Table of Content

30 August 2017, Volume 51 Issue 8 Previous Issue    Next Issue

Select

Comprehensive Optimal Dispatch of Distribution Network Based on  Improved Particle Swarm Optimization Algorithm LI Ke,TAI Nengling,ZHANG Shenxi 2017, 51 (8):  897-902.  doi: 10.16183/j.cnki.jsjtu.2017.08.001 Abstract ( 738 )   Save  The paper proposes a novel model of the comprehensive optimal dispatch of distribution network, the objective function is to minimize the active power losses and the constraints are various electrical conditions and the network topology. Basic particle swarm optimization algorithm has the shortcomings which are easy to fall into local optimum and slow to converge. In order to overcome the shortcomings, an improved particle swarm optimization algorithm is proposed, and it is applied to solve the model. Case studies are carried out on the IEEE 33bus distribution network, and the results show the effectiveness of the model and the high efficiency of the algorithm. References | Related Articles | Metrics

Select

Metal Ablation Affected by Electrode Shapes Under  Long Continuing Lightning Current XIA Hailiang1,2,LIU Yakun1,2,LIU Quanzhen3,LIU Baoquan3,FU Zhengcai1,2 2017, 51 (8):  903-908.  Abstract ( 566 )   Save  Adopting both experimental and simulation methods, this study mainly discusses the effect of electrode shapes on the metal ablation under  lightning long continuing current component. In the experiment, the electrode is made of W80 material, and the test samples are aluminum 3003plates.  The ablation areas and depths of the aluminum 3003 plates are compared under the tests with three types and three curvatures electrodes. Combining the finite element electric field simulation and 2dimensional streamer development model analysis, the mechanism of the electrode’s impact on the metal ablation property is also discussed. The results show that the effect of electrode’s shape cannot be ignored in metal ablation experiments. Under the lightning long continuing current component after the last return stroke, cone electrode leads to the severest ablation both in ablation area and depth, whilst the hemisphere electrode leads to the lightest ablation. Moreover, electrode shape also affects the capability of initial ionization within the gap. The electron density and electron energy density distribution during the process of streamer development dominates the impact of electrodes on the metal ablation. References | Related Articles | Metrics

Select

Command Filtered Adaptive Backstepping Control for Airships HAN Ding,WANG Xiaoliang,CHEN Li,DUAN Dengping 2017, 51 (8):  909-914.  doi: 10.16183/j.cnki.jsjtu.2017.08.003 Abstract ( 892 )   Save  As stratospheric platforms, stratospheric airships are generally so large, it is difficult for them to land back on ground accurately after their tasks. Consequently, the control problem of airship landing with system uncertainties and external disturbances is considered. A sixdegreeoffreedom airship model is used, and a command filtered modified backstepping control law combined with adaptive theory is designed based on Lyapunov theory. The command filter and the improved backstepping algorithm can deal with the uncertainties in both dynamic errors and the external disturbances. Numerical simulation results demonstrate good performance for the landing of the airship even under wind condition. References | Related Articles | Metrics

Select

Simulation Analysis of Temperature Distribution of Turbine Blades by  Thermal Buffer Coating for Aero Engine DUAN Li1,GAO Junchao1,WANG Ruijun2,HU Mingkai1,SU Jingchao3 CHENG Qingqing3,ZHANG Bo3,YUAN Tao2 2017, 51 (8):  915-920.  Abstract ( 969 )   Save  Temperature separation effect of thermal barrier coating (TBC) for aeroengine turbine blade applications has been studied extensively with the aid of computer simulation by the finite element method (FEM). In this simulation studies, a general engineering methodology is implemented, i.e. the “InputProcessOutput” methodology as part of the undergraduate participation research program in Shanghai Jiao Tong University. Thermal buffering effect of different TBC materials (ZrO2, HfO2, CeO2, etc.), various combinations of TBC and base metal dimensions and structures are compared. Similar comparison is made on various TBC thickness to provide a qualitative picture on the thermal buffering effect on turbine blade dimensions. The conclusion may provide some guidelines in turbine blade thermal dynamic design. Simulation also shows that for correct calibration of the TBC’s thermal buffering effect proper boundary conditions in the TBC characterization must be specified, and this could explain the various contradictions in different reports on different thermal buffering temperature in various TBC samples. References | Related Articles | Metrics

Select

An Investigation on the Characteristics of Supercooled Large  Droplet Icing Accretions and  Aerodynamic Effects on  HighLift Configuration LI Dong1,ZHANG Chen1,WANG Fuxin1,LIU Hong1，YANG Kun2 2017, 51 (8):  921-931.  doi: 10.16183/j.cnki.jsjtu.2017.08.005 Abstract ( 778 )   Save  This paper uses SJTUICE (Shanghai Jiao Tong University Icing Simulation Code) method of prediction and develops method for the aerodynamic analysis on highlift configurations. After validating the supercooled large droplet (SLD), particle trajectory and icing prediction on multielement airfoils, this paper characterizes the SLD icing accretions and aerodynamic effects on highlift configurations and compares them with nonSLD conditions. The result indicates that the quantity of ice increases, and the upwind horn on the suctionside of the slat grows lager and extends downstream under SLD condition. It is remarkable to detect that the SLD condition induces the large increment of horn ice on leading edge of flap. The ice shape has a larger growth angle that is about to lead to the clogging of the gap. With the angle of attack ranging from 6° to 22°, the SLD condition has a larger degradation on the aerodynamic performance comparison with nonSLD condition. It leads to the decreasing of lift coefficient by 63.5% and causes stall to occur 8° earlier. References | Related Articles | Metrics

Select

Airworthiness Compliance Research of Aerodynamic Performance on  Bird Strike Damaged Fan Blades LU Jiahua，QIANG Xiaoqing，TENG Jinfang，YU Wensheng 2017, 51 (8):  932-938.  Abstract ( 583 )   Save  In order to explore the impact of bird strike damage on the aerodynamic performance of the fan blade and the compliance of the relevant provisions in airworthiness certification, a typical high bypass ratio fan rotor was selected, then a bird strike damage model was simplified and the effect of middlebird typical damage to the aerodynamic performance of the fan blade by fullannulus numerical simulation was researched. The results show: the mass flow at chock point, the peak efficiency, the stability margin, the thrust of peak efficiency point and the maximum thrust of different number of damaged blades decline inordinately compared to the undamaged blade while the magnitude increases due to the increasing number of damaged blades. Wherein, when the number of damaged blade reaches three, the thrust at peak efficiency point decreases by about 11.35% and the maximum thrust decreases by about 20.68% compared to the undamaged blade, which meets the requirement in Airworthiness Certification that thrust losses of middle bird strike damaged fan can’t exceed 25%. Different amount of the damaged fan blade has flow separation from the damage position to the blade tip within different degrees, and leads that the outlet flow field of the fan has different degrees of distortion. References | Related Articles | Metrics

Select

Experimental Investigation of Binary Supercooled  Water Droplet Collision  YIN Jinge1，KONG Weiliang1，WANG Fuxin1， LIU Hong1，YANG Kun2 2017, 51 (8):  939-945.  doi: 10.16183/j.cnki.jsjtu.2017.08.007 Abstract ( 1023 )   Save  The prediction of droplet size distribution is always based on water droplet collision outcome at room temperature, which has a great difference with that in freezing environment. Because of this, the outcome of binary water droplet collisions was investigated experimentally within a certain temperature range. Two monodisperse droplet chains were produced by means of piezoelectric droplet generators and two high speedcameras were used to observe the collision process. Values of the Weber number based on the small droplet sizes are from 0 to 100. Droplet temperature varies from 25℃ to －5℃.  Compared with the outcome at room temperature, the result of the supercooled water droplet collision has obviously changed. ① The coalescence region extends to the separation region. ② The reflexive separation region move towards the region with high Weber number value. ③ The stretching separation region is slightly shifted downward. From the perspective of the supercooled water properties, the influence of temperature on collision results was discussed. The droplet size distribution of supercooled spray has a great difference with the result based on water droplet collision at room temperature. References | Related Articles | Metrics

Select

Simulation of a Thermodynamic Vent System Working at  Room Temperature and Its Preliminary Pressurization Testing  CHEN Zhongcan1, LI Peng2, SUN Peijie2, WANG Tianxiang3, LI Xiaoci1, HUANG Yonghua1 2017, 51 (8):  946-953.  doi: 10.16183/j.cnki.jsjtu.2017.08.008 Abstract ( 651 )   Save  A thermodynamic vent system with refrigerant R141b as working substance has been established for the purpose of revealing the primary principle and validating a modeling program. The experimental TVS was installed within a tank with a 450mm inner diameter cylinder and two  under development elliptical domes, and has a total volume of 0.11m3 approximately. Tests of pressure control under the action of spray bar alone and the joint action of spray bar, throttle valve and heat exchanger were conducted with representative input heat and fill level. The results showed that the experimental system could successfully control the ullage gauge pressure between 80 and 90kPa for 0.98 hour by operating the spray bar alone, while in the combined operation mode only 5.8% (3.35kg) of R141b was vented in 2 hours. The ability of this system for simulating the thermodynamic vent process of evaporative fluids was validated. References | Related Articles | Metrics

Select

ThermalStructure Coupling Analysis of  Microgravity Environment  Simulation  Suspension Structure for  Large Space Deployable Mechanisms ZHANG Liangjun1,2，LI Xiaoci1，WU Jingyi1，CAI Aifeng1 2017, 51 (8):  954-961.  Abstract ( 650 )   Save  This article focuses on a microgravity environment simulation suspension device which used for reliability demonstration testing of largescale space deployable mechanisms. The finite element model of the device is established by Solidworks and the thermalstructure coupling analysis of the suspension device is performed with ANSYS software in the situations of different suspension loadings and temperatures. The thermal deformation and equivalent stress distributions in different conditions of the suspension device are carried out by numerical analysis. The impact of the thermalstructure coupling effect on the tilt angle of long slide rails is discussed. The results provide a reference for optimization design of the microgravity environment simulation suspension device under thermal environment. Besides, the research is also important to guide the actual operation of microgravity and thermal deployment testing and the experimental parameters debugging. References | Related Articles | Metrics

Select

Comparative Experimental Investigation of Effusion Cooling  Performance on  the Annular Combustor Liners at  Nonreacting/Reacting Flow Conditions JI Yongbin1，DU Shiqiang2，YU Jiangpeng1，GE Bing1， ZANG Shusheng1 2017, 51 (8):  962-969.  Abstract ( 746 )   Save  Threenozzle annular model combustor is designed to investigate the effusion cooling characteristics under nonreacting and reacting flow conditions. Temperature was measured on both outer and inner liners of the combustor, and then difference of overall cooling effectiveness distribution with or without combustion is analyzed. The effect of coolant to mainstream air flowrate ratio on the overall cooling effectiveness is studied. Results showed that effusion cooling behavior under reacting condition looks distinctly different from that under nonreacting condition. Specifically, cooling effectiveness showed laterally nonuniform distribution and skewed towards the micro rotation direction result from three separate coswirling flows merge. The most significant phenomenon at reacting flow condition is that low cooling effectiveness region shows up. This is because of the swirling flame impinging on the combustor liners. References | Related Articles | Metrics

Select

Metabolism Adaptive MultiParameter Prediction  Method Based on Grey Theory ZHANG Zhaofei，LUO Jianjun，XU Binghua，MA Weihua 2017, 51 (8):  970-976.  doi: 10.16183/j.cnki.jsjtu.2017.08.011 Abstract ( 798 )   Save  The application of measured shortterm data to the prediction of longterm stability of weapon system is significant to shorten the production cycle of weapons. Considering such prediction problems as inadequate data and small sample sequence, optimized algorithm model was presented based on the drawback analysis of GM(1,1) prediction model. The optimized prediction methods were generalized as multiparameter prediction. At first, the model which used the latest measured data for initialization was established, followed by replacing the old information with the latest through metabolic approaches to realize equal dimension model predication. In addition, fading memory recursive least squares method was adopted for weighted handling of old and new information. The normalized mean relative error was used as accuracy test standard for background value and particle swarm optimization algorithm was adopted. Finally, the calibration parameters stability of a certain type of inertial measurement unit (IMU) was predicted, and the average relative error of the prediction results was reduced by 6%~58%. The results indicate that the prediction method can be applied to the longterm stability of IMU calibration parameters. References | Related Articles | Metrics

Select

Aircraft Attitude Determination Based on Combined Carrier Phase ZHAO Guorong,LIU Shuai,GAO Chao,ZENG Bin 2017, 51 (8):  977-983.  Abstract ( 867 )   Save   A short baseline ambiguity resolution method based on combined carrier phase was proposed to realize the fast ambiguity resolution in global navigation satellite system (GNSS) attitude determination. The resolution method can realize the ambiguity resolution in one epoch. According to the ambiguity resolution results, the baseline vector was calculated with the leastsquares theory and the attitude of the aircraft was determined. Simulation results show that this method can get more than eight satellites’ ambiguities in one epoch. It is of great significance in the field of GNSS attitude determination. Attitude determination results show that both errors of yaw and pitch are less than 0.2°. The fast resolution of ambiguity makes it possible for the GNSS attitude determination in the field of aeronautics and astronautics. References | Related Articles | Metrics

Select

Zero Deviation Characterization of Jet Pipe Servo Valve in ThreeDimensional Centrifugal Environment YIN Yaobao,WANG Yu 2017, 51 (8):  984-991.  doi: 10.16183/j.cnki.jsjtu.2017.08.013 Abstract ( 817 )   Save  In view of the zero deviation problem of jet pipe servo valve under centrifugal environment, a mathematic model of the zero deviation characterization of the jet pipe servo valve under threedimensional centrifugal environment was built. The factors to zero deviation of the jet pipe servo valve including armature component eccentricity, electromagnetic torque coefficient, feedback rod stiffness and moving part quality were analyzed. The measures for decreasing zero deviation value of the jet pipe servo valve under threedimensional centrifugal environment were put forward. The result shows that the zero deviation value has a linear relation with the centrifugal acceleration value. Armature component eccentricity, electromagnetic torque coefficient and moving part quality are the main affecting factors while feedback rod stiffness has little effect. The centrifugal zero deviation can be 0 at each centrifugal acceleration by adjusting appropriate armature component eccentricity or the ratio of spool quality to armature component quality. The verification experiment was carried out by using some type of the jet pipe servo valve. The theoretical result is in good agreement with the experimental data. References | Related Articles | Metrics

Select

Kinetostatic Modeling and Analysis of  an ExeVariant Parallel Kinematic Machine TANG Tengfei1,ZHANG Jun2,ZHAO Yanqin1 2017, 51 (8):  992-999.  doi: 10.16183/j.cnki.jsjtu.2017.08.014 Abstract ( 766 )   Save  A novel Exevariant PKM with a topological arrangement of 2RPU&1RPS was proposed by the authors to achieve a better platform rotational ability over the Exechon parallel kinematic machine (PKM). After introducing the concept design, the mobility analysis and inverse kinematics of the proposed Exevariant PKM are conducted. With the substructure synthesis techniques, a kinetostatic model that includes joint deflections and limb flexibilites is developed to investigate the kinetostatic characteristics of the Exevariant PKM. The platform’s elastic displacements and joint reaction forces/moments of the Exevariant PKM at the extreme position are analyzed. Furthermore, their mappings over any work plane are evaluated throughout the entire workspace. The results reveal that the gravitycaused elastic displacements of the platform and joint force/moment reactions are noticeable. The mappings of platform’s elastic displacements and joint forces/moments reactions in the entire workspace are positiondependant and demonstrate a symmetry over any given work plane. References | Related Articles | Metrics

Select

A Novel Cathode Structure in Electrochemical  MicroMachining of Micro Holes ZHANG Hui1,LIU Weidong1,AO Sansan1,XIE Yan1,LIU Zuming1,LUO Zhen1,2 2017, 51 (8):  1000-1005.  doi: 10.16183/j.cnki.jsjtu.2017.08.015 Abstract ( 714 )   Save  In order to improve the material removal localization of workpiece, uninsulated tools, sideinsulated tools and retracted tip tools are investigated. Electrolyte between anode and cathode is the main research object in the paper. Computational models of electric field are developed, and the distribution of electric potential and current densities in the machining gap are obtained through numerical simulation method. By the numerical results the effects of using retracted tip tools on entrance quality are researched. Furthermore, effects on machining accuracy and efficiency of using retracted tip tools are analyzed, and optimum parameters are obtained based on the simulation results. Results show that good machining accuracy can be obtained with the optimum parameters that retracted tip depth is 50μm, machining voltage 5V and feed rate 3μm/s. References | Related Articles | Metrics

Select

Optimum Design and Simulation Analysis of Slice Cutter for  HighEfficient Machining with High Strength Steel CHENG Yaonan，HAN Yu，GUAN Rui，XU Ming，LU Zhenzhen 2017, 51 (8):  1006-1012.  doi: 10.16183/j.cnki.jsjtu.2017.08.016 Abstract ( 812 )   Save  Milling tests for 508III steel are carried out to analyze the impact of cutting parameters on cutting force by using sliced milling cutters. A cutting parameters optimum model is established under the objective of processing efficiency and tool life. Genetic algorithm is applied to optimize the cutting parameters, and the tool structure is designed according to the cutting parameters. Simulations of the blade are carried out by the combination of different rake angles to optimize the angle parameters. Simulations of cutting force are completed according to the optimization cutting parameters. The research can provide technical support for tool development and cutting parameters optimization for highefficient heavy milling water chamber head. References | Related Articles | Metrics

Select

Simulation of Creep Deformation for P92 Steel Based on  Multiple Damage Parameters ZHANG Wei1,2,WANG Xiaowei1,2,3,JIANG Yong1,2 HUANG Xin1,2,GONG Jianming1,2,WENG Xiaoxiang1,2 2017, 51 (8):  1013-1017.  doi: 10.16183/j.cnki.jsjtu.2017.08.017 Abstract ( 920 )   Save  A twodamage state variable model was used to describe the softening, damage initiation and growth mechanisms of P92 steel at 650℃ under the continuous damage mechanics framework. Based on the analysis of existed creep experimental data and creep model, a methodology was proposed to determine the constitutive constants of P92 steel at 650℃. It was shown that the constitutive constants obtained from analysis of creep experimental data could simulate the creep deformation of P92 steel at 650℃ precisely, and the constitutive equations with multiple damage parameters could be extrapolated to other stress levels. The continuous damage equations based on the multiple damage parameters can give a good description of creep deformation from terms of inelastic strain rate, inner stress and microstructural evolution. Therefore, the study is of profound practical significance in engineering. References | Related Articles | Metrics

Select

Effects of Welding Process Parameters for  Welding Residual Stress of Anchor Pipe HE Xiongjun1,ZHANG Jing1,HE Jia2,XIAO Xiang1,WANG Jingjun3,DONG Jie1 2017, 51 (8):  1018-1024.  Abstract ( 682 )   Save  In order to predict residual stress under different welding parameters and further optimize the welding procedure, the welding residual stress of anchor pipe was studied by numerical simulation and experimental comparison. The welding residual stress of Tjoint welding specimen was simulated with the finite element software ANSYS, and the accuracy of the numerical method was verified by comparing with the measured stress value. On this basis, the welding residual stress of anchor pipe was compared and analyzed in different welding process parameters like welding voltage, welding current and welding speed by simulation. The results show that welding residual stress of anchor pipe is positively correlated with welding voltage and welding current, and the longitudinal residual peak stress at root is greater influenced by welding current. Welding residual stress is negatively correlated with welding speed, which means when welding speed is higher, the longitudinal residual stress along the weld direction reduces obviously and its distribution is more uniform. When welding speed reaches 5mm/s, anchor pipe is not fully welded and the position of peak stress moves, so welding speed can be used as the main control parameter. Based on the results, the simplified residual stress distribution model of anchor pipe section is established, providing a reference for research of the welding residual stress. References | Related Articles | Metrics