1998 Vol. 13, No. 1

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AEROELASTIC TAILORING FOR ROTOR BLADES OF TRANSONIC SWEPT FANS
Zhou Sheng, Yuan Wei, Guo Enmin
1998, 13(1): 1-6.
Abstract PDF(932KB) icon1827 icon499
Abstract:
In order to raise the fan stage pressure,as an important measure to enhance engines thrust/weight ratio,there are two restrictive factors:First of all,the increase of rotor tip wheel speed will strengthen the shock waves in rotor passages,which decrease the efficiency.Then the strengthened shock waves could induce the onset of stall flutter.For the turbofans with small bypass ratio,the stall flutter is the main type of aeroelastic instabilities in the transonic fans.Both the above-mentioned two restrictive factors for raisng the stage pressure ratio are correlated closely with 3D shock wave structure and the largescale separation zone induced mainly by 3D interaction of the shock wave with boundary layer.However,the 3D shock wave structure inside rotor passages is correlated with the spatial curve of rotor blade leading edge closely.So,how to design the spatial curve of blade leading edge becomes an important frontier problem of the turbomachinery aerodynamics.During designing process of some modern transonic swept fans,a kind of integrated aerodynamic/aeroelastic tailoring program has been used.The aeroelastic tailoring,a main part of the integrated tailoring,is described,and an example has been shown in this paper.
A SURVEY ON APPLICATION OF CURVED BLADES TO COMPRESSOR CASCADE
Zhong jingjun, Su Jiexian, Wang Zhongqi
1998, 13(1): 7-12.
Abstract PDF(784KB) icon1739 icon815
Abstract:
Based on the mechanism of controlling the secondary flow with the help of the curved blades in turbomachinery,the specificities of application of the curved blades to the compressor cascade are considered.A survey on current situation of the research,practical application and prospects of the curved blades for compressor cascades is made according to the works published at home and abroad,as well as the results of our experimental investigations.
NUMERICAL SIMULATION OF 3D TRANSONIC VISCOUS FLOW STRUCTURE INSIDE A COMPRESSOR ROTOR WITH CONSIDERATION OF TIP CLEARANCE
Guo Yanhu, Wang Baoguo, Shen Mengyu
1998, 13(1): 13-18,104.
Abstract PDF(415KB) icon2246 icon463
Abstract:
A 3D numerical solution of transonic turbulent flowfield inside a compressor rotor is analyzed with a consideration of blade tip clearance.The complex vortex system structure and shock wave system structure inside this rotor is obtained.Wall flow patterns on the blade surface and hub surface are found out.The complex vortex system structure, such as horseshoe vortex,passage vortex,corner vortex and trailing vortex,and the interaction with shock wave system are researched.Especially,the character of the tip clearance flow inside the rotor passage is revealed,and the interaction between shock wave and tip clearance flow near blade tip and the evolution of tip clearance flow are considered.
APPLICATION OF A MULTI-DIMENSIONAL FLUX FUNCTION TO ANALYSIS OF PLANE TRANSONIC CASCADE FLOW
Yao Shilei, Wang Baoguo, Shen Mengyu
1998, 13(1): 19-22,104.
Abstract PDF(878KB) icon2059 icon428
Abstract:
In two-or three-dimensional flow fields,it is difficult to determine the direction of wave propagation in cascades due to complexity of transonic flow.Now a grid-independent approximate Riemann solver is applied to numerical simulation of two-dimensional transonic cascade flow by the Euler or Navier-Stokes equations.Fluxes on grid faces are obtained via wave decomposition,assuming that information propagates in the velocity difference directions,rather than in the grid-normal directions as in a standard grid-aligned solver.Second-order computations with the grid-independent flux function are used to analyze two typical examples of transonic cascades.The results indicate that the grid-independent model suppresses entropy production over the cascade surface due to either computational diffusion or grid viscosity,and resolves shock and shear waves in transonic flow of cascades much better.
AN EXPERIMENTAL INVESTIGATION ON TREATMENT OF COMPRESSOR CASING WITH SKEW GROOVES
Zhu Junqiang, Zhao Yi, Liu Zhiwei
1998, 13(1): 23-26,105.
Abstract PDF(334KB) icon1757 icon452
Abstract:
Five kinds of skew grooved cases with different geometric parameters were designed and tested on a rig of single stage axial-flow compressor.The detailed measurements of the overall performance and element performance,especially the blade tip flow prove that the treated casings enhance the compressor efficiency,but make slight loss of stall margin.According to analyzing the effects of each structural parameter on the compressor efficiency and stall margin,an optimization of primary geometric parameters has been found out.Then the effects of the grooved casing treatments on the performance of the compressor rotor have been revealed and some valuable conclusions have been reasoned out.
EXPERIMENTAL INVESTIGATION OF FISH SCALE PATTERNED CASCADE
Miao Runtian and, Wang Liangui, Gao Ge
1998, 13(1): 27-29,105.
Abstract PDF(238KB) icon1617 icon402
Abstract:
Several cascades with different patterns have been tested with the purpose of turbulence drag reduction in compressor cascade,after the straight patterned cascade obtained notable effects.The fish scale patterned cascade is the best of them.The main performance comparison is shown as follows: CascadeMa1cr△βdesignδdesign(P2/P1)2Dmaxξi=05°/%△ireference straight pattern fish scale pattern0685 0735 0750408° 417° 411°67° 58° 64°11810 11987 1212757609 34261 30610100° 104° 104° The above test data indicate that most of performance indices of the fish scale patterned cascade,such as critical Mach number Ma1cr,maximum two-dimensional static compression ratio (P2/P1)2Dmax and total pressure loss coefficient at maximum attack angle ξi=05° are improved over the straight patterned cascade.The other performance parameters,namely attack angle range △i,flow deflection angle at design point △βdesign and corresponding deviation angle at design point δdesign,are superior to the reference cascade as well.It is particularly worth to point out that the fish scale pattern and the straight pattern can be together applied to the same blade to obtain advantageous performance.
CYCLIC CREEP ANALYSIS OF TURBINE MONOCRYSTALLINE BLADE
Rao Shouqi and, Wu Bin, Meng Chunling
1998, 13(1): 30-32,106.
Abstract PDF(747KB) icon1941 icon431
Abstract:
Stress cycling creep and stress-thermal cycling creep of monocryctalline turbine blade have been analyzed.The results are compared with static creep.This work lays the theoretical foundation for understanding the behaviours of the cycling creeps at varying regimes.
MEASUREMENT OF THERMAL RESIDUAL STRESS IN THERMAL BARRIER COATING BY MEANS OF PHASE-SHIFT MOIRE INTERFEROMETRY
Shi Xuqing, Nie Jinxu, Zhang Xueren
1998, 13(1): 33-36,106.
Abstract PDF(305KB) icon1737 icon431
Abstract:
There are many difficulties in measuring thermal residual stress in thermal barrier coatings,because of their microstructure and microdeformation.Phase-shift moire interferometry is provided which can precisely measure the deformation of solid bodies under various loading conditions.The fundamental theory and experimental technology of the phase-shift moire image-processing technique are introduced.By combining it with relaxation method,a new technique for measuring thermal residual stress is proposed.With the aid of high temperature moire gratings,the distributions of thermal residual stresses in the EB-PVD(electronic beam-physic vapour deposition)coating has been measured,and compared with those other of methods.
ADAPTIVE RECTIFICATION OF PARAMETERS IN AEROENGINE SIMULATION MODEL
Xie Guanghua, Zeng Qingfu, Zhang Yandong
1998, 13(1): 37-40,106.
Abstract PDF(367KB) icon2221 icon550
Abstract:
An adaptive simulation model has been developed by means of modification factors.A modified conjugate gradient algorithm is employed for solving the nonlinear programming problem in the model.According to the parameter measurements of the engine on test rig and in flight,the component characteristics of the engine are rectified by the adaptive model,as a result,outputs of the model are in accordance with the measurements.As an example,the method provided was adopted to rectify the parameters in the simulation model of a given twin-spool reheated turbojet engine,and the simulation achieved satisfactory accuracy.
APPLICATION OF TWO-VARIABLE FUZZY PI CONTROL TO AEROENGINE CONTROL
Fang Zhongxiang, Huang Wanwei, Zhang Jiazhen, Wu Qihua, Chen Fuqun
1998, 13(1): 41-44,107.
Abstract PDF(701KB) icon1795 icon444
Abstract:
A two-variable fuzzy-PI control algorithm based on the fuzzy reasoning,and a two-variable self-stunning fuzzy control algorithm based on the fuzzy reasoning with four inputs are provided.Then a new two-variable fuzzy-PI controller and the two-variable selfstunning fuzzy controller with four inputs are developed.The attention is focused on the research of those algorithms and the properties of those controllers,as well as their application to aeroengine control by computer simulation.As a result,a new method of aeroengine control is provided.
AN ACCELERATION ADAPTIVE CONTROL FOR TURBOSHAFT ENGINE OF HELICOPTER
Hu Shimin and, Xu Dongsheng
1998, 13(1): 45-48,107.
Abstract PDF(293KB) icon1646 icon477
Abstract:
A scheme of an acceleration adaptive fuel control is put forward for helicopter turboshaft engine.The scheme is based on GG/P *2 closed loop control with adaptive control rule,which corrects the demand of og/P *2 closed loop control PID with surge flag detected by sensed compressor discharge pressure during the engine acceleration,since the engine performance deterioration or damage will initiate the surge in this time.This scheme also provides altitude compensation and surge recovery P *2.It requires only modifying a litte the hardware of an existing FADEC,but mainly the fuel control microcomputer software,so it is easy to upgrade an existing FADEC to the adaptive control level.
A THRUST-VECTORING NOZZLE MATH MODEL
Liu Xiaoyong, Fan Siqi, Chen Fuqun
1998, 13(1): 49-52,107.
Abstract PDF(292KB) icon1617 icon598
Abstract:
A thrust-vectoring nozzle modeling method is developed by means of the Finite Volume Method (FVM) and Back-Propagations neural networks.The neural networks learning samples are the results of the FVM computation.The obtained model describes the functions of the nozzle thrust,thrust coefficient and vectoring angle to the inlet,exit and structural parameters of the nozzle.The model is of great significance for reseaching vectoring nozzle control law and Integrated Flight/Propulsion control.The investigation shows that the deviations among the output of the model,the results of FVM computation,and the test data are quite small.
A GENERAL MODULAR METHOD FOR STATIC SIMULATION OF LIQUID ROCKET ENGINE
Huang Weidong, Zhu Hengwei, Wang Kechang, Chen Qizhi
1998, 13(1): 53-56,108.
Abstract PDF(295KB) icon2126 icon463
Abstract:
A new modular method is proposed for static simulation of liquid rocket engine.The modules of the engine system are calculated iteratively in a predetermined sequence,and a modified Newton method is used to find the unknown variables of the system.This method has generality for the static simulatin of liquid rocket engine,and it can be applied to analyzing the effects of the disturbances on the performance of the engine.The number of the system unknown variables can be cut down by using this method,and the solution can be found quickly and accurately.The program based on the method is realized by the object-oriented programming.The static simulation results of a liquid rocket engine are obtained from this program.
EFFECTS OF AIR COOLANT INJECTION ON CASCADE SURFACE PRESSURE DISTRIBUTION
Chen Fu, Yang Hong, Gong Cunzhong, Feng Guotai, Wang Zhongqi
1998, 13(1): 57-60,108.
Abstract PDF(193KB) icon1463 icon479
Abstract:
The effects on turbine blade surface pressure distribution were investigated experimentally with air coolant discharge from each of nine individual rows of coolant holes on the blade surface in a rectilinear cascade with typical turbine guide van profile.Mass flow ratios of air coolant to mainstream were 0,0.6,and 1.2 percent,respectively.The experimental results showed that the variations of the surface pressure distribution were dependent chiefly on the amount of air coolant and the location of injecting holes.Injection from the blade leading edge right against the mainstream altered the surface pressure distribution slightly,and the pressure surface injection did not change the surface pressure distribution so obviously as the suction surface injection due to the difference of mainstream pressure gradients and mainstream velocity.In general,the surface pressure decrease caused by kidney-shaped vortex was more significant than the pressure increase due to the mainstream stagnation resulted from air coolant injection.
DISCHARGE COEFFICIENTS OF INCLINED MULTI-HOLE WALL COOLING IN A COMBUSTOR
Fang Ren, Lin Yuzhen, Li Bing, Liu Gaoen
1998, 13(1): 61-64,109.
Abstract PDF(924KB) icon1821 icon401
Abstract:
Discharge coefficients are investigated with five inclined multi-hole test plates of different geometrical configurations. The physical nature and influential factors of discharge coefficients are considered.The results show that the momentum ratio I1 and Renolds mumbers of little holes have important effect on discharge coeffcients but momentum ratio I2 has no influence.Parameters of the geometrical configuration P/D,S/D,α,β and L/D have great influence,but the rows of holes has little effect on discharge coefficients.
AN EXPERIMENTAL INVESTIGATION OF ADIABATICEFFECTIVENESS OF INCLINED MULTIHOLE WALL FULL-COVERAGE FILM COOLINGWITH HEAT-MASS TRANSFER ANALOGY METHOD
Fang Ren, Li Bin, Lin Yuzheng, Liu Gaoen
1998, 13(1): 65-68,109.
Abstract PDF(309KB) icon2262 icon470
Abstract:
Using the method of heat-mass transfer analogy,experimental research was carried on to investigate adiabatic film effectiveness of inclined multi-hole full-coverage film cooling.The hole configurations were regular patterns of staggered discrete circular holes,and holes inclined at an angle of 30 deg to the surface of experimental plate. Spanwise hole-to-hole spacing range is from 60 mm to 90 mm,streamwise row-to-row spacing from 45 mm to 18 mm,and hole diameter from 1.0 to 20 mm.Within the range of blowing ratio from 1.0 to 4.0,the experimental results of the adiabatic film effectiveness distribution for five plates were compared and analyzed.Finally,the optimum number of hole spacing and row spacing as well as the influences ofblowing ratio on the adiabatic film effectiveness were obtained.
INVESTIGATION OF SINGLE FILM COOLING HOLE WITH COMPOUND-ANGLE ORIENTATION
Xu Hongzhou and, Wang Sanglin, Liu Songling and, Cheng Fuqun
1998, 13(1): 69-71,110.
Abstract PDF(585KB) icon1392 icon432
Abstract:
The effects of blowing ratio at M=10 and 20 on downstream flow field single film cooling hole with compound-angle orientations have been investigated experimentally.It is found that a pair of counterrotating vortices,one of which is strong and another is weak,were observed in the downstream region of jet exit.The hole with a fan-shaped angle of 0° or 15° was oriented so that its angles with respect to the test surface are 60° in a stream/normal plane projection,and 30° or 45° in a spanwise/normal plane projection.Contours of longitudinal velocity show asymmetric kidney shape.The fan-shaped hole effectively decreases the strength of longitudinal vortex and increases the spreading of jet so that the film cooling effectiveness would be much greater than that found in the downstream of a circular hole.
A SURVEY ON PROPELLANT LEAK DETECTION TECHNIQUES FOR LIQUID ROCKET PROPULSION SYSTEM
Wang Jianbo and, Yu Daren
1998, 13(1): 72-76,110.
Abstract PDF(782KB) icon1898 icon601
Abstract:
The integrity test of Liquid Rocket Engine (LRE) must be carried out before its launch.The tests include the leak detection of liquid propellant and other liquid systems.It is necessary to set up an automated propellant leak detection system.This paper summarizes the leak detection techniques of LRE,which are classified into groups and considered in details.Finally,several prospects of the leak detection techniques are presented.
“POWER-LAW” AND “QUICK” SCHEMES IN NUMERICAL STUDY OF NONSYMMETRY DIFFUSER
Xu Jinglei, Shujuan Huang, Xu Zhong
1998, 13(1): 77-80,110.
Abstract PDF(382KB) icon1516 icon392
Abstract:
Speziale's nonlinear k-ε model is used to calculate the turbulent flow in nonsymmetry diffuser.Attention is focused on effect of the two typical convective difference schemes,“Power-Law” and “QUICK” schemes,on the performance of the models (the standard and nonlinear k-ε models).The results show that both convective difference schemes have little effect on the prediction of the models.So it is no longer to puzzle brain about choice of convective difference schemes,when applying to nonlinear k-ε models.
APPLICATION OF A SECOND-ORDER UPWIND SCHEME TO PISO ALGORITHM
Lin Weidong, Wang Zhenguo, Zhou Jin
1998, 13(1): 81-84,111.
Abstract PDF(766KB) icon2284 icon413
Abstract:
Numerical simulation of spray combustion in liquid propellant rocket engine with PISO algorithm was implemented.A second-order upwind scheme developed by the authors was combined with thePISO algorithm to ensure the numerical accuracy.The Navier-Stokes equation in cylindrical coordinates was transferred into general curvilinear coordinate system and discretized by finite-volume method with non-staggered grid.The body-fitted grid generated by TTM method was used in the calculation.A stochastic spray model was employed to determine the droplet initial conditions,and the chemical reaction rate was given by Arrhenius model.The results show that the numerical method and physical models are proper for simulation of spray combustion processes.
AN EXPERIMENTAL STUDY ON PRIMARY NOZZLE TYPES OF EXHAUST EJECTOR SYSTEMS
Li Li
1998, 13(1): 85-88,111.
Abstract PDF(614KB) icon1690 icon391
Abstract:
Optimum distances between primary nozzle exit and mixing tube inlet,static pressure recovery of the mixing flow in mixing tube、total pressure distributions at the exit of mixing tube、pumping coefficients and total pressure losses of the exhaust ejector systems with four different types of primary nozzles have been measured in the experiments.The results have an important reference value for selecting primary nozzle types of exhaust ejector systems.
NONLINEAR PERTURBATION METHOD FOR ANALYSIS OF MODAL SENSITIVITIES WITH REPEATED EIGENVALUES
Cui Bowen and, Shen Yunwen
1998, 13(1): 89-92,111.
Abstract PDF(693KB) icon1811 icon441
Abstract:
An algorithm was made out for analyzing the modal sensitivities with repeated eigenvalues of real symmetric matrices by means of nonlinear perturbation equation.It has advantage in retaining the symmetry and band structure of the original eigensystem matrices.A numerical example shows that the method has high accuracy and can be easily implemented on computer.
TRANSIENT RESPONSES OF BLADES TO BIRD IMPACT COUPLED WITH DEFORMATIONS OF BLADE
Chen Wei, Qi Wenkai, Gao Deping
1998, 13(1): 93-95,112.
Abstract PDF(275KB) icon1480 icon394
Abstract:
It is necessery to calculate the transient responses of blades precisely in analysis of blade damage due to bird impact.Because the deformations of blade can influence the distribution and magnitudes of bird impact loads,the coupling of the bird impact with blade deformation has a remarkable influence on the transient responses of the blade.A simple and effective method is provided to analyze the responses of blades with consideration of this coupling.Taking a model blade as an example,its influence extent is also sized up.
A DOUBLE-CHAMBER VAPORIZING COMBUSTORWITH HIGH TEMPERATURE RISE AND UNIFORM EXIT TEMPERATURE FIELD
Chen Binglu, Tang Ming, Wu Erping
1998, 13(1): 96-98,112.
Abstract PDF(570KB) icon1543 icon388
Abstract:
A new type of combustor,a double-chamber vaporizing combuster has been developed for heating apparatus of heating calibration tunnel.Its average exit temperature can reach 1850℃,the highest temperature rise from inlet to exit can reach 1600℃.In addition,this combustor has many other excellent characteristics,such as constant exit temperature field.Some experiences and keys to its development are described herein.
3-D NUMERICAL SIMULATION OF BLADE-ANGLE SLOTTED HUB TREATMENT
Li Ling and, Lu Yajun
1998, 13(1): 99-102,112.
Abstract PDF(333KB) icon1780 icon399
Abstract:
Three-dimensional incompressible steady time-averaged N-S equation,continuity equation and k-ε turbulence model equations are applied to calculation of the flowfield in the cascade passage with blade-angle slotted hub treatment.The mechanism of extending stability by blade-angle slotted hub treatment is elaborated by means of a three-dimensional viscous numerical simulation.It is revealed that a pressure difference between suction and pressure sides induces a strong flow which enters in the rear of the slot and pours out from the front of the slot.This flow blows off the low energe boundary layer and retards stall emergence.The SIMPLE algorithm with non-stagger grid is employed to solve the problem of the pressure oscillation.

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