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In Gas Insulated Switchgear (GIS) the loop resistance is a key parameter which can characterize the contact condition of the conductive circuit. The current method to measure loop resistance was mostly proposed and used in routine test, commissioning test and overhaul. The monitoring of abnormal conditions of contacts in operation has not been realized yet. To early detect the hidden contact defects...
In the premise of the measured circulation flow rate, the conjugate heat transfer in turbulent flow within one coupled rotor model of a 250-MW hydrogenerator was calculated. The flow rate changes of the fluid in the support, yoke ducts, pole gap, and the air gap between stator and rotor were researched using the finite volume method, also their effects on the operating rotor temperature. The analysis...
Five parts including environment air supply duct, air supply structure, display cabinet, air return structure and environment air return duct were integrated and the modified two fluid model was employed to simulate the air flow and heat transfer in a vertical display cabinet with environment air supply. The temperature field characteristics were analyzed and the predicted temperatures were compared...
By the study on design method of requirement product and hot-runner product, uniform matter-element model has been used for the modeling of requirement product. Extension theory has been used, and design process of extense design of hot-runner requirement product has been constructed. Merit rating based on Ansys FEA temperature field analysis has been used to evaluate the results, and the optimal...
In this paper A 250MW air-cooled hydro-generator is taken as the analysis example, the additional loss in rotor while machine rated operating is calculated. Based on this, the distribution of the heat transfer coefficient on surface of exciting windings is determined and the 3D steady temperature field is studied. The influence of varied additional loss on the distribution of the rotor heat transfer...
A numerical procedure has been applied to analyze the temperature distribution in a rolling tire. A 3D finite element model of a rolling tire is established to simulate the mechanical field under the certain inflation pressure, loading and velocity condition. The thermal properties and loss factor of rubber are measured. The strain and the stress of nodes are fit by Fourier Series and are used to...
Compared with the traditional air cooling generator, the large capacity generator with immersion type evaporative cooling technology features the similar simple and reliable structure as the air cooling technology, in the mean time, because of the phase change heat transferring process of the evaporative cooling, the heat exchange rate is highly improved. In this paper, based on the boiling heat transfer...
Evaporative cooling, is superior to other cooling methods. It offers a safe, reliable, and effective whole surrounding for insulation and heat transfer of the running stator. So it's temperature distribution is worthy of being profoundly researched. According to the acceptant technics condition of the manufacture, the paper offers a kind of new stator insulation structure adapting to evaporative cooling...
Fluid jet-dispensing technology has been widely used in micro-electronic encapsulation industry. The fluid viscosity varies as temperature changes, while it affects the process remarkably. Besides basic method on temperature field solution, some thermal behaviors, including heat conduction and heat exchange, boundary conditions and some physical parameters are overall analyzed in this paper. Based...
A three-dimensional heat transfer model was developed to simulate the temperature distribution of the cooling copper mould used in the thin slab continuous casting process. Temperature field of the copper plate of the funneled mould was calculated by finite element method (FEM). It was confirmed that the simulation results are in agree with the experiments and actual online production. Influences...
Temperature fields in the region of the temperature sensors are simulated. Two versions of the sensors placement relative to the heat transfer agent are analyzed. It is established that in the case of sinking the sensor with the bushing into the heat-transfer agent flow the sensor and the part of the surface of the wall of pipe must be covered with thermal insulation. In this case the temperature...
The high-voltage electric power is generally transmitted by underground cables in urban. Considering about the high cost for underground cable, it is necessary for us to get accurately biggest ampacity of electric cables in order to insure the operation of cables in safe. It is relationship of heat transfer with cables and soil. The coefficient of thermal conductivity of soil has great influence on...
By using numerical calculation method, the electromagnetic field of a turbine generator was calculated and the iron loss in stator yoke and tooth was analyzed respectively, and the distribution of iron loss in stator core could be obtained. Compared with the iron loss calculated from traditional method, the numerical calculated result is close to the measured value. Then taking the iron loss as the...
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