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Wang X.-T.,Nanjing University of Aeronautics and Astronautics | Zhang J.-Z.,Nanjing University of Aeronautics and Astronautics | Zhang J.-Z.,Collaborative Innovation Center for Advanced Aerospace Engine | Shan Y.,Nanjing University of Aeronautics and Astronautics
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2016

A simplified physical model of engine nacelle was established. The effects of ventilation cooling and radiation shelter on reducing skin temperature were investigated by numerical simulation and experimental research. The internal heat transfer of the engine nacelle was also analyzed. Results show that the computational temperature distribution on the skin surface is in good accordance with the experimental result. Under the present zonal thermal boundary conditions of the heated wall, the ratio of total heat flux imposing on the inner surface of skin to the heat flux of heated wall is about 78% in case of no ventilation and radiation shelter. This ratio reduces to 20% when the ventilating velocity of the engine nacelle is 1 m/s. When the ventilating velocity is increased from 0 m/s to 3.5 m/s, the maximum temperature on the skin is reduced about 10% relatively. The maximum temperature on the skin with radiation shelter is reduced about 6% in relative to the case without radiation shelter under no ventilation condition. Combination of ventilation and radiation shelter can achieve 50 K reduction of maximum skin temperature in relative to the case of no ventilation and radiation shelter, with about 14% relative reduction. © 2016, Editorial Department of Journal of Aerospace Power. All right reserved. Source


Shi S.,Nanjing University of Aeronautics and Astronautics | Shi S.,Harbin Aircraft Industry Group Co. | Tu B.-F.,Nanjing University of Aeronautics and Astronautics | Tu B.-F.,Collaborative Innovation Center for Advanced Aerospace Engine
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2016

To study stall inception of the axial flow compressor, full-annulus numerical simulation in the first stage of a two-stage low-speed axial flow compressor was presented. Results showed that there existed a kind of velocity fluctuation in the circumference scale in stall inception, which was closely related to the uneven boundary layer separation that first happened on the suction of stator blade rows. With further throttling of the compressor, the fluctuation amplitude increased gradually, and eventually it induced several rotor channels to generate serious boundary layer separation, blocking these channels. The compressor system led to the rotating stall condition. The rotational stall frequency with full development had good coincidence with the experimental result. © 2016, Editorial Department of Journal of Aerospace Power. All right reserved. Source


Luo L.,Nanjing University of Aeronautics and Astronautics | Ji H.-H.,Nanjing University of Aeronautics and Astronautics | Ji H.-H.,Collaborative Innovation Center for Advanced Aerospace Engine | Shi X.-J.,Nanjing University of Aeronautics and Astronautics
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2016

The numerical simulation of oil-gas two-phase flow and heat transfer of complex rotating multi-cavity system in aeroengine air system and lubrication oil system were studied, and the flow and heat transfer characteristics were analyzed. Mixture model and Eulerian model were used to calculate the velocity, pressure and temperature of a multi-inlet and multi-outlet rotating multi-cavity system of the typical small turbofan engine, which consists of cavities behind and in front of the fan disc, the front bearing chamber, and the cavity in front of the axial-flow disc. Result shows that under same calculation condition, the velocities of two models are similar; the pressures are slightly different only in cavity in front of the axial-flow disc, where the pressure of Eulerian model is 93% of the Mixture model; the temperature of Mixture model is higher, and the front and back bearing temperature of Eulerian model is 93% and 94% of Mixture model, respectively; Mixture model costs 63% of the time of Eulerian model in one iteration. © 2016, Editorial Department of Journal of Aerospace Power. All right reserved. Source


Wu B.,Nanjing University of Aeronautics and Astronautics | Wu B.,Institute of the Motor Industry | Huang J.-Q.,Nanjing University of Aeronautics and Astronautics | Huang J.-Q.,Collaborative Innovation Center for Advanced Aerospace Engine
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2016

Given that existing LPV(linear parameter varying) controller design methods is for affine system but not for polynomial LPV system, a self-scheduled control method based on SOS(sum of squares) programming was put forward for the high pressure rotor speed and pressure ratio controller design. The state-space models were obtained under different rotor speeds by non-linear model, and then these state-space models were used to get engine LPV model by polynomial fitting method. A self-scheduled control structure was proposed to ensure no static error. Combining bounded real theory with SOS theory, the robust stability conditions of the closed-loop system were obtained as SOS constraints, leading to the SOS programming to get gain scheduled controller. LPV model and engine nonlinear model were both used to examine the controller. Results show that the settling time of the high-pressure rotor speed/engine pressure ratio control system is less than 2 s, and the steady state error is less than 0.1 percent. © 2016, Editorial Department of Journal of Aerospace Power. All right reserved. Source


Lin K.,Northwestern Polytechnical University | Yan H.,Collaborative Innovation Center for Advanced Aerospace Engine
Procedia Engineering | Year: 2015

The plasma actuator can make difference in changing the vortex characteristics in supersonic shear layer, leading to mixing enhancement and noise reduction in the supersonic shear layer. Large Eddy Simulation is performed to investigate the effect of plasma actuator on supersonic shear layer, in which the plasma actuator is simplified as heat source. A Mach 1.3 supersonic flow over a backward-facing step with a groove placed upstream of the step is simulated first. Then the plasma actuators are placed inside the groove, and the effect of the plasma actuator is studied. Results show that the cases with heat sources have larger growth of shear layer and area-Averaged vorticity compared with the baseline case, and increasing the amplitude of the actuation is a more efficient way for mixing enhancement. © 2015 The Authors. Source

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