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Zhang H.,Harbin Institute of Technology | Ye Z.,Harbin Institute of Technology | Wang C.,703 Research Institute of CSIC
Proceedings of 2015 International Conference on Fluid Power and Mechatronics, FPM 2015 | Year: 2015

This paper introduces a kind of hydraulic control system using direct drive mode to rotate bucket-wheel, presents the principle of the system and the difference between conventional throttle control, valve control and direct drive. The simulation model of bucket-wheel direct drive hydraulic system was established and simplified correspondingly. Eventually got the transfer function of the system. This paper analyzes the stability and rapidity of system using Matlab Simulink tools for system simulation, and shows the influence of various parameters on the system based on the structure of the transfer function and the simulation result, it has certain practical value. © 2015 IEEE. Source

Jiang Y.,Harbin Engineering University | Zheng Q.,Harbin Engineering University | Dong P.,Harbin Engineering University | Yao J.,703 Research Institute of CSIC | And 2 more authors.
International Journal of Heat and Mass Transfer | Year: 2015

Numerical simulations are performed to explore leading edge and downstream film cooling enhancement by application of injecting water mist into the air. The accuracy of numerical simulation program for conjugate heat transfer methodology is verified with the C3X gas turbine vane cooled with leading edge and downstream film holes. The Eulerian-Lagrangian particle tracking method is adopted to investigate the two phase film cooling. The effects of various parameters including mist concentration, mist diameter and mist injection location on the improvement of cooling performance are investigated in this paper. The results show that the average wall temperature reduction at mid span increases from 20 K to 48 K from 1% to 3% mist ratio, the corresponding average heat transfer coefficient reduction increases from 77 W m-2 K-1 to 103 W m-2 K-1. Mist cooling can decrease the boundary layer temperature without impact on the mainstream temperature and boundary layer thickness. The degree and the location of cooling performance can be controlled by manipulating the sizes of injected water mist. The superimposition of different mist injection locations can be used to further strengthen the two phase cooling performance. © 2015 Elsevier Ltd. Source

Jiang Y.,Harbin Engineering University | Zheng Q.,Harbin Engineering University | Yue G.,Harbin Engineering University | Liu B.,703 Research Institute of CSIC | Wei X.,Beijing Institute of Machinery
Numerical Heat Transfer; Part A: Applications | Year: 2016

A comparative study of the flow field and heat transfer characteristics between swirl and impingement of mist/air cooling on blade leading edge is carried out to find a better cooling configuration for phase transition cooling. The Eulerian-Lagrangian particle tracking technique is used to investigate mist/air cooling. Comparisons are made between these two cooling forms in such aspects as vortex structure, heat transfer enhancement, pressure loss, and thermal uniformity with and without mist injection. The influences of mist ratio and Reynolds numbers on these parameters are studied in this paper. Results show that heat transfer is enhanced while pressure loss and thermal uniformity are improved by the swirl flow created by vortex impingement. The heat transfer performance increases by about 46.2 and 51.9%, respectively, for impingement and swirl cooling with 8% mist injection, and the pressure loss coefficient increases by 19%. The difference of heat transfer coefficient between swirl and impingement cooling with and without mist injection at high Reynolds number is larger than that at low Reynolds number. In addition, the heat transfer nonuniform coefficient of swirl cooling is about 15% lower than for impingement cooling. © 2016 Taylor and Francis Group, LLC. Source

Xue K.,Harbin Engineering University | Li Y.,Harbin Engineering University | Wang H.,703 Research Institute of CSIC
Key Engineering Materials | Year: 2014

It is high in efficiency to cut rectangular steel pipes with flame cutting mode compared with milling mode, and it is simple in processing equipment. When cutting the four arc angles of steel pipe, the steel pipe carries out the uniform rotational motion while cutting torch carries out plane two-dimensional motion, in order to achieve uniform motion in a straight line relative to the round arc angle of steel pipe. The rotation speed of steel pipe is proportional to the cutting speed. And the X component and Z component for the speed of cutting torch will respectively change according to the sine and cosine curves. The space geometrical relationship and motion relationship of round corner torch track and steel pipe corner are described by means of parametric equations. And the correctness of the algorithm in CNC rectangle pipe cutting machine has been verified.©(2014) Trans Tech Publications, Switzerland. Source

Wang C.,Northwestern Polytechnical University | de Fang Z.,Northwestern Polytechnical University | Jia H.-T.,703 Research Institute of CSIC
Journal of Marine Science and Application | Year: 2010

To reduce vibration and noise and increase transmission efficiency, a three segment method for modifying the pinion profile was proposed. Cutter surface equations were deduced by changing the shape of the cutter-edge, substituting three segment parabolas for the line. The influence of longitudinal tooth modifications on tooth surface load distributions was discussed. Transmission error minimization and uniformity of tooth surface load distribution were chosen as optimization goals and the modified parameters were obtained by applying the complex method. Finally, an experiment comparing the loaded transmission error, vibration, and noise both before and after modifications was carried out. The results indicate that the modified design is reliable. © 2010 Harbin Engineering University and Springer Berlin Heidelberg. Source

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