bob手机在线登陆学报自然版

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2023, 43(1)

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2023, 43(1): .

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Review of Combined Cycle Power System and Analysis of Key Research Points for Aviation Application

DING Shuiting, SONG Yue, DU Farong, ZHU Kun, ZHAO Shuai, ZHOU Yu

2023, 43(1): 1-17. doi:10.15918/j.tbit1001-0645.2022.006

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On the basic of fully investigating and analyzing of development status of the international and national combined cycle power system, the advantages and disadvantages of the various power systems were summarized, and the bottleneck technical problems restricting their development were analyzed. Based on the development status and challenges of small aviation power system in China, the performance requirements of combined cycle power system suitable for aviation field were proposed, including high power-to-weight ratio, high reliability, low structure complexity, high thermal efficiency and low fuel consumption. Analyzing the existing research results and application experience of combined cycle power system used in other fields, some technical difficulties were summarized for the development of combined cycle power system applied in the aviation field, such as structure design and layout, theoretical and experimental research methods, control strategies, and corresponding solutions. In this paper, some technical suggestions were provided for the aviation application of combined cycle power system, and a new direction was pointed out for the development of high-performance and high-level small aviation power system in China.

Simulation Analysis and Optimization for Blast-Resistant Performances of Aluminum Honeycomb Sandwich Structure

RONG Jili, LIU Dongbing, ZHAO Zitong, WEI Zhenqian

2023, 43(1): 18-26. doi:10.15918/j.tbit1001-0645.2022.013

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A finite element analysis of the blast-resistant performance of the aluminum honeycomb sandwich structure was conducted by using the CONWEP calculation model. The maximum deformation of the back plate and the specific absorption energy of the sandwich layer were used as the blast-resistant performance indexes, the benchmark model of the aluminum honeycomb sandwich structure was established according to the composite structure of different matrix materials. Based on the benchmark model, the effects of structural parameters and cell types on the blast-resistant performance of aluminum honeycomb sandwich structure were quantitatively studied. The results show that the composite structure with Al2024T351 for the front plate and RHA for the back plate has excellent blast-resistant performance; compared with the thickness change of the back plate, the influence of thickness change of the front plate on the blast-resistant performance index is more significant. The multi-objective optimization design of the blast-resistant performance of the aluminum honeycomb sandwich structure was done by using the method of building a surrogate model, and the blast-resistant performance of the aluminum honeycomb sandwich structure was obviously improved, which has certain guiding significance for the engineering design of the blast-resistant structure.

Influence of Aluminum Content on Energy Output Structure of CL-20-Based Explosives Driving Cylinder Wall

LÜ Zhongjie, GAO Chenyu, ZHAO Kaiyuan, HUANG Ning, LIU Yan, HUANG Fenglei

2023, 43(1): 27-35. doi:10.15918/j.tbit1001-0645.2022.015

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In order to study the influence of aluminum powder content on the energy output structure of hexanitrohexaazaisowurtzitane (CL-20)-based aluminum-containing explosives in the process of driving the cylinder wall by explosion, a model of energy output of the explosion-driven cylinder wall was established, based on the micro-element method and the detonation products equation of state, and taking into account the axial motion of cylinder wall and detonation products. Standard 50 mm cylinder tests were carried out on two kinds of CL-20 based explosives (CA5, CA30) with different aluminum contents and the corresponding lithium fluoride explosives (CF5, CF30). The expanding velocities of cylinder were measured by using the photonic Doppler velocimetry. The results show that when the content of matrix explosive decreases from 89% to 64%, the ability of CL-20-based aluminum-containing explosive and lithium fluoride explosive to drive metal decreases; when the content of aluminum powder increases from 5% to 30%, the internal energy at the end of expansion increases; the energy conversion rate of CL-20-based explosives with different lithium fluoride contents is about 93%, which is higher than that of the corresponding aluminum-containing explosives.

Modeling and Optimization of Compression Ignition Device Based on Absolute Nodal Coordinate Formulation

SHUI Xiaoping, WANG Bin, MA Shizhou, HU Deqiang, CHENG Wanying, LIU Cheng

2023, 43(1): 36-44. doi:10.15918/j.tbit1001-0645.2022.025

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The accurate modeling and product performance optimization of pressure ignition device were studied. The reduced plate element based on the absolute nodal coordinate formulation was used to model the circuit board of the pressure ignition device. The material parameters of the circuit board and the nonlinear stiffness characteristics of the support springs and the trigger devices were determined by experiments. The mechanical model of the support springs and the trigger devices were established by using the nonlinear force-displacement relationship, and the accurate finite element model of the structure of the pressure ignition device was established. The loading experimental system of the compression ignition device was designed, and the correctness of the finite element model was verified by experimental data. According to the target trigger load range, the stiffness and length parameters of the support springs in the compression device were optimized. The numerical simulation directly guides the parameter design of the pressure ignition device and has been successfully applied to the type development.

Water-to-Air Stability of Trans-Phase Missile

ZHU Rui, ZHANG Huanbin, ZHUANG Qibin, WEN Weiqi, HE Xingyu, LIU Zhirong

2023, 43(1): 45-53. doi:10.15918/j.tbit1001-0645.2022.031

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The influence mechanism of the missile-head shape, launch angle and ejection velocity on the missile trans-phase stability was studied to provide the experimental and theoretical support for the design of diversified ballistic trans-phase weapon/aircraft. Carried out the missile water-to-air trans-phase experiments and numerical simulations, obtained the missile trans-phase deflection angle variation and trajectory through processing the transient images, established the high-precision air/water trans-phase numerical model, and the function mechanism of the missile head, launch velocity, launch angle on the load-sustaining distributions on the missile surface and the trans-phase stability as passing through the air/water interface was revealed. The research results indicated that the calculation error of the missile air/water trans-phase numerical model is < 5%; for the same missile model, the water-to-air trans-phase stability increases as the launch velocity, angle increase; under the same launch conditions, the water-to-air trans-phase stability of different missile-head shapes: round head > 90° conical head > 120° conical head > flat head; the better symmetric water film shape on the missile surface and the smaller water film area variation amid trans-phase process will reduce the missile trans-phase radial load amplitude, which improves the trans-phase stability.

Experimental Study on the Characteristics of a Two-Stroke Opposed Engine

LI Zhipeng, ZHANG Fujun, LIU Bolan, ZHAO Zhenfeng

2023, 43(1): 54-60. doi:10.15918/j.tbit1001-0645.2022.008

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Two-stroke opposed engines are widely used in unmanned aerial vehicles and other fields due to their excellent power-to-weight ratio. The working method of spark ignition makes them more suitable for gasoline as the active medium. Aiming at the technical requirement of using aviation kerosene for equipment development, a test comparison was carried out between different media (kerosene and gasoline) and different injection systems (air-entrained fuel injection and port injection). The results show that when the fuel is the same as gasoline, under other throttle valve opening conditions, the engine power with air-entrainment infusion is better than port injection; only the air-entrainment method can make kerosene realize cold start; In the machine test, under high-speed conditions, the throttle opening is increased from 30% to 80%, and the power and torque are increased by about 10 kW and 65 N·m respectively. The working process is almost the same as a traditional spark ignition engine; Finally, the performance difference between kerosene and gasoline under the air-entrainment mode with the throttle valve controlled at 50% was explored, which showed that the power performance of gasoline fuel was better, and the power and torque were increased by about 5 kW and 35 N·m, respectively.

Mechanical Fault Detection of Permanent Magnet Synchronous Motor Based on Improved DFA and LDA

ZHAO Sifang, SONG Qiang, ZHANG Yanming, ZHANG Wei

2023, 43(1): 61-69. doi:10.15918/j.tbit1001-0645.2022.010

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In order to improve the detection accuracy, a mechanical faults detection method was studied for permanent magnet synchronous motors under variable speed conditions. Firstly, the vibration characteristics of the bearing, the eccentricity, and the compound faults were analyzed. Secondly, the components of fault characteristic were extracted with Vold-Kalman arithmetic. And the extracted signals were reconstructed to remove the influence of the speed change on the components of fault characteristic. And then, a mechanical fault detection method was proposed based on improved detrended fluctuation analysis (DFA) and linear discriminant analysis (LDA) to realize the reconstructed signal feature extraction and fault detection. Finally, a verification experiment was carried out for the proposed fault detection method. The results show that the detection accuracy of the proposed fault detection method can reach up to 88%.

Flow Control Accuracy of Load Sensing Pump and Energy Loss of Displacement Control Mechanism

WANG Hujiang, WANG Zhenyu, WANG Tao, TANG Shousheng, FANG Wenhua, LIU Xiaochao, YANG Qifu

2023, 43(1): 70-80. doi:10.15918/j.tbit1001-0645.2022.033

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In order to improve the control characteristics of load sensing pump control system, a dynamic mathematical model and a dynamic simulation model of load sensing pump control system were established, and the correctness of the models were verified by bench test. Based on the dynamic model, the influence of the key matching parameters of the displacement control mechanism on the flow control accuracy of load sensing pump control system and the energy consumption characteristics of the displacement control mechanism was emphatically analyzed. The results show that proper radial fit clearance of load sensing valve and pressure shut-off valve and proper negative cover amount of load sensing valve port are not only conducive to improve the flow control accuracy of load sensing pump control system, but also constrain the energy consumption of displacement control mechanism at a low level. Excessive clearance and excessive negative cover amount will not only greatly increase the throttling loss of displacement control mechanism, but also greatly reduce the flow control accuracy of load sensing pump control system.

Target Tracking ECO Method Based on Response Value Judgment

CHEN Xinlin, WANG Jianzhong, SUN Yong

2023, 43(1): 81-86. doi:10.15918/j.tbit1001-0645.2022.024

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Target tracking ECO (Efficient Convolution Operator) method is more and more widely used in various tracking scenes because of its superior tracking performance, but it shows poor tracking effect in the face of complex engineering practical situations such as occlusion, motion blur, target deformation and background clutters. To solve this problem, the ECO method was improved, and a correlation filter response value judgment mechanism was added to determine the update time of the sample model according to the maximum response mean of the previous frames and the standard deviation of the response peak of the current frame. Comparing with the original ECO method based on the same experimental video sequence, the tracking effect of the improved ECO method was showed. On OTB2015 data set, the accuracy and success rate of the improved ECO method can reach up to 88.0% and 79.9%, 1.5% and 1.2% higher than the original ECO method respectively, especially in common engineering situations such as occlusion, motion blur and background clutters. It shows that this method can provide more flexible model updating strategy and stronger ability to adapt to the actual situation of complex engineering.

Frequency Agile and PRI Jitter Radar Group Target Detection Based on Improved SAMP

DU Huiqian, GAO Haodong, FU Xiongjun, LANG Ping, DONG Jian

2023, 43(1): 87-93. doi:10.15918/j.tbit1001-0645.2022.028

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To improve sparse reconstruction effect caused by unknown number of targets and mesh mismatch in group target scene, an improved sparsity adaptive matching pursuit (SAMP) algorithm was designed for target detection of frequency agile and pulse repetition interval (PRI) jittered radar. First, improving the atom selection strategy in the backtracking stage, selecting atoms with similar energies through regularization for grid mismatch correction, the algorithm was arranged to effectively reduce the reconstruction error and suppress the reconstruction spurious peak. Then, adaptively expanding the search step (group target number estimation) according to the power change rate of the reconstructed signal, the algorithm was arranged to speed up algorithm search. Simulation results show that, comparing with SAMP and traditional group target detection algorithm, the improved SAMP algorithm can improve reconstruction effect and reduce the target range and velocity estimation error.

Using Ground Penetration Characteristics of GNSS Signals to Retrieve Soil Moisture

LI Jie, YANG Dongkai, WANG Feng, YANG Lei, HONG Xuebao

2023, 43(1): 94-103. doi:10.15918/j.tbit1001-0645.2022.029

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It has been widely concerned by domestic and foreign research institutions that make the Global Navigation Satellite System Interferometric Reflectometry (GNSS-IR) used in soil surface moisture inversion because of its excellent characteristics, needing not for signal sources, suiting wide detection area, etc. In order to solve the complex problem of tradition GNSS penetration model, a method was proposed to calculate the vertical distance between the antenna phase center and the actual surface reflector by GNSS-IR according to the geometric configuration. Firstly, the height measurement deviations under different soil moisture were calculated by simulation, establishing the linear relationship of the GNSS signal with the theoretical penetration depth and the inverse proportion relationship with soil moisture. Considering the influence of the change of the satellite altitude angle on the altitude retrieval, a modified altimetry model was adopted, and the Lomb-Scargle spectral analysis method was used to calculate the altitude measurement deviation. Then, in order to reduce the influence of surface vegetation on the vertical distance between the inversion antenna phase center and the actual surface reflector, a normalized vegetation index was used to correct the height measurement deviation. And, a first-order inverse proportional model of GNSS signal height measurement deviation and soil moisture was established. Finally, verification experiments were carried out for the proposed models. The results show a better effect of the application of the GNSS signal surface penetration characteristics in the soil moisture inversion for the scene of long-term large-scale changes in soil moisture.

Simulation Analysis of the Plane Detection System for Distribution of Aerosol Concentration

CHEN Siying, CHEN Yuanyuan, GUO Pan, ZHANG Yinchao, CHEN He, HAO Wei, LI Xin

2023, 43(1): 104-110. doi:10.15918/j.tbit1001-0645.2022.032

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To realize imaging detection of aerosol distribution, a plane detection system was proposed based on planar laser-induced fluorescence (PLIF) technology for distribution of aerosol concentration. Firstly, the single pixel detection ability of this plane detection system was analyzed theoretically. And then, taking fluorescein as the target particle, the power distribution and attenuation changes of planar laser at wavelength 450 nm were calculated. Finally, according to fluorescence signal in the wavelength range of 500~600 nm and SNR formula of the single pixel of the sCMOS camera, the influence of different system parameters on the detectable particle minimum number of single pixel and their distribution differences in the detection plane were discussed. The results show that the simulation analysis can help to understand the influence of different parameters on the performance of imaging detection of aerosol distribution, and provide an effective method and theoretical basis for plane detection of aerosol distribution.

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