| The nozzle is a very important device in the system of semi-dry flue gas desulfurization,and the atomization characteristics of the nozzle directly affect the desulphurization efficiency of the system.Currently the mechanical rotary nozzle and the pneumatic nozzle are widely used in the system of semi-dry flue gas desulfurization.Compared with the mechanical rotary atomizing nozzle and the pneumatic type nozzle,the spiral nozzle has the characteristics of simple structure,wear resistance,corrosion resistance,fogging performance and anti-blocking performance.And the atomization system costs lower and its operation is convenient.So it is of great significance to study the atomization characteristics of spiral nozzles for the application of semi dry flue gas desulfurization and the design of the nozzle.Firstly,the article summarized the classification and the research status of atomizer and researched on the liquid atomization and the influencing factors of the spiral nozzle by means of a large number of relevant literatures.Secondly,in order to study the atomization characteristics of the nozzle,the experimental system that comprises the liquid atomization system and the measurement system for atomization characteristics have been designed and built.Finally,the experiment of different types of spiral nozzles is carried out using the water as working fluid.The influence of different structures and pressures on atomization characteristics of nozzles was obtained.The fitting relation of the experimental data was obtained by using the MATLAB software.At the same time,the jet breakup of liquid was photographed at close range,and was analysed.By means of the experimental research on spiral nozzles,the following conclusions were drawn:(1)The SMD increases with the increase of the diameter of the nozzle spray hole.The SMD of the solid cone screw nozzle is smaller than the SMD of the hollow cone screw nozzle.The SMD decreases with the increase of pressure.The atomization criterion of the spiral nozzle is obtained by the method of dimensional analysis,and the relationship between the SMD and Weber number is fitted.(2)The helix structure of spiral nozzle has no effect on the atomization angle.The atomizing angle increases with the increase of the diameter of the nozzle spray hole.The atomizing angle increases with the decrease of the helix angle of the nozzle.With the increase of pressure,the condition of atomization angle increases and finally tends to be stable.And the relationship between the conditions of atomization angle and volume flow is fitted.(3)The helix angle and helical structure of spiral nozzle have no effect on the nozzle flow.The volume flow increases with the increase of the diameter of the nozzle spray hole in the case of the same pressure.The volume flow increases with the increase of pressure.And the relationship between volume flow and pressure is fitted.(4)The length of the liquid membrane decreases with the increase of pressure for the solid cone spiral nozzle.When the pressure increased to 0.14 MPa,the liquid immediately was broken after leaving the nozzle. |
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