2002 Vol. 17, No. 2

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Study and Application of Calculation Method for Adjusting the Matching Parameters of Turbine Nozzle Area and Engine Nozzle Radius
WANG Hua qing, CHEN Mao zhang
2002, 17(2): 145-149.
Abstract PDF(368KB) icon1898 icon524
Abstract:
The stability,reliability and performance of two spool turbojet engine will be affected by the matching correlation between 1st and 2nd turbine nozzle areas and engine nozzle area.An analysis method is presented in this paper based on six equations which are easy to apply.A programme of constant low pressure turbine power is adopted to replace the programme of constant low pressure rotor speed.The parameters measured on the engine test bed are used to define component parameters.The calculation was conducted only at design rotational speed.The computation results were used to guide the triarea adjustment of a new developed engine and attained the suitable triarea adjustment range.The engine based on this programme and adjustment is proved to be stable and reliable in flight.
Numerical Simulation and Design for Aerospike Nozzle
ZHENG Meng wei, ZHANG Yang jun, ZHUGE Wei lin, ZHANG Bao ning, LIU Yu, ZHU Sen yuan
2002, 17(2): 150-154.
Abstract PDF(356KB) icon1931 icon438
Abstract:
Aerospike nozzle engines are considered as a candidate for the next generation of propulsion system for reusable launch vehicles because of the possibility of improving performance.In order to provide an insight into performance and to control flow field development of plug nozzles,numerical optimization of truncated plug nozzles was performed by solving the Navier Stokes equations.Parameters investigated included spike length,pitch angle and secondary flow rate.Results indicated that significant performance gains result from the external freestream expansion,which self adapts to external pressure variation,as well as the short compact design for high expansion ratios.The expansion waves,compression shocks and the separated base flow dominate the flow structures and affect the aerospike nozzle rocket engine performance.Secondary flow may eliminate the recirculating base flow region and better performance will be obtained.
Experimental Investigation of Exhaust Jet Infrared Suppression for Supersonic Flow
YANG Xu, XIA Huan ming, LIU De zhang
2002, 17(2): 155-159.
Abstract PDF(298KB) icon1910 icon496
Abstract:
The supersonic exhaust jet infrared suppression is one of the most important components of the supersonic aircraft performance.The projects of the second swirl flow and the combined petal lobe are provided in this paper.Their mechanism is that mixer ejector can cause large scale streamwise vortices into the downstream.It is these vortices that intake much more amount of atmosphere which also can stir up the main flow.The mixing zone between plume and external flow increases and the length of the central core zone of turbulent flow becomes shorter,so the infrared radiation of the jet exhaust decreases.The swirl ejector is used in the first project.The experimental results show that the higher is the speed of external swirl flow,the better is the performance of stir.The experimental results also show that when the angle of swirl flow is about 30 degrees,the performance is the best for the project.The combined petal lobe is used in the second project.The experimental results show that it is practicable to use combined petal lobe for the infrared suppression of supersonic flow.
Study of Selecting Parameters and Fault Diagnosis for Turboshaft
LI Ben wei, HU Guo cai, GAO Guo sheng, HOU Zhi qiang, GAO Yong
2002, 17(2): 160-164.
Abstract PDF(814KB) icon2118 icon450
Abstract:
A method about how to select performance parameters and monitoring parameters for fault diagnosis of turbo shaft is introduced in the paper.A means to resolve the non static fault equation is proposed.This approach is achieved due to less numbers of monitoring parameters than that of performance parameters during developing the mathematical model of fault diagnosis by introducing fault factors.The similar degree of maximum probability solutions which is the index for judging effectiveness of engine fault diagnosis after diagnosing engine health condition with given rules is given.The fault equation is separately verified either with non fault data of engine or with simulating single fault and combination of two faults.It shows that the developed fault diagnosis equation is creditable.Conclusions have been obtained that different faults can be separately diagnosed by means of selecting many adequate monitoring parameters and the effective degree of diagnosis effects can be increased by decreasing measured errors of parameters.The diagnosis system has practical value for monitoring health condition of turbo shaft on active duty and has reference usages for other engines.
The Analysis of Economic Performance Properties of Engines
LI Shi wu
2002, 17(2): 165-169.
Abstract PDF(946KB) icon1653 icon481
Abstract:
Performance properties of an engine specify its performance and states.In the full life cycle of research,manufacture and operation of the engine, the performance properties which make the engine be in the state of maximal economic property are referred to as economic performance properties.Economic property of an engine not only incarnates in the develop stage but also in the full period of its develop and operation.From the point of view of improving economic property of engines,the analysis of engine properties is made in this paper.It is found that thermal efficiency is only an index to evaluate its economic property,but is unfitted to regard as a decision index for selecting economic performance properties of engines.For an engine of gas turbine,the economic optimization model is founded with the objective function of its life cycle cost,and the solution of the model is obtained by calculation.Through the comparison with the object function of thermal efficiency,the former can obtain economic performance properties of engines,whereas the latter cannot.It is emphasized in this paper that introducing the economic performance properties for developing engines,researching the methods and modes of determining the economic performance properties,and accumulating and collecting the information about the relationship between performance properties with costs are an important aspect of improving the performance of engines.
Analysis of Distortion Test Data by Inlet Flat Baffle
WANG Ru gen, JIANG Yong, ZHANG Qi fa
2002, 17(2): 170-172.
Abstract PDF(198KB) icon1829 icon460
Abstract:
In this paper,a method of installing a movable flat baffle upstream the inlet for inducing a distortion flow field is introduced.The airflow disturbance level (W) and the airflow pulsation intensity of engine intake is defined.The test data of distortion flow field at engine intake was analysed,which was obtained by inlet/engine matching test.It is showed that the distribution of dynamic pressure sensors is very important for the disturbance level (W) and the airflow pulsation intensity.And the data sampling rate and sampling time of dynamic pressure can be decreased.
Study on the Method Establishing the Revolution Difference Map for a Two-Spool-Turbojet Engine
WANG Hua qing, CHEN Mao zhang
2002, 17(2): 173-177.
Abstract PDF(350KB) icon1881 icon483
Abstract:
The revolution difference is one of the delivery acceptance test parameters for a two spool turbojet engine.It is adjusted according to a standard revolution map which was established specially for this type of engine.The level of appropriateness of the established map will affect the operating performance,stability and reliability for the engine usage.This paper expounds the establishment of the standard revolution difference map and its usage for a two spool turbojet engine.The uppermost and lowermost limits of the revolution difference map will affect the engine operation.To define the uppermost and lowermost limits two methods were suggested:operation point checking method and stable working range checking method.These two methods are suggested to be jointly used.These methods have been proved successful in a new engine development.
Numerical Methods for Three-Dimensional Viscous Rotor/Stator Interactions in Turbomachinery
REN Yu xin, WANG Zhu
2002, 17(2): 178-182.
Abstract PDF(766KB) icon1955 icon484
Abstract:
A numerical method is developed for the simulation of three dimensional viscous rotor stator interactions in turbomachinery.The governing equations are three dimensional unsteady Navier Stokes equations in absolute frame of reference with velocity components relative to blade fixed rotating coordinates.The simple Baldwin Lomax two layer algebraic model is adopted to account for the turbulence effects.Central type finite volume method with anisotropic artificial viscosity is used for the spatial discretization of the governing equations.An efficient implicit time marching scheme is proposed in terms of dual time stepping technique.This time marching scheme is in similar form to Runge Kutta method with residual smoothing but it does not need any free parameter and runs faster than traditional four stage Runge Kutta scheme.At the interfaces of rotor grids and stator grids,a conservative method is developed for the evaluation of numerical flux.The proposed method has been applied to simulating the three dimensional viscous rotor/stator interactions in a subsonic turbine stage under different rotational speed and rotor/stator distance.The numerical results agree favorably with the experimental data.
The Experimental Investigation of Using Suction Surface Fences to Control Secondary Flow in Compressor Cascade
ZHONG Jing jun, WANG Hui she, LIU Hui juan, LI Wei jun, WANG Zhong qi
2002, 17(2): 188-191.
Abstract PDF(227KB) icon1571 icon501
Abstract:
The effects of suction surface fences at different blade height on the cascade loss and secondary flow in compressor cascade were investigated through the detailed cascade exit flow field survey in low speed wind tunnel.The experimental results show that if the position of the suction surface fence can be properly selected,the secondary flow in the compressor cascade can be controlled effectively and the total cascade loss can also be reduced.
A Numerical Model for Duct Fan Vortex Intensity
TU Qiu ye, TANG Di yi
2002, 17(2): 192-195.
Abstract PDF(731KB) icon1700 icon476
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Duct fans play an important role in WIG propulsion system.The vortex system of duct fan can be divided into two parts,inner sheet and boundary sheet,which are induced by each other.It is assumed that the boundary sheet should eliminate the radial velocity disturbance of inner sheet,match the discontinuity between the intersections of boundary sheet,not induce the inner sheet,and ensure the constraint that the sum of vortices equals zero.Based on the classical theory of propeller,Kutta conditions,vortices induced equations,and assumptions of duct fan,a numerical model for calculating duct vortex intensity of fan blades is set up in this paper.Results show that the vortex intensity reaches its maximum value at the blade tip for the duct fan.This intensity profile is much different from that of the general propeller.
Aerodynamic Design of High Load Transonic Compressor Stage
LI Min jiang, QI Yi, DENG Bao yang, JING Rong qiang, GUI Xing min
2002, 17(2): 193-187.
Abstract PDF(754KB) icon1862 icon469
Abstract:
A design method combining three dimensional direct analysis with two dimensional inverse design is applied to a high load transonic compressor stage.First,the flow structures of the available stage ATS 2 (Advomced Transonic Stage) were analyzed by the 3D N S code in order to find out the existing problems.Secondly,aerodynamic numerical optimization is used to redesign the hub of the original rotor.Furthermore,the new flow structure is checked by using the 3D code.The numerical analysis indicates that the optimized stage is improved both in flow structure and performances,especially the stall margin.
The Principal Component Analysis Method for Engine Flight Mission Profiles Categorization
SONG Ying dong, GAO De ping
2002, 17(2): 196-200.
Abstract PDF(828KB) icon1978 icon487
Abstract:
In this paper,the principal component analysis method is proposed for engine flight mission profiles categorization.Eighteen flight mission profiles of a fighter engine are categorized.The categorization is based on 4 parameters,namely,flight height,flight Mach number,engine rotational speed and overload on the engine center of gravity.4 principal components of the mentioned 4 parameters are obtained,the accumulated contribution ratio of the first two principal components arrives at 81 1%.The qualitative categorization can be done from the first and the second principal components distribution range in the principal plain.Finally,a tree shaped category graph is acquired by quantitative categorization using center of gravity method.The results show that the proposed method is feasible.
The Joint Acceptance Function in Response Analysis of Cylindrical Shell Excited by Noise
CAO Mao-guo, LI Lin
2002, 17(2): 201-204.
Abstract PDF(248KB) icon1877 icon481
Abstract:
In analysis of structures excited by noise a special function joint acceptance function should be calculated.This function represents the coupled relation between structural modes and sound modes.It is an integration of them in space.In general,this function can be obtained only in the case where the analytical experssions for both structural modes and sound modes have been established.However,for most engineering structures such as the casing of aero engine it is difficult to obtain the analytical expression for its modes (either structural or sound).The article presents the research work in view of this problem.Considering the main structural type of the aero engine,we take cylindrical shell as studied structural type.In the article it is studied how to calculate the joint acceptance function based on the result obtained by finite element method,which is used widely in structure analysis.A general numerical calculating method is presented.The result obtained by this method is compared with the analytical result.
Experimental Research of Bending and Torsional Vibrations of a Double Disc Rotor Due to Rotor-to-Stator Contacts
DENG Xiao-wen, LIAO Ming-fu, Robert Liebich, Robert Gasch
2002, 17(2): 205-211.
Abstract PDF(282KB) icon1770 icon466
Abstract:
In this paper,a new rotor to stator contact test rig,which consists of a rotor with two discs mounted on a shaft and a stator,is well built and used to investigate the bending/torsion coupled vibrations of a rotor and an elastic stator due to contacts.The test rig is able to demonstrate partial rub and also the heavily destructive dry friction whip when the rotor rolls on the stator’s inner surface in the real rotating machinery.Both the bending and torsional vibration of rotor and stator vibration are monitored and analysed during the test.Many different kinds of rotor to stator contacts are experimentally simulated with this test rig,such as different rotor imbalance attributing to sudden blade loss,stator support and clearance between rotor and stator,etc.The results show that the torsional vibration of the system reveals very important characteristic of the vibration of rubbing rotor.Rotor to stator contact provokes mainly torsional natural frequency vibration and many phenomena predicted by theoretical studies are found in those experiments.The rotor to stator contact problem can be detected by monitoring the torsional vibration signals.
Aeroengine Composite Maneuver Loading Spectrum Derivation
SONG Ying-dong, GAO De-ping
2002, 17(2): 212-216.
Abstract PDF(404KB) icon2096 icon450
Abstract:
According to the principle of equal fatigue,creep and thermal impact damage,namely the amounts of main loading cycles,loading duration and the sequence of loading turns are equal in measured loading spectrum and composite loading spectrum,this paper derived an aeroengine’s composite maneuver flight loading spectrum,which provides the basis of formulating accelerated mission test spectrum.Firstly,according to the measured data,the mission profiles are categorized and the flight mission segments are identified.Secondly,the rain flow count loading cycles and the loading duration are obtained by statistical calculation and the damage of the partial loading cycles is analyzed.After averaging the same flight segments by multiplying mission mix rates,then the weighted mean profiles can be obtained,which represent the composite maneuver flight loading spectrum.Finally,the working loading spectra are calculated from altitude velocity characteristic,flight altitude and flight velocity.
Experimental Study on Acceleration Mobility Measurements for Rotor/Fuselage Coupled Model of Helicopter
GU Zhong quan, YUAN Sheng tao
2002, 17(2): 217-221.
Abstract PDF(626KB) icon1625 icon543
Abstract:
The acceleration mobilities of rotor and fuselage subsystem and coupled system are key parameters for determining natural frequencies of the rotor/fuselage coupled system by using mobility matching method.We have deduced the analytical expressions.In order to verify the feasibilities of the expressions,it is necessary to measure those mobilities.But it is difficult to measure them because of the rotor rotation effects.Therefore,a model test,as an inltial step,is required.In this paper the test approaches and procedures for measuring the acceleration mobilities of rotor and fuselage subsystem and coupled system are introduced.The measured and calculated results for self designed rotor/fuselage model are summarized and compared.The results show that our test approaches and methods are feasible and analytical expressions are correct.
Traveling-Wave Vibration of Rotating Shells by Finite Element Method
CAO Hang, ZHU Zi gen
2002, 17(2): 222-225.
Abstract PDF(735KB) icon1575 icon507
Abstract:
The finite element equations of the traveling wave vibration of rotating shells with the effects of the Coriolis and centrifugal force are established in this paper.Because of the effect of Coriolis force,the frequencies of forward and backward wave are different even under the rotating coordinate system.This is the main difference between rotating shells and disks.The Coriolis and centrifugal stiffness matrixes are formed by modifying the lump mass matrix and introduced into finite element program MSC/NASTRAN by DMAP (Direct Matrix Abstraction Program).To validate the present analysis,comparisons are made with existing results for a rotating shell and good agreement is obtained.
Ground Simulation Testing of Solar Receiver for the Space Station
XING Yu ming, YUAN Xiu gan, CUI Hai ting, HOU Xin bin, WANG Chang he
2002, 17(2): 226-230.
Abstract PDF(628KB) icon1577 icon448
Abstract:
The solar dynamic power module proposed for the space station uses the heat of fusion of a phase change material (PCM) to efficiently store thermal energy for use during eclipse periods.Experimental investigation has been conducted in solar simulation testing for the heat receiver in the Brayton engine used as the solar dynamic option for the space station.This paper discusses solar receiver ground based experiments and analytical heat transfer studies.The hardware,test procedures,and test results from these experiments are discussed.After more than 100 simulated space station orbital cycles,no canister cracks or leaks were observed and all data were successfully collected.The results show that the output temperature of the gas from the working fluid tubes met the expected demand during the sunlight and eclipse periods,the maximum temperature and average temperature of the PCM container were all within the safe range.
Numerical Simulation of High Temperature Phase Change Heat Storage System
XING Yu ming, XU Xin, YUAN Xiu gan, CUI Hai ting, ZHANG Yun hao
2002, 17(2): 231-235.
Abstract PDF(866KB) icon1607 icon443
Abstract:
Numerical results pertaining to cyclic melting and freezing of an encapsulated phase change material (PCM) have been reported.The cyclic nature of the present problem is relevant to latent heat thermal energy storage system used to power solar Brayton engines in space.Specially,a physical and numerical model of the single tube phase change heat storage system was developed.A high temperature eutectic mixture of LiF CaF 2 was used as the PCM and dry air was used as the working fluid.Numerical results are compared with available experimental data.The trends were in close agreement.
Impingement Fluid Characteristics from Rib Roughened Surface within Arrays of Circular Jet
ZHANG Jing yu, CHANG Hai ping, ZHOU Chang chun
2002, 17(2): 236-239.
Abstract PDF(311KB) icon1554 icon423
Abstract:
Impingement heat transfer is one of the useful cooling methods for high temperature gas turbine blades and/or guide vanes in aeroengines.After the cooling jet impinges on the leading edge of the turbine blade and/or guide vane,it flows downstream and turns to be the initial crossflow for the aft row of impinging jet.The process of impingement heat transfer is quite complicated, especially when the target surface is rib roughened. In this paper,impingement fluid characteristics from rib roughened surface with two dimensional arrays of circular jet with initial crossflow have been investigated experimentally.Through thousands of experimental data,the effect of several flow parameters ( Re j=7000～15000,G c/G j =0～0.5) and geometric parameters ( Xn=5～15,Zn=1 5～5,p/e=5～12,e/d =0 5～1 5) on fluid characteristics has been studied.It would be useful for the design in gas turbine hot section.
Interaction between Boiling Bubbles on a Heated Wire
WANG Hao, PENG Xiao feng
2002, 17(2): 240-245.
Abstract PDF(325KB) icon1534 icon498
Abstract:
When the bubbles grow from the surface of heated wall,violent interaction takes place among them.Disturbance in temperature field plays a key role by affecting forming and growing of bubbles.The relationship between bubbles and temperature distribution of a heated thread was analyzed.The physical models and mathematic descriptions were proposed to understand the mechanism of interaction among bubbles.The temperature sharp decrease was found to greatly depress the bubble generation in the adjacent region.The observation indicated that boiling on a wire and boiling on wall are different.Bubble can cause major temperature decrease on a thread.This kind of temperature decease even breaks off bubble growing and/or generation.It is an important reason for higher superheat of boiling on a thread due to its weaker capability of heat conduction.Finally,computer simulation was carried out and some new aspects were observed.
Heat Transfer and Pressure Drop of Short Pin-Fin Array with Different Diameter and Shape
ZHU Hui ren, XU Du chun
2002, 17(2): 246-249.
Abstract PDF(308KB) icon1677 icon481
Abstract:
Measurements of heat transfer and pressure drop in the short pin fin array used in trail cooling channel of turbine blade have been performed.Effects of diameter and shape of pin on heat transfer and pressure drop were investigated.The results show that:(1) The pressure drop increases with the increase of diameter and the pressure drop of round pin fin array is greater than that of cone pin fin array.(2) The heat transfer on the endwall of round pin fin array channel is stronger as compared with that of cone pin fin array channel.(3) As diameter increases,the increase of pressure drop is faster than that of heat transfer and the ratio of heat transfer to pressure drop of cone pin fin array is larger than that of round pin fin array.
Robust H∞/H2 Mixed Control for Aeroengine Parameter Uncertainty Systems
WANG Xi, CHEN Hua rong
2002, 17(2): 250-254.
Abstract PDF(717KB) icon1623 icon426
Abstract:
Based on introducing structured parameter uncertainty problems into general H ∞ controller involving free parameters and taking into consideration of H 2 cost performance,a design method of mixed H ∞/H 2 controller with structured parameter uncertainty in the plant is presented.Necessary and sufficient conditions for solving corresponding problems are derived.It is shown that the solution to this problem involves solving three algebraic Riccati equations.Simulations on nonlinear model of twin spool turbojet engine aerothermodynamics are performed to verify the results.
Investigation on Fault Reasoning for Power System Used in Space Vehicles
ZHANG Chun liang, ZHANG Zhen peng, YUAN Jun ya, ZHU Gang
2002, 17(2): 255-258.
Abstract PDF(302KB) icon1677 icon457
Abstract:
The space propulsive system is a power system composed of various types of engines.It must be capable of working in space for a long time with very high reliability.When a fault appears,it needs to be detected in time and shut off effectively.In the paper,the authors have introduced a fault reasoning method (fault directional graph) used in space propulsive system,and a corresponding fault reasoning model has been set up.Numerical simulation and theoretical analysis show that the model is simple and effective,and it is possible to be used for space application in a real time way.
An Optimum Method for Low Flow High Speed Centrifugal Pump
YUAN Jun ya, ZHANG Zhen peng, ZHANG Chun liang
2002, 17(2): 259-262.
Abstract PDF(323KB) icon1640 icon449
Abstract:
Low flow,high speed centrifugal pump can be used in kinds of equipment of aeronautics,astronautics,power engineering and computing techniques.It always has small size and low specific speed.But the existing theory mostly is based on the empirical designs of medium and high specific speed pumps.When used in low flow,high speed pumps,good results cannot be obtained.In this paper,a performance prediction model of low flow,high speed centrifugal pump is presented.The influence of disk diameter and auxiliary system exit pressure on system efficiency is analyzed.An optimum design method using them as design parameters and system efficiency as object is established.On the basis of this method,an example is calculated to prove that the method is feasible and effective.
Temperature and Velocity Measurements in Arcjets
CHEN Li ming, ZHAO Wen hua, DANG Dao yuan
2002, 17(2): 263-267.
Abstract PDF(316KB) icon1578 icon415
Abstract:
In this work some diagnostic techniques are introduced,including emission spectroscopy,laser induced fluorescence,and electrostatic probe.These measurements can be broadly divided into two categories:intrusive and non intrusive.The measurements of electronic temperature,heavy particle,and plume velocity are described and some of the results are analysed.It is emphasized that different diagnostic techniques will produce different results of temperature measurement and the relationships of temperature to techniques are given.It can be seen that laser techniques can investigate the detail of flow properties and will become the main technique for the measurement of Arcjets’ properties.
Study on Contact Ratio of Spiral Bevel Gears and Influence of Pitch Error
DENG Xiao zhong, FANG Zong de, REN Dong feng, WEI Bing yang
2002, 17(2): 268-272.
Abstract PDF(346KB) icon1755 icon459
Abstract:
Applying TCA(Tooth Contact Analysis)and LTCA (Loaded Tooth Contact Analysis) techniques,the influence of pitch error on the meshing behavior of aviation spiral bevel gears with contact ratio 2 0 was studied.First,the relative pitch error was defined and its amount was selected according to the accuracy degree of aviation gears,then the influence of this error on the real contact ratio,transmission error,load distribution on tooth surfaces and load share between teeth was analyzed numerically.Further,the effects of load changes under certain pitch error and pitch error changes under certain load were analyzed to provide conditions for application of aviation spiral bevel gears with high contact ratio.

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