1990 Vol. 5, No. 1

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AN INVESTIGATION ON FILM-COOLING FROM TWO-STAGGERED ROWS OF HOLES ——(1)HEAT TRANSFER COEFFICLENTS
Zhang Mingyuan, Chen Xuejun, Zou FuKang, Ge Shaoyan, Chen ShiJun
1990, 5(1): 1-5,89.
Abstract PDF(361KB) icon1615 icon418
Abstract:
The film cooling performance downstream of injection from two staggered rows of holes were investigated in a Ludwieg tube wind tunnel.For the first time,heat transfer measurements were conducted in both streamwise and spanwise directions in a short duration flow facility.The details of wall temperature and heat transfer coefficient in region close to injection holes have been were obtained.
AN INVESTIGATION ON FILM-COOLING FROM TWO-STAGGERED ROWS OF HOLES ——(2)EFFECTIVENESS
Zhang Mingyuan, Chen Xuejun, Zou Fu Kang, Ge Shaoyan, Xu Jingzhong, Chen ShiJun
1990, 5(1): 6-10,89.
Abstract PDF(355KB) icon1508 icon498
Abstract:
The experimental results and numerical computation of film cooling effectiveness downstream of injection from two staggered rows of holes are presented in this paper.On the basis of measured effectiveness in both streamwise and spanwise directions,especially in the region close to injection holes,the different heat transfer behaviors of the jets from upstream and downstream rows are analyzed.In the computation,a three dimensional calculation procedure is used to solve the related elliptic equations and the results agree well with present measurements far downstream.The discrepancies are increased in the near injection region.
PREDICTION FOR FLOW AND HEAT TRANSFER OF IMPINGEMENT IN A SEMICIRCULAR CLOSURE
Zhu Gujun, Qiu Xuguang, Chen Zhongjun
1990, 5(1): 11-14,89-90.
Abstract PDF(356KB) icon1195 icon467
Abstract:
Calculation for two dimensional flow and heat transfer of impingement in a semicircular closure has been completed with a Finite Element Method.It is found that the impinging flow in closure is much different from the impingement in free space.Except the circulations on the two sides of inlet nearby the inner wall,it is possible to induce two contrary circulations nearby the out wall in down stream.The effects of the currents on isotherm and heat transfer are given graphically.
EXPERIMENTAL STUDY OF FLAME EXTINCTION CHARACTERISTICS FOR A GAS TURBINE COMBUSTOR BURNING LOW BTU GAS
Jiao Shujian, Zhu Xuelei
1990, 5(1): 15-20,90.
Abstract PDF(375KB) icon1657 icon489
Abstract:
For developing the Integral Gasification Combined Cycle in China,Gas turbine combustors would have to burn a variety of coal derived low Btu gases.A worse flame extinction characteristic is one of weakness of these gases,especially used in the case of gas turbine.In this paper,a series of experimental studies of flame extinction characteristics have been completed for a gas turbine combustor from a Aero gas turbine modifier with two different kinds of air swirlers,fuel gas injectors and flame liners.the effects of such geometrical factors on flame stability have been obtained obviously ,which are useful in designing gas turbine combustors burning such low Btu gases.
PREDICTION OF HEAT TRANSFER COEFFICIENT ON TURBINE BLADE PROFILES
Wu Dingyi, Liu Songling
1990, 5(1): 21-25,90.
Abstract PDF(346KB) icon1859 icon451
Abstract:
Several problems involved in the prediction of heat transfer coefficient on the turbine blade profiles without film cooling are studied in this paper for the purpose of improving the accuracy.These problems are:heat transfer in the vicinity of stagnation point,the location of boundary layer transition,heat transfer of transitional boundary layer and the influence of free stream turbulence intensity.Cebeci Smith method is used to solve the boundary layer equations obtaining the similar solution in the vicinity of stagnation point.It is assumed that the free stream velocities near the leading edge of a blade can approximately be expressed as that for a cylinder,the radius of which equals to that of leading edge circle or to the radius of a“equivalent cylinder”,the solution obtained by this method in the vicinity of stagnation point is used as a initial profiles of velocity and enthalpy for the computation of boundary layer along the blade surface.STANS [9] with some modifications is used to calculate heat transfer coefficient on the rest part of the blade surface.Transition origin and transition length are predicted by using the models suggested by Seyb [5] and Dhawn at el. [12] respectively.In order to take the free stream turbulence intensities into account,a turbulence viscosity is introdued as a part of effective viscosity of the fluid.Several numerical examples obtained by the proposed method in this paper indicate better agreement with the experimental data than by original STAN 5.
CALCULATION FOR EVAPORATION OF AEROKEROSENE PROPLET
Li Ruhui, Zhang Zhentang, Dong Yaode
1990, 5(1): 26-28,94.
Abstract PDF(258KB) icon1547 icon515
Abstract:
This paper discribes a new method for calculating the evaporation history of a droplet of multicomponent fuel.In this method kerosene is treated as a multicomponent fuel posed of ten fictitious components.The calculation is done by applying configuration of Kerosene Distillation.Also a new method is introduced to find the physical properties of the fictitious components.Finally,the methed is developed to calculate the evaporation history of a multicomponent liquid droplet by means of the evaporation equations.It is a more reliable and practical method than that used before.Some computational results are presented for three kinds of Chinese Aviation Kerosene,and compared to data obtained from our experiments favourably.
THE EFFECT OF SWIRLER ON SHORT REVERSAL-FLOW ANNULAR COMBUSTOR
Hong Yan
1990, 5(1): 29-31,94.
Abstract PDF(240KB) icon1732 icon433
Abstract:
A short reversal flow annular combustor has been tested with three different flame liner heads.The gas parameters of exit section are detected by a turning measuring system,and data are processed by a PC 8001 microcomputer.Experimental results of efficiency,temperature field of exit section,flame stabilization and pressure loss are presented.The effect of a swirler on the short reversal flow annular combustor is illustrated by comparison and analysis.The experimental study shows that it is suitable to install a swirler on the flame liner head in a short reversal flow annular combustor.This method can improve the combustor performance greatly.However,it should be noted that when a swirler is installed ,its direction angle ought not to be too big,other wise,as a result,carbon deposit will emerge,the swirler will give a negative effect on the combustor.
RESEARCH ON EVAPORATION PERFORMANCE FOR FUEL SPRAY VAPORIZER
Jiang Yijun
1990, 5(1): 32-34,94-95.
Abstract PDF(303KB) icon1581 icon448
Abstract:
A way to construct a clean combustor with high performance and low contamination is proposed by means of installation with beforehand mixing and evaporating.Direct measurement or accurate calculation of the evaporation rate in the evaporation installation is very difficult. According to energy relation,calculation is made based on the quasi steady state evaporation model at the angle of engineering use.The concept of greatest evaporation rate of fuel in the evaporating installation is presented,and the effect of some primary factors is analysed.The calculated results are compared with test data.
STUDY ON TRAVELLING WAVE VIBRATION OF BLADED DISKS IN TURBOMACHINERY
Yan Litang
1990, 5(1): 35-38,91.
Abstract PDF(307KB) icon1307 icon414
Abstract:
The exciting sources for axial vibration of disk,especially the new axial gas dynamic force induced by travelling waves and its properties,and influence on the vibration of disks are studied.It is shown that the travelling wave induces new gasdynamic force which can damp out the foreward traveling wave vibration and induces the self exciting vibration for the backward travelling wave vibration.Because it is unavoidable that various distributed stationary forces act on the disk,the resonance in company with the self exciting stationary wave vibrations is excited during the critical speeds of disk.The resonance,in essentials the self exciting vibration,is the reason for dangerous stationary wave vibration.This is a new conception.The equation for calculating the instabitity of the stationary wave vibration of the disk is also given in the paper.
ENERGY DAMAGE THEORY OF THERMO-FATIGUE AND CREEP LIFE
Xiong Changbing
1990, 5(1): 39-42,91.
Abstract PDF(314KB) icon1643 icon420
Abstract:
A new life prediction method of temperature and load damage for high temperature components of engine is presented.In consideration of the interaction between thermo fatigue and creep,the new method includes the damage summation of elastic energy,plastic energy and creep energy of material.The precise finite element method of thermal elastic plastic creep conditions is used to solve the correlation of maltiple physical parameters of material (stress,strain,Young ′s modulus,thermal expansive coefficient,yield limit,plastic hardering exponent,creep hardering exponent,etc,) with temperature effect.In the new method the correction can be made according to the changes of temperature and time,so that it expands the applicable area of general damage mechanics.This paper makes reference to the experimental results of famous“Strain Range Partitioning (SRP)”and“Strain Energy Partitioning (SEP)”methods.The calculated results by the presented method locate between the experimental results of SRP and SEP methods.The new method has the advantages in clearness of physical concept,convenience of calculation and wide range for application.It is satifactory for engineering practice in life prediction of high temperature components.
RELIABILITY ANALYSIS OF DIRECTIONALLY-SOLIDIFIED TURBINE BLADE
Lu Wenlin, Duan Zhenlong
1990, 5(1): 43-47,91.
Abstract PDF(352KB) icon1805 icon425
Abstract:
This paper is based on stress analysis of directionally solidified turbine blade with the Finite Element Method.The reliability analysis method with a simple failure model is proposed.The failure function is established by Hill Criterion.The second order moment method and Hasofer Lind method for multiple random variables and nonlinear failure function are used to find the failure point and reliability of the failure model.The methods are checked by Monte Carlo method.
GEAR VIBRATION CONTROL WITH VISCOELASTIC DAMPING MATERIAL IN AEROENGINE
Ren Xingmin, Xu Ming, Gu Jialiu
1990, 5(1): 48-52,92.
Abstract PDF(343KB) icon1635 icon398
Abstract:
A research on gear vibration control with viscoelastic damping material has been completed.A technique for determining the optimum damping material distribution for some particular modes of vibration has been developed.The damping work expressions have been set up by modal analysis,and the optimum damping material distribution has been obtained by calculating the individual mode of the structural.The proposed method features:firstly,it takes into account the influence of loading frequency and the environment temperature;secondly,it cuts down computer time.The experiments have been done for the gear model without and with the damping material.The results show that the response of the gear with the damping material is decreased and the damping ratios are increased.It is also testified that the results of the vibration control are satisfactory.
THE BEHAVIOR OF MAIN BISTABLE OPERATION IN FLEXIBLE ROTOR-SQUEEZE FILM DAMPER SYSTEM WITH CENTRALIZING SPRINGS
Zhu Changsheng
1990, 5(1): 53-56,92.
Abstract PDF(298KB) icon1648 icon404
Abstract:
Based on theoretical analyses and experiments of flexible rotor squeeze film damper system with centralizing springs,this paper presents the investigation of the main resonant bistable operation occurred near the main resonant speed of the system,and deals with the regularity of occurence of the bistable operation and the influence of system parameters on the behaviors of the bistable operation.The calculated results and the experimental data are in a good agreement.It is found that the main resonant bistable operation is characterized by the sudden change of rotor vibration amplitude and by the transposition disc mass center.The reasons of the difference between theoretical analyses and experiments are discussed.
TECHNIQUE OF VARYING-LIP SIMULATING TOTAL PRESSURE DISTORTED FLOW FIELD
Chen Xiao, Mao Jian
1990, 5(1): 57-64,92-93.
Abstract PDF(525KB) icon1907 icon395
Abstract:
A technique of vaying lip simulating total pressure distorted flow field has been investigated experimentally.The effects of the various geometric parameters of the lip on the total pressure distribution and the turbulence of the total pressure fluctuation are analysed,some rules have been obatined.The relations of the total pressure recovery and the mean turbulence to the mean Mach number for the axisymmetrical lip of various shapes are also presented.Therefrom the approach and the concept for simulating the real total pressure distorted flow field are deduced.Moreover,two kinds of the real total pressure distorted flow fields are simulated.
A NUMERICAL CALCULATION OF TURBULENT FLOW IN GENERAL NON-ORTHOGONAL CURVILINEAR COORDINATE SYSTEM
Li Yiguang, Yan Chuanjun, Wang Hongji
1990, 5(1): 65-68,93.
Abstract PDF(314KB) icon1680 icon379
Abstract:
The expressions of the governing equations of turbulent flow with contravariant physical velocity components in a general non orthogonal curvilinear coordinate system are derived by means of tensor theory.A numerical method and a computer program for turbulent recirculating flow in the general non orthogonal curvilinear coordinate system are developed.Since the velocity and the displacement vectors are decomposed into their contravariant components,the method has the main advantages of its obviousness in physical meanings,easiness in treatment of boundary conditions and the suitability to the numerical calculations of turbulent flow in various complex geometries.The flow fields in some kinds of complex geometries are calculated.
THEORETICAL RESEARCH ON THE RESPONSE OF AN AXIAL COMPRESSOR TO INLET PERIODIC DYNAMIC DISTORTION
Feng Qi, Zhuang Huimin
1990, 5(1): 69-73,93.
Abstract PDF(342KB) icon1519 icon417
Abstract:
A flow model of flow field is formulated for axial compressors under periodic dynamic distortion.The frequency response of the flow field model is analysed.A computer program for problems of various types of periodic dynamic distortion has been written according to the flow field model and the numerical method.The flow fields of a two stage L.P.compressor under inlet total pressure periodic dynamic distortion were simulated.The results of computation and experiments are shown in good agreement either in the amplitude or in phase of total pressure fluctuation.The characteristics of propagation of dynamic distortion through the compressor are analysed,sensitivity of compressor to some frequency is found according to the results of computation.
EXPERIMENTAL RESEARCH ON THE RESPONSE OF AN AXIAL COMPRESSOR TO INLET PERIODIC DYNAMIC DISTORTION
Feng Qi, Zhuang Huimin
1990, 5(1): 74-75,95.
Abstract PDF(208KB) icon1464 icon370
Abstract:
A pitot pressure pulsation generator and a data acquisition and processing system have been built up for this research.The response of a low pressure compressor to two kinds of inlet dynamic flow modes (axisymmetric or distorted) are investigated under the conditions of the compressor with or without a plenum.The results show that there is a sensitive frequency at which the perturbation is amplified through the compressor.The sensitive frequency is influenced not by inlet distortion,but by the plenum in the present research.
A DESIGN OF A TWIN VARIABLE CONTROL SYSTEM FOR AERO-TURBOJET ENGINE
Zhang Jiazheng, Hua Kai, Guo Yingqing, Liu Fang
1990, 5(1): 76-78,95.
Abstract PDF(253KB) icon1991 icon397
Abstract:
Under twin variable control with the equal low compressor speed and equal low turbine exit temperature,the twin spool turbojet can obtain higher power performance.In this paper,firstly,the engine dynamic model with two inputs and two outputs is deduced.Then with the aid of LQR theory,the optical regulator of twin variable control system is designed,and the approaches for processing some problems existed in the design process are recommanded.Finally,the control system designed in terms of optical method is simulated numerically.The results show that,in the condition of a state perturbantion on the system,the transient performance of the system recovered to original state is more satisfactory,and the variation of control mediators is in allowable limits of the controllers.
A NUMERICAL SOLUTION FOR INSTRUCTION TRACING PROBLEM
Zhang Linguan
1990, 5(1): 79-81,96.
Abstract PDF(233KB) icon1764 icon399
Abstract:
This paper describes a simple numerical solution for instruction tracing problem in the engine multivariable control system.In this method the instruction tracing problem turns into the regulator problem to be solved only by simple algebraic transformation,and the optimal feedback control can be obtained with the matrix Riccati equation.Besides,a practical example is presented in which the method is applied in the simulating an aeroengine control system.
DIGITAL ELECTRONIC CONTROL FOR WJ6G4A ENGINE
Tan Fengxiang, Chen Youbin
1990, 5(1): 82-84,96.
Abstract PDF(229KB) icon1658 icon422
Abstract:
This paper deals wirh the technical problems in developing a dual channel electronic control system JYZD-01 for a modified turboshaft aeroengine WJ6G4A which serves as a powerplant of a locomotive.All performance tests and cyclic duration tests of the WJ6G4A engine burning keroscne and heavy fuel have been done under control of the developed system.The measured data meet the design reguirements.
A COMPUTATIONAL APPROACH TO THE LOADS SHARED BETWEEN THE TEETH OF TURBINE LUGS
Sheng Yuansheng
1990, 5(1): 85-87,95.
Abstract PDF(250KB) icon1583 icon512
Abstract:
A displacement superposition method based on the principle of compatibility of deformation is approached for solving multi contact problems.The formulas derived in this paper has been programmed to solve the load distribution between the teeth of a turbine disk lugs in association with FEM program,and then the maximum stress at each fillet of tooth is calculated.A study on fracture mechanics of the disk lug with different cracks in the tooth fillet is also presented.The results are in satisfactory agreement with data of the photoelastical experiments.

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