Investigation On Phase Flow Of Pressure Swirl Nozzle With Unilateral Tangential Entrance

Because of its simple structure, low installation and maintenance requirements, unilateral tangential inlet centrifugal nozzle has been used widely in the horizontal tube falling film evaporator of seawater desalination device. The spray effects directly affect the heat transfer efficiency and stability of the entire unit, therefore the research to the internal and external flow field characteristics of centrifugal nozzle is needed. The related numerical simulation has been performed to research the gas-liquid phase flow of the nozzle for follow-up experiment.The flow conditions inside the nozzle determine the characteristics of the spray nozzle outlet. In this paper, the VOF method is carried out for the filling process inside the nozzle. Depth study of the characteristics of speed in stable condition in swirl chamber nozzle has been done, include the characteristics of speed in shrink and outlet sections. The movement of liquid into the nozzle and the formation of air-core has also been described after three-dimensional numerical simulation. The function of each place about the nozzle has been clear.Unilateral tangential inlet centrifugal nozzle has circumferentially asymmetric flow field. Comparative analysis of three kinds of nozzles (top with no special structure, top with ring baffle and top with spiral baffles) indicate that the nozzles, top with special structure, have more uniform flow field.By changing the inlet pressure of centrifugal nozzle, the study found that when the nozzle inlet pressure is greater than a certain value, the movement of exports of liquid led by inertia force, the spray cone Angle is a specific degree and remains unchanged, and film thickness decreases with increasing pressure.By amplifying the centrifugal nozzle, the study found that when the inlet pressure is in the range of 100kPa-200kPa, geometrically similar but different size nozzles has similar flow field, and their air core is the same proportion. The experimental results of geometrically similar but big size nozzles can apply to actual small size nozzles.