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Xu Y.,Northwestern Polytechnical University | Zhu R.,Northwestern Polytechnical University | Yu D.,The 703 Research Institute of CSIC | Su W.,Northwestern Polytechnical University | Duan C.,Northwestern Polytechnical University
Jixie Qiangdu/Journal of Mechanical Strength

Tooth shape parameters such as bottom clearance factor, addendum coefficient are important factors affecting the shape of fillet curve of gear root, and bending bearing abilities of gear root with different fillet curves are different. In order to acquire high bending bearing capacity and prolong the working life of gear, beginning with the processing and designing of the cutter of fillet curve, the cutting tool with single arc and the cutting tool with double arc are considered separately. Moreover, the mathematical model of gear fillet curves is built, and the computational model of folding section applied local stress of gear root is determined. The optimal variation range of bottom clearance factor and addendum coefficient of gear based on high bending bearing capacity under two fillet curves are investigated. Then the impact of addendum coefficient and bottom clearance factor on bending bearing capacity of gear root is analyzed and the theoretical analyses are validated by the finite element method. According to the research, choosing reasonable addendum coefficient and bottom clearance factor under specific fillet curve model can enhance bending bearing capacity of gear root largely, which provides theoretical foundation for the designing of gear with high bending strength. Source

Dong H.,Wuhan Naval University of Engineering | Wen X.-Y.,The 703 Research Institute of CSIC
Future Mechatronics and Automation - Proceedings of the 2014 IMSS International Conference on Future Mechatronics and Automation, ICMA 2014

Large Eddy Simulation (LES) is a credible and feasible tool for researching a combustor, but appropriate Sub-Grid Scale (SGS) models must be adopted to gain the best performance from an LES. The Smagorinsky-Lilly (S-L) model, the Dynamic Smagorinsky-Lilly (Dynamic S-L) model, the Wall-Modelled LES (WMLES) model, and the Dynamic Kinetic Energy SGS model are used for large eddy simulation of the nonreacting flow in a Lean Direct Injection (LDI) combustor. The LES results were compared with the RANS results and with the experimental data, and they showed that all the LES results were more reasonable than the RANS results. Among these LES results, the WMLES model and the Dynamic Kinetic Energy SGS model showed the best performance. The Dynamic S-L model can also provide reasonable results, while the S-L model is not good enough. © 2015 Taylor & Francis Group, London. Source

Jiang Y.-T.,Harbin Engineering University | Zheng Q.,Harbin Engineering University | Luo M.-C.,The 703 Research Institute of CSIC | Yue G.-Q.,Harbin Engineering University | And 2 more authors.
Tuijin Jishu/Journal of Propulsion Technology

Conjugate simulations for the blade leading edge of two phase impingent cooling were carried out to enhance the heat transfer. The mist/steam cooling with jet impingement onto a concave surface was used to verify the accuracy of numerical simulation program. The Eulerian-Lagrangian particle tracking method was adopted to investigate the two-phase impingement cooling for blade leading edge. The effects of various parameters, such as mist ratio, mist diameter and mist-wall boundary conditions on the improvement of cooling performance were investigated. The results show that the largest average heat transfer enhancement coefficient increases from 1.67 to 4.94 with increasing mist ratio from 3% to 8%, and it decreases from 2.128 to 1.164 with increasing mist diameter from 5 μm to 20 μm. The rebound and rebound with break up boundary conditions show the better cooling performance than the trap and trap with break up boundary conditions. ©, 2015, Editorial Department of Journal of Propulsion Technology. All right reserved. Source

Li J.,Northeast Dianli University | Song B.-B.,Northeast Dianli University | Zhao Y.-Q.,Guodian Nanjing Automation Co. | Bo M.-M.,Northeast Dianli University | And 2 more authors.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control

In the study of the basic principle and work characteristics of interphase power controller (IPC) and static synchronous series compensator (SSSC), a new IPC based SSSC is proposed, in which SSSC is used to replace the phase shifting transformer of the traditional IPC to realize the phase shifting function of inductance branch and capacitance branch. The typical PI control is used to control the voltage source converter by changing the reference voltage and achieve the purpose of changing injected voltage, to change the phase shifting of IPC fast and continuously, thereby controlling the power flow of tie-line flexibly. Compared with conventional IPC, the improved IPC can improve the overvoltage problem, when the relative phase slippage between the power systems on both sides of the tie-line happens. The simulation of Matlab/Simulink verifies the improved IPC can make the power flow of tie-line under control completely and improve the overvoltage problem. Source

Gao J.,Harbin Engineering University | Zheng Q.,Harbin Engineering University | Xu T.,The 703 Research Institute of CSIC | Zhang Z.,Harbin Engineering University
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica

Numerical investigation is performed to simulate the tip leakage vortex (TLV) breakdown characteristics and its effect on leakage losses in the first-stage rotor blade of GE-E3 (Energy Efficient Engine) turbines at various tip clearances, by solving the Reynolds-averaged Navier-Stokes equations in conjunction with a standard k-ω two-equation turbulence model. The tip leakage vortex breakdown phenomenon and its dynamics are analyzed; so are the effects of tip clearance height on the tip leakage vortex structure and the vortex breakdown characteristics. Furthermore, the relationship between the tip leakage vortex breakdown and losses is investigated. Numerical results show that the turbine tip leakage vortex is unstable. When the tip leakage vortex has sufficient strength to overcome the entrainment of the tip passage vortex, and forms a complete vortex structure, the tip leakage vortex breakdown is initiated in the adverse-pressure region of the second half of the rotor blade, which leads to extra vortex breakdown losses. The tip clearance height has a great impact on the vortex breakdown location, and the tip leakage vortex tends to be relatively stable at large tip clearances. The tip mixing losses are divided into two stages marked by the tip leakage vortex breakdown. A lot of mixing losses occur after the tip leakage vortex breakdown, which is the main part of the tip mixing losses. Source

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