No704 Research Institute

Shanghai, China

No704 Research Institute

Shanghai, China
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Wu T.-M.,University of Shanghai for Science and Technology | Liu Q.,University of Shanghai for Science and Technology | Liu J.-H.,Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering | Xu X.-J.,No704 Research Institute
Reneng Dongli Gongcheng/Journal of Engineering for Thermal Energy and Power | Year: 2017

Due to the fact that thevolumetric expander outlet pressure does not agree with back pressure in the condenser and leads irreversible loss, a new type of rolling piston expander which can adjust expansion ratio was designed and its working principle was analyzed in this paper. With R245fa as working fluid, the effect of system parameters on the optimum expansion ratio was studied by assuming no superheat in generator, no undercooling in condenser and no leakage in expander. The results showed that the optimum expansion ratio is marginally affected by expander efficiency, while greatly influenced by generator temperature and condenser temperature. Higher the generator temperature leads to larger optimum expansion ratio, while higher condenser temperature results in smaller optimum expansion ratio. While some system parameters are varying, adjusting other system parameters can lead to the expander operating at the optimum expansion ratio. This paper is believed to provide a reference for designing expansion ratio and determining working condition for expander. © 2017, Editorial Department of "Journal of Engineering for Thermal Energy and Power". All right reserved.


Zhou X.-Q.,University of Shanghai for Science and Technology | Liu J.-H.,Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering | Xu X.-J.,No704 Research Institute | Zhang L.,University of Shanghai for Science and Technology
Reneng Dongli Gongcheng/Journal of Engineering for Thermal Energy and Power | Year: 2017

In this paper, the heat transfer performance of the flow boiling in microchannel with R290 refrigerant was experimentally studied.The microchannel/tube diameters tested were 1mm and 2mm, the heat flux varied from 20 to 65 kW/m2, and the mass flux ranged from 100 to 200 kg/m2 s, with dryness from 0.1 to 0.9 and the saturation temperature between 15 and 25℃ in the experiment.The influences of pipe diameter, heat flux, and mass flow rate and saturation temperature on the flow boiling heat transfer were analyzed by experimental data.The results showed that the heat transfer coefficient can increase significantly as the test tube inner diameter decreases, with an average increase of approximately 31%.The heat transfer coefficient can also increase extensively with the rise of the heat flux, whose mean increase is 131%, while it increases slightly with the rise in the mass flux, with an average improvement of 14%.It was also shown that the rise in the saturation temperature leads to a moderate increase in the heat transfer coefficient, with an average of 12.6%. © 2017, Editorial Department of "Journal of Engineering for Thermal Energy and Power". All right reserved.


Wang H.,Wuhan Naval University of Engineering | Fu L.,Wuhan Naval University of Engineering | Jie G.,Wuhan Naval University of Engineering | Xiao F.,Wuhan Naval University of Engineering | Wan Z.,No704 Research Institute
Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University | Year: 2013

Conventional linear quadratic regulator (LQR) method is regarded as an unsatisfactory solution for voltage source inverter (VSI) systems because it can not ensure reference voltage command tracking. Although linear quadratic tracker (LQT) method can ensure command tracking performance, its control effect may be weakened when the system exhibits non-linear behavior because it can not eliminate steady-state amplitude and phase errors. This paper proposes a new controller based on state-feedback with proportional-resonant (PR) control for three-phase inverter system. Following redefining the LQR problem, this controller improves the capability of optimal tracking, which is placed within a general structure offered by the internal model principle (IMP) of control theory. The method solves these two drawbacks of LQR method in context of command tracking, and eliminates steady-state errors with good tracking performance as LQT. The simulation and experiment verify that the scheme is able to eliminate steady-state amplitude and phase errors and to provide nice dynamic and static characteristics. The total harmonic distortion of output voltage gets lower than 1%, and voltage unbalance factor lower than 1.5% with 30% unbalance load.


Gao Y.-Q.,No704 Research Institute | Li Y.-X.,No704 Research Institute | Zhou Z.-D.,No704 Research Institute
Hedongli Gongcheng/Nuclear Power Engineering | Year: 2013

Considering that the power level drops significantly and steam flow separates from the outlet of rotor blades in the last stage of steam turbine at low load conditions, the last stage in whole working conditions was calculated and the height of flow separation in different volume flow was obtained. Different conditions of turbine under the same flow path with nozzle governing and throttle governing were calculated respectively. The results show that the flow separation bubble and separation height increased dramatically when volume flow decreased; the throttle governing at low load conditions increased the steam rate of turbine and the enthalpy drop of pressure stage, while reduced the changes of power distribution under the influence of steam parameters changing; in the same load, the throttle governing increased the volume flow in last stage, and reduced the separation height of rotor blades accordingly; it was propitious to improve the flow of the last stage at low load conditions, and postpone the emergence of zero power conditions.


Lu Q.,Zhejiang University | Yao Y.,Zhejiang University | Ye Y.,Zhejiang University | Dong J.,No704 Research Institute
2016 11th International Conference on Ecological Vehicles and Renewable Energies, EVER 2016 | Year: 2016

The permanent magnet linear synchronous machine (PMLSM) with long primary is a suitable candidate for ropeless elevator due to high force density and low thrust ripple. For the PMLSM with multi-segment long primary, it is impractical to excite all primary segments. The ordinary method is only energizing the primary segments covered by the secondaries, that is to say, section power supply technology. The switch control technology of primary sections has great influence on system performance because the parameters of PMLSM change with the secondary position. Based on finite element analysis, this paper investigates the characteristics of the PMLSM applied in ropeless elevator, including dand q-axis inductances, PM flux linkage, thrust force, etc. The suitable switching method of primary sections is then proposed to lower the copper loss and thrust force ripple. The fast and steady velocity trajectory tracking is obtained, which is validated by simulation and experiment results. © 2016 IEEE.

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