2008 Vol. 23, No. 8

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Numerical study of the effect of internal coolant crossflow on film cooling effectiveness
BAI Jiang-tao, ZHU Hui-ren, LIU Cun-liang
2008, 23(8): 1353-1358.
Abstract PDF(1334KB) icon1623 icon461
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This paper investigated numerically the effect of a coolant crossflow on film cooling effectiveness.Computations were performed to investigate the three-dimensional film cooling flow and cooling effectiveness with two crossflow ratios(Cr=0.39,0.78) and two blowing ratios(Br=1,2) and two length to diameter ratios(l/d=4,8).The results of the present investigation show that there is a profound effect of how the coolant is supplied to the hole on the film-cooling performance in the near hole region,for example,crossflow ratio has great influence on the film-cooling effectiveness of surface,a bigger length to diameter ratio brings about regular flow within film holes,and a bigger blowing ratio leads to poorer adhesion of jet stream and lower film-cooling effectiveness.Therefore,crossflow at the hole entry side has to be taken into account when modeling film-cooling schemes of turbine blades.
Numerical simulation of flaming gas generator with catalytic reforming process
HOU Ling-yun, LU Xiao-feng
2008, 23(8): 1359-1363.
Abstract PDF(542KB) icon1549 icon437
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Catalytic reforming gas generator is the effective method of producing on-line hydrogen,which is good for the ignition and combustion of hydrocarbon fuel in the scramjet.The combustion and catalytic reforming process were simulated numerically in the new designed gas generator.Based on the agreement between simulated results and experimental data,the parameter variation laws affecting the content of exit gas were concluded.The optimal parameters,the internal combustion characteristic and the content of difficult measured components were obtained.They are a supplement of the experimental results and provide the theory foundation for the design.
Numerical simulation of a steam-cooled vane
TONG Qi-bao, WANG Suo-fang
2008, 23(8): 1364-1369.
Abstract PDF(2195KB) icon1532 icon442
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The steam cooling method was applied in this paper to study the design and characteristics of cooling structure for a vane of gas turbine.The unstructured meshes and realizable k-ε turbulence model were used to study the flow behaviors both inside and outside the grid-ribbed rectangular channel with 15°,30° and 45° rib-roughened wall through 3-Dcoupled numerical simulation.Coupling heat exchange was achieved by heat transfer and solid conduction on the coupled-side of fluid and solid.The cooling medium was steam which had greater Cp and lower viscidity than air.Results show that the flow of the passage is very complex.Heat transfer is enhanced because of the ribs.Ribbed wall has better heat transfer effect than the no rib wall and the cooling effect is obvious.Cooling effect is better by using the steam than by using the air.The numerical result shows the temperature on pressure surface is lower than suction surface.
Experimental study of flow field of a model combustor with two swirlers
HAN Qi-xiang, XU Tie-jun, HUANG Jian
2008, 23(8): 1370-1374.
Abstract PDF(1010KB) icon1542 icon485
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The flow field of a model combustor with double axial swirlers was studied experimentally using particle image velocimetry(PIV) technology in this paper.The flow field structure of side-and end-view velocity profile of the combustor and the effect of swirler parameters on recirculation zone were analyzed.It is concluded that the flow field structure in the combustor is irregular with two non-axisymmetrical eddies on the central axis,the jets from the primary holes pass at different depth,and streamwise vortex exists in the flow field.The recirculation zone could be expanded with the reduction of cross area and swirl number of primary swirler,or the increase of swirl number of secondary swirler,meanwhile,the recirculation zone could be diminished with the increase of cross area of secondary swirler.
Numerical investigation on improvement of film cooling effectiveness with small coolant jets
JIANG Yong-jian, HE Li-ming, SU Jian-yong, YU Jin-lu
2008, 23(8): 1375-1380.
Abstract PDF(1213KB) icon1799 icon447
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To investigate the influence of small coolant jets on film cooling effectiveness,the distributions of the flow fields and cooling effectiveness with the small jets at different outlet placement under several blowing ratios were numerically studied.And the distributions were compared with the distributions of the baseline holes to reveal the good effects of the small coolant jets on the film cooling performance.The results show that,the new interaction between the weaker counter-rotating vortex pairs(CRVP) generated by the small jets and the CRVPgenerated by the main coolant jet weakens the mixing strength of the coolant jets with the hot cross flow,so the film effectiveness is higher with better coverage on the hot side under several blowing ratios.And the spanwise cooling effectiveness is improved significantly when the distance between the two small coolant jets is longer and the blowing ratio is higher.
Numerical investigation of control ablation process with transpiration cooling
XIE Yuan-yuan, WANG Jian-hua
2008, 23(8): 1381-1386.
Abstract PDF(847KB) icon1538 icon541
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A numerical method was developed to simulate the transient control ablation process by transpiration cooling.The influence of surface ablation and charring of thermal protective structure on cooling performance and the mass losses due to the ablation and charring was considered.In order to exactly predict the performance of the control ablation and cooling process,the influences of heat flux intensity,coolant injection velocity,initial temperatures of porous matrix and coolant on the cooling effect were discussed.
State-of-the-art of ground-experiments of loop heat pipe
LIN Gui-ping, LI Nan, ZHANG Hong-xing
2008, 23(8): 1387-1396.
Abstract PDF(1793KB) icon1798 icon442
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Loop heat pipe(LHP) is the most advanced heat-transfer device in the spacecraft thermal-control field,and dual compensation chamber LHP(DCC-LHP) has become hot spot in the aero and ground applications since it can work without the limit of the orientation between the evaporator and compensation chamber.In this paper,the state-of-the-art investigation on ground-experiments of LHPand DCC-LHPhad been analyzed;the visualized experiments' results had been summarized;due to the investigative deficiencies in some aspects of the heat-transfer mechanism and circulating behaviors in LHP,more visualized experiments should be carried out for the steady-state,transient performance and active thermal-control characteristics,and the visualized validation should be made to previous theories and assumptions.
Numerical investigation of hydrogen combustion-heater for scramjet ground test
WANG Liao, XU Xu
2008, 23(8): 1397-1402.
Abstract PDF(1450KB) icon1917 icon473
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Fluent was used to investigate numerically the internal flow field of combustion-heater for direct-connect scramjet ground test facility.The hydrogen multi-hole injection and hydrogen single-hole injection was computed,respectively.The results show that the exit flow field can meet the design requirements of total temperature 1900 K,Ma=1.85,and the hydrogen single-hole injection is superior to hydrogen multi-hole injection.Meanwhile the computational results also indicate the shortcomings of these two design schemes.
Numerical investigation of effect of static bush with rub-grooves on the straight-through labyrinth seal leakage
JI Guo-jian, JI Hong-hu
2008, 23(8): 1403-1408.
Abstract PDF(946KB) icon1559 icon478
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A numerical investigation of influence of rub-grooves in the inner surface of static adradable bush on the leakage of a straight-through labyrinth seal was conducted,while the shape of rub-grooves and relative axial/radial locations of labyrinth teeth tips and the groove were studied.The results show that the rub-grooves not only change the flow direction of the jet and decrease the residual energy,but also affect the change of throttle location and the throttle area of the teeth tips,presenting great influence on the sealing performance of the labyrinth seal.
Experiment of carbon nanotube suspension on the thermal performance of a miniature flat heat pipe evaporator with micro-grooved surface
ZHAO Jie, XIONG Jian-guo, LIU Zhen-hua
2008, 23(8): 1409-1412.
Abstract PDF(554KB) icon1551 icon452
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Based on miniature flat heat pipe(MFHP) with the micro-grooved surface,an experimental study was performed to understand the boiling characteristics and critical heat flux(CHF) of carbon nanotube(CNT) suspensions at different pressures and CNTmass concentrations.The experimental results indicate that,the concentration of CNTsuspensions could enhance significantly the boiling heat transfer characteristics of flat heat pipe evaporator,and the heat transfer enhancement of CNTsuspensions and CHFenhancement greatly increases with the decline of the test pressure.The concentration of suspensions has great influence on the boiling coefficient and CHF.At the lower concentration,boiling coefficient and CHFwill grow slowly with the increase of concentration.But,if the concentration exceeds 2%,the influence of concentration will disappear.
Experimental research on nonlinear dynamic characteristic of gas lubrication bearings and high speed rotors
CHEN Ce, YANG Jin-fu, NIE Chao-qun
2008, 23(8): 1413-1419.
Abstract PDF(1671KB) icon1608 icon473
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A stability experiment on high speed rotor and gas lubrication bearings was presented in this paper.Based on shaft center orbits,frequency coupling 3-D plot,frequency spectrum and bifurcation plot,the nonlinear characteristics of rotor bearing system were analyzed.The experiment proved that,gas whirl in gas bearing and rotor system was a major contributing factor to nonlinear instability.Double periodic bifurcation caused by gas whirl was an inevitable path to chaos vibration.The instability rotational speed will vary a lot from design speed by modulation of the coupling relationship between system's inherent frequency and gas whirl frequency,meanwhile effective control of chaos vibration based on bounded ness of chaos is a new method to improve nonlinear stability of rotor and bearings.
Research on sliding bearings and rotor system stability
YANG Jin-fu, YANG Sheng-bo, CHEN Ce, WANG Yong-jun, WU Wen-feng
2008, 23(8): 1420-1426.
Abstract PDF(2433KB) icon1898 icon512
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Based on the load balance equations of sliding bearing fluid-solid coupling motion,the mechanism of instability in bearing-rotor system was presented.According to the coupling relationship between whirl frequency and nonlinear coupling vibration frequency,a new technology was put forward to perform rotor-bearings system frequency coupling modulation.Through experiments of oil whirl,sub-harmonic resonance and other self-excited vibration,a criterion for rotor-bearing stability and nonlinear dynamics characteristics were presented.Moreover,relevant theoretical and experimental references were provided to achieve effective control of rotor-bearing nonlinear vibration.
Dynamic response analysis of the transmission of tilt-rotor in different modes
MIAO Jun, WANG San-min, NING Song
2008, 23(8): 1427-1431.
Abstract PDF(719KB) icon1769 icon457
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Based the transmission structure in the nacelle of tilt-rotor,the complex gears and shafts coupling dynamic modeling and dynamic response equations were built.And,three types of the force characteristics on the blades: cruise,hover and transition were analyzed.The dynamic response was computed using Runge-Kutta method to obtain the dynamic gearmesh coefficient.Finally,the natural frequency was discussed.The results provide some useful information to analyze the reliability and the dynamics optimization of the transmission.
Eigen-fusion technique based on information poor system
WANG Ya-hong, XIA Xin-tao, WANG Zhong-yu
2008, 23(8): 1432-1437.
Abstract PDF(770KB) icon1774 icon456
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The eigen-fusion technique based on the information poor system was proposed to simulate an unknown distribution under the condition of small sample.Analyzing and fusing the characteristic information of every individual from different view sides,the probability distribution of a population was inferred,by using multifold mathematical ideas such as membership function,maximum membership grade,bootstrap,grey bootstrap,arithmetic mean,and maximum entropy.The experiment on rolling bearing noise shows that the eigen-fusion technique can effectively simulate the probability distribution of the information poor system.
Research on bending strength of face-gear transmission based on contact finite element method
GUO Hui, ZHAO Ning, FANG Zong-de, SHEN Yun-bo
2008, 23(8): 1438-1442.
Abstract PDF(1557KB) icon2368 icon454
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The fillet surface equation of face gears was presented when the top of the shaper tooth was rounded.A 'mesh filter method' was proposed in view of the particularity of face-gear's structure,and the distortion of the element shape was corrected.Based on tooth contact analysis(TCA),the variation of bending stresses during the cycle of meshing was computed with 3-Dcontact finite element method when some parameters changed.The results indicate that both of the nominal pressure angle and shaft adjustments of face-gear have significant influence on the bending strength.
Application of level set method in microstructure optimization of multiphase material
SUN Jie, SONG Ying-dong, SUN Zhi-gang, GAO Xi-guang
2008, 23(8): 1443-1448.
Abstract PDF(2151KB) icon1323 icon396
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Topological microstructure and macro-mechanic performance of multiphase materials were combined using high-fidelity generalized method of cell(HFGMC),so a single cell was dispersed into finite elements;the presence or otherwise of the microstructure was described by materials in the elements,and topological optimization of discrete variables was transferred into continuous variables' shape optimization,thus achieving microstructure optimization of multiphase materials.The microstructure of a multiphase material was optimized,and property of auxetic performance was obtained,helping to prove the validity of this method.
Improved method for adjusting critical speeds of rotor systems
WANG Dong-hua, LIU Zhan-sheng, DOU Wei
2008, 23(8): 1449-1454.
Abstract PDF(1635KB) icon1534 icon455
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The problem of critical speeds optimal adjustment in rotor systems was provided and an improved method was presented based on the analysis of existing methods.Minimizing the adjustment cost was the object function and adjusting current critical speeds to the desired values was treated as a constraint.The proposed method predigests the design process without needing correction.The results of study on a rotor system show that the improved method can get the optimal solution and save much time.
Finite element analysis of thermal conductivity of three dimensional and five directional braided composites
LI Dian-sen, LU Zi-xing, LIU Zhen-guo, LI Zhong-ping
2008, 23(8): 1455-1460.
Abstract PDF(1687KB) icon2139 icon477
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The finite element model for thermal conductivity was established based on the micro-structure of 3-D & 5-Dbraided composites and the assumption of the braiding yarn with the hexagon section and the axial yarn with the square section.The transverse and longitudinal thermal conductivity coefficients of 3-D & 5-Dbraided composites were calculated by the finite element method and compared with the corresponding results of 3-D & 4-Dbraided composites.The influences of the braiding angle and fiber volume fraction on the thermal conductivity coefficient were also analyzed.In addition,the distributions of the temperature,the thermal gradient and thermal flux of composites were determined,providing a basis for the analysis of the coupling problem of thermo-mechanics.
Two-dimensional model mathematical simulation of brush seals
WANG Zhi-li, LIANG Xiao-feng, HUANG Qi-wu
2008, 23(8): 1461-1465.
Abstract PDF(1339KB) icon1486 icon419
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The anisotropic porous model covering the bristles bending deflections was used to establish the calculation model.The effect of bristles for the flow media was considered a resistance force,which was added into N-Sequation as a source term.The model was established on the basis of the Finite Volume Method and the SIMPLEmethod.To this effect,the pressure field,velocity vectors distribution and leakage of brush seal were obtained from calculation of flow field.The influences of main parameters,such as: structure and working condition,on the sealing performance of brush seals,were analyzed and compared,showing that this method is suitable for the study of the brush seals.
Analysis of unsteady vortex sheet in2-D axial compressor
ZHOU Xiao-bo, HOU An-ping, ZHOU Sheng
2008, 23(8): 1466-1473.
Abstract PDF(2076KB) icon1620 icon467
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The flowfield in turbomachinery is characterized by unsteady vortex flow.Contradictorily,the current analysis and design system of axial compressor is based on the spatial structure of the flowfield under the assumption of steady flow.It is understood that one of the methods to investigate the real flow inside the axial compressor is to analyze the temporal-spatial structure of the flowfield.In this paper,an axial compressor stage embedding interlaced rotor and stator rows was simplified into a single blade row,and then further into a 2-Dcompressor cascade.In this way,the temporal-spatial structure of the unsteady vortex flowfield could be described from the angle of unsteady vortex sheet of the cascade.For illustration,the temporal-spatial structure of the flowfield in cascade was transformed through controlling the evolution of vortex sheet by synthetic jet normal to the suction surface of the cascade.The presented unsteady vortex sheet model could be used as an analysis tool for further research on the temporal-spatial structure of stator/rotor interaction in multistage turbomachinery flowfield.
Investigation on improving the capability of predicting separation of Spalart-Allmaras turbulence model
MA Wei, WANG Dan-hua, LU Li-peng
2008, 23(8): 1474-1479.
Abstract PDF(893KB) icon2116 icon473
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Two methods were applied to improve the capability of predicting separation of Spalart-Allmaras turbulence model.One was to improve the capability of predicting Reynolds normal stress based on the property of Spalart-Allmaras turbulence model,the other one was to calibrate the production coefficient based on the non-equilibrium of turbulence in separation region.The results show that: the first one contributes little to improving the capability of prediction separation of Spalart-Allmaras turbulence model,because the capability of predicting Reynolds normal stresses is not improved considerably;while the second one improves obviously the capability of prediction separation of Spalart-Allmaras turbulence model,because the capability of S-Amodel in capturing the non-equilibrium turbulence is improved notably.
Research on mechanism and flow drag character of an aerodynamic valve with blunt block and backflow damping orifices
LI Hai-peng, HE Li-ming, LI Tian-liang, JIANG Yong-jian, WU Wei
2008, 23(8): 1480-1485.
Abstract PDF(1065KB) icon1536 icon461
Abstract:
An aerodynamic valve with blunt block and backflow damping orifices was designed for pulse detonation engines(PDEs),and its mechanism was analyzed.The flow field in the aero-valve and the flow drag character were examined numerically.The result shows that the valve presents good single-direction flow performance.The flow is found moving smoothly to the detonation chamber when the pressure at the valve inlet is between100 kPa and 500 kPa.However the drag rises linearly along with the increase of the inlet pressure when the flow direction is reversed.The simulation results in detonation environment show that,the single-direction flow performance,the mixing quality and the exit flow field uniformity of the aerodynamic valve will be enhanced greatly,and the backflow drag rises dramatically.
Fitting of component characteristics of turbine engine based on non-uniform rational B-splines
SUI Yan-feng, ZHANG Zhi-qiang, ZHAO Jun
2008, 23(8): 1486-1489.
Abstract PDF(600KB) icon2054 icon463
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Non-uniform rational B-splines(NURBS) was used to fit component characteristics of aerothermodynamic model for approaching turbine engine.This method ensures that the overall and local characteristics of the model can be improved greatly with NURBS.The validation of method is demonstrated by one-spool turbojet engine.
Numerically investigate the effects of freestream turbulence on dynamics of a low-pressure turbine stage
LUO Hua-ling, QIAO Wei-yang, XU Kai-fu, LI Wei
2008, 23(8): 1490-1497.
Abstract PDF(1797KB) icon1602 icon456
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Based on SSTturbulence model coupled with Langtry-Menter transition model,a three-dimensional,vicous,steady CFDanalysis was performed for investigating the effects of freestream turbulence on the dynamics of a LPturbine stage at different Reynolds numbers.From the CFDprediction results,the rules of freestream turbulence effects on the flow mechanics on blade suction surface,and on Reynolds number effects on this LPturbine stage efficiency were obtained.Also,based on a kind of loss separation method,freesteam turbulence effects on the flow loss components,such as the profile loss,the endwall boundary loss,and the tip clearance loss inside this LPturbine stage were further distinguished.
BVF application on blowing control of flow separation of a compressor cascade
GUO Ming, ZHENG Xiao-yu, ZHOU Sheng, LI Qiu-shi
2008, 23(8): 1498-1503.
Abstract PDF(753KB) icon1648 icon472
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Controlling flow separation with blowing-slot was simulated numerically on a 2-Dcascade in collaboration with boundary vorticity flux(BVF).The results show that steady blowing can take away the slow airflow of the boundary layer,the separated flow is controlled and the performance of cascade is greatly improved.By means of investigation on the cascade performance variation with slot position,blowing angle and slot width,the best slot scheme is obtained.BVFaerodynamics analysis indicates that the high positive peak of BVFis a sign of large scale flow separation,BVFdistribution and cascade performance are interrelated,the blowing can adjust BVFdistribution well to improve the performance.The best slot position is located behind the positive BVFpeak and in a small zone near separation point.By selecting an appropriate slot position,the best effect could be obtained in a wide operating range.
Key turbomachinery technology of civil high-bypass-ratio turbofan engine
ZOU Zheng-ping, LI Yu, LIU Huo-xing, ZHANG Zheng-qiu, YE Jian, LI Wei, CHEN Jing-wei
2008, 23(8): 1504-1518.
Abstract PDF(2604KB) icon2059 icon692
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The research progress on partial turbomachinery technology of high-bypass-ratio turbofan engine were reviewed and analyzed in the present study and the partial key technology of turbomachinery required for our country's high-bypass-ratio turbofan engine were also expatiated.The main contents included four aspects: fan/compressor design technique,turbine design technique,flow and noise control and multi-disciplinary coupling technique.
Design and experiment demonstration of a booster of small turbofan engine
DING Jian-guo, ZOU Xue-qi, Wu Zhi-qing, YANG Jing-jing, HU Jun
2008, 23(8): 1519-1522.
Abstract PDF(773KB) icon1557 icon503
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By means of test-proven one dimension project design procedure library and arbitrary airfoils blade design procedure of turbo machine matching the axial symmetry streamline curvature approach design code,a booster of small turbofan engine was designed and tested successfully by combining three dimension computational fluid dynamics,one dimension and two dimension aero-dynamics designs.The experiment results indicate that,the booster has high efficiency over a wider range and better stall margin,and the design results correspond with experimental results.
Influence of squealer tip on tip leakage flow in axial turbine
LI Wei, QIAO Wei-yang, XU Kai-fu, LUO Hua-ling
2008, 23(8): 1523-1529.
Abstract PDF(1847KB) icon1663 icon422
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In order to reduce the tip leakage loss,a pressure-correction based,3-D Reynolds-averaged Navier-Stokes equations CFDcode with Reynolds stress model and wall function was used to simulate the effects of the passive control of a partial squealer tip around tip platform on the tip leakage flow in a turbine rotor.The effect of squealer tip with different rim heights and widths on the tip leakage flow was sequentially simulated.The results show that recirculation region appeared in the tip region and the rim near suction side could block the tip leakage flow,which decrease the tip leakage loss.The height of tip platform rim had more influence on the turbine efficiency,and it had an optimal value,where the turbine efficiency could increase by 0.13 percent.The rim width had less influnce on the flow field,but it made the cavum became large,so the turbine efficiency slightly increased.
Research ofdamage mitigating and life extending method for liquid-propellant rocket engines based on main object
LIU Hong-gang, WEI Peng-fei, XIE Ting-feng, CHENG Yu-qiang, WU Jian-jun
2008, 23(8): 1530-1535.
Abstract PDF(1921KB) icon1524 icon460
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The optimization method of damage-mitigating and life-extending control(DMLEC) for liquid-propellant rocket engines was presented mathematically in this paper by constructing the object function,acquiring the constraints and analyzing the solutions.Then,the main object method of DMLECpolicy analysis and synthesis was developed for a certain LOX/kerosene rocket engine with turbine blade selected as the critical component.Simulated results under diverse situations show that,the method proposed is feasible and effective,since it can not only achieve the expected goal of damage-mitigating by implementing the tradeoff between the system performance and the damage of critical components,but also provide valuable reference for improving and optimizing the design of engines being developed.
Application of SolidWorks API of grain burning surface calculation
XIONG Wen-bo, LIU Yu, XIE Kan, LIAO Hui
2008, 23(8): 1536-1540.
Abstract PDF(677KB) icon1703 icon457
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The application of parameterization in grain burning surface calculation of solid rocket motor was investigated based on SolidWorks application programming interface.Asimpler and more accurate grain burning surface calculation method was developed while grain burning surface calculation was achieved through different modeling methods for the burning process of grain.The results show that this calculation method is feasible and highly precise.The calculation results match the experiment results,so this calculation method is suitable for actual engineering calculation.Some new ideas and methods for grain burning surface calculation were also proposed.
Experimental on control of liquid hydrocarbon fueled scramjet combustor
WU Xian-yu, CHEN Hui, LIU Rui, DING Meng, WANG Zhen-guo
2008, 23(8): 1541-1545.
Abstract PDF(721KB) icon1874 icon452
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The control loop of scramjet combustor was designed to control the thrust force increment and combustor-isolator interaction(CII) by feedback of force and isolator pressure measurements,where the fuel mass flow was regulated by fuel mass flow control system based on controllable cavitating Venturi.On the direct-connect test system,two experiments were conducted to implement single level thrust force control and multi-level thrust force/CIIcontrol,respectively.The test results show that: the fuel mass flow control system works reliably with fuel regulated accurately by directed movement of Venturi;the thrust force varies with fuel mass flow almost synchronously;and the thrust force increment and CIIare controlled efficiently.This work lays a foundation for further study of scramjet combustor control.
Flight control for an aerospace vehicle's reentry attitude based on thrust of reaction jets
QIAN Cheng-shan, WU Qing-xian, JIANG Chang-sheng, ZHOU Li
2008, 23(8): 1546-1552.
Abstract PDF(716KB) icon1948 icon528
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The problems concerning an aerospace vehicle's(ASV) atmospheric reentry flight attitude control system were researched.During reentry through the atmosphere,the control moment is generated by thrusters of the reaction control system(RCS) to control attitudes of the ASV,and to compensate for the shortage of aero-surfaces that fail to offer enough moment because of the partially or completely lost efficiency.Along with the increase in air density,aero-surfaces gradually intervene the control system,and the RCSdrops out of use.Because the control torque is determined by the fast loop controller and the torque is assigned to actuators by the control allocation algorithms,a multi-model switching control method based on T-Sfuzzy control is proposed and is employed to design the controller for the fast-loop such that the required virtual control input is tracked and the actuators' chattering is reduced.Therefore,the control input is softened.The effectiveness of the proposed method is demonstrated by the simulation results.

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