A real-time calculation method for the wind resistance and work added by the airflow in the turbine disc cavity

Abstract

The present application belongs to the field of aviation engine technology, and particularly relates to a real-time calculation method for the wind resistance work added by the airflow in the turbine disc cavity. It comprises: step one, obtaining a first reference internal heat source calculation model; step two, determining the key influencing factors of the internal heat source calculation in the first reference internal heat source calculation model, and transforming the first reference internal heat source calculation model according to the key influencing factors to obtain a second reference internal heat source calculation model; step three, fitting the second reference internal heat source calculation model into a third reference internal heat source calculation model of the turbine disc rotation angular velocity w in a polynomial manner; step four, performing a transient full-process calculation based on the third reference internal heat source calculation model. The present application can calculate the wind resistance work added by the airflow in the corresponding turbine disc cavity in real time according to different engine test processes, thereby providing important wind resistance data support for the accurate temperature field calculation of the turbine disc.

Description

Technical Field

[0001] The present application belongs to the field of aero-engine technology, and in particular relates to a real-time calculation method for the wind resistance and work added by airflow in a turbine disc cavity. Background Art

[0002] The turbine disk is a critical working component in an aircraft engine. Operating in a high-temperature, high-pressure environment and rotating at a high speed, it experiences high stress levels, directly impacting the safety of engine operation. The accuracy of the turbine disk temperature field calculation plays a crucial role in its strength analysis and design. The accuracy of the turbine disk temperature field calculation depends on the accuracy of the heat transfer coefficient and heat transfer temperature. Among the various factors that influence the accuracy of the heat transfer temperature, the three most important are intake temperature, the influence of thermal balance, and windage. Windage refers to the fact that during high-speed rotation of the turbine disk, due to the mismatch between the airflow speed within the turbine disk cavity and the disk speed, the static friction consumes turbine work, converts it into heat, and adds it to the gas within the disk cavity, causing a windage temperature rise in the gas within the disk cavity.

[0003] In the existing technology, there are two methods for real-time calculation of wind resistance: one is a one-dimensional calculation method based on empirical formulas, and the other is a two-dimensional or three-dimensional calculation method based on CFD calculation tools. The former, a key area of ​​academic research, relies on detailed parameter calculations such as airflow density, rotational Reynolds number, and swirl ratio. These parameters are obtained by calculating the entire engine fluid domain during post-processing and cannot be obtained in real time with the engine status. The latter is more accurate and can reflect the detailed information and physical nature of wind resistance, but the calculation efficiency is too low to achieve the effect of real-time calculation during engine test runs.

[0004] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned deficiencies of the prior art. Summary of the Invention

[0005] The purpose of this application is to provide a real-time calculation method for the wind resistance and work added by the airflow in the turbine disc cavity, so as to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is:

[0007] A real-time calculation method for the wind resistance and work added by airflow in a turbine disc cavity comprises:

[0008] Step 1: Obtain the first benchmark internal heat source calculation model:

[0009] Q=0.5*C m *ρ*r 5 *w 3

[0010] Among them, Q is the reference internal heat source, C m is the dimensionless torque coefficient, ρ is the density in the disk cavity, r is the radius, and w is the angular velocity of the turbine disk;

[0011] Step 2: Determine the key influencing factors of the internal heat source calculation in the first benchmark internal heat source calculation model, and transform the first benchmark internal heat source calculation model according to the key influencing factors to obtain a second benchmark internal heat source calculation model, wherein:

[0012] The key influencing factor is ρ*w 3 ;

[0013] The second benchmark internal heat source calculation model is:

[0014] Q=QC*ρ*w 3

[0015] Among them, QC is the wind resistance correction coefficient;

[0016] Step 3: Fit the second reference internal heat source calculation model to a third reference internal heat source calculation model of the turbine disk rotation angular velocity w in a polynomial manner:

[0017] Q=QC*(a1*w 3 +b1*w 2 +c1*w+d1)

[0018] Among them, a1, b1, c1, and d1 are the corresponding coefficients respectively;

[0019] Step 4: Perform full-process transient calculation based on the third benchmark internal heat source calculation model.

[0020] In at least one embodiment of the present application, in step 1, the density within the disk cavity in the first reference internal heat source calculation model is inversely deduced using the ideal gas state equation, where the ideal gas state equation is:

[0021] P=ρ·Rg·T

[0022] Where P is the pressure inside the disk cavity, T is the temperature inside the disk cavity, and Rg is the ideal gas constant.

[0023] In at least one embodiment of the present application, in step 2, the windage correction coefficient QC is calibrated using test data.

[0024] In at least one embodiment of the present application, step three further includes performing piecewise function fine adjustment on the third reference internal heat source calculation model, and the adjusted third reference internal heat source calculation model is:

[0025] In the first speed state:

[0026] Q=0 (N<8000rpm)

[0027] In the second speed state:

[0028] Q=QC1*(a1*w 3 +b1*w 2 +c1*w+d1) (8000rpm <N<12000rpm)

[0029] In the third speed state:

[0030] Q=QC2*(a1*w 3 +b1*w 2 +c1*w+d1)(N>12000rpm)

[0031] Among them, QC1 is the wind resistance correction coefficient under the second speed state, and QC2 is the wind resistance correction coefficient under the third speed state.

[0032] In at least one embodiment of the present application, the wind resistance correction coefficient QC1 is calibrated using test data at the second speed state.

[0033] In at least one embodiment of the present application, the wind resistance correction coefficient QC2 is calibrated using test data at a third speed state.

[0034] The invention has at least the following beneficial technical effects:

[0035] The real-time calculation method of the wind resistance added work of the airflow in the turbine disc cavity of the present application obtains the wind resistance added work of the airflow in the turbine disc cavity by calculating the internal heat source generated by the wind resistance friction of the airflow in the turbine disc cavity. The corresponding wind resistance added work of the airflow in the turbine disc cavity can be calculated in real time according to different engine test histories, thereby providing important wind resistance data support for the accurate temperature field calculation of the turbine disc. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a flow chart of a method for real-time calculation of wind resistance and work added by airflow in a turbine disc cavity according to one embodiment of the present application. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be understood as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0038] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as limiting the scope of protection of this application.

[0039] The following is combined with Figure 1 This application is described in further detail.

[0040] The present application provides a real-time calculation method for the windage resistance and work added by the airflow in a turbine disc cavity, comprising the following steps:

[0041] Step 1: Obtain the first benchmark internal heat source calculation model:

[0042] Q=0.5*C m *ρ*r 5 *w 3

[0043] Among them, Q is the reference internal heat source, C m is the dimensionless torque coefficient, ρ is the density in the disk cavity, r is the radius, and w is the angular velocity of the turbine disk;

[0044] Step 2: Determine the key influencing factors of the internal heat source calculation in the first benchmark internal heat source calculation model, and transform the first benchmark internal heat source calculation model according to the key influencing factors to obtain a second benchmark internal heat source calculation model, wherein:

[0045] The key impact factor is ρ*w 3 ;

[0046] The second benchmark internal heat source calculation model is:

[0047] Q=QC*ρ*w3

[0048] Among them, QC is the wind resistance correction coefficient;

[0049] Step 3: Fit the second reference internal heat source calculation model into a third reference internal heat source calculation model of the turbine disk rotation angular velocity w in a polynomial manner:

[0050] Q=QC*(a1*w 3 +b1*w 2 +c1*w+d1)

[0051] Among them, a1, b1, c1, and d1 are the corresponding coefficients respectively;

[0052] Step 4: Perform full-process transient calculation based on the third benchmark internal heat source calculation model.

[0053] The present application provides a real-time calculation method for the amount of wind resistance added to the turbine disc cavity. Wind resistance in the turbine disc cavity of an aircraft engine affects the temperature in the disc cavity in the form of an internal heat source. The problem of calculating the temperature in the disc cavity, which is greatly affected by wind resistance, is abstracted into a specific technical problem, namely, when the pressure P in the disc cavity, the temperature T in the disc cavity, and the real-time operating speed N of the aircraft engine turbine disc are known, the size of the internal heat source generated in the disc cavity due to the friction of the wind resistance of the airflow in the turbine disc cavity is solved.

[0054] In this embodiment, in step 1, the density in the disk cavity in the first reference internal heat source calculation model is inversely deduced using the ideal gas state equation, wherein the ideal gas state equation is:

[0055] P=ρ·Rg·T

[0056] Where P is the pressure inside the disk cavity, T is the temperature inside the disk cavity, and Rg is the ideal gas constant.

[0057] The real-time calculation method of the wind resistance work added by the airflow in the turbine disc cavity of the present application is as follows: by analyzing the first reference internal heat source calculation model, it can be known that the dimensionless torque coefficient C m The change range of is small, and the radius r is a geometric fixed value. Therefore, it can be considered that under different engine speeds in the same engine, the internal heat source Q and ρ*w 3 Directly related, so the key impact factor is ρ*w 3 At this time, the first reference internal heat source calculation model can be simplified to the second reference internal heat source calculation model, wherein the initial value of the drag correction coefficient QC is preliminarily determined based on the first reference internal heat source calculation model, and the calibration value of the drag correction coefficient QC needs to be calibrated based on the existing test data of the engine.

[0058] The present invention's real-time calculation method for the windage drag work added by the airflow within the turbine disc cavity requires fitting a second baseline internal heat source calculation model to a function of the turbine disc's rotational angular velocity w using a polynomial, multiplying it by the windage correction factor QC to obtain a third baseline internal heat source calculation model that changes in real time with the engine's state. This third baseline internal heat source calculation model automatically changes with the engine's state, ensuring analysis accuracy without requiring detailed calculations of parameters such as the rotational Reynolds number and the density within the disc cavity.

[0059] It should be noted that due to the drag correction factor, the internal heat source Q has essentially become an equivalent internal heat source. Its specific value requires calibration based on test data. The internal heat source Q derived from the third-baseline internal heat source calculation model is used only as an equivalent value for this transient heat transfer phenomenon and is not directly equivalent to actual turbine power consumption. The QC value calibrated based on data from a single test run can be used to calculate real-time drag power across subsequent test runs of the same engine model, achieving a high degree of accuracy.

[0060] In a preferred embodiment of the present application, the third reference internal heat source calculation model is further finely regulated using a piecewise function. The adjusted third reference internal heat source calculation model is:

[0061] In the first speed state:

[0062] Q=0 (N<8000rpm)

[0063] In the second speed state:

[0064] Q=QC1*(a1*w 3 +b1*w 2 +c1*w+d1) (8000rpm <N<12000rpm)

[0065] In the third speed state:

[0066] Q=QC2*(a1*w 3 +b1*w 2 +c1*w+d1) (N>12000rpm)

[0067] Among them, QC1 is the wind resistance correction coefficient under the second speed state, and QC2 is the wind resistance correction coefficient under the third speed state.

[0068] The real-time calculation method of the wind resistance added by the airflow in the turbine disc cavity of the present application is fine-tuned by piecewise function according to the deviation compared with the test data. When the speed is low, the wind resistance added is defined as 0; when there is an inconsistency between the high and low state deviations, different wind resistance correction coefficients are adopted in the low state and the high state respectively, so as to perform fine-tuning through piecewise function. Taking the speed as the boundary, in the second speed state, the corresponding wind resistance correction coefficient QC1 is calibrated by the test data; in the third speed state, another wind resistance correction coefficient QC2 is calibrated by the test data to take into account the accuracy requirements of the entire engine test process. The results are verified by adding Q as an internal heat source to the transient fluid-solid coupling heat balance equation.

[0069] The real-time calculation method of the wind resistance added work of the airflow in the turbine disc cavity of the present application realizes the real-time calculation function of the wind resistance added work of the airflow in the turbine disc cavity of an aircraft engine in terms of functionality, and can automatically follow the engine test process, reflecting the dominant influencing factors and the magnitude of changes; in terms of accuracy, the wind resistance correction coefficient calibrated through a single test process has good adaptability under different test processes; in terms of efficiency, the calculation efficiency is high, and the wind resistance added work calculation time for 1 second of test physical time is no more than 1 second, and it can follow the engine test process for calculation in real time.

[0070] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A real-time calculation method for the wind resistance and work added by the airflow in the turbine disc cavity, characterized in that: include: Step 1: Obtain the first benchmark internal heat source calculation model: Q=0.5*C m *ρ*r 5 *w 3 Among them, Q is the reference internal heat source, C m is the dimensionless torque coefficient, ρ is the density in the disk cavity, r is the radius, and w is the angular velocity of the turbine disk; Step 2: Determine the key influencing factors of the internal heat source calculation in the first benchmark internal heat source calculation model, and transform the first benchmark internal heat source calculation model according to the key influencing factors to obtain a second benchmark internal heat source calculation model, wherein: The key influencing factor is ρ*w 3 ; The second benchmark internal heat source calculation model is: Q=QC*ρ*w 3 Among them, QC is the wind resistance correction coefficient; Step 3: Fit the second reference internal heat source calculation model to a third reference internal heat source calculation model of the turbine disk rotation angular velocity w in a polynomial manner: Q=QC*(a1*w 3 +b1*w 2 +c1*w+d1) Among them, a1, b1, c1, and d1 are the corresponding coefficients respectively; Step 4: Perform full-process transient calculation based on the third benchmark internal heat source calculation model.

2. The method for real-time calculation of wind resistance and work added by airflow in a turbine disc cavity according to claim 1, characterized in that: In step 1, the density in the disk cavity in the first reference internal heat source calculation model is inversely deduced using the ideal gas state equation. The ideal gas state equation is: P=ρ·Rg·T Where P is the pressure inside the disk cavity, T is the temperature inside the disk cavity, and Rg is the ideal gas constant.

3. The method for real-time calculation of wind resistance and work added by airflow in a turbine disc cavity according to claim 2, characterized in that: In step 2, the wind resistance correction coefficient QC is calibrated using test data.

4. The method for real-time calculation of wind resistance and work added by airflow in a turbine disc cavity according to claim 3, characterized in that: Step three also includes performing piecewise function fine adjustment on the third reference internal heat source calculation model. The adjusted third reference internal heat source calculation model is: In the first speed state: Q=0(N<8000rpm) In the second speed state: Q=QC1*(a1*w 3 +b1*w 2 +c1*w+d1)(8000rpm<N<12000rpm) In the third speed state: Q=QC2*(a1*w 3 +b1*w 2 +c1*w+d1)(N>12000rpm) Among them, QC1 is the wind resistance correction coefficient under the second speed state, and QC2 is the wind resistance correction coefficient under the third speed state.

5. The method for real-time calculation of wind resistance and work added by airflow in a turbine disc cavity according to claim 4, characterized in that: The wind resistance correction coefficient QC1 is calibrated using the test data at the second speed state.

6. The method for real-time calculation of wind resistance and work added by airflow in a turbine disc cavity according to claim 4, characterized in that: The wind resistance correction coefficient QC2 is calibrated using the test data under the third speed state.

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