Acoustically absorptive treatment in aircraft engine nacelle is an essential part of the overall aircraft noise reduction effort. The investigation on the optimization of multi-liners plays an important role in noise ...Acoustically absorptive treatment in aircraft engine nacelle is an essential part of the overall aircraft noise reduction effort. The investigation on the optimization of multi-liners plays an important role in noise reduction. Based upon the mode analysis method of sound propagation in a circular duct with multiple liners, a flexible tolerance method is used to optimize the acoustic parameters(impedance), geometric structure parameters(such as open area ratio, cavity depth and hole diameter) and operating condition parameters(such as blade passing frequency). The mathematical models for these kinds of optimization are presented here. The optimum values of the design variables are determined when the in-duct sound suppression approaches a maximum. It can be derived from the optimum results that the emphasis of the engineering optimization design of the perforated plate honey-comb structure should be placed on the optimum choice of the open area ratio and cavity depth. Some reference criteria for the engineering design of the multi-linings are also provided.展开更多
In the process of inlet/engine matching,large-scale distortion vortexes would be generated due to lip separation,curved duct,shock-wave boundary layer interaction and other factors of inlet,resulting in complex combin...In the process of inlet/engine matching,large-scale distortion vortexes would be generated due to lip separation,curved duct,shock-wave boundary layer interaction and other factors of inlet,resulting in complex combination distortion of total pressure and swirl,which would affect the stable and efficient operation of fans/compressors of aero-engine.On the basis of main distortion vortex characteristics of a typical S-shape inlet and its theoretical model of velocity and pressure distribution,this paper establishes an inlet boundary condition definition method to generate three-dimensional distortion vortex,and presents a study of coupling effect between steady distortion vortex and NASA Rotor 67.The results show that the fan’s performance curve would move to smaller mass flow direction under the influence of the co-rotating distortion vortex,while fan’s operation curve would change to the opposite direction if the inlet distortion vortex direction is opposite to the fan’s rotating direction.Compared with co-rotating distortion vortex,the efficiency loss caused by counter-rotating distortion vortex would be larger and total pressure ratio loss would be smaller.The vortex core size has significant influence on the stability margin of the fan,but has little influence on the efficiency and total pressure ratio characteristic.As the vortex core size increases,the range of fan’s tip region with high attack angle would become larger and cause the fan to stall in advance.Due to the non-uniform suction of the downstream fan,the inlet distortion vortex accelerates to mix with the surrounding main flow.The total pressure distortion decreases and swirl distortion increases along sections from inlet boundary to the fan leading edge.展开更多
In order to solve the aero-propulsion system acceleration optimal problem,the necessity of inlet control is discussed,and a fully new aero-propulsion system acceleration process control design including the inlet,engi...In order to solve the aero-propulsion system acceleration optimal problem,the necessity of inlet control is discussed,and a fully new aero-propulsion system acceleration process control design including the inlet,engine,and nozzle is proposed in this paper.In the proposed propulsion system control scheme,the inlet,engine,and nozzle are simultaneously adjusted through the FSQP method.In order to implement the control scheme design,an aero-propulsion system componentlevel model is built to simulate the inlet working performance and the matching problems between the inlet and engine.Meanwhile,a stabilizing inlet control scheme is designed to solve the inlet control problems.In optimal control of the aero-propulsion system acceleration process,the inlet is an emphasized control unit in the optimal acceleration control system.Two inlet control patterns are discussed in the simulation.The simulation results prove that by taking the inlet ramp angle as an active control variable instead of being modulated passively,acceleration performance could be obviously enhanced.Acceleration objectives could be obtained with a faster acceleration time by5%.展开更多
To reduce the propulsion system installation thrust loss under high angle of attack maneuvering,a control method based on real-time optimization of the integrated aeropropulsion is proposed.Firstly,based on data fitti...To reduce the propulsion system installation thrust loss under high angle of attack maneuvering,a control method based on real-time optimization of the integrated aeropropulsion is proposed.Firstly,based on data fitting and physical principle,an integrated onboard model of propulsion system is established,which can calculate various performance parameters of the propulsion system in real time,and has high accuracy and real-time performance.Secondly,to improve the compatibility of optimization real-time performance and search accuracy,the online optimization control of aero-propulsion system is realized based on an improved trust region algorithm.Finally,by controlling the auxiliary intake valve,a good match between inlet and engine is realized,which solves the problems of intake flow reducing and total pressure recovery coefficient declining,and improves the installation performance of propulsion system.The simulation results indicate that,compared with the conventional independent engine control,the real-time integrated optimization method reduces the installed thrust loss by 3.61%under the design condition,and 4.58%under the off-design condition.Furthermore,the simulation on HIL(Hardware-In-theLoop)platform verifies the real-time performance of integrated optimization method.展开更多
文摘Acoustically absorptive treatment in aircraft engine nacelle is an essential part of the overall aircraft noise reduction effort. The investigation on the optimization of multi-liners plays an important role in noise reduction. Based upon the mode analysis method of sound propagation in a circular duct with multiple liners, a flexible tolerance method is used to optimize the acoustic parameters(impedance), geometric structure parameters(such as open area ratio, cavity depth and hole diameter) and operating condition parameters(such as blade passing frequency). The mathematical models for these kinds of optimization are presented here. The optimum values of the design variables are determined when the in-duct sound suppression approaches a maximum. It can be derived from the optimum results that the emphasis of the engineering optimization design of the perforated plate honey-comb structure should be placed on the optimum choice of the open area ratio and cavity depth. Some reference criteria for the engineering design of the multi-linings are also provided.
文摘In the process of inlet/engine matching,large-scale distortion vortexes would be generated due to lip separation,curved duct,shock-wave boundary layer interaction and other factors of inlet,resulting in complex combination distortion of total pressure and swirl,which would affect the stable and efficient operation of fans/compressors of aero-engine.On the basis of main distortion vortex characteristics of a typical S-shape inlet and its theoretical model of velocity and pressure distribution,this paper establishes an inlet boundary condition definition method to generate three-dimensional distortion vortex,and presents a study of coupling effect between steady distortion vortex and NASA Rotor 67.The results show that the fan’s performance curve would move to smaller mass flow direction under the influence of the co-rotating distortion vortex,while fan’s operation curve would change to the opposite direction if the inlet distortion vortex direction is opposite to the fan’s rotating direction.Compared with co-rotating distortion vortex,the efficiency loss caused by counter-rotating distortion vortex would be larger and total pressure ratio loss would be smaller.The vortex core size has significant influence on the stability margin of the fan,but has little influence on the efficiency and total pressure ratio characteristic.As the vortex core size increases,the range of fan’s tip region with high attack angle would become larger and cause the fan to stall in advance.Due to the non-uniform suction of the downstream fan,the inlet distortion vortex accelerates to mix with the surrounding main flow.The total pressure distortion decreases and swirl distortion increases along sections from inlet boundary to the fan leading edge.
基金co-supported by the Fundamental Research Funds for the Central Universities(No:NZ2016103)the National Natural Science Foundation of China(No: 51576096)
文摘In order to solve the aero-propulsion system acceleration optimal problem,the necessity of inlet control is discussed,and a fully new aero-propulsion system acceleration process control design including the inlet,engine,and nozzle is proposed in this paper.In the proposed propulsion system control scheme,the inlet,engine,and nozzle are simultaneously adjusted through the FSQP method.In order to implement the control scheme design,an aero-propulsion system componentlevel model is built to simulate the inlet working performance and the matching problems between the inlet and engine.Meanwhile,a stabilizing inlet control scheme is designed to solve the inlet control problems.In optimal control of the aero-propulsion system acceleration process,the inlet is an emphasized control unit in the optimal acceleration control system.Two inlet control patterns are discussed in the simulation.The simulation results prove that by taking the inlet ramp angle as an active control variable instead of being modulated passively,acceleration performance could be obviously enhanced.Acceleration objectives could be obtained with a faster acceleration time by5%.
基金supported in part by the National Natural Science Foundation of China (Nos. 51906102 and 52176009)the National Science and Technology Major Project, China (Nos. J2019-II-0009-0053, J2019-I-0020-0019 and 2019III-0014-0058)+2 种基金the Innovation Centre for Advanced Aviation Power, China (Nos. HKCX2020-02-022 and HKCX2020-02-027)the Research on the Basic Problem of Intelligent Aero-engine, China (No. 2017-JCJQZD-047-21)the Fundamental Research Funds for the Central Universities, China (No. NZ2020002)
文摘To reduce the propulsion system installation thrust loss under high angle of attack maneuvering,a control method based on real-time optimization of the integrated aeropropulsion is proposed.Firstly,based on data fitting and physical principle,an integrated onboard model of propulsion system is established,which can calculate various performance parameters of the propulsion system in real time,and has high accuracy and real-time performance.Secondly,to improve the compatibility of optimization real-time performance and search accuracy,the online optimization control of aero-propulsion system is realized based on an improved trust region algorithm.Finally,by controlling the auxiliary intake valve,a good match between inlet and engine is realized,which solves the problems of intake flow reducing and total pressure recovery coefficient declining,and improves the installation performance of propulsion system.The simulation results indicate that,compared with the conventional independent engine control,the real-time integrated optimization method reduces the installed thrust loss by 3.61%under the design condition,and 4.58%under the off-design condition.Furthermore,the simulation on HIL(Hardware-In-theLoop)platform verifies the real-time performance of integrated optimization method.