1992 Vol. 7, No. 3

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1992, 7(3): 199-203.
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ENGINE FLIGHT LOAD RELIABILITY ANALYSIS
Cheng Dejin, He Jingyang
1992, 7(3): 205-209,288.
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Engine Flight L oad Reliability Analysis”is a special reliablity re- search on the subject of engine integral load chart based on“JX/TJ(Trubojet) X Engine Flight Load Mesurement”.This paper makes full scale statistics and analysis on a greatnum- ber of data obtained form the actual measurements of flighttesting and quite a number of da- ta collected from flight- line service.Atheorticalresearch has been made on application of dou- ble design works to engine low cycle fatigue life calculation and testing.
EFFECTS OF ROTATION ON 3-D BOUNDARY LAYER
Zu Guojun, Chen Maozhang
1992, 7(3): 210-214,288.
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The basic effects of rotation have been surveyed in this paper.On the basis of theoretical analysis of three dimensional rotational incompressible boundary layer equations,the effects of centrifugal force,coriolis force and normal pressure gradients ( p/x 2 ≠0) due to rotation on the calculational results of these equations have been discussed in detail.The turbulent boundary layers on compressor rotor blades and on a rotating cylinder surface have been calculated as numerical examples.The results are consistent with the phenomena revealed in experiments.As a conclusion,the authors proposed that the coriolis force and the centrifugal force should be considered in the engineering computations of rotational problems and the normal pressure gradients are of great importance also in this case.
NUMERICAL STABILITY ANALYSIS IN 3-D BOUNDARY LAYER CALCULATION WITH BOX METHOD
Zu Guojun, Chen Maozhang
1992, 7(3): 215-218,289.
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The authors have proved that the Box method is unstable in three dimensional boundary layer calculation although it is stable in two dimensional boundary layer calculations.The Neumman stability analysis method has been applied to dealing with this problem.But the stablity equation obtained is too complex to solve analytically,so the numerical computations have been proposed,and some valuable conclusions have been drawn.The results are in accordance with the phenomena that occured in three dimensional boundary layer calculations with Box method.
LIMIT POINT FLOW MODE ANALYSIS OF EXHAUST DIFFUSER AND OPERATION CHARACTERISTICS OF INJECTOR
Zhang Guozheng
1992, 7(3): 219-222,289.
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This paper analyzes the great effect of injection transfer characteristics on limit point operation parameters in an injector and flow character of injected flow according to injector limit point data measured in tests of Science Foundation Subject No.24001.The actual flow mode at injector limit point is presented.The paper also analyzes the impassability of limit expansion ratio for the injector and the reason why the limit expansion ratio calculated from the injector engineering method is much less than its value obtained from the tests.The eyisting conclusion that “the injector limit expansion ratio is the highest possible pressure ratio” is refuted by the theoretical demonstration and injector operation characteristics measured in tests.It is proved that the operational expansion ratio can be increased much beyond the limit expasion ratio when the injector absorbs injection transfer mass.The “Operation test characteristics of injector” from low expansion ratio to high expanion ratio beyond the limit expansion ratio is first accomplished.
NUMERICAL ANALYSIS OF 3-D TURBULENT FLOWS IN 90° BENDS
Xi Guang, Shang Hong, Wang Shangjin
1992, 7(3): 223-225,290.
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The 3 D turbulent flows in 90° bends with different cross sections have been analyzed with incompressible,time averaged N-S equation.The capability of k ε turbulence model for predicting the flow field with very strong curvature has been verified by the pipe bend ( Rc/D =0 87) experimental data made by the authors.Calculations of 3 D flow field in a 90° duct bend and a 90° pipe bend are presented.The results show that,before occurrence of the low velocity area formed mainly by the interchange of secondary flows near the inner wall,the mean velocity field predicted by the k ε turbulence model is proved in reasonably good agreement with the experimental data even though the curvature of bends is very strong.But as soon as the above mentioned low velocity area appears,the prediction accuracy of the k ε turbulence model greatly drops down.
APPLICATION OF SUBMERGED VORTEX GENERATORS FOR SEPARATION CONTROL OF A SUBSONIC DIFFUSER
Chen Xiao, Jing Ping
1992, 7(3): 226-228,290.
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The effects of the main geometrical parameters of the submerged vortex generators on the diffuser performance are analysed.A combination of corotating and counter rotating votex generators was used in the study.In the center part of the channel,four pairs of counter rotating vortex generators were used to eliminate the flow separation.At the two corners,two corotating vortex generator blades and one pair of counter roataing blades were used respectively to improve the three dimensional separation flow fields in these corner regions.The experimental results show that the static pressure recovery coefficient C P is enhanced remarkably and the total pressure loss is also reduced,if the geometrical parameters and the location of the vortex generators are selected properly.A comparative study between the submerged vortex generators of concave shape and the conventional vane type vortex generators is also presented.Both of them have almost the same efficiency for separation control,but the parasitic drag of the former is less due to its submergence in the boundary layer;and it is convenient for practical application because its distance to the separation starting point on the diverging wall of the generator is much shorter.
TURBOFAN WITH A SMALL BYPASS RATIO FOR FIRST STAGE OF A TWO-STAGE TO-ORBIT VEHICLE
Yang Kaitian
1992, 7(3): 229-231,290-291.
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As turbomachinary is superior to rocket and ramjet at lower flight speed,a computational analysis of five sorts of hydrogen fueled turbomachinary,i.e.ATR engine,rocket fan,tip turbine fan,two spool hydrogen expander engine and turbofan has been accomplished.The results show that the turbofan with small bypass ratio is superior to the others in the performance at flight Mach number below 3 5.After choice of better cycle parameters,further performance calculation of the turbofan has been carried out.The total residual thrust of six engines is shown to be more than 411 88kN at flight Mach number below 3 5.It is indicated that the specific impulse of the engine is more than 31 63kN·s/kg at flight mach number below 3 5 and 73 55kN·s/kg at flight Mach number below 0 9 respectively.This type of turbofan combined with a ramjet is proved to be suitable for a powerplant in the first stage of a two stage to orbit vehicle.
EFFECT OF THERMODYNAMIC PARAMETERS ON PERFORMANCE AND COST OF TURBINE ENGINE
Wang Rugen
1992, 7(3): 232-234,291.
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A method for estimating life cycle cost of aircraft turbine engine manufactured in China is provided on the basis of a statistic technology and a definition of life cycle cost ratio has been used.Changes in thrust,specific fuel consumption and life cycle cost have been calculated when thermodynamic parameters(π  k,T  3 and T  af )and mean time between overhauls of the engine increase.It was found that there was a marked growth of the engine thrust when T  3 increased,but life cycle cost ratio of the engine should,too,quickly grow.In order to make the growth of life cycle cost ratio acceptable for the Air Force,mean time between overhauls and total operation time of the engine must be lengthened.And a overhigh pressure ratio of the compresser often makes the thrust drop down and life cycle cost ratio grow up.
RESEARCH ON AIRCRAFT LIFE CYCLE COST REDUCTION
Wang Rugen
1992, 7(3): 235-237,291.
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On the basis of cost data collected from factories and the Air Force,the variation of life cycle cost is analyzed for the fighters in which one of four kinds of engine is installed respectively.It has been found that there should be a marked drop in the aircraft life cycle cost,if the suitable fund is allocated to increasing reliability,decreasing specific fuel consumption and lengthening time between two overhauls of the aircraft engine.
RESEARCH ON ALTITUDE SIMULATION OF STARTING FOR A SINGLE-SPOOL SMALL TURBOJET
Zhu Qing
1992, 7(3): 238-240,291.
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Altitude simulation ignition tests of a single spool small turbojet starting were completed at an altitude test rig.Some conclusions from the test data analysis have been drawn.It is very useful to supply secondary oxygen jet for high altitude ignition and starting.The use of high energy igniter improves ignition and starting performance and reduces starting time.Fuel flow must be matched with air flow during the high altitude starting.The fuel flow must be controlled by the rotational velocity of the rotor to limit temperaturet 4 and to avoid hang up during the starting.
A DESIGN OF A ROTATING PROBE FOUR-AXIS TRAVERSE MECHANISM
Zhang Hong, Jiang Haokang, Xiao Ling, Xing Shuchu
1992, 7(3): 241-247,291.
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A mechanism fully controlled by computer and stepping motor can move a probe in four axes (Null,Radial,Tangential and Axial) for completing flow measurement inside the rotor passage of the turbomachine during rotation.The mechanism can also move the probe for flow measurement inside the stator passage as a fixed one.The technical characteristics,principle of operation,construction design and running balance of the mechanism are discussed in detail.
A PLATINUM-FILM RESISTANCE TEMPERATURE PROBE FOR UNSTEADY FLOW MEASUREMENTS
Peng Jian, Jiang Haokang
1992, 7(3): 248-252,292.
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A platinum film resistance temperature probe has been designed.Steady tests show that the linearity error of the probe is less than 0 5%.The thermal response of the probe has been checked by both shock tube and high frequency hot jet.It is shown that the frequency response of 6 kHz can be expected.According to heat transfer analysis,the thermal properties and the size of the base bar are the main factors of the effect on thermal response of the probe.The probe has been successfully used for measuring rotating stall signals of a single stage transonic compressor.The study shows that the film resistance temperature probe features high frequency response,fine linearity,high sensitivity and ease to use,so it has a bright prospect in application to unsteady flow measurements.
A PARALLEL MULTI-CHANNEL HIGH-SPEED DATA ACQUISITION SYSTEM BHD 200-Ⅱ FOR DYNAMIC MEASUREMENT IN TURBOMACHINE
Xong Zhang, Liu Xudong, Chen Wangmei, Jiang Haokang
1992, 7(3): 257-260,292.
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A parallel multi channel high speed data acquisition system has been designed for dynamic flow measuremaent in turbomachine.With the swallowing and spitting capacity of 800 kc/s in all,the system can parallelly sample and process 16 channel signals.The structure,principles of operation,function and operation of the system are described in detail and two typical application examples are given.
EXPERIMENTAL RESEARCH ON CONDITION MONITORING AND FAULT DIAGNOSIS
Yang Leping, Chen Qizhi, Wang Kechang
1992, 7(3): 257-260,292.
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A micro computer system is introduced for condition monitoring and fault diagnosis in the ground testing of a throttling liquid rocket engine.The system presented is capable of monitoring all conditions of the static and dynamic performance parameters of the tested engine under each condition.According to the original data and curves provided by the monitoring system,it is possible to realize fault diagnosis for the throttling liquid rocket engine system in ground testing.The corresponding testing data and curves are presented in the this paper.
THE MECHANISM OF LIQUID-COOLING OF VANE IN HIGH-TEMPERATURE TURBINE
Liu Dezhang, Liu Minhou, Wu Weidong
1992, 7(3): 261-265,292-293.
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In this research kerosene is used as coolant instead of water in the respect of identical and distinct properties.The heat transfer coefficient along full flow path has obtained with the kerosene coolant through an even heated straight tube,and relation between the heat transfer cooling of kerosene and water has been determined in the case of the vapor liquid two phase boiling flow.The key problem of the kerosene used as coolant is “coking property” and instability of wall temperature.However,it does happen in some particular working conditions,but the working conditions can be regulated with an empirical formula for the initial point annular flow Z N to eliminate the coking zones.The Several useful conclusions have been drawn for the cooling passage of turbine vane.
STUDY ON FLOW CHARACTERISTICS OF SEPARATED IMPINGEMENT JETS AT SHORT DISTANCE
Kang Ying, Qiu Xuguang, Cao Yuzhang, Zhou Wei
1992, 7(3): 266-268,293.
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In conventional practice a row of separated circular jets is used in turbine blade or vane for impingement cooling and the relative distance z n/d n is very small ( z n/d n ≤2).In this case,study on longitudinal uniformity of the cooling on the surface of the blade or vane is necessary.In our experiments,the uniformity of the velocity distribution at large relative distance ( z n/d n >10) is achieved by free jet in atmosphere,but the distribution of jet velocity is rapidly uniformized when the jets srtike against the target surface and flow along the surface.The reason of the uniformization is the turbulence mixing and the effect of pressure difference.This work contributes to good understanding for uniformization of cooling on the surface of the blade or vane.
ON APPROXIMATING THERMODYNAMIC PROPETIESOF INDIVIDUAL SUBSTANCES
Dregalin A.F., Nazyrova R.R.
1992, 7(3): 269-271.
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A method for complex approximation of the thermodynamic functions,such as en- thalpy,entropy and heatcapacity,with regard for the fixed points is presented,which has been suc- cessfully used in approximating about150 0 tables within temperature range from10 0 to2 0 0 0 0 K.
COMPARATIVE EXPERIMENTAL RESEARCH ON SPRAY FIELDS OF HEAVY AND CONVENTIONAL AVIATION KEROSENE
Wang Jian, Wang Jiahua
1992, 7(3): 272-274,293.
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Laser holography was used to measure the fuel spray characteristics of heavy jet kerosene and conventional aviation kerosene downstream after a simple orifice injector.The spatial distribution of droplet size and Sauter Mean Diameters (SMD) for two kinds of kerosene have been obtained and compared.In this paper,the effects of air velocity and pressure drop on the fuel spray field are considered.The following conclusions are drawn from the experimental data:1.The magnitude and distribution of droplet size are determined by the air velocity.2.The SMD for the two fuels are,to some extent,related to the fuel pressure.3.The variation of the fuel pressure has less influence on the SMD of the two fuels.4.The empirical formulas are provided for evaluating the effects of the air velocity and the fuel pressure on the SMD.
RESEARCH ON WZ-5 TURBOSHAFT ENGINE WITH A REBUILT HIGH-TEMPERATURE TURBINE
Tian Wangnan
1992, 7(3): 275-277,293-294.
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A WZ 5 turboshaft engine has been modified with a rebuilt high temperature turbine as a ground power plant.The engine can make full use of its turbine inlet temperature through varying areas of both gas generator turbine and power turbine nozzles and reduce the rotor speed,thus a sufficient surge margin is provided and the output shaft power is enhanced.Therefore,the engine meets the requirements for long time operation when it serves as a power plant in varied ground industrial complex.The practice of its usage has shown that the modified WZ-5 is of considerable economic and social benefits.
PRELIMINARY RESEARCH OF STEAM INJEETION FOR WZ-5 AEROENGINE COMBUSTOR
Liu Gaoen, Wang Huafang, Qian Yanshen
1992, 7(3): 278-280,294.
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The experimental investigation has been carried out at atomospheric testing rig to determine the effect of steam injection on combustion performance.The combustor used in the experiment was a modified WZ 5 annular combustor in which two steam injection sets were installed in the front and rear parts respectively.The tested fuel was gaseous fuel with medium heating value.The results show that steam injection had no impact on combustion efficiency and exit temperature pattern when the mass injection ratio (steam mass flow rate/air flow rate) is less than 5%.The exit temperature pattern factor increases and exceeds the acceptable value 0 25 to 0 30,as the steam mass injection ratio increases to about 10%.In addition,the test results also show that the process of the front part injection must be conducted smoothly,otherwise extinction of burning would occur.
EXPERIMENTAL INVISTIGATION OF LOW BTU COAL GAS COMBUSTION
Xiao Tongfu, Chen Dongwang
1992, 7(3): 281-283,294.
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Experimental investigation of an gas turbine combustor adapted to coal gas with heat value over 2500kJ/Nm 3 has been completed at all operation conditions.Test results show that the configuration of the chamber head with double swirlers provides high combustion efficiency and wide stable operation range when excess air coefficient of head ( α 1 ) is in the range of 0 731 to 0 925.Carbon monoxide emission is confined within the required limits.
PREDICTION OF LNG DENSITIES WITH PRINCIPLE OF CORRESPONDING STATE OF SHAPE FACTOR
You Lixin, Gu Anzhong
1992, 7(3): 284-286,294.
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UNIVERSAL PHYSICAL EQUATIONSOF TURBULENCE
GaoGe
1992, 7(3): 287-288.
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Using the rate of deformation tensor and the perturbed deformation displacement to de-compose the fluctuating velocity of turbulent flow,and then using density- weighted off- cen-tre ensemble average method,instead of the conventional Reynolds average,the N- Sequa-tion has been averaged in a new way.

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