2000 Vol. 15, No. 3

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Display Method:
Calculation of off Design Performance of Multistage Compressors with Uniform and Radial Distorted Inlet Flow
Hu Jun
2000, 15(3): 225-228.
Abstract PDF(281KB) icon2171 icon453
Abstract:
A model to calculate axial flow compressor off design performance with uniform and radial distorted inlet flow is proposed,which takes into account variable specific heat and full radial equilibrium of the flow,including streamline curvature and radial gradients of total enthalpy and entropy.The efficiency is determined from a total pressure loss coefficient which is taken as the sum of a calculated reference loss coefficient and an off reference increment in loss coefficient.The correlated data are used for diffusion factors from 0 to 1 0 and Mach numbers from 0 to 1 6.The compression work or the total pressure ratio of a compressor is determined through the use of cascade element performance data concerning deviation angle.The model allows user to specify the mass flow at each blade row i.e.allows existence of flow bypass between two blade rows.Results for a five stage high speed compressor are analyzed in detail,and the comparison with the experimental data demonstrates that the model is reliable.
Calculation of off-Design Performance of Multistage Compressor with Circumferential Distorted Inlet Flow
Hu Jun
2000, 15(3): 229-232.
Abstract PDF(487KB) icon1745 icon424
Abstract:
A model is proposed to analyze the influence of inlet circumferential distortion on axial flow compressor off design performance.The model describes the flow fields in blade free sections using two dimensional,compressible unsteady Euler equations,and replaces each blade row of the multistage compressor with a compressible “actuator disk”.The axisymmetric characteristics of each blade row in the model is directly calculated with the help of same method as in the subsystem with uniform inlet flow.Thus there is no difficulty in the model to give the characteristics of each blade row of the compressor calculated.Attenuation of an inlet circumferential total pressure distortion through a five stage high speed compressor and it's influence on the compressor performance are analyzed in detail.The comparison of the analyzed results with the available experimental data demonstrates that the model is reliable.
Effects of Forward-Skewed Rotor on Boundary Layers
Liu Fubin, Du Chaohui, Zhong Fangyuan
2000, 15(3): 233-236.
Abstract PDF(288KB) icon1989 icon415
Abstract:
The momentum integral technique for predicting the boundary layer growth in three dimensional flow along the rotor chordwise has been developed.The aerodynamic characteristics of the forward skewed rotor and the straight rotor have been simulated,analyzed and compared at the off design regimes.The boundary layer thickness of the forward skewed rotor decreases in the top of blade due to reduction of the secondary flow loss.This fact conforms with experimental investigation.The conclusion that the forward skewed rotor has a higher efficiency and wider off design performance is validated once more.
A Study on Geometric Methods for Designing Supersonic Aerofoil of Axial Flow Compressor
Xiao Min, Liu Bo, Zhong Yongxing
2000, 15(3): 237-240.
Abstract PDF(336KB) icon1981 icon494
Abstract:
Three geometric methods for designing supersonic airfoil meanline are studied.The parameters which control curvature in the leading region of airfoil and their variations are considered.The flow fields of the cascade designed with these methods are analyzed.It is shown that the Mach number distribution of designed blade surface is ideal,shock wave structure is reasonable.But the exponential method is superior.
A Numerical Simulation of Turbine Stage with Tip Clearcance
Yan Ning, Zhang ZhenJia, Wang Songtao, Feng Guotai
2000, 15(3): 241-245.
Abstract PDF(375KB) icon1563 icon424
Abstract:
By using nonoverlapping domain method,a 3 D viscous code had been developed to calculate flow field in a cascade with tip clearance and craping along casing.A turbine stage of NASA is also simulated.The results show that the relative exit flow angle (and axial flow angle) is reduced by leakage flow on top of the rotor.As a result,the flow angle on top is underturned and its loading is reduced.The shock wave structure on top of the rotor becomes very complex and out of order due to interaction between the leakage flow and the shock wave.This out of order shock wave structure will bring high loss.
Effects of Front Guide Vanes on Exit Vortices in a Turbine Cascade
Han Wangjin, Gu Zhonghua, Lu Wencai, Zhou Xun, Wang Zhongqi
2000, 15(3): 246-250.
Abstract PDF(334KB) icon1399 icon478
Abstract:
The exit flow fields of a turbine cascade with or without the front guide vanes were investigated.The measured results show that the similar vortex structures are formed in these two cases,but the mechanisms of their formations are different.In addition,the amounts and distributions of the losses in the case with the front guide vane are also changed in comparison with those in the cascade without the front guide vanes.
Experimental Investigation of Turbulence Characteristics in a Turbine Vane Cascade
Dong Zhirui, Guo Tao, Zhu Huiren, Liu Songling
2000, 15(3): 251-254,259.
Abstract PDF(551KB) icon1969 icon450
Abstract:
The characteristics of turbulent flow in a high pressure turbine cascade were investigated experimentally.The mean velocity,fluctuating velocity and the correlation factor of Reynolds shear stress were measured by means of two dimensional hot wire,within the several pitch/streamwise planes.The test Reynolds number based on the incoming flow and the blade chord was 100000.The measured results were analyzed in conjunction with the flow fields mapped by using five hole probe.In result,the distribution of turbulence parameters in the passage of cascade was found.The experimental results show that the turbulent flow near the endwall of the turbine cascade is to be fairly isotropic.There are turbulence cores within the passage vortex and horseshoe vortex,in which the turbulence intensity and Reynolds shear stress are quite high.
The Effects of Structural Parameters on Sealing Performance of Magnetic Fluid Seal
Zhao Guowei, Chi Changqing, Wang Zhishan, Wang Guangzhen
2000, 15(3): 255-259.
Abstract PDF(315KB) icon1248 icon435
Abstract:
The effects of structural parameters on the performance of magnetic fluid seal are researched on the basis of magnetic field analysis.The parameters include seal gap,structural parameters of pole tooth,structural parameters of permanent magnet and the number of teeth on the pole.In the process of magnetic field analysis,magnetic field method and unequally spaced net finite difference method are used to obtain accurate data.A qualitative explanation to the data is given by magnetic circuit analysis.In order to testify the theoretical research,an optimized magnetic fluid seal has been designed and tested.The experiment results show that the weight and size of the optimized seal are reduced by more than 50 percent.
A New Multi-Grid Scheme for Radial Flow Inside a Centrifugal Compressor
Yi Tongxun, Jiang Yong, Zhang Xiaofeng, Suo Yisheng
2000, 15(3): 260-262.
Abstract PDF(237KB) icon1404 icon466
Abstract:
Under the elicitation of Professor Denton's effective research of turbomachinery CFD (Cambridge University of the United Kingdom),a new multiple grid scheme is put forward in combination with explicit time marching method,finite volume difference code and distributed body force (by Professor Denton) to calculate the internal flow field of H.Krain centrifugal impeller.The results show that the multi grid scheme greatly improves the converging speed and that the calculation results are consistent with the measurements
A Two-Dimensional Model of Thermal Energy Storage(TES) Canister for Space Power System
Xing Yuming, Hou Xinbin, Li Weifang, Yang Chunxin, Yuan Xiugan
2000, 15(3): 263-267,273.
Abstract PDF(404KB) icon1592 icon447
Abstract:
High temperature phase change heat storage using molten fluoride salts is one of the key techniques for space solar thermal dynamic power system.On the basis of heat conduction governing differential equation under micro gravity(microg),a two dimensional numerical analysis of PCM container has been completed using the enthalpy method.A novel void model has been developed and the previous simulation has been improved.
Heat Transfer in Translucent Thermal Barrier Coatings of Turbine Engine
Wang Pingyang, Tan Heping, Liu Linhua, Luo Jianfeng
2000, 15(3): 268-273.
Abstract PDF(544KB) icon2076 icon443
Abstract:
Some of thermal barrier materials for coating in aeroengine,such as zirconia and ceramic,are partially transparent to thermal radiation.So it is necessary to estimate quantitatively the radiation effect in the thermal analysis of turbine engine under high temperature.In this paper,various surface radiative characteristics are considered including opaque (with soot) and semitransparent (without soot) coating surfaces,specular and diffuse reflections.The radiative transfer coefficients of the absorbing and isotropic scattering coatings are derived by the ray tracing/node analysis method.The transient coupled radiative and conductive heat transfer in the coatings are numerically simulated by the radiative transfer coefficients in combination with the full implicit control volume method.The radiative properties of the coatings are modelled by two or four spectral bands.The analysis includes the effects of the opaque surface emissivity,the coating thickness,and the surface radiative characteristics on the temperature distributions and heat flux densities.
Numerical Simulation of Coolant Jet Structure in Turbine Cascade
Wang Songtao, Feng Guotai, Wang Zhongqi
2000, 15(3): 274-277.
Abstract PDF(295KB) icon1663 icon446
Abstract:
The structure of coolant jet from suction surface of turbine cascade was simulated with N S solver.Governing equation was discreted with third order Godunov scheme which has TVD property.The kidney shape vortex was generated gradually during the mixing process between coolant jet and main flow.The coolant jet bent to suction surface gradually due to the pressure gradient from pressure surface to suction surface.The dimension of kidney shape vortex increased while its strength decreased gradually during coolant jet development.A saddle point and horse shoe vortex were formed in the front of the hole because of the rigid body character of coolant jet near the hole.It is also testified that the kidney shape vortex disappeared in main flow instead of boundary surface under the condition of large coolant jet velocity.
Transient Heat Transfer Characteristics of Shrouded Rotating Disk with Unsteady Centric Air Inflow
Luo Xiang, Wang Jianning, Xu Guoqiang
2000, 15(3): 278-281.
Abstract PDF(272KB) icon1460 icon465
Abstract:
The transient heat transfer characteristics of a shrouded rotating disk were investigated experimentally as the mass flow rate was changed.The disk diameter was 400 mm and its maximum rotating speed was up to 300 r/min.The disk was heated at rim to simulate the heat conduction from turbine blades.One side of disk was cooled by air and another side was adiabatic.The temperatures of cooling side and heating side were measured synchronously at different time interval.The variation of averaged Nusselt number with non dimensionalized time was obtained.It was found that the averaged Nusselt number enlarged with the increase of inlet mass flow rate,but reached its steady state value rapidly after the change of mass flow rate.
Transient Heat Transfer Characteristics of Shrouded Rotating Disk with Variation of Rotating Speed
Luo Xiang, Wang Jianning, Xu Guoqiang
2000, 15(3): 282-285,290.
Abstract PDF(327KB) icon1806 icon450
Abstract:
A gas turbine disk was simplified to be a shrouded rotating disk system with central cooling air inflow,the disk was heated at rim.Transient heat transfer characteristics of the disk were investigated experimentally as the rotating speed was varied.The disk diameter was 400 mm and its maximus rotating speed was up to 3000 r/min.The results show that the rate of temperature vs time at large radium is greater than that at small radius.Averaged Nusselt number enlarges with the increase of Rotational Reynolds number.There are no significant difference in averaged Nusselt number between the stepwise abrupt variation and linear variation in the rotating speed.
The Effects of Tip End Ejection Area Ratio and Installation Angle on Heat Transfer of Orthogonally Rotating Rectangular Duct with Staggered Pin Fins
Ji Honghu, Wang Baoguan, Wang Daijun, Deng Huayu
2000, 15(3): 286-290.
Abstract PDF(325KB) icon1732 icon437
Abstract:
An experimental research was conducted on orthogonally rotating rectangular ducts with staggered pin fin array and radial outward throughflow,to determine the effects of the duct tip end ejection area ratio and installation angle on the heat transfer of the duct.In order to study the effect of ejection area ratio (the ratio of the tip end ejection area A 0 to the area of the cross section of the duct A) three models were used with A 0/A equal to 0.067,0.38 and 1.0 respectively.For the investigation of the effect of installation angle α,two models with α equal to 0 and 20 degree were tested.The effects of Reynolds number Re,rotation number Ro and other relevant parameters on heat transfer were also investigated.
A New Stress-Rupture Equation with High Reliability and Confidence
Zhang Shaobo, Fu Huimin
2000, 15(3): 291-294.
Abstract PDF(478KB) icon1474 icon439
Abstract:
The stress rupture equation with high reliability is an important basis in the design of the mechanism working in high temperature environment.But the stress rupture equations with high reliability and confidence obtained by using the traditional method can not satisfy the specified reliability and confidence.So the creep rupture strength and creep life predicted is overestimated.Therefore,a new stress rupture equation with high reliability and confidence is derived,which overcomes the shortcomings in the current method.This equation can accurately predicted the creep rupture strength and creep life with high reliability and confidence.
Estimation of response Power Spectrum of Panel Structure under Acoustic Loads
Cao Maoguo, Li Lin
2000, 15(3): 295-297,302.
Abstract PDF(267KB) icon1903 icon497
Abstract:
An estimation of the response of panel structure under acoustic loads is based on the linear vibration theory and research of the dynamic response of panel structure.The joint acceptance has been used to consider the relative effect between the acoustic wavelength and the structure modal wavelength.The method is able not only for a single panel but also for complexity panel structure.This method is based on modal analysis,and the contribution of each modal is taken into account.The coupling degree between acoustic wave length and structure modal wavelength is considered,finally the total response spectrum of panel structure has been obtained.
Data Communication Model and Its Application in Object-Oriented Areoengine Simulation System
Tang Hailong, Zhang Jing
2000, 15(3): 298-302.
Abstract PDF(415KB) icon1652 icon452
Abstract:
A new concept “port dictionaries” is proposed,based on the analysis of the areoengine simulation theory and common used data shared models in aeroengine simulation programs.Several data communication models are analyzed and their advantages and disadvantages are compared.The results indicate that the areoengine simulation system built on the two port/connector model with the induction of port dictionaries is superior in logical clarity,enhances reliability and extensibility.
A Model of Fault System Description for Automatic Reliability Analysis
Song Zhiping, Li Yinghong
2000, 15(3): 303-306.
Abstract PDF(260KB) icon1923 icon448
Abstract:
In order to analyze the systematic reliability automatically,a model of fault transfer table for describing fault system is developed in two aspects:(1)the format of fault transfer table is improved obviously;(2)the energy flow fault class is put forward so as to supplement the fault transfer table.Using this ameliorated model,multi mode and complicated fault conjunctions can be described expediently.This model has been applied to fault description of an aeroengine hydraulic mechanical control system,and the fault tree has been built automatically,in result a success has been reached.
Gas Turbine Simulation Integration and its Distributed Object Implementation
Xie Zhiwu, Su Ming, Weng Shilie
2000, 15(3): 307-310.
Abstract PDF(205KB) icon1687 icon468
Abstract:
In order to systematically, rather than analytically investigate the interdisciplinary phenomenon during the engine's life cycle,the concept of gas turbine simulation integration is proposed.The technological obstacles in its realizeation are identified.Then a prototype distributed object implementation is presented from the viewpoint of the cross platform attribute of the simulation integration.For engine overall performance simulation based on its components' performance on a heterogeneous distributed computing platform,the IEEE standard for distributed object computing,CORBA,is conformed throughout the implementation.The implementation is tested on a network environment consisting of 3 Pentium Ⅱ PCs and 1 SUN Ultra 1 workstation interconnected through a LAN.The functionality of simulation integration is fully verified and various simulation results of different configurations are presented and analyzed.It is concluded that,without real time support,the above implementation can only be used in interdisciplinary researches not requiring any real time capabilities.Some potential applications of the implementation,including remote collaborative engine design and simulation,are also proposed.
Application of Fuzzy Petri Net in Fault Diagnosis of Gas Turbine
Huang Xiaoguang, Gao Meimei, Wang Yonghong, Weng Shilie
2000, 15(3): 311-313.
Abstract PDF(360KB) icon1558 icon471
Abstract:
This paper presents a fuzzy Petri net modal (FPN) to represent the fuzzy production rules of a rule base system.Based on the fuzzy Petri net modal,an efficient fault diagnostic reasoning algorithm is proposed.Its accuracy and feasibility in a gas turbine diagnosis system is verified.
Experimental Investigation on AVEN Wall Static Pressure Distributions
Jin Jie, Zhao Jingyun, Zhang Mingheng, Lai Chuanxing
2000, 15(3): 314-316.
Abstract PDF(219KB) icon2138 icon480
Abstract:
An experimental investigation has been conducted with a scale model to determine the wall static pressure distributions of an axisymmetric vectoring thrust nozzle (AVEN) with different nozzle pressure ratios (NPR).The results indicate that the internal flow characteristics is complex 3 Dimensional in convergent and divergent sections at flow vectoring,and the shock waves as well as flow separations appear non symmetrical and vary with the geometric vector angle while the NPR was less than design pressure ratio.
Spray and Combustion Investigation of Gas/Liquid Coaxial Injectors
Sun Jiguo, Tian Changyi, Cheng Shengqing, Wang Jue, Zhou Jin, Wang Zhenguo
2000, 15(3): 317-320.
Abstract PDF(424KB) icon1980 icon486
Abstract:
Cold flow spray tests utilizing water and air to imitate gas and liquid oxygen in subcritical conditions and firing tests using liquid oxygen and gas in supercritical pressure for coaxial injectors have been done.Cold spray characteristics are investigated,such as flow rate,atomization and mixing,influences of gas and liquid on these characteristics,and combustion performance of coaxial injectors at supercritical pressures are completed.The strong and weak points of four coaxial injectors are obtained from these cold and firing tests.
Influence of Inlet Conditions on Thrust and Specific Impulse of Solid Fuel Ramjet
Tan Jianguo, Chen Xiaoqian, Zhang Weihua, Yang Tao
2000, 15(3): 321-324.
Abstract PDF(278KB) icon1913 icon460
Abstract:
The relations of thrust and specific impulse to inlet air flow and temperature are derived from theoretical analysis of solid fuel ramjet (SFRJ) performance.Then numerical simulation of the SFRJ performance is completed with these relations and the results show that the thrust increases with the inlet air flow and specific impulse also increases,but the rate of increasing slows down as the flow increases.When inlet air temperature rises,the thrust increases but the specific impulse decreases.However,the influence of the inlet air flow is greater than that of the air temperature and reasons for both of the influences are also discussed qualitatively.
A Finite Element Method for Thermal Transient Response of Structure
Wu Hengan, Liang Haiyi, Wang Xiuxi
2000, 15(3): 325-327.
Abstract PDF(360KB) icon1894 icon487
Abstract:
Traditional thermal stresses analyses consider thermal load as static load or quasi static load.When the temperature field of the structure varies drastically,these analyses can not satisfy the real need.A finite element method is presented for solving the response of structure under dynamic thermal load (including thermal impulse).A numerical example verifies the feasibility and validity of the presented method.
Incompletely Decoupled Adaptive Control in Aeroengine System
Fan Ding, Liang Chunyan
2000, 15(3): 328-330.
Abstract PDF(205KB) icon1736 icon487
Abstract:
An incompletely decoupled model reference adaptive control method is proposed for aeroengine binary control system.A new adaptive control method is applied to every incompletely decoupled subsystem,then remains of coupling and nonlinear influence can be resolved by adaptive principle robustness.This binary decoupled adaptive controller can diminish the coupling gradually and has excellent robustness to model uncertainty and external disturbances.Simulation results demonstrate the effectiveness of the incompletely decoupled adaptive controller.
The Design of Aero-engine Optimal Controller Suitable for All Flight Envelope with Neural Network Approximator
Zhang Hong, Yang Yunbo, Guo Yinqing
2000, 15(3): 331-333.
Abstract PDF(216KB) icon1946 icon404
Abstract:
An aero engine optimal control scheme is presented,which is suitable for all points in the engine whole flight envelope with a neural network approximator.Firstly,local controllers are designed according to local linear models around some design points.Then a neural network approximator is trained to imitate the relation between the parameters of local optimal controllers and the flight conditions and the states of the engine.Finally,a global nonlinear controller is obtained with this approximator.In this approach,nonlinear control system can be designed by the use of many mature linear control methods.And the control system has simple structure,is easy of real time realization.The simulation results show that the aero engine control system has excellent characteristics in both design and non design points in whole flight envelope.
Adaptive Neural Network PID Control for an Aeroengine
Jiang Yanjun, Huang Jinquan
2000, 15(3): 334-336.
Abstract PDF(420KB) icon1874 icon459
Abstract:
A multivariable adaptive neural network PID control scheme is proposed for a turbofan engine.The parameters of the controller are adjusted by on line conjugate gradient method.The precise model of the engine is not necessary for the design of the control system.The designed controller has many advantages such as fast response,strong interference free ability and good robustness.The control algorithm is simple,easy to realize and adaptable to full flight envelope.

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