Study of the Two-phase Flow Pressure Drop in Inner Evaporative Cooling Generator

The evaporative cooling technology is a kind of new generator cooling method, which is high-security, energy-saving and highly efficient and the inner evaporative cooling system is one of the most important application modes of it. In self-circulation inner evaporative cooling system of stator busbar in hydro-generator and forced circulation inner evaporative cooling system of stator hollow conductor in turbo-generator, the prediction of two-phase flow pressure drops in busbar and hollow conductor plays an important role to the normal operation and safety of generator. In this paper, through comparing the experimental data and simulation results, the prediction accuracy of some two-phase flow frictional pressure drop correlations for these inner evaporative cooling systems was discussed. By analyzing the experimental data, the most suitable correlation for the prediction of self-circulation evaporative cooling system of stator busbar in hydro-generator was suggested and a new modified correlation of Chisholm-B method for the prediction of forced circulation evaporative cooling system of stator hollow conductor in turbo-generator was proposed. The conclusions provide good theoretical basis for the design of inner evaporative cooling system in actual engineering computation.