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2010 Vol. 36, No. 2

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Perspective view of virtualization technologies for avionics system
Zhang Jiong, Lü Zixu, Hu Yanyan, Long Xiang
2010, 36(2): 127-130.
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Virtualization technology was used to achieve the designing of avionics system. Virtual machine system was used to implement a sharing management of hardware resources and to make a partitioned schema for software sub-systems subject to the requirements of ARINC 653, which required that the avionics system should be featured with modularity, reliability, isolation and openness. A triple-layer architecture, composed with hardware, virtual machine monitor(VMM)/partitioning OS, avionics application, was implemented to meet the functional and interfacing requirements of integrated modular avionics(IMA), which was a highly integrated and modularized avionics system. In order to achieve these features, VMM should be modified to resolve some problems so as to be compatible with ARINC 653 and traditional partitioned operating system should also be modified with several critical components or mechanisms, such as processor privilege level and privileged instruction, interrupt trap, memory management, device drivers and so on. With these improvements, a VMM-based IMA system could be constructed.
Prediction of aeroengine-s performance parameter combining RBFPN and FAR
Lü Yongle, Lang Rongling, Lu Hui, Tan Zhanzhong
2010, 36(2): 131-134.
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Exhaust gas temperature is one of the performance parameters which reflect aeroengines- running state most efficiently. The prediction analysis of the sequent takeoff exhaust gas temperature margin (EGTM) is helpful to estimate aeroengines- future working performance, which can offer sufficient time reference and decision-making support for the fault prevention and elimination. When building the prediction model according to the EGTM historical observation sequence which was characterized by nonlinearity and nonstationarity, a solution combining radial basis function prediction networks (RBFPN) and functional coefficient autoregressive model (FAR) was proposed based on the sequence partition with singular value decomposition filtering algorithm. The respective advantages of RBFPN and FAR in modeling the trend element and the random element of EGTM sequence were taken complementally and cooperatively. It is indicated by experimentation that the solution can effectively restrain the shortcomings of separate employment of RBFPN or FAR, and improve the prediction performance.
Numerical simulation of external MHD generator on board reentry vehicles
Chen Gang, Zhang Jinbai, Lee Chun-Hian
2010, 36(2): 135-139.
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A scenario of external magnetohydrodynamic (MHD) generator on board blunt-cone based reentry vehicles was proposed, and numerical parametric studies by employing an MHD model based on the low magnetic Reynolds number approximation were performed. Following the numerical results, the physical features of the external MHD generator were drawn. One may conclude that the power output of the external MHD generator is capable of providing energy output up to 1.28 MW under the typical reentry condition (flight height 46km,velocity 7km/s). Under the MHD power extracting operation, the drag coefficient of the reentry vehicle is raised by 13.7%, whereas the total wall heat flux varies mildly. However, the distribution of heat flux density in the MHD power extraction zone and downstream differs distinctly from that in the original N-S flow. The peak heat flux densities in the area occur at the tips of the electrodes.
Region-based statistical signal processing scheme for image fusion
Wang Rui, Wang Lin, Yuan Yan
2010, 36(2): 140-144.
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A new image fusion scheme based on region statistical signal processing was proposed. The region growing technique using gray-level clustering was employed to segment the source images into different regions whose borderline represented with crack edge. The registered source images and their segmented mapping were decomposed into a multi-resolution representation with both low-frequency coarse information and high-frequency detail information respectively. The expectation maximization algorithm modeled with noise statistic distribution was used to fuse the low-frequency coarse information of the registered images,while the match and salience measures were applied to fuse the high-frequency detail information of the registered images. The final fused image was obtained by taking the inverse transform of the composite multi-resolution representations information. Fusion experiments on real world images indicate that the proposed method is effective and efficient, which achieves better performance than the most generic fusion method.
Application of MDO algorithm to multi-tier trajectory optimization design for a surface-to-air missile kinetic kill
Liu Hengjun, Jiang Huan, Chen Wanchun
2010, 36(2): 145-149.
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A multi-tier trajectory optimization framework for a surface-to-air missile to optimize the kill probability was proposed based on the multi-tier optimization process(MTOP). The missile-s intercepting process was divided into three tiers, which were the midcourse trajectory optimization, the terminal homing phase and the kinetic tungsten rods lethal enhance kinetic kill process. A tier can be seen as a subsystem, the multi-tier trajectory optimization problem is essential a multidisciplinary design optimization (MDO) problem. A solution of the multi-tier trajectory optimization framework was presented based on the MDO theory and methods through discipline analysis and system analysis. The global sensitivity equation (GSE) method and All-in-One method were used to solve the system optimization problem. The results show that both methods are effective for solving the MTOP problem, and the All-in-One is much better.
Target threat assessment technology based on cloud model
Ma Shidong, Han Liang, Gong Guanghong, Song Xiao
2010, 36(2): 150-153.
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The accuracy and good characteristic in real-time of target threat assessment have important significance to military campaign simulations. The target threat assessment technology based on cloud model was proposed, and the staff gauge clouds were obtained through Bayes revision on the membership clouds gained depending on experts- experience which evaluated on qualitative concepts. Finally the cloud diagram of target threat assessment was obtained through battlefield situation information matching the staff gauge clouds and data disposal, and the assessment was realized. The description of battlefield situation with qualitative concept and membership clouds achieve a good integration in fuzziness and randomicity, which reflect uncertainty when pilots obtain information in air war. An example was given to validate the target threat assessment technology based on cloud model, and the results indicate that threat level assessment can be realized availably by this technology.
Numerical simulation of three-dimension mixture gases plume and its effects
Zhang Jianhua, He Bijiao, Cai Guobiao
2010, 36(2): 154-158.
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To simulate actual attitude control thruster plume flow and its effects, the three-dimensional plume effects were studied by the approach which combines difference solution of Navier-Stokes(N-S) equations and the three-dimension mixture gases direct simulation Monte Carlo method(DSMC), according to the layout of the thruster on the satellite and actual attitude control thruster-s exhaust consisting of mixture gases. The plume parameters of the flow field, aerodynamic force and aerodynamic thermal effects to solar cells were obtained for a 5 N hydrazine satellite attitude control thruster. The result shows that N2 and NH3 should be paid more attention for the plume effects- protection of solar cells and the plume can bring the force and thermal effects on the solar cells. The peak value of aerodynamic force and aerodynamic thermal effects is on the front of the solar cells. The work is helpful for the plume effects research.
Boundary sampling and statistical techniques in DSMC method
Hou Fenglong, Cai Guobiao
2010, 36(2): 159-162.
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A boundary sampling technique suitable for three-dimensional DSMC(direct simulation Monte Carlo) calculations was studied, which could be used to give proper entering particle parameters according to the inlet conditions. A new kind of boundary statistical technique was proposed, which could be taken to obtain macroscopic flow parameters just at the boundary interface, from the statistical data of the entering or escaping particles or the ones impinging on the wall. This new statistical technique makes up for the defective of traditional DSMC statistical technique, which can only get the inner flow field parameters, but can not get the interface parameters. This statistical technique is essentially a universal arithmetic, not just suitable for the DSMC method. A calculation of infinite far flow passing around a sphere was carried out. The results show that the sampling and statistical techniques are effective.
Mode tracking techniques in flutter analysis
Wu Zhigang, Song Chen, Yang Chao
2010, 36(2): 163-167.
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Flutter solution is an eigenvalue problem which has variable parameters (such as air speed). In flutter mode identification and flutter prevention, the correspondence between the baseline and perturbed eigenvalues due to parameter variation should be determined accurately, and mode crossing should be avoided. For mode tracking in flutter solution p-k/i> procedure, the forecast tracking method was developed, which was based on the perturbation theory of eigenvalues. The method used the baseline eigenvalues and the left and right eigenvectors to estimate perturbed eigenvalues, and sorted modes by their estimated values. The forecast tracking method was compared with two existing methods, one was similarity sorting method, the other was orthogonality check method. Two testing cases were used to validate the effectiveness of the methods. The numerical results show that the forecast tracking method is better than the existing methods in effects of mode tracking.
Simulation of helicopter rotor aerodynamic force in conditions of high angle of attack and dynamic stall
Su Yuan, Cao Dong, Cao Yihua
2010, 36(2): 168-171.
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Using Pitt-Peters dynamic inflow model and Wang’s vortex theory, helicopter inflow model was set up. The distribution and magnitude of rotor induced velocity in helicopter maneuvering flight were obtained. According to blade element theory and state-space function, rotor unsteady aerodynamic model was established, and the rotor dynamic response characteristics were calculated for different azimuth angles. The agreement between the computational results and the referenced data indicates that the models are feasible and effective. Finally, for the two flight conditions with dynamic stall and deep dynamic stall, MATLAB software was taken as the computational platform, and rotor loads responses at high angles of attack for pop-up maneuver can be obtained. The theoretical method can provide the references for the simulation of the unsteady aerodynamic forces in helicopter maneuvering flight.
Advanced ultra capacitor modeling method and applications
Gai Xiaodong, Yang Shiyan, Lei Lei, Xi Lingling
2010, 36(2): 172-175.
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An ultra capacitor(UC) modeling method based advanced physical terminal behavior was proposed. This model with perfect stable and dynamic characteristics according to the actual physical properties was consisted with three parts of the branch circuits, a voltage controlled voltage source serried by a constant capacitance was used in real-time branch circuit to simulate real-time characteristics of super-capacitors. The method to determine model parameters was also proposed. Simulations results show that this model can well reflect the nonlinear charge and discharge behavior and demonstrate self voltage recovery behavior after charge and discharge. This model has been successfully applied to the optimum design of equalization circuit and it is simple enough to be easily applied for simulation of power electronics applications involving UC practically.
New method for the sensors sensitivity calibration in water-filled tube
Jin Zhongkun, Wang Tongqing
2010, 36(2): 176-179.
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The error brought up by the sensitivity difference of sensors was analyzed in the transfer function measurement using two-sensor method in acoustic tube. Based on the transfer function found from the known reflectance of known interface the ration of sensors sensitivities could be measured, a new method for sensors sensitivity calibration in acoustic tube was brought forward. An experimental validation of the known transfer function was carried out in air-filled tube with rigid terminator by exchanging the microphones in the acoustic tube. In water-filled tube with air terminator the experimental validations of the new method were carried out in the condition with environment pressure and higher pressure, it illustrates the validity of the new method, which overcomes the difficulty of exchanging hydrophone in water tube.
Radar altimeter alarm signal testing approach based on data fitting
Wang Weibin, Lu Hui, Lang Rongling
2010, 36(2): 180-183.
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The radar altimeter auto test system and the original test method were introduced, and the disadvantage that this method is inefficient was brought forward. The method of radar altimeter sensitivity testing using dichotomy method, which was used to improve the efficiency of radar altimeter sensitivity testing, was proposed. The test result and test flow were presented. Using this method a few stimulating and output voltage data were used to fitting the relation function, which was used to calculate the begin stimulate voltage, and then adjust the stimulate voltage with small voltage to test alarm signal precisely. According to the test result, the conclusion can be reached that the optimized method can be much more efficient while the testing precise of the sensitivity is the same.
Risk modeling and entropy decision on large complex project
Ma Liyi, Qiu Wanhua, Yang Yaqin
2010, 36(2): 184-187.
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To solve problems as large scale, complex structure, numerous risks and difficult to make decision of large complex project, the risk decision method was proposed, based on hierarchical modeling, risk filtration, risk ranking and entropy decision. The hierarchical holographic modeling technique was applied to identify system risk. The risk identification model of satellite system development was developed, which overcame the limitation of sole model describing risk sources. The risk filtration, ranking and management technique was used to measure the identified risk factors through qualitative assessment and quantitative analysis. All the risks were ranked and the essential risks were determined. The entropy decision model was finally applied to evaluate the key risks. The optimal program was determined. A case of satellite development program decision was developed by using this method, which provided a new method for the large complex project risk decision making.
Approach to modeling user interests using conceptual clustering
Liu Yongli, Ouyang Yuanxin, Wen Jia, Xiong Zhang
2010, 36(2): 188-192.
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The exponential increase of internet resources accelerated the development of effective personalization techniques. A new method for modeling user interest, named UIM2C2 (user interest modeling method based on conceptual clustering) was presented. The method analyzed documents that each user ever browsed and created a suffix tree. According to different pair-wise base cluster similarity thresholds, base clusters could be merged in the range of different granularity. Combining with the inclusion relation between merged base clusters under different granularity, an interest hierarchy was generated. UIM2C2 carried out incremental, unsupervised concept learning over Web documents so that user profiles could be acquired and updated easily. Experimental results prove the effectiveness of the method in Web page recommendation.
Extension and improvement for schemes in hypersonic thermal and chemical non-equilibrium flows
Zhou Yu, Yan Chao
2010, 36(2): 193-197.
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Six high accuracy schemes (ROE, MAPS, LDFSS, HLLC, HCUSP and ECUSP) were successfully extended from ideal gas model to thermal and chemical non-equilibrium gas model. All the schemes were analyzed in detail. Some of them were improved by ROE averaging numerical speed. Five species seventeen reactions Dunn-Kang chemical reaction model and Park-s two-temperature kinetic model were used to compute three-dimensional sphere test. The results show that in thermal and chemical non-equilibrium flow, the ROE and MAPS schemes have higher accuracy than LDFSS, HLLC and CUSP type schemes. The numerical speed given by ROE averaging can obviously strengthen the robustness of scheme, and improve oblique shock capturing capability, while the physical variables in flow field will be not influenced. The MAPS and ECUSP schemes are improved successfully by using the numerical speed given by ROE averaging. The reference to choose schemes has been provided.
Investigation of aerodynamic characteristics on saucer-shaped lifting-body
Yu Junli, Wang Linlin, Gao Ge
2010, 36(2): 198-201.
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Saucer-shaped aircraft is a new type aircraft configuration with blended fuselage and wing. Through the method of changing centre of gravity, flight stability was acquired and validated in the flight test. A type of fin-shaped wing-tip winglet applied to this aircraft to reduce induced drag was presented. Compared to the original type without winglet, the lift to drag ratio of new model can be improved by 70% at the speed of 30m/s in wind tunnel. The results of tunnel experiments were verified successful in test flights. Not only its load was increased but also its aerodynamic performance was good. In order to realize its aerodynamical characteristics, computational investigation was performed to the flow field. By analyzing the results, wingtip vortex had important influence to its performance.
Moving object detecting technique based on motion vector in H.264 coding
Ding Wenrui, Yang Hua, Liu Chunhui, Jiang Zhe
2010, 36(2): 202-205.
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Considering the applications of joint realization of video compression and moving object tracking,by studying the moving information included in the motion vector of the H.264 video coding international standard and analyzing motion estimation principle, a motion vector based on moving object detecting technique was proposed, and the relationship between the motion vector and the moving object was set up. The key part of detecting algorithm is to divide moving object from background. By setting two threshes properly, the detected objects could be changed according to their moving velocity. As the disturbance of background moving eliminated by the algorithm, it can be used in some cases when the camera is moving. For motion vectors come from H.264 coding progress directly, the calculation complexity is reduced, so it is easy to realize by hardware.
Distributed range-free localization algorithm in wireless sensor networks for 3D space
Wang Dehua, Xing Jianping, Zhang Jun
2010, 36(2): 206-209.
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To solve the node localization problem for wireless sensor networks deployed in stereoscopic environments, a novel three-dimensional distributed range-free localization algorithm (3D-DRL) was proposed. Based on the grid-based representation and after voting for each cubic cell, 3D-DRL assumed the centroid of cells with highest votes as the estimated location of that unknown node. The scheme avoids the interaction between unknown nodes, costs lower communication overhead, is independent of the anchor node density and robust to the network topology. Simulation results under ideal radio propagation model indicate that the average localization error is 8% when all nodes are randomly deployed in 100 m×100 m×100 m scenarios with 50 m communication range of the unknown node. Especially, all unknown nodes can localize themselves by increasing VANR.
New method of continuous well trajectory measurement
Zhang Yanshun, Wang Yue
2010, 36(2): 210-213.
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To achieve autonomous high-precision well trajectory measurements a well trajectory measurement program based on an improved attitude heading reference system including two gyroscopes and three accelerometers to form inertial measurement unit was proposed. The attitude angles could be gained by the output data from the inertial measurement unit, and then three-dimensional position of the well trajectory could be computed with the known length of the rope used spacial integral. The simulation results show that the algorithm overcomes the shortcomings of the emanative inertial navigation position error over time and has high position accuracy, the scheme reduces the volume of the inclinometer, lower cost and power consumption so that it is suitable for the well trajectory.
Design of IEEE 1394/GbE conversion system based on SOPC technology
Liu Dong, Jin Huihua, Yan Meng
2010, 36(2): 214-217.
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The achitecture and implementation of an image acquisition system which makes a real-time IEEE 1394/GbE conversion was discussed. The system can transmit the image data from the IEEE 1394-based camera to the Ethernet. System on a programmable chip(SOPC) technology was employed in the design. A Nios II processor, a GbEMac and a selfmade interfacing logic for IEEE 1394 link layer chip were integrated into a field programmable gate array(FPGA) chip, and the main hardware module was built by connecting all these internet protocol(IP) components with the Avalon buses. Together with the software programming, the system realized real-time transmission of the high speed picture data. The design achieved good performance, high degree of integration, simplicity and flexibility, and this shows the advantage of the SOPC technology.
Numerical simulation on influencing parameter of micro-blowing technique
Li Jian, Lee Chun-Hian, Jia Liping, Zhen Huaping
2010, 36(2): 218-222.
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Taking micro-porous plates PN3 and PN23 of NASA Glenn Research Center as prototypes, four flat plates made of micro-channels aligning in single-, four-, eight- and sixteen-row patterns were chosen as the numerical models, and parametrical studies on skin friction reduction utilizing micro-blowing through micro-porous walls were performed for different geometric and physical parameters. Numerical results demonstrate that the velocity near the porous wall is decelerated by the micro-blowing, and thus affects the local skin friction distribution. The parametric studies also reveal the influences on the drag reduction capacities by various relevant parameters, which will provide some guidance on the application of micro-blowing technique (MBT) for drag deduction.
Low speed characteristics of the saucer-shaped aircraft
Wang Linlin, Gao Ge
2010, 36(2): 223-226.
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The saucer-shaped aircraft is a novel aircraft adopting blend-wing-body configuration. The wind tunnel experiments, stability analysis and flying tests were conducted to investigate the aerodynamic characteristics and stability features of the saucer-shaped aircraft under low speed conditions. The results show that the highest lift to drag ratio is 12.2, the stall angle of attack is 28°. Meanwhile saucer-shaped aircraft has stable longitudinal mode, rollover mode and Dutch roll mode. The spiral mode is unstable. The saucer-shaped aircraft exhibits superior flight qualities and excellent comprehensive performances.
Numerical simulation and experimental validation on gas jet blowing-off process of submarine emergency
Yang Sheng, Yu Jianzu, Cheng Dong, Gong Shaofeng
2010, 36(2): 227-230.
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Principle tests of submarine emergency gas jet blowing-off process, the small-scale-model of emergency blowing system with gas generator for submerged vehicle, were carried out, which simulated the drainage regularity and the major performance parameters of emergency gas jet blowing-off process while at 100m depth underwater. Physical model which was used to simulate the small-scale experiment of the blowing-off process was built, and the two-phase fluid domain for computing was dispersed and meshed by applying the structured hexahedral grid. The process in the model was numerically calculated while simulating the emergency condition of 100m depth under the sea water. As a result, the research had gained the material description of the gas bubble growing rules and the in-depth understanding of the blowing-off process. The simulation results match the experiment results of actual situation very well as the relative errors of gaseous mixture pressures and blowing-off volumes are less than 5%, therefore the feasibility of the simulating method is proved.
Random network coding based optimal scheme for wireless packet retransmission problems
Gao Zhenguo, Zhao Yunlong, Cai Shaobin, Zhao Jinhua
2010, 36(2): 231-234.
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Network coding (NC) provides a new approach to solve wireless packet retransmission problems (WPRTPs). The property that the number of retransmitted packets of optimal NC-based schemes for a perfect WPRTP (P-WPRTP) equals to the maximum number of requested packets of a receiver was proposed and proved. Based on random network coding (RNC) technology, an optimal scheme for P-WPRTPs named as random network coding based optimal scheme(RNCOPT) was proposed where coefficients in network coding matrix are randomly selected from a pre-determined Galois field except for its element zero. Network coding matrix re-creation mechanism was used to guarantee a 100% success probability of decoding. Format of assembled packets and operation process of senders in RNCOPT were described. Simulation results show that, when receiver number and packet number are both 30, number of retransmitted packets in RNCOPT reduces about 32% when compared with traditional scheme where NC is not used, but meanwhile a typical NC-based scheme CliqueNC shows little performance gain.
Fast method of eliminating extraneous in near filed measurement of calibration load
Yang Shan, Bai Ming, Miao Jungang
2010, 36(2): 235-238.
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A method to analyze and eliminate the extraneous wave from near field measurement of the radiometer temperature calibration load based on fast inverse diffraction algorithm was presented. The inverse diffraction algorithm is used for field reconstruction by calculating the backward propagation of a diffraction field. Both the fast-Fourier-transform direct integration(FFT-DI) and diffracted Gaussian beam analysis(DGBA) were implemented and combined with the inverse diffraction algorithm for fast inverse diffraction algorithm. An outline of the analysis on the near field measurement was presented, along with the filtered field without extraneous wave, which verifies the performance of this method. Furthermore, it was suggested that combination of these two fast inverse diffraction algorithm for higher efficiency.
Analysis of necessary condition for minimal software reliability demonstration test suite
Li Qiuying, Jiang Mengcen
2010, 36(2): 239-243.
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The sample size determination method in statistics was adopted in the software reliability demonstration testing(SRDT). The conception of the necessary condition for minimal software reliability demonstration test suite was proposed. The recommended test case number for the minimal test suite was suggested, which guaranteed satisfaction to both the first hazard and the second hazard. The influencing factors to the minimal value were analyzed and the existing software reliability demonstration plan was revised. Accordingly the process of SRDT was put forward under the direction of the minimal test suite. The method remedies the existing methods- defects that the reliability estimation value may depart far from the actual value in some situations.
Laminar-to-turbulent transition onset prediction of hypersonic flows based on laminar kinetic energy equation
Song Bo, Lee Chun-Hian
2010, 36(2): 244-247.
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Onset locations of laminar-to-turbulent transition were predicted for flared-cones with freestream Ma of 5.91 by solving a laminar kinetic energy transport equation based on the linear stability theory numerically. The transitional flowfields were simulated by employing the shear-stress transport(SST) turbulence model, in conjunction with an algebraic intermittency model. Numerical results demonstrate that the current laminar kinetic energy transport equation is capable of predicting the frequencies of unstable disturbances under adverse pressure gradients. The computed transition onset locations of adiabatic wall are in good agreement with experiment data measured from the quiet wind tunnels. Wall cooling promotes the growth of second mode instability, and transition occurs earlier. The length of the transitional zone and temperature peak value are not adequate when the algebraic intermittency model is employed.
Local thermal buckling analysis method of combustor liner
Hong Jie, Gao Jinhai, Ma Yanhong, Chen Meng
2010, 36(2): 248-252.
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The discriminant of thin-wall structure thermal buckling instability boundary was derived from governing equations of plates in which the stress function and deflection function are two variables, and the two buckling factors which are local temperature and compressive stress were included in the equations. Then, the gained thermal load and design pressure load were used to capture the dangerous place of combustor liner through static analysis considering thermal buckling instability factors. The critical temperature and critical compressive stress which are required parameters of local thermal buckling discriminant were calculated with finite element method (FEM) and sub-model technique. Finally, a judgment of local thermal buckling was performed through the discriminant. In order to verify the method, the results of certain combustion chamber calculated by the method were compared with the experimental data. It is concluded that the local thermal buckling analysis method is accurate and effective.

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