Research On Cooling Effect Of A1400MW Nuclear Turbogenerator With Different Rotor Sub-slot Structures

Large advanced PWR nuclear power plant major project CAP1400is a subitemof National science and technology major project among "Long–term Science andTechnology Development Plan of China(2006–2020)". As an importantelectromechanical energy conversion device in nuclear power plant, researches onthe nuclear turbogenerator attract extensive concern worldwide. With the increasingcapacity of the nuclear turbogenerator, its thermal load increases continuously aswell, which gives rise to the large turbo heat cooling problems. Therefore, it makesgreat significance to ensure the reliable operation of large generators by designingventilation to cool the generator appropriately and predict the structure of themachine temperature accurately.Focus on the internal state of the fluid flow and heat dissipation of rotor coil innuclear turbogenerator during complex rotor structure of ventilation, this article takesa nuclear1400MW4–pole turbogenerator which has rotor using sub–slot structureunder study and hydrogen cooling system as example, ascertain the half–axial lengthof the generator and a3D fluid field within the range of circumferential rotor circularpitch, build coupled calculation heat transfer model in temperature field. The articlegets the picture of how the cooling hydrogen ventilation holes in radial distributionof exciting windings heated up, using the finite volume method. Flow from studyabout the flowing law of cooling medium, it makes the distribution of temperaturefield inside the exciting windings clear. Using lumped parameter thermal networkmethod, it also establishes three–dimensional thermal network model taking radial,circumferential and axial thermal resistance into account, and calculates thetemperature distribution within the rotor by fewer nodes and lower computationalcost. Through comparing the results of the two methods of settlement analysis above, this article verifies the accuracy of the two methods of calculation, and proves theexperience to design thermal network method in the beginning of predicting thegenerator temperature rise in the meantime.In order to get a better cooling effect, contraposes two improved cooling systemin sub–slot: the axial and radial mixing stepped equal ventilation holes coolingstructure and axial and radial mixing stepped unequal ventilation holes coolingstructure a computational fluid cooling system and temperature fields, thecomparative study of the three scenarios under how the cooling hydrogen and thetemperature distribute inside the exciting windings, draws some useful conclusionsabout large turbogenerator rotor ventilation structure design.