2009 Vol. 24, No. 5

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Convective heat transfer simulation in holes of inclined multihole wall film cooling
XU Quan-hong, LI Tao, XUE Hang, LIN Yu-zhen
2009, 24(5): 957-962.
Abstract PDF(1199KB) icon1828 icon501
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Characteristics of convective heat transfer in holes of inclined multihole wall were investigated numerically by two different ways.One was focused on the purely aerothermal effects of the cooling flow,and the other one on the conjugate heat transfer.The results reveal that the conjugate heat transfer simulation is more accurate in reflecting convective heat transfer in holes.The results also show that the Nusselt number at the entrance of the holes is the maximum,and the influence of the entrance on the local convective heat transfer is variable with the Renolds number.
Comparative analysis of computational methods of supersonic combustor flowfield
WANG Cheng-peng, YANG Yong-yang, LIU Chen, WANG Jiang-feng, CHENG Ke-ming, WU Yi-zhao
2009, 24(5): 963-969.
Abstract PDF(1962KB) icon1694 icon435
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The calculation of H2/air supersonic combustion flowfield in a typical combustor with "a constant-area section + an expansion section" was carried out with three methods: quasi-one-dimensional flow model,axisymmetric and three-dimensional Reynolds-averaged Navier-Stokes Solver.The hydrogen/air mechanism of 13 species and 32 reactions was used.The study shows that the quasi-one-dimensional flow model and three-dimensional Navier-Stokes Solver are effective for predicting the distribution of the parameters in the supersonic combustor.Good agreement is achieved between the calculated and experimental static pressure data except the precombustion shock train region.The quasi-one-dimensional flow model coupled with the finite-rate chemistry equations provides a rapid methodology with strong adoptability for performance prediction.The three-dimensional numerical simulation could depict the detailed information in the flow,but it will take up a great deal of time.Given different advantages,these two models would be used in different design phases of supersonic combustor.
Parametric optimization design of curvilinear heat sink based on the minimization of entropy generation rate
ZHOU Jian-hui, YANG Chun-xin
2009, 24(5): 970-979.
Abstract PDF(1130KB) icon1572 icon415
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Based on the procedure of the parametric design and numerical simulation,the parametric design software for optimally designing the radial heat sink was developed utilizing VB language,allowing to generate automatically high quality hexahedral meshes.The numerical simulation could also be performed automatically,and the results of the entropy generation rate of fan-sink assembly were obtained.Geometry parametric investigations achieved quickly by the program were carried out to examine the effect of various design parameters on the performance of the fan-sink assembly by choosing one parameter as the control variable,which can provide physical insight into the flow and heat transfer characteristics of the heat sinks and deep understanding for the optimization of the heat sinks.The multi-parameter constraint structural optimization procedure based on the combination algorithms with parallel computational fluid dynamics(CFD) was performed on the fan-sink assembly for minimization of the entropy generation rate.Results show that the entropy generation rate of optimal curvilinear heat sink is decreased by 7% as compared to the initial design.
Two dimensional simulation of continuous detonation engine
SHAO Ye-tao, WANG Jian-ping
2009, 24(5): 980-986.
Abstract PDF(1036KB) icon1865 icon513
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Physical model and propagation mechanism of continuous detonation engine(CDE) were introduced.The wave structure of CDE was physically analysed.Two dimensional simplified model of CDE was simulated by two step chemical reaction model.The simulation results show a serial of detonation waves repetition processes along a 4 cm perimeter circle surface which is extracted from the cylindrical combustion chamber.The simulation results of the wave structures agree well with the corresponding experimental results.The numerical simulation results allow us get more detailed parameters of CDE and are good for further study of the CDE.
Experiment on spray characteristics of baffle-type injector in cross flow
LIU Yang, MA Wen-jie, LI Rui-ming, XING Fei, YANG Mao-lin
2009, 24(5): 987-993.
Abstract PDF(1104KB) icon1574 icon415
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A new type of fuel baffle-type injector was developed.With the injector spraying in cross flow,Malvern laser particle analyzer was used to measure the spray characteristic parameters.The initial atomization process and special spray feature were analyzed.Furthermore,the paper made a primitive study of the influences of air velocity,fuel injection pressure and injector structure design sizes on the atomizing characteristics.The results are of significance to the application and numerical calculus of this injector.
Investigation on flow and heat transfer characteristics and optimum structural design in the rectangular microchannels
WANG Meng, WU Hong, XU Guo-qiang, TAO Zhi, LIU Qing-dong
2009, 24(5): 994-999.
Abstract PDF(1050KB) icon1491 icon435
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For obtaining the basic characteristic of flow and heat transfer in the rectangular microchannels,experiment was executed under different hydraulic diameters,and a great deal of numeration simulations were carried out and validated experimentally.The transformation laws of Nusselt number and resistant coeffcient were obtained.The critical Reynolds number was brought forward to about 1 200～1 300 in the studied scale range.Meanwhile,the correlation of Nusselt number and resistant coeffcient within the studied scale range were built by multivariate linear regression.The optimization procedure(genetic algorithms) was carried out to optimize the structure of microchannels,providing beneficial theoretical and experiment data for engineering application.
Experimental investigation on film cooling of expanded hole at both inlet and outlet with various injection angles
LI Guang-chao, ZHU Hui-ren, FAN Hui-ming
2009, 24(5): 1000-1005.
Abstract PDF(1252KB) icon1500 icon439
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To study the film cooling characteristics of expanded holes,heat transfer coefficient ratios and film cooling effectiveness was investigated downstream of a row of holes with inclination angles of 20° 45° and 90° as well as three varying hole diameters.Momentum flux ratios vary in the range of 1 to 4.The discussion was focused on the effect of momentum flux ratios and inclination angles on heat transfer coefficient ratios and film cooling effectiveness in the presence of mainstream zero pressure gradient.The experimental results show that the increasing momentum flux ratios leads to the increasing heat transfer coefficient ratios and film cooling effectiveness.The effect of momentum flux ratios on cooling effectiveness becomes weaker with the increase of angles.The angles have complex influence on heat transfer coefficient ratios.The increasing angles lead to the decreased cooling effectiveness.Film cooling effectiveness of inclination angle of 20° is bigger than those of 45° and 90°.
Matching research of resonant PDE's resonator and jet
JIANG Ri-hong, WU Xiao-song, WANG Dong
2009, 24(5): 1006-1010.
Abstract PDF(940KB) icon1580 icon492
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This paper analyzed the influence of nozzle shape(slot and annular nozzles) and nozzle size(four different annular nozzles) on jet collision,shock forming and focus based on numerical simulation.It's learnt that annular nozzle's focus effect is better than slot nozzle,and the geometry matching relationship of resonator and nozzle could help ignite the detonation wave by using shock.
Characterization of flame stabilization for V-gutter in centrifugal force field
AN Shuai, LIN Yu-zhen, ZHANG Chi, GUO Xin-hua
2009, 24(5): 1011-1015.
Abstract PDF(706KB) icon1545 icon526
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Experimental and numerical studies were conducted to understand the characteristics of flame stabilization in centrifugal force field.A curving pipe was used for simulating the combustion in centrifugal force field and a numerical simulation was used for validating the experiment.The difference of combustion performance between curving pipe and straight pipe was also investigated.The investigation observes that the weak extinction performance in centrifugal force field is worse because the recirculation zone in the curving pipe is destroyed.It is also found that the weak extinction limit decreases with the increasing acceleration coefficient of centrifugal force.
Effects of pin-fin's geometry parameters on flow resistance and heat transfer characteristics of lamilloy
YUAN Xing, LV Dong
2009, 24(5): 1016-1021.
Abstract PDF(1347KB) icon1682 icon471
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This paper dealt with a numerical simulation of the flow resistance and heat transfer characteristics on fifteen different laminated porous wall models.The effects of pin-fin's fill ratio and diameter ratio were investigated.This investigation considered fifteen geometry models: pin-fin's fill ratio and diameter ratio were varied from 0.15 to 0.35 or from 0.3 to 0.7 respectively,while pin-fin's fill ratio was kept at 0.25.Length and height of the whole model were 4 mm and 2 mm respectively;height of pin-fin was 1 mm,diameter of holes in entrance surface and coolant supply plane was 0.5 mm,and the injection angle of outlet with the coolant supply plane was 60°.Results are presented as the coefficient of flow resistance and the heat transfer efficiency.The results show that:(1) the increase of pin-fin's fill ratio is propitious to decrease the flow resistance and improve the heat transfer efficiency,(2) the increase of main pin-fin's diameter is propitious to decrease the flow resistance,and the heat transfer efficiency is best when main pin-fin's diameter is same with assistant pin-fin's diameter.
Effects of non-equilibrium chemical reaction flow on the performance of scramjet nozzle
WANG Xin-yue, YANG Zhen-peng, WANG Yan-qing
2009, 24(5): 1022-1027.
Abstract PDF(1111KB) icon1731 icon445
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The RNG k-ε turbulence models and finite volume method were used to solve the conservative Reynolds-averaged Navier-Stokes equations.7-specice,8-step finite-rate chemical reaction models were employed to calculate the flow of the scramjet single expansion ramp nozzle.The characteristics of the nozzle were numerically studied under various free-stream Mach numbers and various flight heights.The calculation shows that the performances of the nozzle are notably advanced under the combustion in the nozzle.The non-equilibrium chemical reactions should always be considered in research of the performance of scramjet nozzle.
Investigation of disturbed board total pressure distortion on a certain turbofan engine
MA Yan-rong, MA Ming-ming, WANG Xiao-feng, QU Ji-yun, WANG Yan-ping
2009, 24(5): 1028-1034.
Abstract PDF(1973KB) icon1875 icon422
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Total pressure distortion flow field test of a certain turbofan engine was conducted based on disturbed board installed in nacelle inlet,and the values about inlet total pressure distortion of the engine under some operating states were obtained.This paper focused on studying the influential factors to the total pressure distribution of engine inlet,and also discussed the influences of engine operating states and the relative depth of disturbed board on the inlet section total pressure recovery and engine inlet distortion indexes.Moreover,computational fluid dynamics(CFD) computation on steady total pressure distribution and circumferential steady total pressure distortion index was carried out based on test data,representing its agreement with the test.The studies in this paper have established a necessary basis for further distortion test and surge test in the air.
Prediction of aeroengine exhaust gas temperature using process neural network
DING Gang, XU Min-qiang, HOU Li-guo
2009, 24(5): 1035-1039.
Abstract PDF(787KB) icon1739 icon472
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From the perspective of functional analysis,the prediction of the aeroengine exhaust gas temperature could be seen as a functional approximation problem in nature.Utilizing the functional approximation capability of the process neural network,an aeroengine exhaust gas temperature prediction method was proposed based on the process neural network.In order to overcome the problem that the learning speed of the existing learning algorithm for process neural network is slow,a Levenberg-Marquardt learning algorithm based on the expansion of the orthogonal basis functions was developed.Finally,the proposed prediction method with the corresponding learning algorithm was used to predict the exhaust gas temperature of some aeroengine,and the results were satisfactory.
Research about the characteristic of drag reduction over riblets surface based on average velocity profile in the turbulent boundary layer
HU Hai-bao, SONG Bao-wei, LIU Zhan-yi, HUANG Ming-ming, PAN Guang
2009, 24(5): 1040-1047.
Abstract PDF(982KB) icon1875 icon494
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Through thorough analysis about the characteristic of average velocity profile in the turbulent boundary layer over riblets surface that was measured by a hot wire anemometry in a miniature special wind tunnel,the drag reduction ranges and rules were acquired.In the calculation of virtual origin and wall friction velocity of riblets surface,a modified method was presented to obtain virtual origin and wall friction velocity together by least-squares fitting method,based on Spalding formula in the turbulent boundary layer.In the calculation of the friction drag of models,a calculating method based on momentum integral equation for boundary layer was adopted,which could efficiently reduce the effect of testing errors of local testing point on calculation precision of models' friction drag.Ultimate results show that riblets thicken the viscous sub layer in the turbulent boundary layer,and decrease normal velocity grads of near wall,and boost up the buffer zone and logarithm region;the range of none dimension riblet width s+is about 6 to 18,when there exists the drag reduction effect,and the maximal drag reduction quantity about 7.7% appears when s+≈12.
Effects of throat geometry on micro nozzle's performance
TONG Jun-jie, XU Jin-liang, LI Yu-xiu, CEN Ji-wen
2009, 24(5): 1048-1054.
Abstract PDF(1174KB) icon1643 icon427
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The FLUENT6.1 software was applied to simulate the supersonic flow in micro convergent-divergent nozzle with 5.4 expansion ratios.The simulation was complemented by computing steady two-dimensional Navier-Stokes equations to study the effect of mass x velocity and total pressure from throat,which has arc or not and different throat arc radius.Also,the fluent mass and thrust force effects were studied.It is observed by the study that x orientation mass velocity of thrust exit and thrust force are effected by the throat which has arc or not and throat arc radius.With the increase of throat Reynolds,the corresponding throat radius for the maximal fluent mass and thrust force increases accordingly.
Studies on flying qualities of a tandem helicopter at hover
LI Guo-zhi, CAO Yi-hua
2009, 24(5): 1055-1060.
Abstract PDF(883KB) icon1547 icon466
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Based on the flight dynamic model suited to evaluate the flying qualities of a tandem helicopter,the open-loop flying qualities of a tandem helicopter at hover were studied by using military specification flying qualities of piloted vertical/short takeoff and landing(V/STOL) aircraft(MIL-F-83300) and handling qualities requirements for military helicopters(ADS-33E-PRF).According to those requirements,the dynamic response characteristics and the bandwidth were analyzed,along with the control characteristics and the attitude quickness.The interaxis coupling and the disturbance of the lateral gust were also studied.At last,the conclusions are summarized in this paper.
Application of pattern recognition with statistics for engine fault diagnosis
ZHU Da-ming, ZHU Zhi-li
2009, 24(5): 1061-1065.
Abstract PDF(1362KB) icon1746 icon443
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A combined method of pattern recognition and statistics was examined to diagnose the double faults of a double-shaft dividually-exhausting turbofan engine.The pattern recognition is based on the engine performance simulation model.Balance technique of engine was used during recognition process and the non-linear characteristic was considered.The result got by pattern recognition was treated statistically,compensating the deficiency in fault isolation decided purely by comparability.The right fault index is defined and calculated,proving that it is effective for double faults isolation.
Evaluation of a numerical calculation method for unsteady flow in turbomachinery
GE Ning
2009, 24(5): 1066-1070.
Abstract PDF(1118KB) icon1577 icon471
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The real blade-to-blade passage geometry can be computed owing to approximate treatment of the flow continuity condition on periodic boundaries.This technique is specifically intended to reduce the computational domain.The boundary treatment induces some approximate computation of the unsteady flow phenomena.These were analyzed in the cases of the E3 high-pressure turbine in which the viscous flow was computed.The main conclusion is that,this approach doesn't affect the time average performance parameters and can also be applied to multi-stage turbines.
Experimental study on cooperative control of unsteady separated flow in axial-flow compressors
LI Zhi-ping, LI Qiu-shi, YUAN Wei, LU Ya-jun, WU Yu-lin
2009, 24(5): 1071-1078.
Abstract PDF(1201KB) icon1793 icon505
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The control methods of large-scale separated flows inside a low-speed axial-flow compressor facility were investigated by external acoustic excitations.The focus of research was put on the coupling relationship between excitation frequency and typical shedding frequency of unsteady separation vortex,while the influences of excitation amplitude and the types of the excitations signal wave on the flow control were explored.The experimental results indicate that the excitation frequency and excitation amplitude are the most importance parameters for controlling large-scale separated flows.The types of the excitation signal wave has some effects for separated flow control too.When the unsteady excitation was the most effective frequency with proper amplitude,the large-scale separated flow was delayed or controlled,and the flow field became more regular near the compressor's stall margin.
Numerical research of three dimensional flow-path in a ram-rotor
HAN Ji-ang, ZHONG Jing-jun, YAN Hong-ming, SUN Peng, YU Yang
2009, 24(5): 1079-1088.
Abstract PDF(1733KB) icon1776 icon452
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According to the design method of a typical three dimensional supersonic intake,a kind of three dimensional flow-path of a ram-rotor was designed.The three dimensional Reynolds-averaged Navier-Stokes equations and the Spalart-Allmaras turbulent model were adopted to simulate numerically the flow field of the designed three dimensional flow-path of the ram-rotor.It has been found that,unlike the linear shock wave system in three dimensional supersonic intake,the shock wave in the three dimensional flow-path is curved shock wave.As compared to the two dimensional flow-path,the shock wave system in the three dimensional flow-path is more vaguer and complex.The back pressure and the rotational speed have great influence on the performance of the three dimensional flow-path.
Study of an air-cooled turbine blade profile with depression feature at leading edge
WANG Kai, WANG Song-tao, WANG Zhong-qi
2009, 24(5): 1089-1095.
Abstract PDF(1422KB) icon1439 icon418
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A new air-cooled turbine blade profile with depression feature at leading edge was presented in this paper.The flow field of this blade profile at the transonic condition was simulated in detail.The change of vortex position induced by the leading edge cooling air injection along the blade profile was observed.The aerodynamic characteristics of the new blade,such as film effectiveness,energy loss and pressure field,were compared with the traditional air-cooled turbine blade.The result shows that this new blade locks up the vortex induced by the leading edge cooling air injection in its depression part.The mixing of cooling air and mainstream becomes weak.Thus,the number of the leading edge cooling air injection holes can be reduced along with the decreasing amount of injection.
Numerical analysis of the secondary flow and tip clearance leakage loss
SHI Bao-long, QI Xing-ming, JIAO Jin-yi, YANG Rong-yu
2009, 24(5): 1096-1100.
Abstract PDF(1124KB) icon2499 icon510
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The secondary flow loss plays a main part in the total loss of high pressure turbine's(HPT).Based on the structure of one type aero-engine,this paper is focused on mechanic of the tip clearance structure,which influences the turbine characteristics.Numerical results agree well with the experiment data.The detailed information of the flow fields shows that,with the same tip clearance flow area,the step and shrink tip clearance shape perform better than line tip clearance shape,while the groove and bulge shape is worse relatively.Suppressed by the up passage vortex at upstream side of blade,the intensity and scale of the tip clearance leakage vortex is decreased.There are flow separations at the front blade of bulge tip clearance.The high speed area of groove tip clearance increases the secondary flow loss dramatically.
Application of endwall contour on subsonic axial flow compressor stage
LU Jia-ling, CHU Wu-li, HU Shu-zhen, LIU Zhi-wei
2009, 24(5): 1101-1107.
Abstract PDF(1092KB) icon1573 icon460
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For exploring the beneficial usage of profiled endwall on axial flow compressors.A profiled endwall was designed and numerically studied on a subsonic axial flow compressor stage of Northwest Polytechinical University was numerically studied.According to the nature of the adverse pressure gradient working environment of compressors,the contouring of the stator endwall was conducted on both streamwise and circumferential directions.Detailed design method was introduced in the paper.Research of this paper shows that: endwall contouring can effectively reduce the stator hub corner separation,and consequently improve the compressor pressure ratio and working efficiency.
Multi-objective optimization design of turbine stage with consideration of variables
CHEN Zhi-peng, YUAN Xin
2009, 24(5): 1108-1113.
Abstract PDF(1528KB) icon1371 icon450
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Optimization design method was used to optimize the flow-path modeling of one turbine stage.The parametric modeling method based on non-uniform rational B-spline(NURBS) technology was used for turbine stage flow-path parametric modeling.The maximum isentropic efficiency and minimum temperature at rotor hub of the leading edge were selected for multi-objective optimization design.Combinatorial optimization strategy based on parallel sub space was introduced for the large-scale and multi-objective optimization so as to improve the efficiency of the optimization and shorten the design cycle optimization.Optimal design of the turbine-efficiency was improved by 0.664%,the maximum temperature at rotor hub of the leading edge dropped within the range of 1.5%.This work shows that this design method of turbine design is of great value.
Investigation on the inlet radial distortion of axial-flow fan
QIAO Qing-hua, ZHONG Fang-yuan, YANG Bo
2009, 24(5): 1114-1121.
Abstract PDF(902KB) icon1558 icon462
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The inlet velocity distortion was analyzed by di-actuator theory in this paper.The research on the inlet distortion was implemented by changing the inlet velocity distribution via di-actuator theory.The computational results were compared with the experimental results,and then a rational velocity distribution was obtained in this paper.
Investigation on the aerodynamic adjustment between inlet guide-vane,stator,and operating speed of three-stage axial compressor
GONG Wei, ZHANG Hong-wu, NIE Chao-qun
2009, 24(5): 1122-1128.
Abstract PDF(1188KB) icon1562 icon469
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With the use of 3-D viscous flow analysis technology,this paper analyzed the separation losses and stall margin at design speed and off-design condition,by changing the angle of inlet guide vane and stator.In the event of matching of stagger angle between inlet guide vane and stator,the change tendency and characteristics of compressor efficiency and stall were investigated.It shows the linkage controlling scheme of vane-stator is related to rotating speed.The result provides a basic standard for scheme design of self-adaptive control in practice.
Experiment on flow control using Gurney-flaps for a low-pressure turbine cascade
ZHANG Jun-sheng, QIAO Wei-yang, SUN Da-wei
2009, 24(5): 1129-1135.
Abstract PDF(790KB) icon2098 icon525
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An experiment was conducted to study the flow control effects of the Gurney-flaps which were fixed on the trailing edge of the pressure surface of PAK-B low-pressure turbine blade.The experiment adopted different shapes of Gurney-flaps with different heights under various flow conditions.The experimental results show that Gurney-flaps can effectively reduce flow loss when PAK-B profile is stall.At Re=23 000,Ma=0.021,FSTI=1%,the loss coefficient of total pressure is reduced by about 29% and the flow turning angle is increased by about 3.12% when fixed round Gurney-flaps with H=1% chord length;meanwhile the inlet primary flow mass is reduced by about 5%;the Gurney-flaps can also delay boundary layer separation,reattach on blade profile suction side and diminish the wake zone,thus reducing the flow loss.
Research on low speed characteristics of compressor based on parabola extrapolation
WANG Yu, LIU Jian-xun, LI Ying-hong, ZHENG Tie-jun
2009, 24(5): 1136-1142.
Abstract PDF(942KB) icon1783 icon509
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The main difficulty in aeroengine startup procedure lies in lack of component characteristics at low speed.In order to solve this problem,a method of acquiring compressor's low speed characteristics based on parabola extrapolation was studied.According to the examples for compressors of two different types of engines and the reasonable criterion,this method is characterized by exactness and universality.
Fuzzy reliability allocation method for engine based on the experts' knowledge
GU Ying-kui, HUANG Kai-qi
2009, 24(5): 1143-1149.
Abstract PDF(1971KB) icon1733 icon532
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A fuzzy reliability allocation method for engine was proposed based on multi-field experts' knowledge.In this method,fuzzy set theory was used to decrease subjective preferences of decision makers as well as fuzzy and uncertain factors in reliability allocation process.The mathematical model of fuzzy reliability allocation for engine was constructed based on the analysis of influential factors to engine reliability allocation.A fuzzy evaluation matrix method was proposed to determine the weights of the influential factors in which the triangular fuzzy numbers were utilized to substitute the scaling scheme of conventional analytic hierarchy process.Experts' opinions and the risk index of the product development process were also taken into account in the method.An application example was used to verify effectiveness and feasibility of the proposed method.
Numerical simulations of bird impact on helicopter rotor blades
WEN Hai-tao, GUAN Yu-pu, GAO De-ping
2009, 24(5): 1150-1157.
Abstract PDF(1743KB) icon1482 icon449
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As a example,helicopter rotor blade was numerical simulated,adopting advanced arbitrary Lagrangian Eulerian(ALE)fluid-structure interaction algorithmic theory,with dynamic transient analysis software(MSC.Dytran).The results show that: the stress in the course of impact equals 199 MPa,but not oversteps yield limit of the blade material.Analysis results are important for improving the anti-impacting damage ability of helicopter rotor blades under bird impact.
Analysis of nonlinear response of shrouded blades system
SHI Ya-jie, SHAN Ying-chun, ZHU Zi-gen
2009, 24(5): 1158-1165.
Abstract PDF(2424KB) icon1579 icon469
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Base on the idea of alternating frequency/time(AFT) domain,an approach to predict the nonlinear response of a shrouded blade system was developed using free mode shapes.Some sources of error in the process of previous AFT were eliminated and the instantaneous variety of contact stiffness was taken into account,improving evidently the correctness and efficiency.Comparison of the calculated and experimental results proves that this method meet the engineering need of blade damping design fully.Furthermore,influences of the number of free mode shapes on the calculated results are studied.It is found that in the neighborhood of the fully slip region,few number of free mode shapes are required in order to obtain the accurate resonant response of a shrouded blade system;however,it need much more number of free mode shapes to obtain the accurate response in the neighborhood of the fully stuck region.
Method of failure reporting,analysis and corrective action system model for aircraft engine
LIN Hai-ying, WANG Jing-ran
2009, 24(5): 1166-1170.
Abstract PDF(966KB) icon1594 icon483
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The method of failure reporting,analysis and corrective action system(FRACAS) for aircraft engine was proposed in this paper,whereby we can investigate,analyze and correct the design in a well-planned and orderly manner.It can be used for identifying the exact reasons and ensuring the availability of corrective action.This method is effective to control the failure in close loop and get rid of reasons affecting the product.In this way,the method can guide the programming of simulation software.The result is to improve the ability of rivalship and the ability of market reaction.It can help the aircraft engine manufacturers to achieve success in quality management and efficiency for high level and zero failure.The method is useful and effective in the practice.
Design of rotor system for micro turbine jet engine
CHEN Wei, DU Fa-rong, DING Shui-ting, LI Yun-qing
2009, 24(5): 1171-1176.
Abstract PDF(961KB) icon1967 icon542
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A micro turbine jet engine,as a research object,was studied in order to conduct the design process and methods of micro turbine jet engine rotor system.Firstly,this paper introduced the engine and it's rotor system structures,generalized the design principles of rotor system,and then emphasized the design process of rotor system from bearing choices,rotor dynamic characteristics,vibration absorber techniques,rotor dynamic balance and bearing failure formats.These design experiences can be references for improving design ability of domestic micro turbine jet engine.
Powerflow transfer ratio of vibration path systems in frequency range
ZHAO Qun, ZHANG Yi-min, ZHAO Jin-fang
2009, 24(5): 1177-1181.
Abstract PDF(580KB) icon1574 icon471
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Based on the theory of powerflow and the generalized probabilistic perturbation method,this paper studied the path powerflow transfer probability of multiple sources exciting floating raft system in frequency range;and,the new concept and effective approach of path powerflow transfer ratio for vibration transfer path systems in frequency range were presented.The powerflow transfer ratio among multiple and/or multi-dimensional paths was described correctly and expressly in frequency range when uncertain factors were considered.
Investigation on pressure oscillation propagation from combustion chamber to pipeline through injector
YANG Li-jun, FU Qing-fei
2009, 24(5): 1182-1186.
Abstract PDF(1568KB) icon1589 icon417
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In order to investigate the effect of injector on pressure oscillation propagation from liquid rocket engine combustion chamber to pipe-line,the process of pressure oscillation propagation from combustion chamber to pipe-line was theoretically researched in this paper;and the transfer function was also deduced.The dynamic characteristic of pipe-line linked with various injectors was discussed.The influences of pipe-line length,combustion chamber pressure,injector type and configuration on pressure oscillation propagation process were calculated,the influence rule of injector and operating condition parameters on propagation process was gained finally.
Research on the low frequency characteristics of LOX/kerosene staged combustion cycle engine
LI Bin, DU Da-hua, ZHANG Gui-tian, ZHANG Ji-tong
2009, 24(5): 1187-1191.
Abstract PDF(1869KB) icon2130 icon477
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Based on the modeling technology of modularization and topology generation,a linear small perturbation dynamics transfer matrix model was developed for analysis of a LOX(liquid oxygen)/kerosene staged combustion cycle engine.In the process of modeling,the gas-path model of the adiabatic flow assumption was adopted,and the entropy wave affections were emphatically studied.As per the alternating current fluid network theory,the low frequency characteristics of the engine system were investigated by using transfer function method;the research of this paper can benefit the POGO and engine dynamics studies of liquid rockets.
Working parameters measurement and precision analysis of ground experiment on arcjet thrusters
ZHANG Xin-ai, TANG Hai-bin, LIU Chang, ZHANG Zhen-peng, MA Bin, LIU Yu
2009, 24(5): 1192-1196.
Abstract PDF(622KB) icon1542 icon464
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A data acquisition system was built to determine the characters and performance of lower power arcjet thrusters in the ground experiments.Testing principle of working parameters,composition of software and hardware of the system,correlative technical parameters of hardware were depicted in details.Measurement accuracy in working channels were analyzed.Typical testing results were also given.A conclusion can be drawn through the analysis that this data acquisition system can measure working parameters of thrusters accurately,especially obtain the micro mass flow rate and small thrust data,so that the ground experimental status is reflected really.This data acquisition system provides a test platform with reliability for further study on low power arcjet thrusters.

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