The influence of initial and operating conditions on spray flash evaporation characteristics was investigated based on a new high-temperature and high-pressure spray flash evaporation system. Water was used as the working fluid. The initial liquid temperature was raised to above 100℃ and the pressure inside the flash chamber was maintained positive for the first time. A specially-designed swirl nozzle with two S-shaped internal vanes was used to inject liquid upward or downward into the flash chamber. The experiments were conducted at initial temperatures ranging from 135 to 150℃

pressures of 121

126

131

136

141 and 146 kPa and superheats from 30 to 46℃. The results indicated that the mass flow rate of vapor generated by flashing increased with the increase of initial temperature and decreased with the increase of pressure. Downward injection outperformed upward injection for higher vapor generation rate and less water carried out by vapor. The flash efficiency was found to increase linearly with the degree of superheat. An empirical equation between flash efficiency and the degree of superheat was proposed based on a large amount of experimental data. The results provided reference for the application of spray flash evaporation at high temperature and high pressure in industrial fields.