Experimental Investigation On The Spray Characteristics Of Pressure Swirl Nozzle For Liquid Distribution

As the common equipment for liquid distribution,pressure swirl nozzles which were able to uniformly distribute liquid can improve the effect of liquid into film and the performance of heat transfer in the falling-film evaporator.Experiments were carried out to investigate spraying process and internal fluid flowing and breakup process of pressure swirl nozzle in different inner structure for exploring the variation law of characteristics of spraying and gas-liquid flowing on flowing parameters and geometry structures.The main investigation is as follows:(1)An experiment system has been designed to measure spray characteristics of pressure swirl nozzles which include pressure-flow relationship,spray cone angle,spray density,and observe the process of internal flowing and breakup.(2)Experiments were carried out to investigate spray characteristics,internal flowing and breakup process of hollow-nozzle which wear circular table structure.With higher inlet pressure,the spray flow increases,and the spray angle gradually increases to a constant value,and the spray distribution always keep constant characteristic of parabolic distribution in both edges of the spray diameter.With higher pressure or lower spray height,the peaks gradually move to center position.Based on the principle of “peak-valley superposition”,it is possible to uniformly distribute liquid by arranging nozzles reasonably.The pressure and internal structure are hidden reasons which resulted in changes of spray characteristics,because they influenced the flowing status,then affected the breakup effect of continuous fluid what inertia force,surface tension,viscous force and gravity force interact with.(3)Experiments were carried out to investigate spray characteristics of solid-nozzle which wear triangle structure at the top.Compared with experiment conclusion of hollownozzle,the variation law of pressure-flow relationship and pressure-spray angle relationship keep consistent.However,there are some differences in the spray density characteristic.It is possible to uniformly distribute liquid by enhancing the symmetry of top structure.In conclusion,the variation law of spray characteristics has been obtained by investigating different inner structure nozzle experimentally.It can apply data support and theoretical guidance to enhance working performance of falling-film evaporators.