Numerical Simulation Of Jet Reactor

With the economic development of our country,the utilization rate of chemical products is getting higher and higher.The mixing of gas-liquid fluids is involved in the production process of many chemical products.The mixing equipment is inevitably used during mixing.The traditional mixing equipment has poor mass transfer effect,complex structure and high energy consumption.As a special fluid mixing device,the jet reactor can break the gas into extremely small bubbles,thereby significantly increasing the contact area between the materials,enhancing the effect of mass and heat transfer,and shortening the reaction time.It is widely used in the chemical industry because of its simple structure,convenient maintenance and low energy consumption.The breakage of bubbles in the jet reactor and the structure of the jet reactor have a great influence on the mass transfer effect,but there are few studies on these aspects.Based on this,this thesis takes the jet reactor as the research object,and conducts a series of studies on the bubble breaking mechanism,the structural performance and the stirring effect of the jet reactor by numerical simulation,so as to provide some theoretical support for the industrial application of the jet reactor.The specific research contents are as follows:(1)Based on the theory of computational fluid dynamics,a three-dimensional geometric model of the fluid domain of the jet reactor was established.The Realizable k-εmodel,Schiller-Naumann model,Luo breakup model and Luo coalescence model were used for numerical simulation.The mechanism of bubble breakup in the jet reactor was studied by the results of velocity,pressure,turbulent kinetic energy and bubble diameter.And the effects of throat-mouth distance,liquid inlet velocity and gas inlet velocity on bubble breakup in the jet reactor were considered.The results show that when the liquid passes through the nozzle,the velocity increases and the pressure decreases,forming a local negative pressure zone,which has a entrainment effect on the surrounding gas.The two collide sharply in the suction chamber and the throat,and the large bubbles are sheared and broken into small bubbles.The average diameter of the bubble at the throat outlet decreases with the decrease of the throat-mouth distance.The average diameter of bubbles at the throat outlet decreases with the increase of liquid inlet velocity.The average diameter of bubbles at the throat outlet increases with the increase of gas inlet velocity.(2)Based on the fluid-solid coupling theory,a three-dimensional geometric model of the solid domain of the jet reactor was established.The pressure results of the fluid domain of the jet reactor were transmitted to the corresponding solid domain surface for strength analysis.And the influence of wall thickness and liquid inlet velocity on the structural performance of jet reactor was considered.The results show that the maximum deformation occurs at the junction of the throat and the suction chamber,and the maximum equivalent stress occurs at the junction of the intake pipe and the suction chamber.The maximum deformation and maximum equivalent stress decrease with the increase of wall thickness.The maximum deformation and maximum equivalent stress increase with the increase of liquid inlet velocity.The values of maximum deformation and maximum equivalent stress are low,so the structure of the jet reactor can meet the needs of use.(3)Based on the theory of computational fluid dynamics,the influence of the installation angle,installation number and installation height of the jet reactor on the stirring effect was studied by numerical simulation.The results show that when the installation angle of the jet reactor is 90°,the number of installations is 4,and the installation height is 1000 mm,the stirring effect is better.