2011 Vol. 26, No. 11

  Previous Issue | Next Issue 
Display Method:
Analysis on rubs of double rotor-stator coupling system
YUAN Hui-qun, HE Wei, HAN Qing-kai
2011, 26(11): 2401-2408.
Abstract PDF(1217KB) icon2763 icon357
Abstract:
Since the double rotor structure has been applied largely in aircraft engine, the double rotor-stator coupling system of an Aircraft engine has simplified the rotor system into double rotor-stator coupling dynamic system, in which the bearing was simplified into spring and damping. Considered the coupling of the low pressure rotor and high pressure rotor through the intermediate bearing, the fourth-order partial differential equations of motion of the continuum double rotor multi-disk-stator system were formed. Applying the variable step size fourth order Runge-Kutta method, rub response of the double rotor system was simulated, analyzed the affect of speed and intermediate bearing's stiffness to the rub response, found some nonlinear dynamic characteristics of the double rotor model when rubs happened, which provides some reference methods for the actual engineering problems and has certain engineering significances.
Laser shock processing and aluminizing compound technology used on steel blade
LI Ying-hong, LI Wei, HE Wei-feng, LI Yu-qin, LI Qi-peng
2011, 26(11): 2409-2415.
Abstract PDF(1005KB) icon1654 icon107
Abstract:

Scanning electron microscopy (SEM),X-ray diffraction (XRD) and other techniques were used to detect the influence of laser shock processing (LSP) on aluminizing layer,which is infiltrated into the stainless steel blade for antisepticising.The results show that the aluminizing layer will be destroyed when LSP is implemented after aluminizing.And the quality of aluminizing layer will be improved while LSP is implemented before aluminizing.The influence on the LSP by the high temperature in the course of aluminizing was studied through residual stress test and metallographic analysis.After 150 minutes in the condition of aluminizing temperature 510℃,the residual compressive stress in the LSP zone was still -295MPa and the refined grain did not grow up remarkably.The residual compressive stress and grain refinement layer induced by LSP had good thermo stability.Finally,the vibration fatigue performance of different states stainless steels was tested.When the maximum stress is 660MPa,the fatigue life of “LSP before aluminizing” is about 3.98 ×106,which is about fourteen times than that of aluminizing.
Failure mode research on CCF 300 and T300 carbon fiber composite laminates with delamination under compressive strength
FU Hui-min, YANG Yu-song, ZHANG Yong-bo
2011, 26(11): 2416-2421.
Abstract PDF(1397KB) icon2467 icon90
Abstract:
The compression test was conducted on the homemade and T300 carbon fiber composite laminate with one delamination. According to the macro-shape and the ultrasonic C-scan result of post-failure specimens which contain different sizes and different positions of delaminations but the same thickness, an investigation has been conducted by this study on the effects of delmaination sizes and positions on the failure mechanism of homemade and T300 carbon fiber composite laminates. Also the differences of failure mode have been analyzed between these two kinds of composites. The final result shows that the imbedded delaminations have all propagated, and the position of delamination proposed to be the most important factors affecting the compressive failure mode. To the laminates with deep delamination the failure mode presented to be the first propagation of delamination and second shear buckling failure of sub-laminate. Based on these analyses we find that the failure mode of homemade carbon fiber composite is same with the T300 carbon fiber composite generally.
Vibration analysis on turbofan engine intershaft bearing with outer race defect
LIAO Ming-fu, MA Zhen-guo, DENG Wei
2011, 26(11): 2422-2426.
Abstract PDF(1027KB) icon2192 icon109
Abstract:
According to structural characteristics and kinetic characters of dual-rotor turbofan engine,a intershaft bearing test rig was developed to experiment and test vibration of a intershaft bearing with contact fatigue spalling.Defect characteristic octave frequency formula of intershaft bearing and a model was developed to describe the vibration signals and its envelope signals produced by a intershaft bearing with defect.
Flexible multi-body dynamics simulation of cold state axial-symmetric vectoring exhaust nozzle
WANG Han-ping, ZHANG Yu-bing, YANG Ming
2011, 26(11): 2427-2432.
Abstract PDF(967KB) icon2195 icon86
Abstract:
The crucial parts of axial-symmetric vectoring exhaust nozzle(AVEN) were meshed into flexible bodies with solid-shell elements.A flexible multi-body dynamics model of AVEN was built based on MSC.ADAMS command batch processing technique and tree-shape parametric technique.A part of contact constraints in the dynamics model were simplified with point-curve constraints to reduce the computational size.By means of simulation of shaking and swinging movement of the AVEN on normal temperature condition,the loading and dynamic characteristics of the mechanism were achieved.Provided an important reference for virtual design and virtual experiment of AVEN.
ICT assisted detection for remainders in the internal cooling channel of the turbine blade
YANG Min, SUN Jing-jing, LI Xing-dong, WEI Dong-bo
2011, 26(11): 2433-2438.
Abstract PDF(1110KB) icon1871 icon98
Abstract:
In order to detect remainders in the internal cooling channels by non-destructive means with high accuracy,industrial computed tomography was used to scan the tested blade.The position displacement parameters between the tested blade and the standard specimen were calculated base on the rigid transformation and sinogram projection.Then the sinograms of the scanned slice and the corresponding standard slice were matched together in order to extract the sinogram of the remainders and the reconstructed images of them were obtained.The experimental results prove that this method can extract remainders in the internal cooling channels effectively.Compared to the traditional remainder extraction algorithm based on CT(computed tomography) image,the proposed algorithm is realized in the projection domain,and it is rarely affected by projection data incompleteness,scanning system bias and the reconstruction artifacts,so it has a higher accuracy.
Consistent test of accelerated storage degradation failure mechanism based on rank correlation coefficient
FENG Jing
2011, 26(11): 2439-2444.
Abstract PDF(895KB) icon1861 icon91
Abstract:
The premise of predicting storage life from accelerated storage test data is the consistency of failure mechanism between use condition and raised stresses. Nonparametric consistent test method for accelerated storage degradation failure mechanism was proposed based on Spearman rank correlation coefficient.If the failure mechanism is consistent in different stresses,the shape of the degradation path is the same.This is essential to consistent test.The Spearman rank correlation coefficient was proposed to measure the difference of the curve shape in different stresses.At last,two examples were given to illustrate the validity of the method.
Research on aeroengine vibration fault diagnosis based on support vector machine and generalized roughness feature
WU Ya-hui, LI Xin-liang, HONG Bao-lin, ZHANG Da-zhi
2011, 26(11): 2445-2449.
Abstract PDF(799KB) icon1820 icon99
Abstract:
The signal was decomposed based on wavelet transform and the generalized roughness vector of the signal was formed by making use of the local energy distributions and the roughness of the sub-band signal.Then the desired parameters serve as the fault characteristic vectors to be input to the support vector machine classifier and the work conditions and fault patterns were identified by the output of the classifier.The analysis results from the aeroengine vibration signals show that the fault diagnosis method can classify working conditions and fault patterns effectively.
Parametrical FE modeling of blade and design optimization of its gravity center eccentricity
WANG Zhen-pei, WANG Dan, ZHU Ji-hong, ZHANG Wei-hong
2011, 26(11): 2450-2458.
Abstract PDF(1314KB) icon2370 icon142
Abstract:
A parametric discretization method for blade was proposed based on the FE (finite element) mesh morphing technique.This method has advantage of realizing automatic and rapid updating of the finite elements meshes without any change of the mesh topology.Moreover,a general procedure was established for the design optimization of the gravity center eccentricity of blade in combination with design sensitivity analysis.Numerical examples were solved successfully.Optimization results show that the stress level and distribution can be largely improved by means of the proposed design procedure.
Unit cell of 2.5 dimension C/SiC and its stiffness prediction
KONG Chun-yuan, SUN Zhi-gang, GAO Xi-guang, SONG Ying-dong
2011, 26(11): 2459-2467.
Abstract PDF(1228KB) icon1785 icon115
Abstract:
A kind of unit cell for 2.5 dimension C/SiC composites was established by extracting the boundary of warp,fitting the curve using robust least square and simplifying the fitted curve.The elastic properties of 2.5 dimension C/SiC composites were predicted using dual-scale model;the dual-scale model was micro-scale which considered the scale of matrix/fiber/pore,and also meso-scale which considered the scale of warp/weft/cavity.The method for predicting the elastic properties of 2.5 dimension C/SiC composites was stiffness average method and energy method;finally the relationship between the porosity in the micro-scale and the elastic properties of 2.5 dimension C/SiC composites was discussed.Numerical results show that the theoretical results using energy method and stiffness average method have little difference;when considering the micro-scale porosity,the theoretical results can fit the experimental results better.
Effect of combined cycle load upon the fatigue performance of titanium alloy TC11
ZHAO Zhen-hua, CHEN Wei
2011, 26(11): 2468-2474.
Abstract PDF(1653KB) icon1793 icon75
Abstract:
In order to ascertain the effects of the combined cycle situation on the fatigue life,the high and low combined cycle fatigue tests,high cycle fatigue tests and low cycle fatigue tests on titanium alloy TC11 were performed.The results indicate that the combined cycle loading degrades the fatigue resistance of TC11 related to low cycle or high cycle fatigue loading.The CCF life is highly effected by the mean stress σ major and stress ratio R minor of the minor stress cycles.Fractograph and macrograph of fracture aspects under different kinds of loadings were investigated using scanning electron microscope(SEM).The fractograph of CCF fracture surfaces obviously differs from that of high cycle fatigue fracture surfaces.The slippage due to low cycle is the main reason of reducing the CCF life.
Reliability evaluation of communication satellite thruster
MAO Xiao-fang, YUE Xiao-rui, FU Hui-min
2011, 26(11): 2475-2479.
Abstract PDF(786KB) icon1616 icon47
Abstract:
A reliability evaluation and life prediction method on communication satellite thruster was established for its characters of long life,high manufacturing cost and experimental expense,and most of the obtained data are zero-failure data or very few failure data.For the difficulty to evaluate the reliability of satellite thrusters,a converting principle of information among different test conditions was provided,and successfully solved this problem.Based on these approaches,the reliability of communication satellite thruster can be evaluated with high precision.Data from impulse test and steady test of a thruster were analyzed,and the reliability evaluation for its geostationary orbit and transfer orbit were derived.
Experiment on the liner wall temperature of a slinger combustor
WANG Yi-yang, SONG Shuang-wen, CHEN Yan-geng
2011, 26(11): 2480-2484.
Abstract PDF(1235KB) icon2528 icon265
Abstract:
In an engine overall experiment,the liner wall temperature of a slinger combustor with diffusion cooling was measured by thermoindicator paint which may change color with varied temperature.The wall temperature distribution rule of the slinger combustor's liner was obtained.The experiment results were compared with numerical computations of flow field.The researches indicate that:(1)the temperature distribution of the liner wall is uniform,and the cooling method of the slinger combustor liner is acceptable;(2) the liner wall temperature gradient is small and the maximum wall temperature is much lower than the liner material's allowable operating temperature,hence,the liner is expected to have long endurance life.
Experiment of drag characteristics of a novel variable geometry flame-holder
LIU Yang, JIN Jie, WANG Hui-ru, LIU Yu-ying, YANG Mao-lin
2011, 26(11): 2485-2494.
Abstract PDF(1080KB) icon1430 icon59
Abstract:
A novel variable geometry flame-holder (VGF) based on V-gutter was presented. The structural characteristics of the flame holder were introduced. Experimental study on drag characteristics of the VGF on un-burning and burning states was conducted in a rectangular combustion test rig. The influence of the change of gutter trailing edge width w on pressure recovery in different operating conditions was analyzed emphatically. Furthermore,drag characteristics in different trailing edge width variation modes were discussed. Results show that: (1) Narrowing w can observably raise the total pressure recovery σ but the highest σ is not obtained at minimum w. (2) The relationship of drag coefficient ψ and w in the un-burning conditions can be well expressed in a form of exponential equation (w/d>0.4). (3) Drag characteristics are not sensitive to the variation modes and speeds of w . (4) In the burning condition,σ decreases with the increasing of w basically and the course can be divided into three stages. The results and experimental data presented in this paper would enhance the phenomenological understanding of this type of VGF,and would contribute to the next experimental study and numerical calculus of this novel VGF.
Atomization and evaporation performance experiment of evaporating tube for trapped vortex combustor
ZHANG Rong-chun, FAN Wei-jun, SONG Shuang-wen
2011, 26(11): 2495-2502.
Abstract PDF(1038KB) icon2031 icon54
Abstract:
Two kinds of evaporating tubes were designed for trapped vortex combustor,and their atomization and evaporation performance was experimentally investigated under different conditions of environmental temperature,vapour-liquid ratio,temperature and velocity of air for atomization.The results show that these conditions have great impact on the performance of atomization and evaporation,and there is a significant difference of atomization performance at different axial positions of the outlet of evaporating tube.The performance of two kinds of evaporation tubes was compared,and the better one was used as the oil supply device of the interstage turbine trapped vortex combustor.According to the results of the combustion performance tests,high combustion efficiency,wide range of stable combustion and low wall temperature can be achieved in the trapped vortex combustor.
Experimental investigation on improved piezoelectric synthetic jet actuator of geometric parameters
ZHANG Li, WANG Bang-feng, ZHOU Yong
2011, 26(11): 2503-2509.
Abstract PDF(1193KB) icon1669 icon43
Abstract:
A novel piezoelectric synthetic jet actuator was studied experimentally.The velocities of outflows were detected by hotwire anemometer.The frequency responses of time-average velocity and maximum velocity during one period were obtained.The results show that:in the region of low frequency,the time-average velocity and maximum velocity decrease monotonically;in the region of high frequency,the maximum velocity is affected by geometric parameters of the actuator evidently.And there is an optimum geometric size for the actuator to obtain the maximum peak velocity during the high frequency region.
Preliminary experimental investigation on pulse detonation rocket engine with central cone configuration
YAN Yu, FAN Wei, WANG Ke, MU Yang
2011, 26(11): 2510-2514.
Abstract PDF(852KB) icon1627 icon46
Abstract:
In order to improve the atomization of liquid fuel and mixing of reactants inside the pulse detonation rocket engine using liquid fuel,a pulse detonation rocket engine with a different configuration was invented.A central cone instead of Shchelkin spiral was used in this engine.Reactants could be injected into the engine both through the engine head and the central cone.With kerosene used as fuel,oxygen as oxidizer and nitrogen as purge gas,fully developed detonation waves were generated in this engine,which could operate steadily on multi-cycle mode.The result also indicates that this engine could greatly shorten the DDT (deflagration to detonation transition) run-up distance,and the DDT run-up distance is approximately five times of the inner diameter of detonation tube.Compared with the approach of installing Shchelkin spiral in the detonation tube as DDT enhancement device,the DDT run-up distance of this engine was shortened by 57.5%.
Numerical simulation on impingement cooling characteristics of pulsed detonation tube
WANG Xing-tao, ZHANG Jing-zhou, TAN Xiao-ming
2011, 26(11): 2515-2521.
Abstract PDF(990KB) icon1791 icon55
Abstract:
According to axial wall temperature distributions on pulsed detonation chamber wall measured from experiment,the quasi-steady state heat flux along the detonation tube with ladder distribution was deduced under a specific frequency.Based on the quasi-steady thermal load,a series of computations were conducted to analyze the cooling effects with array jet impingement.The results show that:the jet velocity from rear rows is bigger than that from the front rows due to end wall effects,the cooling action is stronger near the pulsed detonation tube edge,and the impingement cooling effect is worse in the middle part because the impinging jet is weakened by cross-flow forming from the front rows.Under the same cooling flow Reynolds number at circular passage inlet,the array jet holes are reasonably arranged at middle area of pulsed detonation chamber.When the ratio of the impinging space to diameter is 1.5,the cooling effect seems to be best with uniform axial temperature distribution and lowest peak temperature.And smaller diameter of the cooling holes is also beneficial to improving the cooling effects.
Experiment on the effects of side load and pipe diameter on the characteristics of boiling two-phase pipe flow
SHAN Shao-rong, SONG Bao-yin, MA Qi-cheng
2011, 26(11): 2522-2527.
Abstract PDF(970KB) icon1750 icon46
Abstract:
Serial experiments were conducted to obtain the flow and heat transfer characteristics of boiling two-phase pipe flow under different diameters and side load.By analyzing the measured parameters such as pressure drop,Reynolds number,void fraction,heat flux and heat transfer coefficient in the test pipe,the effects of side load and pipe diameter on the characteristics of boiling two-phase flow were studied.The results show that the greater the side load,the higher the pressure drop,the heat dissipation,and the lower the flow rate,the void fraction and the heat flux.Dynamic load increases the heat transfer coefficient for single-phase water flow.However for boiling two-phase flow,with the increase in side load,the heat transfer coefficient decreases somewhat first,then increases and finally decreases again.Pipe diameter also has great influence on Reynolds number,pressure drop,void fraction and heat dissipation.The pipe with smaller diameter has a larger flow resistance,and good heat exchange ability.
Study on ground-based inerting process influenced by different gas distribution for multi-bay fuel tank
FENG Chen-xi, LIU Wei-hua, LU Shi-hua, FENG Shi-yu
2011, 26(11): 2528-2533.
Abstract PDF(927KB) icon1890 icon42
Abstract:
Under the constant temperature and pressure boundary conditions,a mathematical model of fuel washing was established based on the numerical integration method.Firstly,the validity of the model was verified by comparing the calculated results obtained from the model of Boeing 747 with the experimental data published in foreign literatures,showing good agreement of the results.Secondly,the model of Boeing 737 central wing fuel tank was chosen as a research objective,the inerting gas was distributed by uniform and non-uniform ways;when the flow of inerting gas was distributed by volume and quantity ways,the changes of oxygen concentration with time and volumetric tank exchange (VTE) were calculated.The results shows that,when inerting is completed,uniform inlet with nitrogen-rich air distributed by volume costs the shortest inerting time,and uniform inlet with nitrogen-rich air distributed by quantity costs the longest inerting time.The comparison between changes of left side,right side and center in overall average oxygen concentration with VTE shows that non-uniform inlet is better than uniform inlet.
Safety margins analysis on turbocharging system in aircraft piston engine
DING Shui-ting, BAO Meng-yao, DU Fa-rong
2011, 26(11): 2534-2542.
Abstract PDF(1064KB) icon2028 icon51
Abstract:
Aiming to safety and power requirements for unmanned aerial vehicle(UAV) during high altitude long endurance,a simulation model was initially established for a certain aircraft piston turbocharger engine through using the MATLAB/Simulink.The model was constituted by four parts:turbocharger model,mean value engine model,intercooler model and waste gate model.The feasibility of model was verified by empirical data.Then,according to analysis safety margin of turbocharger engine level,the safety requirement for turbocharger engine was proposed,and the impact of key parameters on system safety have been researched.Finally,based on safety margins principles for waste gate was demonstrated,which made the whole turbocharger system of aircraft piston engine performed within the safety margins.The result indicates that the model-based research on turbocharger engine system can obtain safety margin of system,provide reference for further improvement of turbocharger engine system at an acceptable safety level,and ensure the safety requirement during design period.
Performance simulation of turboshaft engines with interstage turbine burner
CHENG Ben-lin, ZHOU Wen-xiang, ZHANG Kun-yuan
2011, 26(11): 2543-2548.
Abstract PDF(818KB) icon2250 icon51
Abstract:
In order to analysis the turboshaft engine performance increase through interstage turbine burner (ITB),two component-level steady performance simulation models of turboshaft engines with ITB were developed.The performance variations of turboshaft engines with ITB were studied through simulation at different ITB temperature rise and total pressure loss.Results show that:The specific and total shaft power of turboshaft engines with ITB are sensitive to the ITB temperature rise and total pressure recovery coefficients.If the ITB total pressure recovery coefficient is 0.95 and temperature rise is 200K,while keeping the engine inlet air flow constant,the specific and total shaft power of turboshaft engine with ITB will increase 17%,and the specific fuel consumption will increase 11%.When the ITB temperature rise is high,it is necessary to enlarge free turbine nozzle area to improve the flow capability,so as to further increase the total shaft power and lower the free turbine inlet temperature;In general,it is better to set the ITB in turbine transition duct for more sufficient space and more excellent performance improvements.
Flow field characteristics of a side-mounted subsonic inlet of unmanned aerial vehicle
JIANG Wu-gen, PENG Yun-hui, LI Bo
2011, 26(11): 2549-2555.
Abstract PDF(1337KB) icon1602 icon49
Abstract:
A side-mounted subsonic inlet of unmanned aerial vehicle (UAV) was designed and the flow field was simulated.The characteristics of the inlet were obtained.The results show that, the inlet lip,the junction of the duct and the engine hub have great influence on the flow filed and characteristics of the inlet.The engine hub can improve the quality of the flow field at the exit of the inlet and reduce the distortion index.The total pressure recovery coefficient of the inlet is more than 0.97 and the distortion index is less than 0.15.The inlet meets the requirements of the engine at all states.
Preliminary study on hypersonic curved shock two-dimensional inlet
ZHANG Lin, ZHANG Kun-yuan, WANG Lei, NAN Xiang-jun, XIANG You-zhi
2011, 26(11): 2556-2562.
Abstract PDF(1067KB) icon1907 icon54
Abstract:
A type of curved compression surface with certain wall pressure distribution was investigated,and a hypersonic curved shock two-dimensional inlet was designed.The performance was compared through numerical simulation with normal hypersonic three-wedge and wedge-isentropic two-dimensional inlets under the same conditions.The result shows:the curved shock inlet with more stable boundary layer can be designed according a proper wall pressure distribution;the inlet can be shortened by 12% and 10%,respectively,as compared with three-wedge inlet and wedge-isentropic inlet,and is not very sensitive to the change of free stream Mach number;the new inlet has obvious superiority on the overall performance and bright prospect in the applications.
Comprehensive design of aerodynamic and infrared stealth of 2-D convergent nozzle with mixed flow
LI Na, JI Hong-hu, HUANG Wei, CHEN Jun, Siren, LIU Chang-chun
2011, 26(11): 2563-2570.
Abstract PDF(1038KB) icon1800 icon57
Abstract:
A design method of two-dimensional convergent nozzle of mixed flow turbofan engine was developed to meet aerodynamic and infrared stealth requirements.The feasibility of the design procedures was verified by numerical simulation.And the results indicate that nozzle inlet section position,nozzle length,throat area and aspect ratio properly play a key role for the required nozzle gross thrust.Choosing a reasonable aspect ratio is important for meeting the infrared stealth requirement.
Design of hypersonic inward turning inlets with basic flowfield using arc tangent curve law of pressure rise
NAN Xiang-jun, ZHANG Kun-yuan, JIN Zhi-guang
2011, 26(11): 2571-2577.
Abstract PDF(1078KB) icon1801 icon63
Abstract:
Numerical simulation was performed to study the performance of axisymmetric basic flowfield with arc tangent curve law of pressure rise,helping to weaken the leading shock wave and reduce the reference internal contraction ratio.This curve has three parameters,whose effects on the performance parameters such as total pressure recovery,static pressure ratio,contraction ratio and internal contraction ratio were studied.Finally,a circular inward turning inlet with the basic flowfield was designed and numerically simulated to get the flow characteristics and total performance.The result shows this inlet has weak leading shock wave and small internal contraction ratio,as well as high mass capture ratio and compression efficiency both on design point and off design point.
Modeling simulation of turboshaft engine IGV digital control system and PID controller improvement
ZHOU Jian-bo, DENG Wen-ge, LIU Tie-geng, SUN Jian-guo
2011, 26(11): 2578-2583.
Abstract PDF(917KB) icon1856 icon58
Abstract:
Simulation of turboshaft engine IGV (inlet guide vane) digital control system was performed with system model,which was obtained through analysis and calculation.PID(proportion integral derivative) controller of IGV was improved based on the above work and a method called predetermined incomplete differential of the second order PID control was proposed.Test results show that the IGV digital control system is improved obviously.The response is more quick without oscillation,and agrees with the design requirements.
Fault diagnosis system design for the sensors and components of aircraft engine based on cloud relational analysis
QIU Xiao-jie, HUANG Jin-quan, LU Feng, LIU Nan
2011, 26(11): 2584-2592.
Abstract PDF(1198KB) icon1806 icon54
Abstract:
Considering low accuracy problem of fault diagnosis for aircraft engine by gray relational analysis,the method of cloud relational analysis was proposed by integrating the cloud theory and the relational analysis.The characteristics of “cloud droplets” reflect fuzziness and randomicity of the mapping,and solve the problem in data mining while representing the distribution change of the integral “shape”.The comprehensive subjection method could mine information fully,then the cloud relation can be calculated.In order to diagnose the single fault for the sensors and components of aircraft engine,a fault diagnosis system based on cloud relational analysis was designed based on analysis of the fault characteristics of the sensors and the components.The simulation results show that the proposed method can not only distinguish the faults of sensors and components,but also locate the fault position of the sensors or the components.The methods can effectively improve the fault diagnosis ability for aircraft engine.
Aeroengine on-board adaptive model based on improved hybrid Kalman filter
LU Jun, GUO Ying-qing, ZHANG Shu-gang
2011, 26(11): 2593-2600.
Abstract PDF(1148KB) icon2007 icon58
Abstract:
A method of establishing aeroengine on-board adaptive model was proposed based on improved hybrid Kalman filter (IHKF). The output of nonlinear on-board engine model (NOBEM) was regarded as the steady-state basic model of piecewise linear Kalman filter(PWKF), while its performance deterioration factor was regarded as the augmented state vector of PWKF for on-line estimation, and fed back to NOBEM for on-line updating. In addition, the switching logic of work mode was established, which could make the IHKF work better. By applying this method to a turbofan engine, a series of simulation results show that the model can always match the actual engine in the whole flight envelope, under different engine states and severe performance deterioration, thus meeting the needs of practical applications.
Impact of run-out and meshing-frequency errors on dynamic load sharing for encased differential herringbone train
ZHU Zeng-bao, ZHU Ru-peng, BAO He-yun, JIN Guang-hu
2011, 26(11): 2601-2609.
Abstract PDF(1269KB) icon2208 icon65
Abstract:
Based on the theory of concentrated parameter,a dynamics model of the encased differential herringbone train was set up.The elastic deformation of the bearings,the time-varying meshing stiffness,the errors and the intermediate floating component were considered in the model.The helical gear meshing stiffness formula was introduced to calculate the time-varying mesh stiffness of herringbone in parallel way.Through solving of the dynamic equation by Fourier series method,the dynamic load sharing coefficients of the train were acquired and the impact of run-out and meshing-frequency errors on the load sharing was analyzed.The research results show that the load sharing coefficient of the differential stage affects the meshing-frequency errors greatly,it is increased with the meshing-frequency errors and is seldom influenced by the run-out errors.The load sharing coefficient of the encased stage is very sensitive to the run-out errors,it is largened with the run-out errors and is hardly affected by the meshing-frequency errors.The meshing-frequency errors have greater influences on the load sharing coefficient of the differential stage than run-out errors' on that of the encased stage,so the differential stage has a bigger load sharing coefficient than the encased stage.
Analysis of performance and interface structure of cylinder gas film seal
MA Gang, LI Xiu-hua, SHEN Xin-ming, HU Guang-yang
2011, 26(11): 2610-2616.
Abstract PDF(1044KB) icon2004 icon49
Abstract:
The type of interface structure obviously influences the performance and design of cylinder gas seal.The paper selected six typical interface structures derived from spiral groove,and performed quantitative analysis of mechanical properties and sealing performance of the gas-film based on finite element numerical analysis method;the relationship between sealing performance of different interfaces and compressibility number(and film thickness) was established;the sealing properties of different interface types and possible advantages and disadvantages of their application were analyzed,providing a basis for selection and design guidance of cylinder gas seal.The structural parameters of these interfaces are selected based on optimal or approximately optimal data of related literature.
Study on the control of the wing-body juncture horseshoe vortex utilizing Venturi tube
WANG Jian-ming, LIU Wei, XU Zhi-hui, AI Yan-ting, WANG Cheng-jun
2011, 26(11): 2617-2622.
Abstract PDF(1040KB) icon1938 icon52
Abstract:
In order to study on the control of the wing-body juncture horseshoe vortex utilizing Venturi tube,a typical wing-body junction region was presented.In order to conduct the control of horseshoe vortex,a wing with a slot placed upstream in the flat plate and a Venturi tube mounted on the other side of the plate was established.Because of the Venturi principle,when the flow passed over the throat,the slot acted as a quality injector.Numerical simulation was conducted to investigate turbulent junction flow with different positions of the slot.The results show that the horseshoe vortex can be controlled well,and furthermore eliminated completely horseshoe vortex,through the modification of the slot position relative to the wing.The proposed method can utilize potential energy,and does not consume any additional power.Therefore,it is a kind of passive control method with a great practical application prospect.The approach of the control of junction flows based on Venturi principle presented in this paper is promising in the engineering application since it is very simple and applicable.
Correlation analysis of blade vibration induced by inlet distortion and rotating stall
DU Jian-jian, LI Shun-ming, FANG Li-cheng
2011, 26(11): 2623-2629.
Abstract PDF(1080KB) icon1645 icon51
Abstract:
To analyze correlation degree between inlet distortion and rotating stall quantitatively,as well as blade displacement responses induced by them,blade vibration characteristics were simulated under inlet distortion or rotating stall by software ANSYS based on measurement data obtained from two stage low speed axial compressor,and correlation analysis between variables was made with statistics theories.The results indicate:two flow pressure data are highly related,and many characteristics are shared by them.Correlation degree between displacement responses is lower than that between inlet distortion and rotating stall.Correlation coefficient curve between displacement responses of the same section is of roughly asymmetrical V shape.Correlation coefficient between displacement responses of blade body from root to tip decreases gradually as it is mainly related to boundary conditions.
Liquid helium heat sink design for experimental study of engine's plume and vacuum effects
LING Gui-long, WANG Wen-long, CAI Guo-biao, ZHANG Jian-hua
2011, 26(11): 2630-2635.
Abstract PDF(891KB) icon1995 icon59
Abstract:
The large horizontal ultra-low temperature heat sink,based on liquid helium cooling,could firstly realize heat sink surface temperature below 10K in China,and is mainly applied to spacecraft-thruster vacuum plume effects' experimental study and the thermal vacuum test of satellite simultaneously.In order to minimize heat loss,the main structure of heat sink frame was removed,and the liquid helium heat sink was enclosed by a liquid nitrogen heat sink.Both of them were designed integrally so that the liquid nitrogen heat sink is not only the anti-radiation panel for liquid helium heat sink,but also the frame brace.To increase the pumping speed of heat sink,a plume adsorption pump was developed and mounted on the end of the vacuum chamber.At the experiment of vacuum plume,vacuum plume adsorption pump and liquid nitrogen heat sink were cooled by liquid helium and liquid nitrogen,respectively.The analysis was conducted for key parameters of heat sink,such as estimating the liquid nitrogen,liquid helium consumption in pre-cooling process and steady-state condition,and comparing the relationship between pumping speed of heat sink and working fluid temperature.The results show that pumping speed of the heat sink for nitrogen can reach 107L/s magnitude.
Fatigue damage of shipborne solid rocket motor propellant under swing loading
QU Kai, XING Yao-guo, ZHANG Xu-dong
2011, 26(11): 2636-2640.
Abstract PDF(886KB) icon2106 icon54
Abstract:
A fatigue damage evaluation method of propellant under swing loading was established for some solid rocket motor(SRM).Firstly,the fatigue damage property of composite solid propellant was acquired by fixed stress amplitude cycle loading experiment.Secondly,the stress spectrums of SRM nodes with time were obtained by method of finite element analysis.Finally,the rain-flowing counting method and the Miner's linear cumulative damage theory were applied to evaluate the fatigue damage of SRM.The results show that the fatigue damage of motor's dangerous area reaches 0.0855 by ship motion loading across a year.

Copyright © 《Journal of Aerospace Power》 All Rights Reserved.

Supported by: Beijing Renhe Information Technology Co., Ltd.