A method and device for simulating the bleed air of a turbofan engine endurance test aircraft

Abstract

This application belongs to the field of aero-engine technology, and specifically relates to a method and apparatus for simulating aircraft bleed air during sustained test of a turbofan engine, wherein the inlet temperature T1 and inlet pressure P1 of the engine are preset to a range; Step S2: Calculate the aircraft bleed air volume W fy The range, the total bleed air temperature T of the aircraft fy The range and total bleed air pressure P fy Range; Step S3: Calculate the cold diameter D of the bleed air nozzle. fy Range; Step S4: Select the cold-state diameter D of the bleed air nozzle fy An aircraft bleed air volume verification test was conducted to obtain the bleed air volume W for the test. fyr When the induced draft volume W in the experiment fyr The requirements are met, and the cold-state diameter D of the expiratory air nozzle is adopted. fy When the induced draft volume W in the experiment fyr If the requirements are not met, return to step S4; ensure that the calculation error of the aircraft bleed air volume is within the required range, and obtain the actual bleed air volume of the engine in various states to the maximum extent through test program design. This test method has the advantages of simple test method, low test cost and high replacement efficiency.

Description

Technical Field

[0001] This application belongs to the field of aero-engine technology, and specifically relates to a method and apparatus for simulating aircraft bleed air during sustained test of a turbofan engine. Background Technology

[0002] In the sustained test and evaluation of turbofan engine development, it is required to simulate the bleed air volume of an aircraft in actual use, referred to as the aircraft system bleed air test. This test is a test item specified in the "General Specifications for Aero-engine Turbojet and Turbofan Engines" and is an important test in the sustained test and evaluation of engines. Therefore, the aircraft bleed air simulation test method for sustained test of turbofan engines is crucial. At present, the methods and test device structures for aircraft bleed air simulation tests are not standardized, and related research is limited. A typical structure involves adding a long curved pipe to the engine bleed air mount to measure the temperature and pressure of the engine bleed air. This method results in relatively large errors in the measured temperature and pressure due to the long test device pipeline and significant airflow losses. Moreover, the long measurement pipeline connecting to the engine causes high-frequency vibrations in the engine during the test, which can cause certain damage to the structure of related components of the engine's outer bypass casing.

[0003] Existing aircraft bleed air testing methods suffer from significant airflow losses due to the long test equipment piping, resulting in substantial errors in temperature and pressure measurements. Furthermore, the long measurement piping connecting to the engine causes high-frequency vibrations during testing, potentially damaging components of the engine's outer bypass casing. Endurance testing, with its lengthy cycle and numerous piping and valves, increases both the cost of the testing equipment and the overall cost of engine testing. Summary of the Invention

[0004] A method for simulating bleed air testing on a turbofan engine during sustained test runs includes:

[0005] Step S1: Preset the range of engine inlet temperature T1 and the range of inlet pressure P1;

[0006] Step S2: Calculate the aircraft bleed air volume W based on the range of inlet temperature T1 and the range of inlet pressure P1. fy The range, the total bleed air temperature T of the aircraft fy The range and total bleed air pressure P fy Scope;

[0007] Step S3: Total bleed air temperature T of the aircraft fy The range and total bleed air pressure P fy Scope;

[0008] Step S4: Based on the aircraft bleed air volume W fy The range, the total bleed air temperature T of the aircraft fy The range and total bleed air pressure Pfy The range of calculations yields the cold-state diameter D of the bleed air nozzle. fy Scope;

[0009] Step S5: Select the cold-state diameter D of the bleed air nozzle fy The range of bleed air nozzle cold state diameter D fy The value and its corresponding total bleed air temperature T of the aircraft fy Total bleed air pressure P fy The inlet temperature T1 and inlet pressure P1 were used to conduct an aircraft bleed air volume verification test using an aircraft bleed air simulation device, and the bleed air volume W of the aircraft bleed air volume verification test was obtained. fyr ;

[0010] Step S6: When the induced air volume W in the experiment fyr The requirements are met, and the cold-state diameter D of the expiratory air nozzle is adopted. fy When the induced draft volume W in the experiment fyr If the requirements are not met, return to step S5.

[0011] Preferably, the aircraft bleed air volume W fy The calculation formula is:

[0012]

[0013] In the formula W fyr要求 The required bleed air flow rate for aircraft is converted to standard sea level, expressed in kg / h.

[0014] Preferably, the cold-state diameter D of the bleed air nozzle is... fy The calculation formula is:

[0015]

[0016] q(λ fy ) is the expiratory air nozzle flow coefficient; K = 0.0404, which is a constant; λ is the velocity factor, which is dimensionless.

[0017] Preferably, in the aircraft bleed air volume verification test, the aircraft bleed air test procedure is used. A certain number of speed steps are set during the process of the aircraft moving from idle state to maximum thrust state. Data is recorded for 20 seconds in the last minute of each speed step, and the aircraft bleed air volume W under that state is obtained by averaging the data. fyr .

[0018] Preferably, the cold-state diameter D of the bleed air nozzle is selected. fy The maximum value within the range is taken as the cold diameter D of the bleed air nozzle. fy value.

[0019] An aircraft bleed air simulation device is used in aircraft bleed air simulation tests to read the bleed air volume W in aircraft bleed air volume verification tests.fyr ,include:

[0020] Flow tube, bleed air nozzle, temperature and pressure composite sensing element;

[0021] One end of the flow tube is mounted on the outer bypass casing of the engine via a quick-release ring, and the other end of the flow tube is equipped with an air bleed nozzle. The flow tube draws airflow from the outer bypass casing of the engine into the flow tube and discharges it through the air bleed nozzle. A measuring mounting base is installed on the side wall of the flow tube, and a temperature and pressure composite sensing element is installed inside the measuring mounting base and inserted into the flow tube cylinder.

[0022] The bleed air nozzle is bolted to the flow pipe via a mounting flange. The bleed air nozzle is available in several different cold-state diameters.

[0023] The advantages of this application include: This invention addresses existing problems by designing a technical solution for aircraft bleed air simulation testing. By designing a simple aircraft bleed air device, the adverse effects of the bleed air device on the engine's bleed air bypass casing during sustained engine testing are reduced, minimizing pressure loss. The measurement and calculation methods are designed to ensure that the calculation error of the aircraft bleed air volume is within the required range, and the actual bleed air volume under various engine conditions is obtained to the maximum extent possible through experimental procedure design. This experimental method has the advantages of simplicity, low cost, and high replacement efficiency. Attached Figure Description

[0024] Figure 1 This is a flowchart of a preferred embodiment of the aircraft bleed air simulation test method for a turbofan engine sustained test.

[0025] Figure 2 This is a preferred embodiment of the aircraft bleed air test procedure diagram of this application;

[0026] Figure 3 This is a preferred embodiment of the aircraft bleed air simulation device of this application;

[0027] Figure 4 This is a schematic diagram of the air duct nozzle structure according to a preferred embodiment of this application. Detailed Implementation

[0028] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings. Other related parts can be referred to the general design. In the absence of conflict, the embodiments and technical features in the embodiments of this application can be combined with each other to obtain new embodiments.

[0029] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer," etc., used in this application description to indicate relative direction or positional relationship are used only to indicate relative orientation or positional relationship, and do not imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly, and therefore should not be construed as a limitation on this application. The terms "first," "second," "third," and similar terms used in this application description are used only for descriptive purposes to distinguish different components, and should not be construed as indicating or implying relative importance. The terms "a," "one," or "the," etc., used in this application description should not be construed as an absolute limitation on quantity, but should be construed as indicating the existence of at least one. The terms "including," "comprising," etc., used in this application description mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects.

[0030] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, terms such as “installation,” “connection,” and “linkage” used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can be a connection within two components. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0031] As shown in the figure, to solve the above problem, such as Figure 1 As shown, this application provides a step 1: determining the standard bleed air volume Wyr required by the aircraft under standard sea level conditions. 标准 ;

[0032] Step 2: Estimate the range of engine inlet temperature T1 and inlet pressure P1 during the test. The inlet temperature T1 and inlet pressure P1 are estimated based on the natural environment during the test, which is basically the atmospheric temperature and pressure.

[0033] Step 3: Based on the estimated range of inlet temperature T1 and pressure P1, the aircraft bleed air volume W is calculated using formula (3). yr Scope;

[0034] Step 4: Based on the estimated inlet temperature T1 and pressure P1 range, estimate the total temperature T of the aircraft bleed air using control laws. fy and total pressure P fy ;

[0035] Step 5: Based on the estimated total temperature T of the aircraft bleed air fy and total pressure P fy And the corresponding aircraft bleed air volume W under the test environment yr The range is calculated by back-calculating the cold diameter D of the bleed nozzle using formula (2). fy Scope;

[0036] Step 6: Calculate the cold-state diameter D of the bleed air nozzle. fy Within the range, select the size of the bleed air nozzle based on the maximum value, and then determine the cold-state diameter D of the selected bleed air nozzle. fy To determine the dimensions, measure the diameters of multiple nozzles, select a nozzle with the same or similar dimensions as described above, and obtain the actual cold-state diameter D of the bleed air nozzle. fy size;

[0037] Step 7: Install the aircraft bleed air simulation device and measure the inlet temperature T1, pressure P1, and total temperature T. fy Total pressure P fy Measurement point installation and testing;

[0038] Step 8: Incorporate formulas (2) and (3) into the data acquisition and calculation program, and verify the aircraft bleed air volume according to the aircraft bleed air program.

[0039] Step 9: When the aircraft bleed air volume verification test obtains the bleed air volume W of the aircraft bleed air volume verification test. fyr When the requirements are met, the cold-state diameter D of the bleed air nozzle is used. fy Proceed to the next step of the project; when the expiratory air volume W fyr If the requirements are not met, a new bleed air nozzle with a cold-state diameter D should be selected. fy Return to step 7.

[0040] One practical method for aircraft bleed air procedures includes conducting tests at at least five temperature points across a range from the lowest temperature in cold weather to the highest temperature in hot weather, from idle to maximum thrust. This verifies the available bleed air volume besides the air volume required by the engine system, and verifies the impact of aircraft bleed air on engine performance. During sustained test runs, aircraft bleed air is used throughout the entire test to simulate the bleed air volume requirements of an aircraft in flight to the greatest extent possible, verifying the impact of aircraft bleed air on the engine and achieving the purpose of sustained test runs. A typical aircraft bleed air test procedure is shown below. Figure 2 As shown, a certain number of speed steps are set from the lowest thrust state to the highest thrust state. Data for 20 seconds is recorded in the last minute of each speed step, and the bleed air volume of the aircraft under this state is obtained by averaging the data.

[0041] The calculation and measurement methods for aircraft bleed air, and the bleed air flow rate measurement parameters of the aircraft bleed air flow tube are shown in Table 1.

[0042] Table 1 Aircraft Bleed Air Measurement Parameters

[0043] Serial Number project code name unit Accuracy requirements 1 Aircraft bleed air measurement total temperature <![CDATA[T fy ]]> ℃ ±2.5℃ 2 Aircraft bleed air measurement total pressure <![CDATA[P fy ]]> kPa ±0.3％ 3 Engine inlet total temperature <![CDATA[T1]]> ℃ ±1℃ 4 Engine inlet total pressure <![CDATA[P1]]> kPa ±0.3％

[0044] Calculate the aircraft bleed air physical flow rate using the following formula:

[0045]

[0046] In the formula: W fy - Aircraft bleed air flow rate, kg / h; q(λ) fy - Air bleed nozzle flow coefficient; A fy -Cold area of ​​the bleed air nozzle, mm 2 K = 0.0404, a constant; λ—velocity factor, dimensionless.

[0047] The formula simplifies to 2:

[0048]

[0049] In the formula: q(λ) fy — Expectorant nozzle flow coefficient, critical state qλ fy =1; D fy —Cold diameter of the bleed air nozzle, mm.

[0050] The flow rate formula converted to standard sea level at T1 = 15℃ and P1 = 101.325 kPa is:

[0051]

[0052] In the formula W fyr要求 —The required bleed air flow rate for aircraft at standard sea level, in kg / h, is less than the standard bleed air flow rate (Wyr) required for aircraft at standard sea level. 标准 Select from the preset range;

[0053] An aircraft bleed air simulation device, such as Figures 3-4 As shown, in the aircraft bleed air simulation test, it is used to read the bleed air volume W in the aircraft bleed air volume verification test. fyr The system includes: a flow tube 7, an bleed air nozzle 1, and a temperature and pressure composite sensing element 4. One end of the flow tube 7 is mounted on the engine outer bypass casing 10 via a quick-release ring 9, and the other end of the flow tube 7 is fitted with the bleed air nozzle 1. The flow tube 7 draws airflow from the engine outer bypass casing 10 into its interior and discharges it through the bleed air nozzle 1. A measuring mounting base 3 is mounted on the side wall of the flow tube 7, and the temperature and pressure composite sensing element 4, inserted into the cylinder of the flow tube 7, is installed inside the measuring mounting base 3. The bleed air nozzle 1 is bolted to the flow tube 7 via a mounting flange. The aircraft bleed air nozzle is designed to operate in a critical state q(λ). fy=1 and the components can be replaced with different diameters to meet the test requirements of different airflow rates.

[0054] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for simulating aircraft bleed air during sustained test of a turbofan engine, comprising an aircraft bleed air simulation device for reading the bleed air volume W in an aircraft bleed air volume verification test. fyr Its characteristics are, include: Flow tube (7), air duct nozzle (1), temperature and pressure composite sensing part (4). One end of the flow tube (7) is installed on the outer bypass casing (10) of the engine via a quick-release ring (9), and the other end of the flow tube (7) is equipped with an air bleed nozzle (1). The flow tube (7) introduces the airflow in the outer bypass casing (10) of the engine into the flow tube (7) and discharges it through the air bleed nozzle (1). A measuring mounting base (3) is installed on the side wall of the flow tube (7), and a temperature and pressure composite sensing part (4) is installed inside the measuring mounting base (3) and inserted into the cylinder of the flow tube (7). The bleed air nozzle (1) is connected to the flow pipe (7) by bolts through the mounting flange. The bleed air nozzle (1) has multiple specifications with different cold-state diameters. The method includes: Step S1: Preset the range of engine inlet temperature T1 and the range of inlet pressure P1; Step S2: Calculate the aircraft bleed air volume W based on the range of inlet temperature T1 and the range of inlet pressure P1. fy Scope; Step S3: Based on the range of inlet temperature T1 and the range of inlet pressure P1, calculate the total bleed air temperature T of the aircraft. fy The range and total bleed air pressure P fy Scope; Step S4: Based on the aircraft bleed air volume W fy The range, the total bleed air temperature T of the aircraft fy The range and total bleed air pressure P fy The range of calculations yields the cold-state diameter D of the bleed air nozzle. fy Scope; Step S5: Select the cold-state diameter D of the bleed air nozzle fy The range of bleed air nozzle cold state diameter D fy The value and its corresponding total bleed air temperature T of the aircraft fy Total bleed air pressure P fy The inlet temperature T1 and inlet pressure P1 were used to conduct an aircraft bleed air volume verification test using an aircraft bleed air simulation device, and the bleed air volume W of the aircraft bleed air volume verification test was obtained. fyr ; Step S6: When the induced air volume W in the experiment fyr The requirements are met, and the cold-state diameter D of the expiratory air nozzle is adopted. fy When the induced draft volume W in the experiment fyr If the requirements are not met, return to step S5.

2. The method for simulating bleed air in a turbofan engine sustained test as described in claim 1, characterized in that, Aircraft bleed air volume W fy The calculation formula is: ； In the formula W fyr要求 The required bleed air flow rate for aircraft is converted to standard sea level, expressed in kg / h.

3. The method for simulating bleed air in a turbofan engine sustained test as described in claim 1, characterized in that, Cold diameter D of the bleed air nozzle fy The calculation formula is: ； q(λ fy ) is the expiratory air nozzle flow coefficient; K=0.0404 is a constant; λ is the velocity factor, which is dimensionless.

4. The method for simulating bleed air intake during sustained test runs of a turbofan engine as described in claim 1, characterized in that, In the aircraft bleed air volume verification test, the aircraft bleed air test procedure was adopted. A certain number of speed steps were set during the process of the aircraft moving from idle state to maximum thrust state. Data was recorded for 20 seconds in the last minute of each speed step, and the aircraft bleed air volume W under that state was obtained by averaging the data. fyr .

5. The method for simulating bleed air in a turbofan engine sustained test as described in claim 1, characterized in that, Select the cold-state diameter D of the bleed air nozzle fy The maximum value within the range is taken as the cold diameter D of the bleed air nozzle. fy value.

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