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Lu Y.-P.,Harbin University of Science and Technology | Zheng G.-L.,Harbin University of Science and Technology | Feng F.,Harbin University of Science and Technology | Qin Y.-S.,Harbin Electric Machinery Co. | Han J.-D.,Harbin University of Science and Technology
Dianji yu Kongzhi Xuebao/Electric Machines and Control | Year: 2010

In order to analyze the cooling effect of different ventilation proposals in the rotor, a physical model of single coil of the longest end winding was established for a large air-cooled turbine generator rotor, which can change the size and location of inlet and outlet as well as the block layout in the case of determining each ventilation segment length. In order to compare the cooling medium flow distribution of different ventilation proposals in rotor, the maximum temperature of the rotor winding and the uniformity of temperature distribution, the rotor flow field and temperature field of the rated operating conditions were simulated according to the computational fluid dynamics principle. The results show that the air inlet position of the rotor end windings determines the length of winding air road, the flow of cooling air, and the temperature distributions of the cooling medium and the winding. Rational arrangement of air inlet can increase the air mass flow rate entering the rotor winding, adjust the percentage of air mass flow rate entering each ventilation segment, ensure that the rotor worked at the temperature below the maximum allowable operating temperature and make the rotor temperature distribution be uniform.

Huo F.-Y.,Beijing Jiaotong University | Li Y.,Harbin University of Science and Technology | Li W.-L.,Harbin University of Science and Technology | Yang X.-F.,Harbin Electric Machinery Co.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010

With the increase of turbogenerator capacity, the heat transferability of cooling system is becoming more and more vital to the component reliability. By reasonablely optimizing the stator structure in a turbogenerator, utilization rate of coolant could be improved, and the maximum temperature of turbogenerator could be reduced. Based on the experimental data and plenty of related operations of a 200 MW air-cooled turbogenerator, two optimization designs about stator structure were proposed. One was to change the iron core thickness with the stableness of overall size, total losses of stator core and the number of stator ventilations, the other is to increase the number of ventilations and reduce their length with the stableness of the overall size and total losses of stator core. With CFD principle and 3-D finite volume method, the modeling equations of air turbulent flow in cooling ducts are solved, and the effect of the ventilations' structure changing on coolant utilization ratio and distribution of stator temperature were studied. The study shows that, by adopting the two optimal structures, coolant can take away more heat from generator and the maximum temperature of generator can be reduced up to 9.13°C more than original structure. © 2010 Chin. Soc. for Elec. Eng.

Wang Q.,Harbin Institute of Technology | Xu Y.,Harbin Institute of Technology | Hu J.,Harbin Institute of Technology | Zou J.,Harbin Institute of Technology | Zhang J.,Harbin Electric Machinery Co.
IEEE Transactions on Plasma Science | Year: 2013

This paper presents an approach for enhancing the thrust force of a tubular transverse flux permanent magnet linear machine (TFPMLM) that has been developed for electromagnetic applications. It is shown that, by introducing auxiliary cores to suppress the leakage flux, the thrust force of the tubular TFPMLM can be significantly enhanced, by ∼130%$, under the same volumetric constraints. The effectiveness of the proposed technique is validated by extensive three-dimensional finite element computations. © 1973-2012 IEEE.

Kang J.W.,Tsinghua University | Hao X.K.,Tsinghua University | Nie G.,Tsinghua University | Long H.M.,Tsinghua University | And 2 more authors.
IOP Conference Series: Materials Science and Engineering | Year: 2015

To improve the production efficiency and reduce residual stress and deformation, a new method-Post Solidification Intensive Riser Cooling (PSIRC) was proposed for heavy steel castings. Risers are cooled by forced air from its top surface as the solidification of a casting finishes, so, the risers are turned into cooling passages during the cooling process of a casting with contrast to their function of feeding passages during the solidification process. This method was applied to a hydro turbine blade with 0.9 ton melt. Its cooling speed increased apparently meanwhile with improved temperature distribution uniformity and the hot spot was pushed almost to the casting bottom. The cooling efficiency was improved 40% before shakeout and its residual stress was reduced meanwhile. © Published under licence by IOP Publishing Ltd.

Kang J.,Tsinghua University | Long H.,Tsinghua University | Li Y.,Tsinghua University | You R.,Tsinghua University | And 4 more authors.
Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science | Year: 2014

The mold-filling process has a determining effect on the quality of castings, and it has always been a hot but difficult research topic. The authors developed a wireless monitoring system for the mold-filling process of castings based on a contact time method and an observation system based on heat-resistant high-speed cameras. By using these two systems, the filling process of a turbine guide vane casting with a stepped gating system was investigated. The filling profile of the casting was recorded, and the filling time of nine typical positions was acquired. These results show that at the beginning, the liquid steel flowed out from the top ingate, which was designed to be the last to fill. The numerical simulation of the filling of the guide vane was performed, and the outflow from the top ingate were predicted. Finally, the gating system of the casting was improved with enlarged sprue. The new design features bigger sprue to ingate ratio; therefore, it could avoid the overflow from the top ingate and realize stable filling. © 2014, The Minerals, Metals & Materials Society and ASM International.

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