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2009 Vol. 35, No. 12

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Development of kind of heat transfer coefficient sensor based on steady method
Quan Yongkai, Xu Guoqiang, Luo Xiang, Ding Shuiting
2009, 35(12): 1413-1416.
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A kind of heat transfer coefficient sensor based on steady state method was developed. A calibration terminal was pulled. The precision was analyzed and the results were compared with the values calculated from the classics empirical equation. The heat transfer coefficient obtained from the calibration terminal and the empirical equation is in a good agreement. The results shows that the calibration method is reasonable. The feasibility of the sensor is proved by the calibration experiment and the modified coefficient K is obtained. The relative error range is from 0.4% to 1.7% between the measured values and standard values. The values of K of separate sensors are different.
Direct numerical simulation of turbulent channel flow of polymer solution
Zhang Jinbai, Zheng Zhaohu
2009, 35(12): 1417-1420.
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The drag reduction characteristic of polymer turbulence in channel flows was investigated using the direct numerical simulation (DNS). In the simulations, the spectral methods employing Fourier series and Chebyshev polynomial were used to make the spatial discretization and the time-splitting method with second-order time accuracy was adopted to carry out time advancement. For three-dimension turbulent channel flows of a polymer solution, based on the FENE-P model, the obtained efficiency of drag reduction for the four cases show that there exists the "onset" phenomena. Based on the O-B model, the simulations show that in low drag reduction, the effect of polymer on turbulence mainly occurs in the near wall region, and in high drag reduction, the effect of polymer on turbulence occurs in the whole flowfield.
Laser frequency discriminator using all fiber unbalanced-arm Mach-Zehnder interferometer technique
Jia Yudong, Ou Pan, Zhang Chunxi, Wang Jiqiang
2009, 35(12): 1421-1424.
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An improved laser frequency discriminator using all fiber unbalanced-arm Mach-Zehnder interferometer technique was studied in detail. The acquisition technique of frequency error signal through utilizing triangular wave to modulate the an arm of interferometer was analyzed quantitatively. The piezo-electric transducer (PZT)-type frequency modulator was replaced with LiNbO3 phase modulator. The interferometer output signal was calculated through emulator. An experimental setup to validate the theoretical analysis was constructed. The result was agreement with simulation result. The modulation signal and environment perturbations were evaluated through experiment. The result shows the system stability is improved greatly, and the modulation dynamic range is extended from Hz to GHz. The phase to frequency responsibility was measured by applying lock-in amplifier, and the peak to peak frequency fluctuation of measured laser can be calculated according to the phase to frequency responsibility.
Multilayer trajectory optimization design for surface-to-air missile based on global sensitivity equation method
Jiang Huan, Zhou Hao, Chen Wanchun, Yang Baokui
2009, 35(12): 1425-1428.
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A multilayer approach to the midcourse trajectory design and terminal phase time constants design for a surface-to-air missile to maximize the kill probability was presented. Three layers were discussed. The first layer represented the midcourse trajectory of the missile, the second layer represented the terminal homing phase, and the third layer was the warhead damaging process. A layer can be seen as a subsystem, the multilayer trajectory optimization problem is a essential multidisciplinary design optimization (MDO) problem. The global sensitivity equation (GSE) method was adopted to compute sensitivity derivatives with respect to design variables, which did optimization in system level and got the trajectory which maximizing the kill probability. At last a case of intercepting air-to-surface missile(ASM) was designed and optimized. Uniform design of experiments and BP neural network were used to avoid long time computing. The result is that GSE method is effetive for multilayer trajectory optimization design problem.
Flutter control of composite panels with embedded piezoelectric materials
Yuan Kaihua, Qiu Zhiping
2009, 35(12): 1429-1433.
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The panel flutter phenomenon with thermal effect was researched. By virtue of von Karman-s large deflection plate theory, piston theory aerodynamics and the quasi-steady thermal stress theory, the aeroelastic model of composite panel with embedded piezoelectric materials was established. In nonlinear finite element equation the Bogner-Fox-Schmit element was adopted. The dynamic equations of motion were transformed into a state space model in order to design controller. An optimal controller based on the nonlinear model was presented. The flutter suppression results in the time domain using the Runge-Kutta method for a simply supported piezolaminated composite panel subjected to uniform thermal loading was realized. The effectiveness of the present control method was illustrated by simulation solution.
Weight allocation of combination prediction based on sequence relative nearness degree
Lü Yongle, Lang Rongling, Tan Zhanzhong
2009, 35(12): 1434-1437.
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Aiming at the weight allocation problems of combination prediction for a time series, a new method was proposed to evaluate the applicability of the employed models and allocate weights, based on the "nearness" between the test sequence and the corresponding prediction value sequence, which overcame the shortages of existing methods such as mean square error reciprocal weight (1/MSE), entropy weight and optimization weight. The definitions of sequence relative nearness degree (SRND), related sequence trend association and scale interval entropy were given and well discussed, as well as the weight allocation expressions based on SRND. By the example which combined the autoregressive moving average model, functional-coefficient autoregressive model and radial basis function prediction networks in the prediction analysis for the takeoff exhaust gas temperature margin time series, the conclusion is drawn that the prediction accuracy can be effectively improved with the proposed method, compared to 1/MSE and entropy weight methods, while the calculation mount is far lower than optimization weight method.
Two-phase software clustering method based on complex network theory
Qian Guanqun, Zhang Lin, Zhang Li
2009, 35(12): 1438-1442.
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GN(Girvan-Newman) algorithm, a famous community detection algorithm, is introduced into software clustering. In order to overtake the weakness of high computation complexity and avoid generating small scale modules, a two-phase software clustering method is proposed. Firstly, cluster software based on its structure pattern. 3 structure patterns are identified, including: star structure, link structure and topology similarity structure. Cluster these structure patterns could efficiently reduce the scale of software network. Secondly, use modified GN algorithm to cluster software. If the remove of the edge with maximal betweenness would produce a module whose scale is smaller than the value set in advance,this remove action is forbidden. The edge with secondly maximal betweenness is tried. The experiment results show that the two-phase clustering algorithms can improve the effect of software clustering and be applied in the large-scale software.
Multinomial Logit model based on Gumbel Copula
Li Huamin, Huang Haijun, Wang Huiwen
2009, 35(12): 1443-1445.
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For the IID(identically & independently distributed) condition of the multinomial Logit model, which requires all random terms existing in the utilities of alternatives to be independent each other, a discrete choice model was proposed, based on the Copula function which can be used to derive the joint probability distribution of multi-random variables. The IID condition is weakened and the distribution of the difference between every two random terms is obtained using the Gumbel Copula function-s property. It is found that this distribution still follows the Logistic type but the difference must be multiplied by a parameter which can be estimated by the likelihood method from survey data. This result is then extended and employed in the discrete choice problem with more than two alternatives. The probability of choosing a specific alternative is rigorously formulated. The work surmounts the difficulty of applying the multinomial Logit model.
Analysis of heat transfer and flow characteristics of composite wicks of loop heat pipes
Bai Lizhan, Lin Guiping
2009, 35(12): 1446-1450.
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Loop heat pipe is one of the most advanced thermal control devices in the spacecraft thermal control system, whereas high quality wicks are the key components for its efficient and reliable operation. To improve the overall performance of the wicks, composite wicks are the developing trend. The mathematical model of the two-layer composite wicks applied in loop heat pipes with a cylindrical evaporator was established, and its heat transfer and flow characteristics especially the effect of the applied heat loads and ratio of the inner and outer layer wick thickness were analyzed. Meanwhile, the performance of the composite wick was compared with that of the single structure wick. The modeling results show that the composite wick can acquire not only high capillary forces and evaporation efficiency, but also low flow resistance and radial conductance, and its overall performance is far better than that of single structure wick. When the size of the composite wick is fixed, as the ratio of the inner and outer layer wick thickness increases, its radial conductance and flow resistance decrease, which contributes to the efficient operation of loop heat pipes.
Impulsive loading of simply supported lattice truss core sandwich beams with axial restraints
Liu Hua, Zhu Xiaoqin, Yang Jialing
2009, 35(12): 1451-1454.
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The dynamic response of a simply supported lattice truss core sandwich beam with axial restraints subjected to uniform transverse impulsive loadings was studied through rigid-plastic analytical model and elastic-plastic finite element (FE) calculation. Firstly, the maximum deflections of the sandwich beam predicted by both circumscribing and inscribing yield loci were given and compared with those predicted by finite element method. It is found that the FE predictions of the maximum deflections are between those predicted by the circumscribing and inscribing yield loci. The FE predictions of the maximum angle of rotation at the simply supported ends approach the analytical model employing the circumscribing yield locus. Then the shock resistance and energy-absorbing capability of the sandwich beam were studied. According to the FE analysis, it is indicated that the maximum deflection and plastic energy absorption of the sandwich beam are sensitive to the relative density and inclination angle of the sandwich core member, and the properly designed sandwich beams have superior energy-absorbing capability and shock resistance.
CCD vidicon image processing simulation
Liu Yudan, Zhang Jiong, Dai Shuling
2009, 35(12): 1455-1458.
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A simulation method based on programmable graphic processing unit (GPU) was proposed to simulate charge coupled device (CCD) vidicon image processing. The flow-operating mode and parallel computation ability of GPU were utilized to process each pixel, including Gamma correction, brightness and contrast adjustment, color-temperature adjustment, and color-saturation processing. The principle of Gamma correction and the necessity to implement it before other operations were analyzed. The relation between luminance and pixel color was discussed. A method to compute luma signal of current image was proposed. The luma scale was defined and image processing was based on it. A method to simulate the dynamic noise in low luminance condition was introduced. The results show that this method can simulate the imaging effect of real CCD vidicon in complex illumination environment with high speed and efficiency which are required in real-time simulation.
Evaluation model of materiel support plan in development phase based on DEA
Qu Lili, Kang Rui
2009, 35(12): 1459-1463.
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To solve the problem that support plan evaluation existed many defects in angles and methods in the previous studies, the evaluation model based on data envelopment analysis (DEA) was presented. The support system general characteristics were abstracted, and evaluation parameters of support system characteristics were established. The model based on data envelopment analysis was established to calculate relative efficiency indexes for assessing support plans, and the evaluation model based on inferior frontier was used to reevaluate several effective support plans, and ranking of alternatives was realized. Evaluating certain type military aircraft support plans were given as an example, feasibility and validity of the model were verified. It could provide excellent decision supporting for defense industrial sections to evaluate materiel support plans in development phase.
Time effectiveness analysis of fault samples for aero-engine reliability assessment
Hong Jie, Wang Dawei, Ma Yanhong
2009, 35(12): 1464-1467.
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It is hysteretic to use reliability model which is set up based on failure data to reflect the changes of system reliability condition. With the enhancement of reliability level, the early failure samples should be processed time effectively in aero-engine reliability assessment. An attenuation factor α was proposed to express the attenuation grade of failure intensity. The attenuation function that describes the attenuation process was captured by improving Gompertz reliability growth model. All useful information was utilized by using Bayes data fusion methods for time effectiveness of samples. A new acquisition turbo-fan engine was statistically analyzed by this model, and the time effectiveness of fault samples for typical failure was studied. The result indicates that this model could provide more scientific evaluation of aero-engine-s reliability.
Selection of reliability parameters and targets assessment for certain missile turbofan engine
Wang Dawei, Zhang Liming, Hong Jie
2009, 35(12): 1468-1472.
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Based on the characteristics of structures and employments on missile turbofan engine, mean time between failure(MTBF), rate of startup successfully(RST)and mean time to failure(MTTF)were chosen as the parameters of reliability evaluation. MTBF reflect the basic reliability, and MTBF evaluation model was erected based on Bayes data fusion technology. RST reflect starting reliability, and RST evaluation model was established by dint of fault tree analysis. MTTF embody mission reliability, and MTTF distribution model according to key components during operation founded. These evaluation methods are evaluated by application on certain missile turbofan engine. The parameters are selected effectively, the models are correct, and the conclusions can be used as reference in reliability evaluation during development and employment.
Infrared radiant computation by OpenGL
Fang Ning, Zhang Xiaolin, Gao Jia, Qi Zhengyun
2009, 35(12): 1473-1476.
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A method of computing the infrared radiant intensity of complex target using OpenGL which achieved the visual infrared radiation calculation was presented. For OpenGL is able to be applied to construct the three-dimensional modal of objects and do three dimensional interaction, the evaluation of complex target-s infrared radiant intensity is available. Utilizing the hidden capability of graphics hardware, the computation of shelter was avoided and the radiant intensity then was obtained by WYSWYG(what you see what you get). Different visual light models were applied to get the self-radiation and the reflection of sun energy of target. The parameters of emission and diffuse reflection in light model determined the color of each pixel in computer screen and then the temperature and the normal of each pixel were obtained. So the computation was implemented visually. A simple model was applied to verify this method-s validity and feasibility.
Analysis and accurate compensation of dead-time for three-phase DC/AC inverter
Zhang Jin, Qi Bojin, Zhang Shaoru, Qin Wenping
2009, 35(12): 1477-1482.
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A novel approach to compensate the dead-time effect based on the existing no-dead-time technique was presented. The reason of the inverter output voltage distortion was analyzed with the consideration of the dead-time and the non-ideal characteristics of the switching devices. The proposed method was implemented by adjusting the pulse width of the original driving signals to compensate the switching delay and voltage drop effect of the power devices, thus the effects were prevented from propagating into the ac-side. An improved current polarity detecting circuit with high precision was introduced to overcome the difficulties in current polarity detecting around the zero current crossing point. A more accurate output voltage synthesis was obtained with simple logic and flexible implementation, by applying this compensation strategy to a general purpose inverter system. Experimental results verify the effectiveness of the proposed method.
Planar linkage mechanism design for bi-objective of trajectory and velocity
Guo Weidong, Wang Xin
2009, 35(12): 1483-1486.
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An optimal synthesis method of planar linkage mechanism for continuous path generation was put forward, which would find the interpolation nodes of planar linkage mechanism-s trajectory generation mechanism, for bi-objective of trajectory and velocity. The interpolation nodes were entrusted with the physical meaning of the velocity by this method. The optimal synthesis model was set up based on the minimization of the error between the path-generating point in the coupler curve and the prescribed position, while the nonlinear optimization algorithm of BFGS(Broyden-Fletcher-Gddfarb-Shanno) quasi-Newton was adopted to find the global optimum solution to approximate kinematic synthesis of planar linkage. With the uniform rotation of the crank, the optimization algorithm calculated the planar linkage mechanism, satisfied the requirements of our bi-objective, and actualized the expectant target. The validity and effectiveness of the proposed method were illustrated by comparing the optimization results of four-bar mechanism and five-bar mechanism.
Multi-target tracking based on cluster min-distance data association
Ding Wenrui, Li Hongguang, Li Xinjun
2009, 35(12): 1487-1490.
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A multi-target tracking algorithm based on cluster min-distance data association was proposed. Three matching distances about target position, target size and target gray value were established, weighted and integrated into final target matching distance function. The algorithm searched for the target list-s follow-up data which had min-matching distance relationship with observed target and the observed target-s precursor data which had min-matching distance relationship with target list. Only when the follow-up relationship and the precursor relationship were both true, the matching relationship was true between them. All the target lists were divided into four clusters. All the observed targets were divided into two clusters. The probable relationships between all clusters were analyzed, with carrying out the above computation. If the target was blocked, a target forecasting algorithm was executed. Based on the theory of instantaneous linear and mean filtering, the position data of target list were input to gian a regression line for forecasting the target-s position of next frame. The target-s size and gray value data were gained by mean filtering for the moment. A good result was presented on multi-human tracking.
Jet mixing enhancement by pulsed blowing
Li Jiajun, Eriqitai, Wang Qiang
2009, 35(12): 1491-1494.
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This work uses a technique for injecting high amplitude and low mass flux pulsed slot jets into subsonic shear layers for the purpose of jet mixing enhancement. The 3-D flow fields of the jets with pulsed jet blowing for mixing enhancement were simulated numerically. The finite volume method, RNG k-ε turbulence model were employed to solve N-S equation. Numerical simulations of low Mach number 0.2 and middle Mach number 0.6 jets exhausting into fluid were conducted. These simulations show that pulsed jet blowing effected on either low Mach number jets or middle Mach number jets causes the jet to expand rapidly in the plane parallel with the actuators and to contract in the plane perpendicular to the actuators, the intensity of motion and associated mixing are higher when the excitation Strouhal number is around 0.2, and small injection flow rates can provide tremendous increases in both velocity and temperature decay rates. With the increase of the pulsed slot jet mass flux, a better mixing can be obtained.
Rapid partitioning of an aircraft 3D model into its assembly cells
Wang Zijun, Zheng Guolei, Du Baorui
2009, 35(12): 1495-1498.
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By the investigation of practical production the methods of aircraft assembly cell partition in the field of home aviation were wildly collected and deeply known about. Refer to the literature and information about the technique of aircraft assembly, the traditional experiences and knowledge of aircraft assembly cell partition were sorted out in detail and deeply analyzed. The digital technique of aircraft assembly cell rapid partition was investigated on 3D modeling of aircraft. The 3D process split surface which becomes the foundation for digital assembly cell partition was put forward and defined, and its modeling arithmetic was constructed respectably. Then based on the 3D process split surface, the methods of the component recognition and modeling for an assembly cell were put forward. The rules of the component recognition were established accordingly and the modeling arithmetic of new assembly cell was constructed. The proposed techniques were initially developed and verified on the CATIA V5 system.
Modifiable Squeezer cluster algorithm used in large-scale matrix
Li Yan, Wang Huiwen, Ye Ming, Liu Dan
2009, 35(12): 1499-1502.
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To solve the clustering method to the large-scale matrixes in the same dimension, the modifiable Squeezer cluster algorithm was proposed, based on the analysis of Squeezer cluster algorithm and the definition of the distance between the matrixes. The modifiable algorithm set a distance threshold, put forward a threshold of radius to control the accuracy of classification, and gave the detailed algorithm steps to realize cluster analysis for a large number of matrices. When the matrix cluster set was obtained, the modifiable algorithm provided the definition of center and radius to describe the properties of the matrix set. The proposed method could control the accuracy of classification in order to prevent chain effect in the course of clustering. The simulation experiment was addressed to validate the rationality and effectiveness of the modifiable algorithm.
Engineering estimation methods of thermal load of airplane
Zhang Xingjuan, Yang Chunxin, Yuan Xiugan
2009, 35(12): 1503-1506.
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The thermal load of the airplane refers to the net heat transmitted in (or out) per unit time when keeping the constant temperature and humidity in the cabin of the airplane, which is the reference to estimate the ability of the temperature conditioning system. On the basis of consulting 25 kinds of foreign related literature on airplane environmental control system, two kinds of thermal load estimation method were proposed as follows.The thermal load of airplane passenger cabin had a good linear relationship with the number of passenger, under determining the number of cabin crew, using estimation model 1 could estimate crew cabin heat loads. The value range of the heat transfer coefficient of the aircraft whole cabin wall was 2.45 ~ 7.97 W/(m2·℃) and the average value was 4.93 W/(m2·℃). In the preliminary design of environmental control system, if the concept of shape is known, using estimation model 2 could also estimate cabin crew thermal load easily. The research results will offer some guidance for the development on civil airplane.
Monte Carlo simulation of polychoric correlation and Pearson correlation coefficient
Wu Ruilin, Wang Jianzhong, Yuan Kehai
2009, 35(12): 1507-1510.
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The more accurate estimates were obtained via the polychoric correlation coefficient rather than traditional Pearson correlation coefficient in multivariate analysis for ordinal categorical data. The statistic model and estimators of the polychoric correlation were introduced. Then a Monte Carlo simulation was conducted to discuss the influence of sample size, category number, correlation degree, and data distribution on the precision of polychoric correlation estimate. The simulation results show that the polychoric correlation coefficient is more robust, and more precise than Pearson correlation coefficient in the most of the simulation setting. To both two correlation estimation approaches, sample size is not an influential factor and the bias has explicit decrease when adding the number of category. The skew distribution would distort the Pearson correlation; however it has a very limited influence on the polychoric correlation.
Aileron control and reconfiguration of flying wing aircraft
Chai Xue, Wang Ganglin, Wu Zhe
2009, 35(12): 1511-1515.
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To decouple the longitudinal and lateral-directional coupled motion caused by the aileron deflection of the flying wing aircraft, the elevator and the split-drag-rudder (SDR) were used to cooperate with the aileron to decouple the coupled motion. In order to increase the flying wing aircraft survivability, the reconfigurable control system had been investigated. In the elevator failure reconfiguration, the pseudo-inverse method was directly used to reconstruct the control system by the aileron. In the SDR jamming failure, an improved pseudo-inverse reconfigurable method based on the routh stability was designed with the proportion-plus-integral (PI) control. The method guaranteed the stability of the reconfigured closed-loop system by using the routh stability criterion, and was capable of solving bad steady precision problems that may occur in the reconfigurable system. Simulation results are provided to show the effectiveness of the proposed method by recover the performance of original system to a maximum extent.
New algorithm integration model applicable for computer aided engineering
He Yunqin, Liang Guozhu
2009, 35(12): 1516-1520.
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In order to solve the important problem of algorithm integration in computer aided engineering(CAE) domain, which exists in many current engineering software systems taking algorithms as the core, using rocket motor design as a representative case and starting point, the characteristics of algorithm application in engineering practices were deeply analyzed, and flaws in current software system were pointed out. Two algorithm patterns were brought forward, and based on them a new algorithm integration model, named "algorithm integration model based on loop and hierarchy", was set up, which has the characteristics of loose-coupling, hierarchy, and flexibility etc. Based on the model, a cross-domain, general and high efficient algorithm integration software environment could be constructed.

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