A real-time monitoring method and device for the throat area of a core engine nozzle

Abstract

This application belongs to the field of aeroengines, and particularly relates to a method and device for real-time monitoring of the throat area of a core engine nozzle. This method tests the engine parameters Pt7, Tt7, and Wnz (W1 + Wf), where Wnz is the flow rate that is easily measurable during the test run. Since the flow rate of the incoming flow from the front section of the engine and the fuel flow rate ultimately pass through the throat of the nozzle, the pneumatic A8 area is inversely calculated based on the real-time flow capacity of the nozzle and Pt7, Tt7. Through the implementation of this method, the accuracy is higher than that of the traditional method for calculating the pneumatic area of the nozzle by the flow coefficient, meeting the requirements for engine performance evaluation. The pneumatic area obtained by this method includes the errors and deviations caused by actual working conditions such as the flow loss of the nozzle and the deformation of components due to high temperature and high pressure, and is an important tool for engine performance evaluation.

Description

Technical Field

[0001] This application belongs to the field of aeroengines, and particularly relates to a method and device for real-time monitoring of the throat area of a core engine nozzle. Background Art

[0002] The core engine nozzle generally adopts a fixed process nozzle without an adjustable mechanism. During the nozzle design process, the pneumatic area is used as the basis for throat area matching and flow path design according to the parameters at the design point. As the rear exhaust device, different throat areas can be adjusted during the test to match different engine states and output characteristic curves. During the test process, due to the influence of temperature, load, deformation, and flow coefficient, the throat area of the nozzle deviates from the theoretical state, and it is difficult to calculate the pneumatic area. The ratio of the pneumatic area to the flow path geometric area is not a constant value, and the empirical estimation method of multiplying the flow coefficient by the flow path geometric area has a large error. If the nozzle area does not meet the design requirements, it will cause great difficulties in judging that the main engine of the engine deviates from the design state and subsequent data analysis.

[0003] The present invention utilizes the relevant data of nozzle commissioning, and through the verification of the overall machine test parameters and the back-calculation of the nozzle pneumatic area, it can monitor the change of the nozzle throat area in real time during commissioning, providing a reference basis for engine parameter matching.

[0004] At present, there is no real-time monitoring test method for the core engine nozzle. The core engine nozzle calculates the theoretical A8 area of the nozzle according to known parameters such as the linear expansion coefficient at high temperature of the material, the flow coefficient, and the mechanical A8 area after nozzle assembly. The dynamic pneumatic area during the actual commissioning process under different pressure and temperature loads cannot be evaluated. After the throat area of the nozzle deviates from the theoretical fixed value, resulting in the deviation of the core engine commissioning characteristic curve, there is no correction value of the nozzle throat area in the corresponding state, which brings difficulties to the subsequent performance analysis of the engine. Summary of the Invention

[0005] The technical problem to be solved by the present invention is mainly the real-time monitoring problem of the A8 during the working process of the core engine nozzle, which is convenient for overall matching parameters. In view of the current lack of a reliable method for calculating the pneumatic area during the actual operation of the nozzle, a method for calculating the pneumatic area based on commissioning analysis is proposed. It can be used as the design and evaluation of the pneumatic area in the iterative design of the subsequent component pneumatic scheme. Through this method, the rationality of the nozzle pneumatic area design can be verified, the functional relationship of the nozzle pneumatic area under different working conditions can be established, and the subsequent performance design can be guided, avoiding the complicated process of repeated design and verification. This application provides a method for real-time monitoring of the throat area of a core engine nozzle, including:

[0006] Step S1: Obtain the fan inlet flow rate, engine fuel flow rate, nozzle inlet total pressure, and nozzle inlet total temperature;

[0007] Step S2: Determine the nozzle flow rate W based on the fan inlet flow rate and the engine fuel flow rate NZ ;

[0008] Step S3: Divide the nozzle operating state into below critical state and supercritical state based on the total pressure and total temperature at the nozzle inlet;

[0009] When P t7 / P0 is greater than the preset value, the nozzle operating state is divided into supercritical state;

[0010] When P t7 / P0 is less than the preset value, the nozzle operating state is divided into below critical state;

[0011] Where: P t7 —Total pressure at the nozzle inlet;

[0012] Step S4: Calculate the throat area of the core engine nozzle;

[0013] When the nozzle operating state is supercritical:

[0014]

[0015] A8—the aerodynamic area of the nozzle, T t7 —Total temperature at the nozzle inlet, P t7 —Total pressure at the nozzle inlet, k—isentropic exponent;

[0016] When the nozzle operating state is below critical:

[0017]

[0018] q(λ)—gas dynamics function;

[0019]

[0020] γ—gas constant.

[0021] Preferably, the total pressure at the nozzle inlet is measured by multiple pressure measurement rakes installed on the nozzle, and the multiple pressure measurement rakes are arranged on the nozzle in an equal annulus; the total temperature at the nozzle inlet is measured by multiple temperature measurement rakes, and the multiple temperature measurement rakes are arranged on the nozzle in an equal annulus.

[0022] Preferably, the average value of the data measured by the multiple pressure measurement rakes is used as the total pressure at the nozzle inlet, and the average value of the data measured by the multiple temperature measurement rakes is used as the total temperature at the nozzle inlet.

[0023] Preferably, the preset value described in Step S3 is taken as 1.85.

[0024] A real-time monitoring device for the throat area of the core engine nozzle:

[0025] Detection module: It includes a flow sensor, a pressure sensor, and a temperature sensor, which are respectively used to measure the fan inlet flow rate, the engine fuel flow rate, the nozzle inlet total pressure, and the nozzle inlet total temperature;

[0026] Judgment module: It is used to judge the working state of the nozzle. The working state includes supercritical state and below critical state, where

[0027] When P t7 / P0 is greater than 1.85, the working state of the nozzle is divided into supercritical state;

[0028] When P t7 / PO is less than 1.85, the working state of the nozzle is divided into below critical state;

[0029] Where: P t7 —Nozzle inlet total pressure, P0 - ambient pressure;

[0030] Nozzle flow calculation module: It is used to calculate the nozzle throat area. The specific calculation formula is:

[0031] W NZ =W1 + W f

[0032] W1 - fan inlet flow rate; Wf - engine fuel flow rate; W NZ - nozzle flow rate;

[0033] Throat area calculation module:

[0034] When the working state of the nozzle is supercritical state:

[0035]

[0036] A8—nozzle aerodynamic area, T t7 —nozzle inlet total temperature, P t7 —nozzle inlet total pressure, k—isentropic exponent;

[0037] When the working state of the nozzle is below critical state:

[0038]

[0039] q(λ)—gas dynamics function;

[0040] γ—gas constant.

[0041] The advantages of the present application include: In view of the current situation that there is a lack of a reliable method for calculating the pneumatic area during the actual operation of the nozzle, a method for calculating the pneumatic area based on test run analysis is proposed. This method can be used for the design and evaluation of the pneumatic area in the iterative design of the subsequent component pneumatic scheme. By this method, the rationality of the nozzle pneumatic area design can be verified, the functional relationship of the nozzle pneumatic area under different working conditions can be established, and the subsequent performance design can be guided, avoiding the complicated process of repeated design and verification.

[0042] The method for calculating the nozzle pneumatic area based on the overall engine test run of the present invention can obtain the A8 area change curve of the nozzle working state under the condition of no test means for the throat, providing data support for the engine performance analysis.

[0043] By using this method, the change curve of the nozzle throat area can be monitored during the engine test run. The traditional method needs to obtain the flow loss through simulation calculation and then obtain the solid wall deformation through strength calculation, and comprehensively superimpose them to obtain the pneumatic area of the nozzle under a certain state. Compared with the traditional method, the present invention avoids the complicated process of repeated design and iteration.

[0044] The method for calculating the pneumatic throat area of the present invention is simple and can also be extended to the calculation of the pneumatic area during the test run of other types of nozzles. Brief Description of the Drawings

[0045] Figure 1 It is a flowchart of the real-time monitoring method for the nozzle throat area of the core engine in a preferred embodiment of the present application. Detailed Embodiment

[0046] To make the purpose, technical solution and advantages of the implementation 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. In the drawings, the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The described embodiments are some but not all of the embodiments of the present application. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts 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.

[0047] Step S1: Obtain the fan inlet flow rate, engine fuel flow rate, nozzle inlet total pressure, and nozzle inlet total temperature;

[0048] Step S2: Determine the nozzle flow rate W based on the fan inlet flow rate and the engine fuel flow rate NZ ;

[0049] Step S3: Divide the nozzle operating state into below critical state and supercritical state based on the total pressure and total temperature at the nozzle inlet;

[0050] When P t7 / P0 is greater than a preset value, the nozzle operating state is divided into the supercritical state;

[0051] When P t7 / P0 is less than the preset value, the nozzle operating state is divided into below the critical state;

[0052] Where: P t7 —Total pressure at the nozzle inlet;

[0053] Step S4: Calculation method for the throat area of the core engine nozzle;

[0054] When the nozzle operating state is the supercritical state:

[0055]

[0056] A8—the aerodynamic area of the nozzle, T t7 —Total temperature at the nozzle inlet, P t7 —Total pressure at the nozzle inlet, k—isentropic exponent;

[0057] When the nozzle operating state is below the critical state:

[0058]

[0059] q(λ)—gas dynamics function;

[0060]

[0061] γ—gas constant.

[0062] Preferably, the total pressure at the nozzle inlet is measured by multiple pressure measurement rakes installed on the nozzle, and the multiple pressure measurement rakes are arranged on the nozzle in an equal circumferential plane; the total temperature at the nozzle inlet is measured by multiple temperature measurement rakes, and the multiple temperature measurement rakes are arranged on the nozzle in an equal circumferential plane.

[0063] Preferably, the average value of the data measured by the multiple pressure measurement rakes is taken as the total pressure at the nozzle inlet, and the average value of the data measured by the multiple temperature measurement rakes is taken as the total temperature at the nozzle inlet. Specifically:

[0064] T t7 =(T t7，1 +T t7，2 +T t7，3 +…+T t7，i ) / i

[0065] P t7 =(P t7，j +Pt7，j +P t7，j +…+P t7，j ) / j

[0066] i is the number of temperature measurement rakes, and j is the number of pressure measurement rakes.

[0067] Preferably, the preset value described in step S3 takes the value of 1.85.

[0068] A real-time monitoring device for the throat area of the core engine nozzle:

[0069] Detection module: It includes a flow sensor, a pressure sensor, and a temperature sensor, which are respectively used to measure the fan inlet flow rate, the engine fuel flow rate, the nozzle inlet total pressure, and the nozzle inlet total temperature;

[0070] Judgment module: It is used to judge the working state of the nozzle. The working state includes supercritical state and below critical state, where

[0071] When P t7 / P0 is greater than 1.85, the working state of the nozzle is divided into supercritical state;

[0072] When P t7 / P0 is less than 1.85, the working state of the nozzle is divided into below critical state;

[0073] Among them: P t7 —Nozzle inlet total pressure;

[0074] Calculation module: It is used to calculate the nozzle throat area. The specific calculation formula is:

[0075] W NZ = W1 + W f

[0076] W1 - Fan inlet flow rate; Wf - Engine fuel flow rate; W NZ - Nozzle flow rate;

[0077] When the working state of the nozzle is supercritical:

[0078]

[0079] A8 - Nozzle aerodynamic area, T t7 —Nozzle inlet total temperature, P t7 —Nozzle inlet total pressure, k - Isentropic index;

[0080] When the working state of the nozzle is below critical:

[0081]

[0082] q(λ) - Gas dynamics function;

[0083]

[0084] γ—the gas constant.

[0085] This method measures the engine parameters P t7 , T t7 and Wnz (W1 + Wf), where Wnz is the flow rate that is easily measurable during the test run. Since the incoming flow rate of the front-section engine and the fuel flow rate ultimately pass through the throat of the nozzle, the aerodynamic A8 area is inversely calculated based on the real-time flow capacity of the nozzle and P t7 , T t7 . Through the implementation of this method, the accuracy is higher than that of the traditional method of calculating the aerodynamic area of the nozzle through the flow coefficient, meeting the requirements for engine performance evaluation. The aerodynamic area obtained by this method includes the errors and deviations caused by actual working conditions such as the flow loss of the nozzle and the deformation of components due to high temperature and high pressure, and it is an important tool for engine performance evaluation.

[0086] As described above, the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A real-time monitoring method for the throat area of a core engine nozzle, characterized in that Including: Step S1: Obtain the fan inlet flow rate, engine fuel flow rate, nozzle inlet total pressure, and nozzle inlet total temperature; Step S2: Determine the nozzle flow rate W based on the fan inlet flow rate and the engine fuel flow rate NZ ; Step S3: Classify the nozzle operating state into below critical state and supercritical state based on the nozzle inlet total pressure and nozzle inlet total temperature; When P t7 / P0 is greater than a preset value, the working state of the nozzle is divided into a supercritical state; When P t7 / P0 is less than the preset value, the working state of the nozzle is divided into below the critical state; Where: P t7 - Total pressure at the nozzle inlet, P0 - ambient pressure; Step S4: Calculate the core engine nozzle throat area; When the nozzle operating state is supercritical: A8 - Nozzle pneumatic area, T t7 — Total temperature at the nozzle inlet, P t7 — Total pressure at the nozzle inlet, k — isentropic exponent; When the nozzle operating state is below critical: q(λ) - Gas dynamics function; γ - Gas constant.

2. The real-time monitoring method for the throat area of the core engine nozzle according to claim 1, characterized in that, The nozzle inlet total pressure is measured by multiple pressure measurement rakes installed on the nozzle, and the multiple pressure measurement rakes are arranged on the nozzle in an equal annulus; the nozzle inlet total temperature is measured by multiple temperature measurement rakes, and the multiple temperature measurement rakes are arranged on the nozzle in an equal annulus.

3. The real-time monitoring method for the throat area of the core engine nozzle according to claim 2, characterized in that, The average value of the data measured by the multiple pressure measurement rakes is taken as the nozzle inlet total pressure, and the average value of the data measured by the multiple temperature measurement rakes is taken as the nozzle inlet total temperature.

4. The real-time monitoring method for the throat area of the core engine nozzle according to claim 1, characterized in that The preset value described in Step S3 takes the value of 1.

85.

5. A real-time monitoring device for the core engine nozzle throat area, characterized in that: Detection module: including a flow sensor, a pressure sensor, and a temperature sensor, which are respectively used to measure the fan inlet flow rate, engine fuel flow rate, nozzle inlet total pressure, and nozzle inlet total temperature; Judgment module: used to judge the operating state of the nozzle, and the operating state includes supercritical state and below critical state, where When P t7 / P0 is greater than 1.85, the working state of the nozzle is divided into a supercritical state; When P t7 / P0 is less than 1.85, the working state of the nozzle is divided into below the critical state; Where: P t7 is the total pressure at the nozzle inlet; P0 is the ambient pressure; Nozzle flow calculation module: used to calculate the nozzle throat area, and the specific calculation formula is: W NZ = W1 + W f W1 - Fan inlet flow rate; Wf - Engine fuel flow rate; W NZ - Nozzle flow rate; Throat area calculation module: When the nozzle operating state is supercritical: A8 - nozzle pneumatic area, T t7 — total temperature at the nozzle inlet, P t7 — total pressure at the nozzle inlet, k - isentropic exponent; When the nozzle operating state is below critical: q(λ) - Gas dynamics function; γ - Gas constant.

Images