2003 Vol. 18, No. 5

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Display Method:
Estimation and Identification for Correlation Coefficient Stationary Series
LIU Cheng rui, FU Hui min
2003, 18(5): 577-582.
Abstract PDF(939KB) icon1342 icon481
Abstract:
The estimation method for the parameters of the correlation coefficient stationary series which can not be measured straightly is presented.After the state equations of the correlation coefficient AR(p),MA(q) and ARMA(p,q)series are established,the filtering,prediction and smoothing for non stationary series can be carried out.In addition,the identification method of the observation system is also given.For the relation between time and the mean,the variance of the noise can be considered,the precision of the present method is higher than that of the traditional methods.
Multiple Regression Analysis Method for Weibull Distribution
HUANG Wei, FU Hui min
2003, 18(5): 583-586.
Abstract PDF(666KB) icon1681 icon494
Abstract:
A new multiple regression analysis method for Weibull distribution and extreme distribution is presented. The best unbiased integral estimation for regression parameters and their covariance are established by the method. The point estimators and confidence intervals of Weibull distribution, extreme distribution and normal distribution are also given. The present method extends the traditional multiple regression analysis that is only suitable to normal distribution and complete data to Weibull distribution, extreme distribution and censored data. Compared with the traditional group test method and best linear unbiased estimation, the present method can fully exploit and apply the crosswise information among the test data in different states; thus it reaches a better precision and a great number of specimens can be saved.
The Aerodynamic Characteristic Experiment and Numerical Analysis of Ram Air Turbine with Autocoarse Pitch
LIU Si yong, FANG Xiang jun, WANG Ping
2003, 18(5): 587-592.
Abstract PDF(955KB) icon1991 icon591
Abstract:
The aim of wind tunnel experiment of ram air turbine was mainly to simulate the real flight refuel conditions on the basis of employing similarity criteria.In the meantime,the output power of the turbine was measured,and its aerodynamic characteristics were further analyzed.An exciter motor generator and a refueling pump were used as the dynamometer machine.The maximal output power could be obtained by means of adjusting the pitch of ram turbine blades.It was found that the output power of ram air turbine can satisfy the flight refuel needs on conditions that the air speed of wind tunnel is 16% lower than the minimal flight speed of aircraft tanker.The Baldwin Lomax turbulence model with highly numerical stability was used to simulate the 3 D internal and external mixed flow fields of ram air turbine.The main dynamic parameters of turbine flow field were investigated and the cause of load distributing on the blades surface was also discussed.It was revealed that the ram air turbine performance could be improved by optimizing the blades near the hub region.
The Application Study of the "Nozzle Blockage" Technique in the Simulated Altitude Test of Aero-Engine
GUO Xin, LIU Zhi you
2003, 18(5): 593-598.
Abstract PDF(864KB) icon1696 icon504
Abstract:
Through the process analysis of determining engine thrust and converting engine thrust of the simulated altitude test,the application mechanism and its applied conditions of the "nozzle blockage" technique in the simulated altitude test of aero engine with the convergent nozzle are clarified.By means of the result analysis of the "engine jam" experiment on Spey engine in the simulated altitude test facility of the Rolls Royce company and on turbojet engine in a simulated altitude test facility,the application feasibility and its rationality are made clear of the "nozzle blockage" technology in the simulated altitude test of the aero engine with the convergent nozzle.The research results extend the workable and applicable scope of the thrust calculation and correction formula of HB6213,which stands for the performance correction standardization of the altitude simulated test of the turbojet and turbofan engines.
Experimental Investigation of Some Turbofan Engine Starting in Plateau Area
LI Wen feng, WANG Yong sheng, LEI Zhen, LUO Hua jun
2003, 18(5): 599-603.
Abstract PDF(733KB) icon1970 icon537
Abstract:
In order to study how the atmospheric pressure affects the starting of engines and to explore the adjusting rule in the course of engine starting,we did the starting experimental investigation of a turbofan engine starting in plateau area.The experimental problems and steps are discussed.An important facility (a small removable ground test bed) for the experiment is introduced.Adjusting methods of starter and engine are studied.Some data of test running are given in the paper.
Numerical Simulation of Airfoil-Tip Vortex Interaction
CAO Yi hua, KANG Peng bin, YU Zi wen
2003, 18(5): 604-607.
Abstract PDF(362KB) icon1730 icon464
Abstract:
The far field noise generated by NACA0012 airfoil/tip vortex interaction is predicted using the combined Euler/Kirchhoff method. Kirchhoff surface is selected as one of the grid surfaces.Firstly,the result of nearfield can be obtained by solving Euler equations.Then the result of farfield can be calculated by Kirchhoff method.Finally, the combined Euler/Kirchhoff method developed here is proved a good try for studying Blade Vortex Interaction (BVI) noise through sample calculations.
Edge-Matching Technique for Unsteady Aerodynamic Design of Turbomachinery
CHEN Jiang, JI Lu cheng, YANG Chun xin
2003, 18(5): 608-614.
Abstract PDF(1208KB) icon1690 icon566
Abstract:
A new degree of freedom for turbomachinery design Edge Matching (EM) technique is presented in this paper.The so called EM is named from spatial relationship (more precisely,phase angle relationship) between trailing edge and leading edge curves of two neighboring blade rows.In fact,the blade trailing edge denotes the profile of outflow,in which the wake,the shock wave and other secondary flow phenomena are involved,while the blade leading edge presents potential interference on the former blade.When the steady flow design method is used,these effects related to the blade edges are considered partly.This means that the relative position between neighboring edges only has little influences on the turbomachinery performance.However,in the frame of unsteady flow this influence is evident and great.The theoretical analysis about EM technique is introduced first.The potential usage of EM technique is clearly pointed out.Then unsteady simulations about a turbine cascade and a linear cascade are conducted.The results show that the EM technique may be widely used in improving the aerodynamic,aeroelastic,aeroacoustic and heat transfer performance of turbomachinery.It is believed that the EM technique will advance the unsteady design of turbomachinery.
Investigation of the Cooling Effectiveness of Lamilloy
YU Xin hua, QUAN Dong liang, LIU Song ling, XU Dun chun, HU Zhu gen
2003, 18(5): 615-622.
Abstract PDF(448KB) icon1855 icon593
Abstract:
Combined with the permeability and heat transfer properties of lamilloy configurations obtained by experiments,a one dimensional porous wall thermal heat transfer model was applied to the analysis of the mass flow rate,and the overall cooling effectiveness of different lamilloys according to the pressure drop between the two sides.The investigation of various effects on cooling effectiveness has been made,the results presented in this paper will be useful for the actual lamilloy design.At the same blow ratios,the double layer porous plate exhibits higher cooling effectiveness than single layer,but the difference of cooling effectiveness between the triple layer plate and the double layer plate is not significant.Compared with the traditional cooling scheme,lamilloy is a prospective cooling scheme for the gas turbine engines of next generation.
Numerical Simulation of Leading Edge Film-Cooling in a Turbine Cascade
YAN Pei gang, WANG Song tao, HAN Wan jin, WANG Zhong qi
2003, 18(5): 623-628.
Abstract PDF(451KB) icon1538 icon427
Abstract:
A finite difference scheme with three order precision and TVD property and a multi block grid technique are adopted.The leading edge film cooling flow field in a turbine with two rows of coolant holes is numerically simulated based on the three dimensional N S equation solver.The characteristics of the flow and temperature fields,including the coolant trajectory,the interaction of two rows of coolant jets and the complicated distribution of film cooling adiabatic effectiveness in the region of leading edge are all expounded under different blowing ratios,injection angles and locations of coolant holes.The results show that the influences of different positions of coolant holes,their arrangement and the blowing ratios on the adiabatic effectiveness are obvious and complicated in the leading edge.
An Experimental Study of Flow Performance in a 180° Turn-Over Channel with Ribs
QI Lei, DING Shui ting, XU Guo qiang, TAO Zhi
2003, 18(5): 629-633.
Abstract PDF(301KB) icon1829 icon516
Abstract:
Compared to the channel with uniform section area,those with various section areas are much similar to the internal cooling structure of the turbine blade.In this thesis,a 180°turn over channel with various sectional areas and 90° parallel ribs is studied of its characteristic of heat transfer.The channel is divided into some heat transfer elements each with one,single rib as the basic character.The influences of every characteristic non dimensional geometric parameter and Reynolds number on the heat transfer of the ribbed walls are studied on the premise that the channel area changes continually.At the same channel inlet Reynolds number,the average Nusselt number of the test model's rib walls is 74%～128% larger compared with Dittus Boelter formula and much larger at smaller Reynolds number.
Numerical Study of Temperature Distribution on Vectored Nozzle Wall
ZHANG Xiao ying, ZHU Gu jun, WANG Xian wei
2003, 18(5): 634-638.
Abstract PDF(333KB) icon2042 icon484
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With a view to study heat transfer process occurring in vectored nozzle installed in aero engine,convection and radiation heat transfer and 2 D distribution of wall temperature in nozzle are computed in this paper.Related cooling method for heated parts are considered and cooling effectivenesses of different film types on expandable regulating part of nozzle are compared.Computation of radiation heat transfer is carry out for a series of spectrums and 3 D distribution of gas temperature and pressure is considered.A general program suitable for axisymmetric symmetrical vectored nozzle,circular to rectangular vectored nozzle and spherical traversing vectored nozzle,both in after burning condition and non after burning condition is developed and computed results of several samples are presented.The results show that the temperature of deflected vectored nozzle varies apparently along the circumference,temperature along the deflecting direction is lower than that of the opposite direction.
The Effect of Fuel-Circumferential-Staging on Lean Blowout Limit at Idle Condition
YUAN Yi xiang, LIN Yu zhen, LIU Gao en, HU Guo xin, GONG Jing
2003, 18(5): 639-644.
Abstract PDF(344KB) icon1990 icon585
Abstract:
The experimental investigation was conducted for the fuel circumferential staging combustor with two domes to improve the lean blowout fuel air ratio.The effects of inlet temperature and inlet velocity were taken into account.Three pieces of clapboard with different length were placed between two domes to eliminate their mutual effects.Results showed that the combustor with fuel circumferential staging could obviously improve fuel air ratio at lean blowout.When the inlet temperature was lower than 400 K,fuel air ratio at lean blowout would decrease obviously with the rising of inlet velocity.When the inlet temperature was higher than 400 K,it wouldn't be sensitive to the inlet temperature and inlet velocity.However,the method was not so good in respect of reducing fuel air ratio at lean blowout by inserting clapboard into two domes.
Research on Heat Receiver in Advanced Solar Energy Dynamic System
GUI Xiao hong, YUAN Xiu gan
2003, 18(5): 645-649.
Abstract PDF(364KB) icon1679 icon485
Abstract:
The research purpose of advanced solar energy dynamic system is to improve efficiency and lay a foundation for further wide use in space.By evaluating and analyzing the structure,performance and designing of four advanced solar energy heat receivers,the designing concept of a new type heat receiver is given.The research result indicates that the mass of solar energy dynamic system is greatly reduced by use of heat pipe receiver which has a good future in use.
Constitutive Relationship of Nickel-Base Single Crystal Superalloys and Applications
YANG Zhi guo, YUE Zhu feng, YIN Ze yong, WEI Peng yi, CHENG Xiao ming
2003, 18(5): 650-657.
Abstract PDF(1079KB) icon2102 icon517
Abstract:
The work carried out in our research group in respect of the mechanic study of nickel base single crystal (SC) superalloys has been reviewed.The models for crystallographic elastoplastic behavior,creep,fatigue and thermomechanical fatigue and life predictive models have been presented and validated.Experiments have been performed for the mechanic behaviors of SC superalloys at different loading conditions for different crystallographic orientations and temperatures,thus the basic data for the validation of the models were acquired.Two ad hoc programs,SLAPSC and umat for ABAQUS,have been developed for the SC blades.The double shear creep specimens and modeling turbine blades have been experimented for the validation of the model.Finally,the SC turbine blades have been analyzed by the models for the strength and life.
Fatigue Life Predication of Notched Composite Material Laminates
QI Hong yu, WEN Wei dongying, CUI Hai tao
2003, 18(5): 658-661.
Abstract PDF(644KB) icon1858 icon513
Abstract:
Based on damage theory and strain equivalent hypothesis,a fatigue model is presented in which the residual strain and stiffness degradation are included.A high capability composite material 300/KH304 developed recently is studied in this paper.Using this model,the fatigue life of these laminates with 5 mm holes is predicated.At the same time the fatigue tests are carried out under different stress levels.Compared with the result,the relative tolerance is less than 12.2%.
Application of Metal-Rubber Damper to the Rotor System
GUO Bao ting, ZHU Zi gen
2003, 18(5): 662-668.
Abstract PDF(527KB) icon1844 icon505
Abstract:
Metal Rubber (MR) is a new damper material,and it offers elasticity of rubber.Theoretical and experimental investigation of hydro turbopump rotor system showed that MR has special advantages as a combined bearing.It can reduce vibration effectively.From the data of tests conducted at the rotating speed very near the first critical rotating speed,it can be seen that the vibration level of rotator with MR damper as its bearing system is reduced by 90%.Other advantages of the MR damper are its easy making craft and good installation conditions.
High Speed Dynamic Balance Technique of a Power Turbine Rotor of a Turbine Shaft Engine
DENG Wang qun, GAO De ping
2003, 18(5): 669-675.
Abstract PDF(893KB) icon1897 icon512
Abstract:
High speed dynamic balance of power turbine rotor which generally runs over the second bending critical speed is a key technique in developing turbine shaft engine.This paper presents an improved multispeed,multiplane and step by step balance precedure developed to balance a power turbine rotor with a long slender hollow shaft,elastic supports and squeeze film dampers,and inherent torque tube.A group of precise balance collars are designed for adding trial masses.A set of balance steps and balance technologies are summarized.Criteria for evaluating the quality are established which involve the limits of both vibration displacement of shaft and vibration acceleration of supports.The procedure is carried out throughout the whole operating speed range and the highest balance speed is over 20,000 rpm.It has been successfully applied to balancing the power turbine rotor in practice.
The Estimation of Aeroengine Expectant Cycle Based on Genetic Algorithm and BP Neural Network
SONG Jin guang, XU Chun sheng
2003, 18(5): 676-680.
Abstract PDF(389KB) icon1984 icon545
Abstract:
The algorithm described in the paper is one of the important instruments for the establishment of aero engine expectant cycle to supervise aero engine scientifically and effectively.By means of experimental method of using real specimens,the optinal algorithm which can estimate aero engine expectant cycle quickly and precisely among BP neural network,GA (genetic algorithm) and compound GA BP can be found.It shows that GA BP algorithm can simulate expectant cycle excellently.First it searches weights of neural network grossly using genetic algorithm,then is trained by using BP network.It has been proved to be effective by real instances.Two softwares have been made.
A New Method for Controlling CFM56-3 No.3 Aft Air/Oil Seals Separation
HUANG Yue, WEI Gui lan, ZHANG You Keng, ZHAO Ji yong
2003, 18(5): 681-685.
Abstract PDF(711KB) icon2015 icon499
Abstract:
Many CFM56 3 No.3 aft air/oil seals were found to be separated due to the performance deterioration of Non Asbestos Adhesive.The experience of China Southern Airlines shows that accompanying the onset of separation,it can often be observed,the oil consumption increases and brown non metal chips emerge.These phenomena prompted the authors to initiate a way to control the separation by monitoring oil consumption and Magnetic Detectors.Meanwhile,the mechanics of the seal separation and relative modification information are also introduced in the paper.
Numerical Study of Two-Phase Flow for Fault Diagnosis in a Tail-Pipe Nozzle
DAN Lin peng, ZHANG Zhen peng, ZHANG Li qun
2003, 18(5): 686-691.
Abstract PDF(352KB) icon1746 icon480
Abstract:
In order to provide analysis results for fault diagnosis in a tail pipe nozzle to make some suggestions,two phase flow field is studied for a tail pipe nozzle by using the trajectory model and finite volume method to obtain the gas temperature and Mach number distributions,and to simulate the collision between the wall and different size particles under different total pressures.The calculation results show that there exists a point on the pipe inner wall where large size particles collide with wall intensively,giving rise to the tail pipe fault as a main cause,higher total pressure makes more collisions between particles and wall while larger size particles provoke makes more collisions.Accordingly some suggestions are prompted to enhance the reliability of heat resistant construction for a tail pipe nozzle.
Coupled Analysis of Turbopump of Liquid Rocket Engine
TAN Song lin, HUANG Dao qiong, ZHANG Ji tong, MAO Gen wang
2003, 18(5): 692-697.
Abstract PDF(325KB) icon1704 icon495
Abstract:
In order to improve the reliability of liquid rocket engine and prevent destructive failure,coupling between the rotating speed frequency and the gas pressure impulse must be avoided.Vibration responses of the turbopump were analyzed by building a transmission model of the excitation.The result that the gas pressure impulse of the gas generator is the main source of the excitation was given.Then,the coupled rules between excitation and rotating speed frequency of the turbine disk were shown and the coupled rotating speed range was obtained.In the end,the calculation results were validated by hot test information of the liquid rocket engine.
Distributed Control Systems for Aeroengines:A Survey
HUANG Jin quan, XU Ke
2003, 18(5): 698-704.
Abstract PDF(183KB) icon4259 icon699
Abstract:
With the development of full authority digital electronic control for aeroengines,distributed control will become an important and promising direction of aeroengine control.The research on distributed control systems for aeroengines in recent years is reviewed.The structure,functions,advantages of aeroengine distributed control systems are emphatically expounded.The advantages and disadvantages of data buses and power buses for aeroengine distributed control systems are compared,and the choices of data buses and power buses are proposed.Influences of the aeroengine running environments on developing aeroengine distributed control systems are analyzed.The importance of developing aeroengine distributed control systems and the future development trend are discussed.
A Rapid Learning Algorithm of Feedforward Neural Network for Identification of Aeroengine Model
WANG Li feng, LI Zheng xi
2003, 18(5): 705-708.
Abstract PDF(256KB) icon1567 icon461
Abstract:
To build a precise model is a key technique to aeroengine adaptive control.A rapid learning algorithm of feedforward neural network for identification of aeroengine model is presented in the paper.By contrast with similar algorithms,the present approach employs the decomposition of Matrix QR to solve a set of linear equations.As a result,inversing of huge matrix inverse and fuzzy solutions can be avoided.The algorithm was applied to the aeroengine nonlinear model identification,and validated by the simulation results of the calculation samples.
Full Process Circled Simulation Flat of Missile Turbojet
NIU Jun, YU Da ren, FENG Guo tai
2003, 18(5): 709-712.
Abstract PDF(320KB) icon1671 icon433
Abstract:
Full process circled simulation flat of some missile turbojet and its oil supplied regulating system based on MATLAB is proposed for factually describing component interaction of engine system.The adopted engine model is built by methods of combing aerodynamics and thermodynamics theories with neural network,and oil supplied regulating system is modeled by methods of mechanism analysis and parameter identification.On the flat,we analyze the effect of diaphragm characteristic upon engine starting and accelerating performance.The results indicate that the circled simulation flat is of high reliability,and it can reflect the actual working process of the turbojet and its oil supplied regulating system.

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