The efficiency rate of a Steam-water injector

Abstract

This paper analyses the influence of relevant parameters on the efficiency rate of a supersonic injector and its parts. Forced condensation in the injector is achieved by the mixing of cold water and steam with the goal of getting higher pressures of hot water (6-12 bar) with an outlet temperature of 70-80 °C to enable distant transportation of hot water and heating. Although the energy potential of pressure is not significant compared to inlet energy of steam, it is of importance since it represents the potential to realize external work. The complex flow process through the mixing chamber, the most important part of the injector, is presented with a diagram of forced condensation energy change, flow and geometry changes of the mixing chamber and the distribution of the relevant forces on the borders of the mixing chamber. It is shown that higher efficiency rates are achieved if condensation is speeded up by the reduced mixing of cold water and steam. Analyses are done according to analytical laws and experimental investigations of a steam-water injector prototype, with the data enclosed. The efficiency rates of the mixing chamber ranges from 60 to 85%, depending upon the following: the injection coefficient, the inlet pressures and the temperatures of the cold water and steam (and the desired outlet hot water temperature and pressure). Investigations are mostly directed to the particular needs of energy and process devices and the significance of the Mach number was not especially emphasized in them.