Aero-engine rotating disc heat exchange temperature calculation method

Abstract

The application belongs to the field of aero-engine heat balance, and particularly relates to a rotating disc heat exchange temperature calculation method of an aero-engine, obtaining a plurality of point position rotational flow ratios of a preset position of a disc cavity and an A cavity rotational flow ratio and a B cavity rotational flow ratio; based on the plurality of point position rotational flow ratios, heat exchange temperatures of the A cavity and the B cavity are respectively calculated; based on the A cavity rotational flow ratio and the B cavity rotational flow ratio, convective heat exchange coefficients of the A cavity and the B cavity are respectively calculated; based on the heat exchange temperatures and the convective heat exchange coefficients of the A cavity and the B cavity, the solid temperature of the turbine disc is solved; the method considers the influence of the internal flow field structure of the rotating system on the heat exchange temperature in the disc cavity of the rotating system, and gives a more accurate heat exchange temperature calculation formula; by taking the relative total temperature as the heat exchange temperature, the accuracy of the heat exchange boundary condition is improved, and the comprehensive calculation precision of the heat analysis is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aero-engine heat balance, and particularly relates to a rotating disc heat exchange temperature calculation method of an aero-engine. BACKGROUND

[0002] In the field of aero-engines, the turbine part is a rotating disc structure, and the temperature field of the turbine disc is of great significance to the structural scheme design strength and service life of the engine. The calculation accuracy of the temperature field of the turbine disc mainly depends on the calculation method of the heat exchange boundary.

[0003] At present, the heat exchange temperature for calculating the temperature field of the turbine disc is mainly the absolute total temperature, which is obtained through air system calculation. When the fluid passes through a specific structure, factors causing temperature change such as wind resistance temperature rise are mostly calculated by using general empirical formula. In combination with other related parameters such as rotating speed and geometric size, the heat exchange coefficient can be obtained through the empirical formula. With the heat exchange coefficient and the heat exchange temperature, the temperature field of the turbine disc can be obtained through the heat conduction equation.

[0004] This paper introduces a rotating disc heat exchange temperature calculation method based on rotational flow, which considers the flow characteristics of the special structure of the rotating disc cavity and corrects the calculation of the turbine disc temperature field to ensure the calculation accuracy. SUMMARY

[0005] In order to solve the above problems, the application provides a rotating disc heat exchange temperature calculation method of an aero-engine. The disc cavity of the rotating disc includes an A cavity and a B cavity. The gas enters the A cavity from the inlet, then enters the B cavity from the A cavity through the hole, and finally flows out through the outlet. The method comprises the following steps.

[0006] Obtaining the rotational flow ratios of multiple point positions of the predetermined position of the disc cavity and the rotational flow ratios of the A cavity and the B cavity;

[0007] Based on the rotational flow ratios of the multiple point positions, the heat exchange temperatures of the A cavity and the B cavity are calculated respectively;

[0008] Based on the rotational flow ratios of the A cavity and the B cavity, the convective heat exchange coefficients of the A cavity and the B cavity are calculated respectively;

[0009] Based on the heat exchange temperatures and the convective heat exchange coefficients of the A cavity and the B cavity, the solid temperature of the turbine disc is solved.

[0010] Preferably, the multiple point positions include a 0th point, a 1st point, a 2nd point and a 3rd point. The first rotational flow ratio includes a 0th point rotational flow ratio β0 of the inlet entry point, a 1st point rotational flow ratio β1 of the inlet exit point, a 2nd point rotational flow ratio β2 of the A cavity entering the B cavity inlet point, and a 3rd point rotational flow ratio β3 of the A cavity entering the B cavity outlet point.

[0011] Preferably, the calculation method of the heat exchange temperatures of the A cavity and the B cavity comprises the following steps.

[0012] Obtain the absolute total temperature of the gas at the first point, the second point and the third point, and calculate the heat exchange temperature of the A cavity and the B cavity based on the absolute total temperature of the gas at the first point, the second point and the third point respectively.

[0013] Preferably, the method for obtaining the absolute total temperature of the gas at the first point, the second point and the third point is as follows:

[0014] According to the static temperature of the gas at the zeroth point and the swirl ratio β1 at the first point, the static temperature, the relative total temperature and the absolute total temperature of the gas at the first point are calculated.

[0015] The power of the gas acting on the wall of the A cavity is calculated, and the static temperature, the relative total temperature and the absolute total temperature of the gas at the second point are calculated based on the power and the swirl ratio β2 at the second point.

[0016] The hole interception loss of the gas after entering the B cavity from the A cavity is calculated, and the static temperature, the relative total temperature and the absolute total temperature of the gas at the third point are calculated based on the hole interception loss and the swirl ratio β3 at the third point.

[0017] Preferably, the calculation method of the convective heat transfer coefficient is as follows:

[0018] According to the flow parameters of the A cavity and the B cavity and the swirl ratios of the A cavity and the B cavity, the rotational Reynolds numbers of the A cavity and the B cavity are calculated respectively.

[0019] The Nusselt numbers of the A cavity and the B cavity are calculated according to the rotational Reynolds numbers of the A cavity and the B cavity respectively, and the convective heat transfer coefficients of the A cavity and the B cavity are inversely deduced according to the Nusselt numbers of the A cavity and the B cavity respectively.

[0020] Preferably, the swirl ratios of multiple points and the swirl ratios of the A cavity and the B cavity are obtained through computational fluid dynamics simulation based on the inlet and outlet boundary conditions of the A cavity and the B cavity.

[0021] Preferably, the entity temperature of the turbine disc is obtained through a finite element calculation tool.

[0022] Preferably, the power of the gas acting on the wall of the A cavity is obtained through an empirical correlation of wind resistance torque.

[0023] The present application establishes a heat exchange temperature calculation method applied to a rotating disc cavity, which considers the influence of the internal flow field structure of the rotating system on the heat exchange temperature in the disc cavity of the rotating system, and gives a more accurate heat exchange temperature calculation formula. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a preferred embodiment of the present application, which is an aero-engine rotating disc heat exchange temperature calculation method flow chart;

[0025] Figure 2 is a preferred embodiment of the application rotating disc cavity gas flow and point position diagram. DETAILED DESCRIPTION

[0026] To make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application. Identical or similar numerals in the drawings represent identical or similar elements or elements with identical or similar functions throughout. The described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation on the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below with reference to the drawings.

[0027] The present application provides an aero-engine rotating disc heat exchange temperature calculation method. The disc cavity of the rotating disc includes an A cavity and a B cavity. Gas enters the A cavity from an inlet, then enters the B cavity from the A cavity through a hole, and finally flows out through an outlet. The method, as shown in Figure 1 , includes:

[0028] Obtaining a plurality of point rotational flow ratios of a predetermined position of the disc cavity, and an A cavity rotational flow ratio and a B cavity rotational flow ratio;

[0029] Based on the plurality of point rotational flow ratios, the heat exchange temperatures of the A cavity and the B cavity are calculated respectively;

[0030] Based on the A cavity rotational flow ratio and the B cavity rotational flow ratio, the convective heat transfer coefficients of the A cavity and the B cavity are calculated respectively;

[0031] Based on the heat exchange temperatures and the convective heat transfer coefficients of the A cavity and the B cavity, the solid temperature of the turbine disc is solved.

[0032] In some optional embodiments, the plurality of points includes a 0th point, a 1st point, a 2nd point and a 3rd point; the first rotational flow ratio includes a 0th point rotational flow ratio β0 of an inlet entry point, a 1st point rotational flow ratio β1 of an inlet exit point, a 2nd point rotational flow ratio β2 of an A cavity entering a B cavity inlet point, and a 3rd point rotational flow ratio β3 of an A cavity entering a B cavity outlet point.

[0033] In some optional embodiments, the calculation method of the heat exchange temperatures of the A cavity and the B cavity includes:

[0034] Obtaining the absolute total temperature of the gas at the 1st point, the 2nd point and the 3rd point, and calculating the heat exchange temperatures of the A cavity and the B cavity based on the absolute total temperature of the gas at the 1st point, the 2nd point and the 3rd point respectively.

[0035] In some alternative embodiments, the method for obtaining the absolute total temperature of the gas at the first point, the second point, and the third point is as follows:

[0036] According to the static temperature of the gas at the 0th point and the swirl ratio β1 at the 1st point, the static temperature, the relative total temperature, and the absolute total temperature of the gas at the 1st point are calculated.

[0037] The power of the work done by the gas on the wall surface of the A cavity is calculated, and based on the power and the swirl ratio β2 at the 2nd point, the static temperature, the relative total temperature, and the absolute total temperature of the gas at the 2nd point are calculated.

[0038] The loss of the gas after passing through the hole section from the A cavity to the B cavity is calculated, and based on the loss of the hole section and the swirl ratio β3 at the 3rd point, the static temperature, the relative total temperature, and the absolute total temperature of the gas at the 3rd point are calculated.

[0039] In some alternative embodiments, the method for calculating the convective heat transfer coefficient is as follows:

[0040] According to the flow parameters of the A cavity and the B cavity and the swirl ratios of the A cavity and the B cavity, the rotational Reynolds numbers of the A cavity and the B cavity are calculated respectively.

[0041] According to the rotational Reynolds numbers of the A cavity and the B cavity, the Nusselt numbers of the A cavity and the B cavity are calculated respectively, and the convective heat transfer coefficients of the A cavity and the B cavity are inversely deduced respectively.

[0042] In some alternative embodiments, the swirl ratios at multiple points and the swirl ratios of the A cavity and the B cavity are obtained through computational fluid dynamics simulation based on the inlet and outlet boundary conditions of the A cavity and the B cavity.

[0043] In some alternative embodiments, the entity temperature of the turbine disc is obtained through finite element calculation tools.

[0044] In some alternative embodiments, the power of the work done by the gas on the wall surface of the A cavity is obtained through an empirical correlation of the wind resistance torque.

[0045] The following will be described below with reference to the attached drawings Figure 2 of an aero-engine rotating disc:

[0046] a) For the inlet and outlet boundary conditions of the disc cavity, computational fluid dynamics (CFD) simulation is carried out to obtain the swirl ratios at the key point positions inside the disc cavity, including the 0th point, the 1st point, the 2nd point, and the 3rd point. The first swirl ratios include the 0th point swirl ratio β0 at the inlet entry point, the 1st point swirl ratio β1 at the inlet exit point, the 2nd point swirl ratio β2 at the A cavity entering the B cavity inlet point, the 3rd point swirl ratio β3 at the A cavity entering the B cavity outlet point, and the core zone swirl ratios in the two rotating cavities: the A cavity swirl ratio β A and the B cavity swirl ratio β B .

[0047] b) Calculate the gas heat exchange temperature T at each position according to the following formula f .

[0048] 1) After the gas flows from the inlet to the rotating cavity through the cross slit, the static temperature of the gas remains unchanged, the gas flow velocity increases due to the work of the rotating disc, and the absolute total temperature of the gas increases:

[0049]

[0050]

[0051] T t0 is the absolute total temperature in the disc cavity at the 0th point; T t1 is the absolute total temperature in the disc cavity at the 1st point, T r1 is the relative total temperature at the 1st point, T s1 is the static temperature at the 1st point; r1 is the radius of the rotating disc at the 1st point; β1 is the swirl ratio at the 1st point; ω is the rotating speed of the disc; c p is the specific heat at constant pressure.

[0052] 2) After the gas enters the A cavity, since the swirl ratio in the cavity is greater than 1, i.e. the rotating speed of the gas is faster than the disc, the gas does work on the wall, and the power is calculated according to the empirical correlation of the wind resistance torque:

[0053] C M = 0.491 (log 10 Rew) -2.58 ,

[0054] ρ is the density; r is the radius of the rotating disc; β is the swirl ratio; ω is the rotating speed of the disc; W is the wind resistance power, M is the wind resistance torque, C M is the torque coefficient, Rew is the rotating Reynolds number, Rew = ρ * ω * r 2 / μ; μ is the dynamic viscosity coefficient.

[0055] After work, the absolute total temperature of the gas decreases, and the temperature T WindA decreased in the A cavity after work:

[0056] T WindA = W / (2 * Cp * m), T t2 = T t1 - T WindA ,

[0057]

[0058] T t2 is the absolute total temperature in the disc cavity at the 2nd point, T r2 is the relative total temperature at the 2nd point, T s2 is the static temperature at the 2nd point; r2 is the radius of the rotating disc at the 2nd point; m is the mass flow rate.

[0059] 3) After the gas enters the B cavity from the A cavity, the total temperature decreases due to the hole interception loss, and the temperature T of the hole interception loss KONG ,

[0060]

[0061] T t3 is the absolute total temperature in the disc cavity at the 3rd point, T r3 is the relative total temperature at the 3rd point, T s3 is the static temperature at the 3rd point; r3 is the radius of the disc at the 3rd point;

[0062] 4) Then the heat exchange temperatures of the A and B cavities are obtained as follows:

[0063]

[0064] T fA is the gas heat exchange temperature of the A cavity; T fB is the gas heat exchange temperature of the B cavity; r A is the average radius of the disc in the A cavity; r B is the average radius of the disc in the B cavity.

[0065] c) The convective heat exchange coefficients h of the A and B cavities are respectively obtained according to the following formula:

[0066] 1) According to the disc cavity gas flow parameters, and considering the influence of the internal rotational flow of the disc cavity, the rotational Reynolds number Re WA of the A cavity and the rotational Reynolds number Re WB of the B cavity are obtained;

[0067]

[0068] 2) The Nusselt number Nu A of the A cavity and the Nusselt number Nu B of the B cavity are respectively obtained according to the rotational disc cavity heat exchange empirical correlation;

[0069] Nu A = 0.0217 Re ωA 0.8 ; Nu B = 0.0217 Re ωB 0.8 ;

[0070] 3) The convective heat exchange coefficient h A of the A cavity and the convective heat exchange coefficient h B of the B cavity are respectively obtained according to the definition of Nu.

[0071]

[0072] λ is the thermal conductivity, with the unit of w / m·K;

[0073] d) after the flow heat transfer coefficient h A , B cavity flow heat transfer coefficient h B , T fA A cavity gas heat transfer temperature, T fB B cavity gas heat transfer temperature, the finite element calculation tool can be solved after the turbine disc entity temperature.

[0074] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An aero-engine rotating disk heat exchange temperature calculation method, the disk cavity of the rotating disk comprises an A cavity and a B cavity, gas enters the A cavity through an inlet, then enters the B cavity through a hole from the A cavity, and finally flows out through an outlet; characterized in that, The method comprises: acquiring multiple point swirl ratios of the disc cavity preset position and A cavity swirl ratio and B cavity swirl ratio; calculating heat exchange temperatures of the A cavity and the B cavity based on the multiple point swirl ratios; calculating convective heat transfer coefficients of the A cavity and the B cavity based on the A cavity swirl ratio and the B cavity swirl ratio; solving the solid temperature of the turbine disc based on the heat exchange temperatures and the convective heat transfer coefficients of the A cavity and the B cavity; the multiple point positions include a 0th point, a 1st point, a 2nd point and a 3rd point; the first swirl ratios include a 0th point swirl ratio β0 of an inlet entry point, a 1st point swirl ratio β1 of an inlet exit point, a 2nd point swirl ratio β2 of an A cavity entry B cavity inlet point and a 3rd point swirl ratio β3 of an A cavity entry B cavity exit point β3； the method for acquiring the absolute total temperature of the gas at the 1st point, the 2nd point and the 3rd point comprises: calculating the static temperature, the relative total temperature and the absolute total temperature of the gas at the 1st point based on the static temperature of the gas at the 0th point and the 1st point swirl ratio β1; calculating the power of the gas working on the A cavity wall, and calculating the static temperature, the relative total temperature and the absolute total temperature of the gas at the 2nd point based on the power and the 2nd point swirl ratio β2; calculating the hole flow loss of the gas after entering the B cavity from the A cavity, and calculating the static temperature, the relative total temperature and the absolute total temperature of the gas at the 3rd point based on the hole flow loss and the 3rd point swirl ratio β3.

2. The gas turbine engine rotating disk heat exchanger temperature calculation method of claim 1, wherein, the method for calculating the heat exchange temperatures of the A cavity and the B cavity comprises: acquiring the absolute total temperatures of the gas at the 1st point, the 2nd point and the 3rd point, and calculating the heat exchange temperatures of the A cavity and the B cavity based on the absolute total temperatures of the gas at the 1st point, the 2nd point and the 3rd point respectively.

3. The method of claim 1, wherein, the method for calculating the convective heat transfer coefficients comprises: calculating the A cavity swirl number and the B cavity swirl number based on the flow parameters of the A cavity and the B cavity and the A cavity swirl ratio and the B cavity swirl ratio; calculating the Nusselt numbers of the A cavity and the B cavity based on the A cavity swirl number and the B cavity swirl number respectively; calculating the convective heat transfer coefficients of the A cavity and the B cavity based on the Nusselt numbers of the A cavity and the B cavity respectively.

4. The method of claim 1, wherein, The multiple point swirl ratios and the A cavity swirl ratio and the B cavity swirl ratio are obtained through computational fluid dynamics simulation based on the inlet and outlet boundary conditions of the A cavity and the B cavity.

5. The method of claim 1, wherein, The solid temperature of the turbine disc is obtained through finite element calculation tool.

6. The gas turbine engine rotating disk heat exchanger temperature calculation method of claim 1, wherein, The power of the gas working on the A cavity wall is obtained through the empirical correlation of wind resistance torque.

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