In this paper, an experimental study of upward jet flash evaporation is carried out to clarify the effect of the nozzle diameter on the evaporation phenomenon and also to obtain empirical equations representing the area of influence by the upward flash evaporation from one nozzle. The nozzles are made of stainless tubes with internal diameters of 52, 83 and 107 mm.The temperature of the inlet superheated water is 24, 30 and 35°C.The mean velocity of the inlet superheated water varies from 1.2 to 2.7m/s.The horizontal temperature distribution is measured by 10 thermoresistances at 25 locations along the jet axis between 0 mm and 600 mm from the nozzle exit.
The results of the experiment show that the temperature of superheated water drops quickly in the case of flash evaporation with a nozzle of larger diameter.By the dimensionless arrangement, two major empirical equations are obtained to estimate the area of influence by the flash evaporation from one nozzle.Using these equations, the designers can calculate the size of the flash chamber and the optimal interval of the nozzles for the upward jet flash desalination plant.
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