecting the end zone flow to deepen the understanding of the complex flow in the end zone; on the other hand, it can serve as a basis for selecting control measures. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problems that the existing technology cannot quickly and accurately quantify and evaluate the impact of key flow factors in the end area. A method for evaluating the impact weights of key flow factors in the compressor end area is creatively proposed to identify the main controlling factors affecting the end area flow and serve as a basis for selecting control measures.

[0005] The present invention is implemented by adopting the following technical solutions.

[0006] A method for evaluating the impact weights of key flow factors in the compressor end area.

[0007] First, according to the geometric parameters of the compressor blade, the B that can characterize the influence of boundary layer intersection in the corner area under the conditions of constant / variable dihedral angle is calculated. m factor and E, which can characterize the influence of the lateral secondary flow in the end area m factor.

[0008] Then according to B m Factor and E m The parameter variation range of the factor is obtained respectively. m 、E m The relative numerical size of the factor.

[0009] Finally, by comparing B m 、E mThe relative numerical value of the factor is used to determine the influence weight of the key flow factors in the middle end area of the compressor blade channel.

[0010] Beneficial effects

[0011] The method of the present invention can be used to identify the main controlling factors affecting the flow in the end zone to deepen the understanding of the complex flow in the end zone, and can also serve as a basis for selecting control measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a flow chart of the method of the present invention;

[0013] Figure 2 This is a schematic diagram of the geometric shape of a compressor cascade;

[0014] Figure 3 This is a geometric diagram of the blade profile of a compressor cascade. DETAILED DESCRIPTION

[0015] The method of the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0016] like Figure 1 As shown, a method for evaluating the impact weights of key flow factors in a compressor end region includes the following steps:

[0017] Step 1: Based on the geometric parameters of the compressor blades, calculate B, which can characterize the influence of boundary layer intersection in the corner area under the conditions of constant / variable dihedral angle. m Factor. B m The empirical relationship of the factors is as follows:

[0018]

[0019] Where α1 and α2 are the inlet and outlet airflow angles of the compressor blade in radians, respectively; ε1 is the dihedral angle of the leading edge of the compressor blade in degrees; Δε is the difference between the dihedral angles of the leading edge and the trailing edge of the blade in degrees; and e represents a natural constant.

[0020] According to the geometric parameters of the compressor blade, E is calculated to characterize the influence of the transverse secondary flow in the end area. m Factor. E m The specific expression of the factor is as follows:

[0021]

[0022] Where σ represents the compressor blade density.

[0023] B mThe factor takes into account the influence of the blade dihedral angle and the change of dihedral angle along the stream direction on the boundary layer intersection in the corner area under the condition of constant / variable dihedral angle, and can accurately evaluate the development of boundary layer intersection in the corner area under the conditions of constant / variable dihedral angle, and accurately quantify the influence of boundary layer intersection in the corner area on the flow in the tip area of the compressor blade.

[0024] Step 2: According to B m Factor and E m The parameter variation range of the factor is obtained respectively. m 、E m The relative numerical size of the factor.

[0025] Among them, B m Factor and E m The parameter variation range of the factor is obtained through the geometric parameters and parameter range of the compressor blades.

[0026] B m The parameter range of the factor is 0.0032~0.58, E m The parameter range of the factor is 0.17 to 1.13.

[0027] Step 3: Compare B m Factor and E m The relative numerical value of the factor is used to determine the influence weight of the key flow factors in the middle end area of the compressor blade channel.

[0028] Specifically, B m 、E m The relative magnitude of the factors Use the following formula to calculate:

[0029]

[0030] Among them, max(B m )、min(B m ) represent B m The maximum and minimum values of the parameter variation range. Calculate E m When the relative value of the factor is large or small, the B in the above formula m Replace with E m That's it.

[0031] Example

[0032] Taking a compressor cascade as an example, the evaluation method of the present invention is used to identify the main controlling factors affecting the end zone flow.

[0033] The geometry of the blades is as follows Figure 2 As shown, its blade geometry and geometric parameters are as follows Figure 3 and as shown in Table 1.

[0034] Table 1 Blade geometry parameters

[0035]

[0036] According to the geometric parameters of the cascade, B is calculated. m Factor and E m The factors are 0.046 and 0.43 respectively. m and E m The parameter variation range of the factor is used to find B m The relative value of the factor is 7.36%, E m The relative value of the factor is 26.91%. m The relative value of factor B is significantly greater than m The factor indicates that the transverse secondary flow on the end wall of the plane cascade channel is the main controlling factor affecting the flow field in the end area.

Claims

1. A method for evaluating the impact weights of key flow factors in the compressor end area, characterized in that: The following steps are involved: Step 1: Based on the geometric parameters of the compressor blades, calculate B, which can characterize the influence of boundary layer intersection in the corner area under the conditions of constant / variable dihedral angle. m factor; Among them, B m The empirical relationship of the factors is as follows: Where α1 and α2 are the inlet and outlet airflow angles of the compressor blade in radians, respectively; ε1 is the dihedral angle of the leading edge of the compressor blade in degrees; Δε is the difference between the dihedral angles of the leading edge and the trailing edge of the blade in degrees; e represents a natural constant; According to the geometric parameters of the compressor blade, E is calculated to characterize the influence of the transverse secondary flow in the end area. m Factor; E m The factor expression is as follows: Where, σ represents the compressor blade density; Step 2: According to B m Factor and E m The parameter variation range of the factor is obtained respectively. m 、E m The relative numerical size of the factors; Step 3: Compare B m Factor and E m The relative numerical value of the factor is used to determine the influence weight of the key flow factors in the middle end area of the compressor blade channel.

2. A method for evaluating the impact weights of key flow factors in a compressor end region according to claim 1, characterized in that: B m Factor and E m The parameter variation range of the factor is obtained through the geometric parameters and parameter range of the compressor blades.

3. The method for evaluating the impact weights of key flow factors in the compressor end area according to claim 1, wherein: B m The parameter range of the factor is 0.0032 to 0.

58.

4. The method for evaluating the impact weights of key flow factors in the compressor end area according to claim 1, wherein: E m The parameter range of the factor is 0.17 to 1.

13.

5. The method for evaluating the impact weights of key flow factors in the compressor end area according to claim 1, wherein: In step 3, B m 、E m The relative magnitude of the factors Use the following formula to calculate: Among them, max(B m )、min(B m ) represent B m The maximum and minimum values of the parameter variation range; calculate E m When the relative value of the factor is large or small, the B m Replace with E m .

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