Two-Phase Flow Characteristics of Evaporative Cooling System for Large-Capacity High-Speed Hydrogenerators' Rotor

Abstract

Research of evaporative cooling system for a rotor is of great significance for large-capacity, high-speed hydrogenerators. The two-phase flow characteristics are important parameters of the evaporative cooling system, and it is urgent to research the two-phase flow characteristics under rotating conditions. In this paper, based on the self-developed experimental platform of pipe-cooled cooling evaporative cooling system for a rotor, a real-time image acquisition system is established. Experiments are conducted under different thermal loads and centrifugal accelerations, and two-phase flow images of the gas outlet section of the system are collected to analyze the characteristics and patterns of two-phase flow. The results show that under the action of a strong centrifugal force field, the two-phase flow in the pipe-cooled cooling evaporative cooling system for a rotor is more turbulent and complex. Bubbles are more likely to break up and form a dispersed flow. Increasing the thermal load can reduce the instability of the two-phase flow in the system, while increasing the centrifugal acceleration can raise the system pressure and exacerbate the instability of the two-phase flow in the system.