A jet precooling control method based on temperature change rate and saturation degree planning
By employing a closed-loop control method based on temperature change rate and saturation planning, the problems of insufficient thrust and excessive water consumption in jet precooling control were solved, achieving more efficient water utilization and mode conversion to power, thereby enhancing the aircraft's payload mission capability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- AECC SHENYANG ENGINE RES INST
- Filing Date
- 2022-12-31
- Publication Date
- 2026-06-26
AI Technical Summary
Existing technologies in jet precooling control suffer from problems such as insufficient thrust or excessive water consumption due to open-loop control methods, which cannot effectively support the combined power mode transition. Furthermore, the amount of water sprayed for cooling is limited by saturation, which cannot meet the aircraft's water load requirements.
A closed-loop control method based on temperature change rate and saturation planning is adopted. By combining PID algorithm and servo control with temperature change rate and water-air ratio calculation, the water supply is precisely adjusted to achieve closed-loop control of engine inlet temperature, thereby optimizing water utilization and thrust gain.
It improves water utilization during the transient control process, increases mode conversion power, reduces the total amount of water carried by the aircraft, and enhances the aircraft's payload mission capability.
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Figure CN116025470B_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of variable control of aero-engines, and specifically relates to a jet precooling control method based on temperature change rate and saturation plan. Background Technology
[0002] In recent years, extensive research has been conducted both domestically and internationally on jet precooling expansion lines for turbine engines. This involves installing a water-spraying precooling device in the intake manifold, injecting atomized liquid water into the intake, and reducing the engine's overall inlet temperature through water evaporation and heat absorption. The basic principles of increasing thrust using jet precooling technology in engines are as follows: First, water evaporation cools the airflow in the intake manifold, lowering its temperature, increasing the fan's converted speed, increasing density, and increasing the airflow entering the engine, thus increasing thrust. Second, although the increase in engine thrust is mainly due to the decrease in air temperature, the vaporization of water injected into the intake manifold also contributes to the additional thrust. Third, the increased moisture content of the working fluid, the increased gas constant, the increased heat capacity of the working fluid, the increased exhaust velocity of the engine, and the increased thrust per unit area all contribute to the increased thrust.
[0003] Currently, the domestic method relies on a mathematical model of the jet precooling device. It utilizes the relationship between water injection volume and cooling rate, combined with engine low-pressure speed and engine inlet total pressure to correct the water supply. This open-loop control adjusts the water injection volume to regulate the jet precooling of the engine inlet total temperature. However, this calculation method is open-loop control and primarily applicable to steady-state controllers. The evaporation rate used in the design process differs from the actual jet precooling operation under installed conditions, leading to insufficient engine thrust or excessively rapid water consumption insufficient to support the entire mode transition, ultimately causing combined power mode conversion failure. Furthermore, since the first principle of jet precooling thrust has the greatest weight, as the amount of cooling water injected into the intake increases, the inlet total temperature further decreases, while the relative humidity of the air further increases. When the evaporation of the cooling water and the cooling of the inlet air reach a dynamic equilibrium, the engine inlet total temperature will no longer change with the relative humidity of the air. At this point, the cooling effect of the injected water on the engine inlet reaches its limit, so the jet precooling water volume generally does not exceed saturation. Moreover, the aircraft's water capacity is limited, necessitating improved water utilization during the transition control process.
[0004] Therefore, it is desirable to have a technical solution to overcome or at least mitigate one of the aforementioned defects of the prior art. Summary of the Invention
[0005] The purpose of this application is to provide a jet precooling control method based on temperature change rate and saturation planning to solve at least one problem in the prior art.
[0006] The technical solution of this application is:
[0007] A jet precooling control method based on temperature change rate and saturation planning includes:
[0008] Step 1: Obtain the target value T2_dem for closed-loop control of engine inlet temperature and the real-time acquisition value T2 of engine inlet temperature sensor. Calculate the difference between the target value for closed-loop control and the real-time acquisition value of sensor to obtain the first control deviation e. And obtain the initial value T2_dot_dem0 for engine inlet temperature change rate control according to PID algorithm.
[0009] Step 2: Select the initial value of the engine inlet temperature change rate control target T2_dot_dem0 from the engine inlet temperature maximum change rate T2_dot_max and the engine inlet temperature minimum change rate T2_dot_min respectively, and then obtain the engine inlet temperature change rate control target value T2_dot_dem.
[0010] Step 3: Calculate the difference between the engine inlet temperature change rate control target value T2_dot_dem and the engine inlet temperature differential value T2_dot to obtain the second control deviation e_T2_dot, and obtain the initial value of the water supply control target W_water0 based on the second control deviation e_T2_dot.
[0011] Step 4: Select the initial value of the water supply control target W_water0 from the maximum water supply W_water_max and the minimum water supply W_water_min respectively to obtain the water supply control target value W_water_dem;
[0012] Step 5: Using the target value of water supply control W_water_dem as the target setpoint, the water supply W_water_real is metered using servo closed-loop control, thereby controlling the engine inlet temperature T2.
[0013] In at least one embodiment of this application, in step one, the initial value T2_dot_dem0 of the engine inlet temperature change rate control target obtained according to the PID algorithm is:
[0014]
[0015] Where, k p T is the proportionality coefficient. i T is the integration constant. D is a differential constant.
[0016] In at least one embodiment of this application, in step three,
[0017] The second control deviation e_T2_dot is then subjected to series lag and lead correction:
[0018] G1(s) = lag1·s+1 / lag2·s+1
[0019] G2(s) = lead1·s+1 / lead2·s+1
[0020] Then, integral control is performed to obtain the initial value of the water supply control target, W_water0.
[0021] In at least one embodiment of this application, in step four, the maximum water supply W_water_max and the minimum water supply W_water_min are obtained according to the following method:
[0022] Obtain the ambient temperature T0 and the engine inlet temperature closed-loop control target value T2_dem, calculate the difference ΔT between the ambient temperature T0 and the engine inlet temperature closed-loop control target value T2_dem, and obtain the water-air ratio f(ΔT) based on the difference ΔT.
[0023] Obtain the converted airflow rate (W) of the engine inlet. 2r Calculate the converted airflow rate W at the engine inlet. 2r The water supply W_water is obtained by multiplying the water-to-air ratio f(ΔT).
[0024] Calculate the product of the water supply W_wate with the maximum saturation coefficient K_max and the minimum saturation coefficient K_min respectively to obtain the maximum water supply W_water_max and the minimum water supply W_water_min.
[0025] In at least one embodiment of this application, the initial value of the ambient temperature T0 is determined according to the Mach number, and a correction coefficient is obtained according to the height H. The product of the initial value of the ambient temperature T0 and the correction coefficient is calculated to obtain the ambient temperature T0.
[0026] The invention has at least the following beneficial technical effects:
[0027] The jet precooling control method based on temperature change rate and saturation planning proposed in this application can improve the water utilization rate during the transition state control process, and comprehensively consider the fuel consumption rate and thrust yield rate of the aero-engine to improve the mode conversion power. At the same time, by reducing the total amount of water carried by the aircraft, it indirectly improves the aircraft's payload mission capability. Attached Figure Description
[0028] Figure 1 This is a flowchart of a jet precooling control method based on temperature change rate and saturation planning according to one embodiment of this application. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.
[0030] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this application.
[0031] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.
[0032] This application provides a jet precooling control method based on temperature change rate and saturation planning, including the following steps:
[0033] Step 1: Obtain the target value T2_dem for closed-loop control of engine inlet temperature and the real-time acquisition value T2 of engine inlet temperature sensor. Calculate the difference between the target value for closed-loop control and the real-time acquisition value of sensor to obtain the first control deviation e. And obtain the initial value T2_dot_dem0 for engine inlet temperature change rate control according to PID algorithm.
[0034] Step 2: Select the initial value of the engine inlet temperature change rate control target T2_dot_dem0 from the engine inlet temperature maximum change rate T2_dot_max and the engine inlet temperature minimum change rate T2_dot_min respectively, and then obtain the engine inlet temperature change rate control target value T2_dot_dem.
[0035] Step 3: Calculate the difference between the engine inlet temperature change rate control target value T2_dot_dem and the engine inlet temperature differential value T2_dot to obtain the second control deviation e_T2_dot, and obtain the initial value of the water supply control target W_water0 based on the second control deviation e_T2_dot.
[0036] Step 4: Select the initial value of the water supply control target W_water0 from the maximum water supply W_water_max and the minimum water supply W_water_min respectively to obtain the water supply control target value W_water_dem;
[0037] Step 5: Using the target value of water supply control W_water_dem as the target setpoint, the water supply W_water_real is metered using servo closed-loop control, thereby controlling the engine inlet temperature T2.
[0038] In the jet precooling control method based on temperature change rate and saturation planning in this application, in step one, the initial value T2_dot_dem0 of the engine inlet temperature change rate control target is obtained according to the PID algorithm as follows:
[0039]
[0040] Where, k p T is the proportionality coefficient. i T is the integration constant. D is a differential constant.
[0041] In one embodiment of this application, in step three,
[0042] The second control deviation e_T2_dot is subjected to series lag and lead correction:
[0043] G1(s) = lag1·s+1 / lag2·s+1
[0044] G2(s) = lead1·s+1 / lead2·s+1
[0045] Then, integral control is performed to obtain the initial value of the water supply control target, W_water0.
[0046] In step four, the maximum water supply W_water_max and the minimum water supply W_water_min are obtained as follows:
[0047] After obtaining the ambient temperature T0 and the engine inlet temperature closed-loop control target value T2_dem, calculate the difference ΔT between the ambient temperature T0 and the engine inlet temperature closed-loop control target value T2_dem, and obtain the water-air ratio f(ΔT) based on the difference ΔT.
[0048] Obtain the converted airflow rate (W) of the engine inlet. 2r Calculate the converted airflow rate W at the engine inlet. 2r The water supply W_water is obtained by multiplying the water-to-air ratio f(ΔT).
[0049] Calculate the product of the water supply W_wate with the maximum saturation coefficient K_max and the minimum saturation coefficient K_min respectively to obtain the maximum water supply W_water_max and the minimum water supply W_water_min.
[0050] The jet precooling control method of this application, based on temperature change rate and saturation planning, obtains the initial value of ambient temperature T0 by looking up a table according to the Mach number. In one embodiment of this application, the relationship between ambient temperature and flight Mach number is shown in Table 1.
[0051] Table 1
[0052] Mach 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 <![CDATA[T0]]> 327.7 341.9 357.1 373.0 389.9 407.5 425.9 445.1 465.1 486.0
[0053] The correction factor for ambient temperature T0 is obtained by looking up the table based on the altitude H. The product of the initial value of ambient temperature T0 and the correction factor is then calculated to obtain the ambient temperature T0. In one embodiment of this application, the correction factor for ambient temperature with altitude is shown in Table 2.
[0054] Table 2
[0055] H 10 11 12 13 14 15 16 17 18 Correction 1 1 1 1 1 1 1 1 1
[0056] After calculating the difference ΔT between the ambient temperature T0 and the engine inlet temperature closed-loop control target value T2_dem, the water-to-air ratio f(ΔT) is obtained by looking up the difference ΔT in a table. In one embodiment of this application, the water-to-air ratio is planned as shown in Table 3.
[0057] Table 3
[0058]
[0059]
[0060] The engine speed N is calculated by the low-pressure relative conversion of the engine. 1r The converted airflow rate W at the engine inlet was obtained by looking up the collected values in a table. 2r In one embodiment of this application, the converted airflow rate at the engine inlet is shown in Table 4.
[0061] Table 4
[0062] <![CDATA[N 1r ]]> <![CDATA[W 2r ]]> 1.05 Actual measurement 1 Actual measurement 0.9 Actual measurement 0.8 Actual measurement 0.7 Actual measurement 0.6 Actual measurement
[0063] By calculating the converted airflow W at the engine inlet 2r The water supply W_water is obtained by multiplying the water-air ratio f(ΔT) by the water supply volume. The maximum water supply W_water_max and the minimum water supply W_water_min are obtained by combining the maximum saturation coefficient K_max and the minimum saturation coefficient K_min.
[0064] This application presents a jet precooling control method based on temperature change rate and saturation planning. It uses the engine inlet temperature as a feedback adjustment parameter to regulate the cooling water flow, achieving closed-loop control of jet precooling based on temperature change rate and saturation planning. This method improves water utilization during transient control and, considering both fuel consumption and thrust yield of the aero-engine, enhances modal conversion power. Furthermore, by reducing the total amount of water carried by the aircraft, it indirectly improves the aircraft's payload and mission capabilities.
[0065] 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 jet precooling control method based on temperature change rate and saturation planning, characterized in that, include: Step 1: Obtain the target value T2_dem for closed-loop control of engine inlet temperature and the real-time acquisition value T2 of engine inlet temperature sensor. Calculate the difference between the target value for closed-loop control and the real-time acquisition value of sensor to obtain the first control deviation e. And obtain the initial value T2_dot_dem0 for engine inlet temperature change rate control according to PID algorithm. Step 2: Select the initial value of the engine inlet temperature change rate control target T2_dot_dem0 from the engine inlet temperature maximum change rate T2_dot_max and the engine inlet temperature minimum change rate T2_dot_min respectively, and then obtain the engine inlet temperature change rate control target value T2_dot_dem. Step 3: Calculate the difference between the engine inlet temperature change rate control target value T2_dot_dem and the engine inlet temperature differential value T2_dot to obtain the second control deviation e_T2_dot, and obtain the initial value of the water supply control target W_water0 based on the second control deviation e_T2_dot. Step 4: Select the initial value of the water supply control target W_water0 from the maximum water supply W_water_max and the minimum water supply W_water_min respectively to obtain the water supply control target value W_water_dem; Step 5: Using the target value of water supply control W_water_dem as the target setpoint, the water supply W_water_real is metered using servo closed-loop control, thereby controlling the engine inlet temperature T2.
2. The jet precooling control method based on temperature change rate and saturation planning according to claim 1, characterized in that, In step one, the initial target value T2_dot_dem0 for controlling the engine inlet temperature change rate is obtained according to the PID algorithm as follows: Where, k p T is the proportionality coefficient. i T is the integration constant. D is a differential constant.
3. The jet precooling control method based on temperature change rate and saturation planning according to claim 2, characterized in that, In step three, The second control deviation e_T2_dot is then subjected to series lag and lead correction: G1(s) = lag1·s+1 / lag2·s+1 G2(s) = lead1·s+1 / lead2·s+1 Then, integral control is performed to obtain the initial value of the water supply control target, W_water0.
4. The jet precooling control method based on temperature change rate and saturation planning according to claim 3, characterized in that, In step four, the maximum water supply W_water_max and the minimum water supply W_water_min are obtained in the following way: Obtain the ambient temperature T0 and the engine inlet temperature closed-loop control target value T2_dem, calculate the difference ΔT between the ambient temperature T0 and the engine inlet temperature closed-loop control target value T2_dem, and obtain the water-air ratio f(ΔT) based on the difference ΔT. Obtain the converted airflow rate (W) of the engine inlet. 2r Calculate the converted airflow rate W at the engine inlet. 2r The water supply W_water is obtained by multiplying the water-to-air ratio f(ΔT). Calculate the product of the water supply W_wate with the maximum saturation coefficient K_max and the minimum saturation coefficient K_min respectively to obtain the maximum water supply W_water_max and the minimum water supply W_water_min.
5. The jet precooling control method based on temperature change rate and saturation planning according to claim 4, characterized in that, The initial value of the ambient temperature T0 is determined based on the Mach number (Mach), and a correction factor is obtained based on the height H. The product of the initial value of the ambient temperature T0 and the correction factor is calculated to obtain the ambient temperature T0.