Analysis Of Fluid And Thermal Characteristics For Megawatt Generator With Radial Ventilation

Recently, the wind power generation and related technologies have beendeveloping rapidly as well as the market demands on efficiency during the powerproduction increasingly. As the result, wind generators with larger electromagneticcapacity have been introduced. Simultaneously, relative problems emerge graduallyduring the process, especially the fever in generator. Whereas, previous researchesmostly concentrated on double fed technique, double fed control strategy and itseffective connection with the power system while fluid and thermal distribution indoubly fed wind power generators, especially large electromagnetic capablegenerators, were just involved in a few of studies. Therefore, analysis of the fluid andthermal characteristics in this5MW doubly fed wind power generator would benecessary and meaningful.In order to present the heat flow characteristics of generators with radialventilation structure, the5MW doubly fed wind power generator will be introducedas an example in this thesis. More specifically, the calculation model of1/2generatoron fluid flow would be established initially, according to generator’s operatingprinciple and physical structure. In this part, basic assumptions will be considered;finite volume calculating method will be applied; the distribution of fluid velocity,pressure and flux would be analyzed to generate the reliable result. After that, somefactors and effects of the flow statement would be discussed, such as the fluctuationof rotor speed that caused by natural wind disturbance and the bending direction ofrotor ventilation channel.Additionally, the heat transfer model of1/6generator will be built on thecalculating result of fluid flow, based on the fluid-thermal interaction theorem. Theresult part will indicate highest temperature point, followed by detailed informationabout the temperature rise of strands, insulation and core. On top of that, theinfluence of insulation material and the stator copper loss on temperature will also be discussed in the thesis. Finally, the rest of the dissertation will focus on analyzing theeffects of fluid flow patterns including not only the changes of rotational speed butwind entrance speed on generators’ temperature rise as well.Overall, this thesis can provide theoretical basis for the design and optimizationof larger electromagnetic capable generators with the similar ventilation structure.