Jiang C.-H.,Beihang University |
Jiang C.-H.,Shenyang Aeroengine Research Institute
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2011
A concept of dual-redundant control law design for aero-engine was proposed and a method of utilizing dual-redundant control law for the control sensors signal fault processing policy was derived in the paper. The technique and principles of the backup control law design were built and applied to the dual-redundant control law design and research of one high performance turbofan engine. The study result indicates that the dual-redundant control law can be made undisturbed conversion and control loop reconfiguration, so that mission reliability of engine is improved. The means may have application in all kinds of engine which is equipped with digital electronic control system.
Liu G.,Harbin Engineering University |
Li S.,Harbin Engineering University |
Li Y.,China Ship Development And Design Center |
Chen H.,Shenyang Aeroengine Research Institute
Journal of Sound and Vibration | Year: 2013
Branched pipes of arbitrary shapes are prevalent in pipe systems. Considering fluid-structure interaction (FSI), an absorbing transfer matrix method in frequency domain for fluid-filled pipelines with any branched pipes is proposed in this paper. A dominant chain of pipeline would be selected, and the point transfer matrix of each junction on the dominant chain would be determined. Here, the point transfer matrix, representing the influence of branched pipes at the junction on the dominant pipeline, was "absorbed" by the dominant chain. Based on these, with transfer matrixes of other elements, the fluid and structure dynamics problem could be solved following the chain transfer matrix method process. Several numerical examples with different constraints are presented to illustrate the application of the proposed method. Moreover, the experiment of cross-shaped pipes with various boundary conditions was carried out. And results from the present approach were validated by measured and numerical data. Then, the forced vibrations of branched pipes were analyzed by considering the effects of various parameters, which shows the fluid pressure and vibrations can be optimized by changing the branch angles and positions. Through these examples, it is shown that the proposed method is efficient and can be used to calculate branched pipes of any shape. © 2013 Elsevier Ltd.
Zhang W.,Beihang University |
Zou Z.,Beihang University |
Qi L.,Beihang University |
Ye J.,Chongqing University |
Wang L.,Shenyang Aeroengine Research Institute
Computers and Fluids | Year: 2015
The effects of inlet freestream turbulence intensity (FSTI) on aerodynamic performance as well as temporal and spatial evolution of coherent structures in separated shear layers are investigated in this paper. Large-eddy simulations (LES) are performed on the T106D-EIZ profile at Reynolds number (Re) of 60,154 (based on the chord and outflow velocity). Four cases are conducted on the conditions without upstream wakes but with FSTI of 0, 2.5%, 5.0% and 10.0% respectively. The results show that the open separations cannot be removed in these working conditions, but could be compressed by FSTI to a certain extent. Meanwhile, the coherent structures in separated shear layers are affected remarkably. The obvious three-dimensional perturbations appear earlier in separated shear layers as FSTI enhanced, which make the spanwise vortices roll up earlier and break down more quickly, therefore, the vortex pairing cannot occur even under relatively low FSTI conditions. The cases in this paper state clearly that the effects of FSTI are more prominent when it is lower than 5%. It is also found that the enhanced FSTI can increase the instability Strouhal numbers of separated shear layers. Nevertheless, the values of the instability Strouhal numbers are still within the typical level. © 2014 Elsevier Ltd.
Shao W.-R.,Beihang University |
Shao W.-R.,Shenyang Aeroengine Research Institute
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2012
The numerical simulation on convergent flap length, nozzle throat arc radius, divergent flap length and nozzle expansion ratio affecting the internal performance of an axisymmetric convergent-divergent nozzle was conducted by applying a three-dimensional(3-D) viscous flow program that the results of the simulation were compared with that of the scale model experiments. The investigation shows that: convergent flap length and nozzle throat arc radius have some effects on the flow coefficient under the condition of a big convergent half angle, and convergent flap length can be properly reduced on condition that convergent half angle is less than 45 degrees; divergent flap length and nozzle expansion ratio have big effect on the thrust coefficient, and selected divergent flap length and nozzle expansion ratio shall work hard for fully expanded nozzle flow on condition that divergent half angle is less than 16 degrees.
Sun X.,Beihang University |
Liu X.,Beihang University |
Hou R.,Shenyang Aeroengine Research Institute |
Sun D.,Beihang University
AIAA Journal | Year: 2013
A general eigenvalue theory on flow stability in turbomachinery is proposed with the emphasis on flow-instability onset. Based on this theory, a stall-inception model including the effects of complex solid geometry is developed for a multistage fan/compressors system. The capacity of the present model to predict the stall-inception point is assessed against experimental data of both a low-speed and transonic single rotor. Comparisons with a simplified two-dimensional model are performed to identify the nonnegligible effects of spanwise distribution of flowfield in a general configuration on the unstable mode of the concerned fan/compressors. It is verified that this model is capable of predicting mass flow at the stall-onset point of both subsonic and transonic flow with a reasonable accuracy, and it is sustainable in terms of computation cost for industrial application. Copyright © 2013 by Christopher Porter, R. Mark Rennie, Eric J. Jumper.
Zhang L.,Shenyang Aeroengine Research Institute |
Hong J.,Beihang University |
Ma Y.,Beihang University
Beijing Hangkong Hangtian Daxue Xuebao/Journal of Beijing University of Aeronautics and Astronautics | Year: 2013
According to the structural and mechanical properties of rotor system on the modern turbofan engine, an investigation about the finite element modeling technology and dynamic characteristics of low-pressure rotor was proposed, based on the finite element method (FEM). The finite element model of rotor system was developed by 2D beam element and 3D solid element separately and the dynamic characteristics were analyzed. Then a principle of finite element modeling, which is called equivalent-disk method, was presented. The equivalent-disk method regards the blades of rotor system as a rigid ring and changes the periodic model into axisymmetric model, which is favorable for FEM software in solving. It can not only keep the structural and mechanical properties of rotor system, but also control the scale of FEM model. The result indicates that this kind of equivalent method can improve the modeling techniques of rotor system on the turbofan engine and it is applicable in engineering.
Zheng K.,Shenyang Aeroengine Research Institute
Applied Mechanics and Materials | Year: 2014
Active magnetic bearing (AMB) is a prime component of the more electric aircraft technology that aims at reducing weight and emissions, and augmenting reliability and efficiency for future aircraft. The effect of maneuvering flight on performance of AMB system is investigated. A mathematical model considering maneuver equivalent force is presented and based on the model stability analysis is presented in terms of asymptotical and regional stability. The research result indicts that maneuvering flight has a great influence on system dynamics and stability. © (2014) Trans Tech Publications, Switzerland.
Chen G.,Nanjing University of Aeronautics and Astronautics |
Li C.G.,Shenyang Aeroengine Research Institute |
Wang D.Y.,Shenyang Aeroengine Research Institute
Journal of Engineering for Gas Turbines and Power | Year: 2010
In this paper, a new rotor-ball bearings-support-stator coupling system dynamic model with rubbing coupling faults is established for practical aeroengine. In the model, the rubbing fault is modeled, the stator motion is considered, the flexible support and squeeze film damper are established, and the nonlinear factors of ball bearing, such as the clearance of the bearing, the nonlinear Hertzian contact force between balls and races, and the varying compliance vibration because of the periodical variety of the contact position between balls and races, are modeled. The numerical integral method is used to obtain the system responses, the effect of support stiffness on rotor responses is studied using a vibration amplitude-rotating speed plot, and the characteristics of the rubbing fault is analyzed using a 3D cascade plot. An aeroengine tester with a stator is established to carry out the rubbing fault experiments, the simulation results from the rotorball bearings-support-stator coupling model are compared with the experimental results, and the consistency of the results show fully the effectiveness of the new rotor-ball bearings-support-stator coupling model with rubbing fault. © 2010 by ASME.
Kai Z.,Shenyang Aeroengine Research Institute
50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference 2014 | Year: 2014
Active magnetic bearing (AMB) is a prime component of the more electric aircraft technology that aims at reducing weight and emissions, and augmenting reliability and efficiency for future aircraft. However, maneuvering flight of the aircraft will introduce great disturbance to control system, which will deteriorate its performance and even cause instability. In this paper, a mathematical model considering maneuver equivalent force is presented and based on the model a feedforward L∞-gain controller to compensate the effect of maneuver flight on the AMB-rotor system. Finally, the effectiveness of the proposed controller is verified by numerical simulations. © 2014 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
Gao S.,Shenyang Aeroengine Research Institute |
Zhang J.,Nanjing University of Aeronautics and Astronautics |
Tan X.,Nanjing University of Aeronautics and Astronautics
Science China Technological Sciences | Year: 2012
Experimental investigation was conducted to investigate the impingement heat transfer performance of a synthetic jet driven by piston actuator on a constant heat flux surface. Effects of jet formation frequency, nozzle-to-surface spacing ratio and conjugation of cross flow were considered. The synthetic jet is of stronger penetration and heat transfer capacity when the piston reciprocates at relatively high frequency. Similar to the continuous jet impingement, nozzle-to-surface spacing ratio plays an important role in the heat transfer enhancement of synthetic jet. The optimum nozzle-to-surface spacing ratio corresponding to maximum heat transfer enhancement is considerably high in the synthetic jet, as compared to that in a continuous jet, which indicates that the synthetic jet introduces a stronger entrainment and more vigorous penetration in the surrounding fluid. The convective heat transfer capacity is enhanced significantly under the conjugate action of a synthetic jet and cross flow in comparison with their individual action. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.