Study on Heat Transfer Characteristics of Spray Droplets under Medium and Low Pressure Saturated Steam Environment

The heat transfer characteristics of spray droplets under medium and low pressure saturated steam environment as the engineering background were investigated in this paper. The results show that the change trends of heat transfer per unit mass with time are basically the same under different initial droplet velocities. The higher initial velocity gives rise to the higher heat transfer coefficient and heat transfer per unit mass. The droplet diameter has a significant influence on the change trend of heat transfer per unit mass with time. The decreasing trend of heat transfer per unit mass decreases gradually with time, and the longer time will be taken for the droplet surface temperature and average temperature reaching to ambient temperature of saturated steam if the droplet diameter is larger. The higher saturated steam pressure gives rise to the more rapid increases of droplet surface temperature and average temperature. Under different steam pressures, the droplet surface temperature or average temperature reach to the saturation temperature nearly at the same time. The surface temperature, average temperature and heat transfer per unit mass change with time basically the same at different initial temperatures. The results are helpful to optimize the design of spray system in practice engineering.