2007 Vol. 22, No. 7

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Best linear unbiased estimate method for incomplete interval censored data
FU Hui-min, AO Liang
2007, 22(7): 1025-1029.
Abstract PDF(292KB) icon1557 icon451
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The probability density function and joint probability density function of rank statistics for incomplete interval censored data are established,including the formulas of mean ranks,median ranks and percent ranks of rank statistics;furthermore,the means,variances and covariances of statistics for incomplete interval censored data are given in the paper.According to this,the best linear unbiased estimate method of location-scale distribution for incomplete interval censored data is presented,the confidence limits of percentiles for the incomplete interval censored data are obtained,and extreme value distribution,two-parameter Weibull distribution,normal distribution are discussed in detail.
Fault diagnosis and maintenance of equipment based on industrial CT technology
LU Hong-yi, XU Ming, YU Guang-hui, SUN Jian-guo
2007, 22(7): 1030-1034.
Abstract PDF(578KB) icon1609 icon439
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With advanced industrial computed tomography(CT) non-destructive testing(NDT) technology,ration NDT was made for inner structure of precise equipments.Every component's assembling relation and fit clearance was determined from the CT image.Then,intact equipment's CT images were compared,and the fault locations were diagnosed along with a repair scheme.For fault-free precise equipments,NDT with industrial CT provides precise measurement functions,enabling you to recognize inner-rotating parts' abrasion or relative displacement among components.And,a maintenance plan could be prepared by deducing the running stage with possible faults in the future.
Theoretic and experimental modal analysis of labyrinth air seals with damping-ring/sleeves
ZENG Liang, GUO Xue-lian, LI Lin
2007, 22(7): 1035-1043.
Abstract PDF(768KB) icon1634 icon430
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Modal analysis of contact system is complex due to its non-linear and chaotic behaviors in the process.This paper builds up the equivalent linear model of labyrinth air seals with damping-ring/sleeves by introducing local contact stiffness and using vibration mechanic theory.The experimental results of natural frequencies and mode shapes of the labyrinth air seals with damping-ring/sleeves verified the validity of the proposed simplified model and the simulation results by finite element method(FEM).The influence of variable parameters(position,width,thickness and gap size)of damping-ring/sleeves are also studied.
Numerical analysis and experiment of counter-rotating dual-rotor's steady-state response
HU Xuan, LUO Gui-huo, GAO De-ping
2007, 22(7): 1044-1049.
Abstract PDF(805KB) icon1676 icon541
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The counter-rotating dual-rotor system in aeroengines can reduce the influence of rotors' gyroscopic moments on aircrafts,cut down the torque of cases and improve the flexibility of airplanes.The steady-state response of a counter-rotating dual-rotor structure with one inter-shaft bearing was analyzed,of which the low pressure rotor is coupled with the inter-shaft bearing's outer ring,and the high pressure rotor coupled with the inter-shaft bearing's inner ring.By using transfer matrix method and corresponding boundary conditions,the steadystate responses of the counter-rotating dual-rotor system were analyzed,and the changing characteristics of the disks' orbits and the centroids' locations were studied experimentally,proving the relevant conclusions from calculations.
A load interpolation transfer method among disciplines in parametric space
LI Li-zhou, WANG Jing-chao, Lü Zhen-zhou, YUE Zhu-feng
2007, 22(7): 1050-1054.
Abstract PDF(989KB) icon1830 icon468
Abstract:
The multidisciplinary analysis(MDA) and optimization(MDO) of turbine blades introduce the needs of load transfer between computation fluid dynamics(CFD) models and computation structural mechanics(CSM) models,as meshes are mostly different on the disciplinary coupling interfaces.The direct interpolation method is the first and easiest method considered for this purpose.But this method requires fine meshes to reduce the influence of geometric curvature on transfer precision,which in turn will block the whole MDO process.In this paper an interpolation method in parametric space was proposed to transfer the loads.The coupled nodes of the dissimilarly meshed,the disciplinary interfaces were mapped into a flat parametric space in the method.There,the loads were transferred.During calculating load of a target node parameterized,several source nodes were selected in a small area around the target point.The load distribution in the area was fitted by a cubic function.Then,the load of the target point was calculated by the function.For the load are transferred in the flat parametric space in the method,the influence of geometric curvature on the interpolation precision is minimized,and the transfer accuracy is good enough even for coarse interface meshes.
Kriging model-based multidisciplinary design optimization for turbine blade
HAN Yong-zhi, GAO Hang-shan, LI Li-zhou, YUE Zhu-feng
2007, 22(7): 1055-1059.
Abstract PDF(411KB) icon1860 icon466
Abstract:
It presented a Kriging model-based multidisciplinary design optimization(MDO) framework for turbine blade.The approximation model,Kriging model,was reviewed and discussed systematically.Interdisciplinary coupling was considered by using loosely-coupled method.Based on multidisciplinary coupling analysis,the multidisciplinary feasible(MDF) method and Kriging model-based MDO method were founded respectively and compared subsequently.The results of optimizing a true blade show that the latter method can converge to the optimum fast and no precision lost obviously.And the overall blade performance improved remarkably demonstrates the efficiency and applicability of the proposed MDO framework.
Study on the influence of aerodynamic mistuned on unsteady aerodynamic force of blade
MENG Yue, LI Lin, LI Qi-han
2007, 22(7): 1060-1064.
Abstract PDF(516KB) icon1649 icon488
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To reduce the resonance stress of rotor blade under wake aerodynamic force of front stator vane,and also extend the fatigue endurance,the aerodynamic mistuned of stator vane was analyzed.Two kinds of design solutions of stator vane's aerodynamic mistuned were considered,one: uneven stator mistuned,and the other: asymmetry stator mistuned.Through calculation of unsteady flow field of stator-rotor model,the spectrum and amplitude of unsteady aerodynamic force of two mistuned design packages were compared.The results show that,uneven stator mistuned design couldn't reduce aerodynamic force of rotor blade,but lead to bigger frequency division of spectrum and amplitude.Though asymmetry stator mistuned may result in bigger amplitude aerodynamic force with the same frequency as rotational speed,it could reduce effectively the aerodynamic force of blade as a whole.
Vibration analysis of the blade-disc coupled structure of compressor
WANG Chun-jie, SONG Shun-guang, ZONG Xiao
2007, 22(7): 1065-1068.
Abstract PDF(1274KB) icon1555 icon479
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While a 3D assembly model of blade-disc structure was established,a finite element model for calculating the vibration characteristics during blade-disc coupling was set up by taking into consideration of the coupling action of contact stress between blade and disc.With the help of ANSYS software,the vibration characteristic of blade-disc coupling structure was calculated and analyzed using cycle analysis method.Through modeling experiment,this method is proved to be feasible for analyzing the rabbet assembly structure.
Numerical investigation on internal and external flows for axisymmetric convergent-divergent nozzles on over-expansion state
HUANG Hong-yan, WANG Qiang
2007, 22(7): 1069-1073.
Abstract PDF(473KB) icon1549 icon412
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When a axisymmetric convergent-divergent nozzle work at an over-expansion state,the strong shock wave and layer separation appear in the interior of the nozzle and the flow characteristic is very complex.The computed results were compared unfavorably with experimental data when adopting RNG k-ε turbulent model with standard wall functions.A wall treatment that combines a two-layer model with enhanced wall functions was employed in the numerical simulation and it was in good agreement with the experimental data.It is suggested that this enhanced wall treatment is more effective to deal with the problem of severe pressure gradients leading to boundary layer separations.
Blockage effect on the flow around a cylinder probe in calibration
WANG Hong-wei, WEI Jun
2007, 22(7): 1074-1081.
Abstract PDF(805KB) icon1317 icon523
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Flow around a 2-D cylinder pressure probe placed in uniform flow,free jet flow,and wind tunnel flow was analyzed with potential flow theory and simulated with numerical method.Blockage effect was investigated under several typical flow Mach numbers.The result from numerical simulation shows a similar trend to the one from potential flow method while varies in quantity.Wind tunnel walls accelerate the flow near the probe and thus produce a blockage effect;Boundary of free jet flow,however,decelerates the flow and thus produces a "negative" blockage effect.A maximum incoming Mach number exists when the probe is calibrated in wind tunnel in high subsonic condition due to choking caused by shocks and shock induced separation.The critical Mach number varies with blockage ratio,which makes high Mach number impossible to achieve in large blockage ratio condition.The blockage effect itself is unavoidable for calibration or measurement although a sufficiently small blockage ratio brings minor effect.Correction can be implemented based on the numerical simulation result presented in this paper and further works.
Application of BVF diagnosis on unsteady rotor/stator matching
RAO Jie, YUAN Wei, LI Qiu-shi, GONG Zhi-qiang, LU Li-peng
2007, 22(7): 1082-1086.
Abstract PDF(561KB) icon1776 icon466
Abstract:
An unsteady numerical simulation for a high-loaded transonic fan was performed.And,BVF(boundary vorticity flux) diagnosis method was employed to study the rotor/stator interaction under unsteady conditions.The results show BVF could capture clearly the influence of rotor/stator interaction upon the flow field,indicating that rotor wake interference was the primary cause of unsteady characteristic in downstream flow.According to the detailed BVF distribution by combining the static pressure and entropy analysis methods,the problems in the rotor tip and stator root for rotor/stator matching were found out.So,BVF diagnosis is a new method that could help reflect the state of rotor/stator matching,and also find out the root of negative factors to the flow field and the solution for flow field improvement.
Analysis of the influence of inlet flow distortion on the off-design performance of fan/booster
ZHAO Yong, HU Jun
2007, 22(7): 1087-1092.
Abstract PDF(903KB) icon1848 icon444
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A dual-shock loss model suitable for high-speed fan/compressor is incorporated into the streamline curvature method to estimate the actual operating condition of high-speed fan/compressor.Moreover,it helps to improve the accuracy of predicting the fan/compressor off-design performance,and further develop the quasi-3D model used to analyze the influence of the inlet flow distortion on the performance and stability of fan/compressor.For a high bypass ratio fan/booster with the Mach number lager than 1.4,the off-design performance and influence of inlet flow distortion is calculated and analyzed.The accurate calculated results,identical to the experimental results,are suitable for engineering applications.
Study of suppression boundary layer separation on the suction surface of supersonic compressor rotor
NAN Xiang-yi, LIU Bo, JIN Jun, CHEN Yun-yong, HOU Wei-min
2007, 22(7): 1093-1099.
Abstract PDF(769KB) icon1730 icon482
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To provide a further prospective of the boundary layer separation of compressor rotor under high load and off-design working conditions,numerical method was used to study the effects of boundary layer suction of compressor rotor at different suction positions and suction flow rates on the aerodynamic performance of rotor.The results show that the suction position has great effect on the suction result.The boundary layer separation on the suction surface can be suppressed effectively through suction in proper downstream separation section.And,the dramatic change of gas flow at the separation point could be improved with lower flow loss,while the stage efficiency and pressure ratio can be improved remarkably.The effect is unsatisfactory in the event of slotted suction far away from the upstream or downstream of separation point.As suction flow rate also has a certain influence upon the suction effect,either bigger or lower suction flow rate has adverse effect on the result.
Influence of slot treatment on flow performance of blade trailing edge
ZHOU Min, WANG Ru-gen, CAO Zhao-hui, ZHANG Xiang-yi
2007, 22(7): 1100-1105.
Abstract PDF(984KB) icon1719 icon623
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The slot treatment technology from pressure surface to suction surface of blade was proposed,while a slot solution starting from 80%～94% blade height of blade trailing edge was designed to conduct numerical simulation of the flow field of compressor after slot treatment.The result shows that,the slot inlet could suck low-speed boundary layer flow on the pressure surface of the blade,such that some boundary layer flow and main flow will be sucked into the slot and speedily discharged from the slot outlet.The low-speed boundary layer flow on the blade trailing edge could be accelerated,enabling to control or restrain separation region of the boundary layer flow,and also reduce the mixing of separated boundary layer flow of trailing edge and the blade trailing flow.The in-depth analysis shows that,the slot outlet flow could also control the migration of boundary layer flow towards the blade tip along the blade root,thus avoiding accumulation of boundary layer flow on the tip.So,the slot treatment technology can help improve the flow performance and stability of the flow field of blade trailing edge.
Large eddy simulation of turbulent diffusion flame combustion using a conserved scalar methodology
K.Wang, Z.Yang, J. J. McGuirk
2007, 22(7): 1106-1117.
Abstract PDF(970KB) icon1398 icon424
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The present paper describes an LES prediction of turbulent diffusion flame combustion in a simplified axi-symmetric combustor geometry.The calculations are carried out using a well-tested finite volume incompressible LES code which has been modified to handle variable density and reacting flows.The basic mixture fraction conserved scalar method is used with the chemical state relationships described by fast chemistry.The turbulence-chemistry interaction is modelled by a sub-grid PDF method and the PDF is assumed to follow a Beta-function shape.The LES predictions have been time-averaged over 3.5 flow-through times to generate the mean radial profiles of mixture fraction,product mass fraction,temperature,axial velocity and axial rms.The agreement of the LES predictions with the experimental data is good for all the above quantities at four different axial positions with largest differences at the first measurement plane.The LES method also provides information on the unsteady nature of turbulent diffusion combustion. For turbulent reacting flows with large density ratio,it was found necessary to use a relaxation method in order to remove unphysical high-frequency fluctuations and to maintain numerical stability.
Development of a micro gas turbine combustor with T-type vaporizers
XU Quan-hong, LIU Jun, XU Jian, LIN Yu-zhen, LIU Gao-en
2007, 22(7): 1118-1126.
Abstract PDF(606KB) icon1934 icon437
Abstract:
The study includes the experimental investigation of the evaporation performance of T-type vaporizer,mainly studied the relationship of the inlet air temperature and vaporizer wall temperature with the evaporation ratio.Then,it studied the LBO(lean blow out) and combustion efficiency of the micro aero-engine combustor with T-type vaporizer on the normal pressure test rig.The inlet air condition is environmental pressure and temperature.The gas analysis method is used to study the combustion efficiency,and the inlet air temperature is 300 K,400 K and 500 K.It could be concluded that the evaporation performance is improved with the increasing of the inlet air temperature and vaporizer wall temperature;the average LBO is 0.003;the combustion efficiency rises with the inlet air temperature,and it remain constant when the fuel/air ratio changed in the range from 0.008 to 0.02.The vaporization ratio is the key factor to determine the combustion performance.
Effect of inclined angle on discharge coefficient of the discrete holes in curved wall
ZHANG Chi, ZHAO Meng-meng, LIN Yu-zhen, LIU Gao-en
2007, 22(7): 1127-1131.
Abstract PDF(547KB) icon1673 icon442
Abstract:
An experimental investigation was conducted on the discharge coefficient of multi-holes cooling with different inclined angles in the curved wall for an aircraft engine combustor.The research purpose is to obtain the tendency of the average discharge coefficients with the pressure parameter,one of the most important influencing factors,and to analyze the flow dynamics.The research results indicate that as an aerodynamics factor the pressure parameter has significant impact on the discharge coefficient of the discrete holes for a given geometrical configuration,and for different inclined angles it has different effects.
Ignition and lean blow out performance of trapped vortex combustor with evaporating tubes fuel injection
KONG Zhao-jian, FAN Wei-jun, YI Qi, LIU Yu-ying, YANG Mao-lin
2007, 22(7): 1132-1137.
Abstract PDF(577KB) icon1946 icon508
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To investigated the ignition and lean blow out performance of a trapped vortex combustor(TVC)test rig,abundant experiments have been employed in variety inlet conditions.The TVC used a new type evaporating tubes as fuel injection manner,with kerosene as fuel.The results of the experiment indicate that the TVC could be used to extend combustion boundary.
Experimental study of heat transfer in snake-shaped variable cross-section channels with different ribs heights
LIU Xiang-yun, DING Shui-ting, TAO Zhi, XU Guo-qiang
2007, 22(7): 1138-1141.
Abstract PDF(287KB) icon1975 icon655
Abstract:
The influence of the rib heights on heat transfer characteristics in U-shaped variable cross-section channels was experimentally studied in the steady state.The design parameters include:relative roughness pitch 15 mm,rib width 2 mm,and relative roughness heights 1 mm,1.5 mm,2 mm,and 2.5 mm,respectively,and Renault number from 12 000 to 56 000.Based on ribless channel of the same shape,the influence of rib heights on heat transfer effect and resistance of a channel with 15 mm pitch was studied,so an empirical relational expression comprising geometrical parameters was obtained.The experimental results show that,the heat transfer of ribbed channel will be improved;the influence of the rib heights on the heat transfer of U-shaped variable cross-section channel is not monotone,but distributed with multi peak values.The influence of rib heights on the resistance coefficient increases with the rib heights.
Experimental investigation of exit temperatures of a infrared suppressor model
ZHU Ying, HUANG Yong
2007, 22(7): 1142-1147.
Abstract PDF(510KB) icon2003 icon410
Abstract:
An experiment was conducted to study the influences of airflow parameters on exit temperatures of an infrared suppressor model.The temperature of the main flow was about 610 ℃ and the pressure of the main flow was atmospheric pressure.The downwash flow velocity ranged from 4.4 to 11 m/s.The temperature of downwash flow was atmospheric temperature.The results show that,the exhaust flow temperature grows linearly with the increase of the main nozzle flux.The entrainment coefficient decreases with the increase of the downwash flow.With the increase of the downwash flow velocity,the exhaust temperature has a peak value the exhausting duct temperature decreases with the increase of the downwash flow velocity.The averaged gas velocity of flowing backward between the exhausting duct and the mixture tube increases with the rise of the main nozzle flux and the downwash flow velocity.
Research on primary jet of a reverse flow combustor model with swirl cup
MENG Jiang-tao, HUANG Yong, GUO Zhi-hui, XU Xu
2007, 22(7): 1148-1152.
Abstract PDF(391KB) icon1994 icon446
Abstract:
The characteristics of primary jets and its effects on the velocity field of reverse flow combustor model,which primarily comprising an axial-radial swirl cup and a primary hole with cooling air,was studied experimentally in the case of operating pressure of 300Kpa and pressure lose of combustor of 2.5%.The results show that,the air intake direction of primary jets into the reverse flow combustor differs from that of straight-flow combustors,namely,the inner jets inclined to downstream direction,and the outer jets inclined to upstream direction.The penetration of the primary jets is very deep to reach almost the opposite liner wall.And,the length of the recirculation zone is shortened remarkably,with L/D(length to diameter of swirl cup) about 0.5D,and L/D of typical straight-flow combustor about 1.3.
Study of performance and profile pressure distribution of transonic compressor under rotor-stator interaction condition
LI Shao-bin, SU Jie-xian, FENG Guo-tai, WANG Zhong-qi
2007, 22(7): 1153-1160.
Abstract PDF(2151KB) icon1728 icon465
Abstract:
The unsteady flow field of a high-load transonic compressor was numerically simulated at its working site,while the aerodynamic interaction of rotor-stator was analyzed in detail.Moreover,the unsteady global performance of this stage was discussed through the total pressure ratio and isentropic efficiency.Based on the static pressure coefficient,the profile pressure distribution and unsteadiness of rotor-stator interaction were analyzed to study the influence of trail and potential flow interference on the unsteady fluctuation for different blades.The results show that aerodynamic interaction has different influences on rotor-stator interaction,providing a further insight into the unsteady aerodynamic interaction of rotor-stator in a high-load transonic compressor.
Analysis of beam refraction effects in laser doppler velocimetry
ZHAO Jun, LIU Bao-jie, LIU Huo-xing
2007, 22(7): 1161-1166.
Abstract PDF(413KB) icon1399 icon419
Abstract:
A general mathematical program is developed in the paper to analyze the change of focus status after laser beams refracted at curved surface and to consider the displacement of focuses caused by refraction with various dimensions of window and various optical parameters.The creditability of the program has been validated and the associated parameters have been reviewed.The analyses of displacement of focus of blue beams,displacement of focus of green beams,and displacement between focus of green beams and focus of blue beams have been conducted in the case of two-dimensional laser doppler velocimetry(LDV) system,while a calculation criterion was presented to determine the superposition of focuses.The results demonstrated that small probe angle and shallow object depth should be essential in the case of lack of special optical correction.
Three-dimensional numerical simulation of rotating stall inside a centrifugal compressor with plenum model
GUO Qiang, ZHU Xiao-cheng, DU Zhao-hui, CHEN Hua, ZHAO Yan
2007, 22(7): 1167-1172.
Abstract PDF(639KB) icon1558 icon534
Abstract:
Numerical simulation results of rotating stall flow phenomenon inside a centrifugal compressor with vaneless diffuser by solving three-dimensional Reynolds averaged compressible N-S equations using commerce computational fluid dynamjcs(CFD) software CFX adopting RNG k-ε turbulence model are presented in this paper.Firstly,the steady performance curve is obtained using steady calculations and compared with experimental results. Secondly,a plenum chamber model is added at the vaneless diffuser outlet to simulate the rotating stall flow phenomenon inside the centrifugal compressor.The paper gives the centrifugal compressor internal flow fields at different times during the stall cycle at the least mass flow rate and observes the stall flow phenomenon.The plenum chamber influence on the rotating stall is also investigated.The simulation indicates the more the plenum chamber volume,the lower the stall frequency.
Analysis of H=0 & Ma=0 test for aero-ngine at ATF
LIU Zhi-you, GUO Rong-wei, HOU Min-jie, TIAN Jin-hu
2007, 22(7): 1173-1178.
Abstract PDF(334KB) icon1777 icon431
Abstract:
H=0 km & Ma=0 test was conducted for aero-engine at altitude simulated test facility(ATF).The reasons for the difference between altitude cell pressure and standard atmospheric pressure were analyzed.Moreover,the effects on the engine test of H=0 km & Ma=0 at a pressure difference between altitude cell and international standard atmosphere(ISA) sea level static(SLS),caused by exhaust gas ejection and cooling-air flow in altitude cell,were also studied.A scheme was thus put forward for the influence of ambient pressure change on the engine test results of H=0 km & Ma=0.Furthermore,several research tests were conducted in two or three test beds of H=0 km & Ma=0 using a turbojet engine and a turbofan engine.The test results show that,corrected results for engine test of H=0 km & Ma=0 at ATF,when ambient pressure is about 70 kPa and ram ratio is between 0.99 to 1.02,are consistent with those under standard atmosphere,sea level static.
Investigation on active control of rotating stall in axial flow compressors via bifurcation theory
WANG Jian, LI Ying-hong, ZHANG Dong-fang, WANG Cheng
2007, 22(7): 1179-1183.
Abstract PDF(304KB) icon2085 icon432
Abstract:
Rotating stall is a fundamental aerodynamic instability phenomenon of axial flow compressors.Firstly,the results of nonlinear dynamic bifurcation analysis on Moore-Greitzer compression system model showed that rotating stall was induced by subsonic pitchfork bifurcation;secondly,an active nonlinear feedback control law was proposed which using compressor pressure ratio as input measuring signal and throttle valve position as output actuating signal;Finally,computer simulation in bifurcation software AUTO was carried,and the simulation results showed that the proposed active nonlinear feedback control law translated the pitchfork bifurcation from subsonic to supersonic,which could eliminate the hysteresis loop associated with rotating stall and extend the stable operating range of axial flow compressors.Moreover,the proposed control system only used 1-dimensional sensor and actuator,so it could be easily applied in the engineering field.
Moving-mass attitude control system based on RBF networks
QIN Li, YANG Ming, GUO Qing
2007, 22(7): 1184-1189.
Abstract PDF(361KB) icon1354 icon415
Abstract:
The ability of moving-mass attitude control system to control a vehicle with three-axial stabilization in intra-atmospheric space is investigated.And general nonlinear motion equations with three internal moving masses are provided.Utilizing on the fast self-learning and adaptive capacities of RBF(radial basis function) networks,use them as the identification of the object under control to tune the PID(proportional integral differential) controller's parameters.The masses are positioned independently to generate modest attitude corrections for the vehicle.Finally,the influence of moving masses' motion on the system performance is discussed and the system stability is analyzed.Simulation results show that the system stabilization can be ensured while effective attitude adjustment for the vehicle is effected and at the same time the system's dynamic performances are improved.
Applications of nonlinear backstepping control strategy in multivariable control of aeroengine
ZHANG Hai-bo, SUN Jian-guo, SUN Feng-cheng
2007, 22(7): 1190-1194.
Abstract PDF(307KB) icon2178 icon418
Abstract:
The applications of nonlinear backstepping control strategy's design method in aeroengine control were analyzed.Firstly,the nonlinear affine dynamic model was established based on small perturbation variable model,and the design method of nonlinear backstepping control strategy was also discussed.Finally,the two-spool speed control rule of some turbofan engine was designed using the nonlinear backstepping control strategy's design method.The simulation results show that,the design method is suitable for aeroengine control systems.
Piston engine speed H_∞ dynamic output feedback regulation based on LMI
SHAO Jin-ju, WEI Min-xiang, WEN Wei-dong
2007, 22(7): 1195-1199.
Abstract PDF(1329KB) icon1418 icon450
Abstract:
Classical proportional integral derivative(PID) speed regulation method provides no guarantees for closed-loop system stability or performances for the full operating range of a piston engine due to the existence of nonlinear behavior,and time varying dead time.In this work,an H∞ dynamic output feedback approach is employed for the control of the piston engine based on linear matrix inequality(LMI),which can provide reference speed tracking despite the presence of torque load disturbances,operating condition changes and variable time delays.The off-line simulations show that the proposed controller can meet the performance requirements for the unmanned helicopter engine use,namely,tracking performance,disturbance rejection and robustness.
A global optimization approach to aero-engine under transient conditions
ZHAO Lin, FAN Ding, SHAN Wei-wei
2007, 22(7): 1200-1203.
Abstract PDF(1149KB) icon1630 icon422
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A global optimization based on sequential quadratic programming(SQP) is proposed for aero engine control in dynamic process.Optimization process consists of an overall and a component phase.The authors have implemented algorithm which employs the overall optimal results to redesign relating objective functions.Based on this,component optimization has been carried out with the purpose of correction and the result has been used for cycle control.This approach is applied to aero-engine control under transient conditions.As a result,the process is perfect.The simulation showed that this method can solve the problem that the general local optimization is unfeasible for the system with pure delay part and unmatched model.
Improvement on simulation software for static characteristics of liquid rocket engine
LI Jia-wen, ZHENG An-yu
2007, 22(7): 1204-1208.
Abstract PDF(724KB) icon1667 icon435
Abstract:
The author improved the former simulation software for static characteristics of liquid rocket engine.Users could add new equations and algorithms by using dynamic link Library.It made the simulation software more general and extended.Users could adjust the models' parameters and the amount of the needing resolve equations directly with the improved software.So the software could do fault analysis and system parameters adjusting without modifying the input files.

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