Numerical Investigation Of The Critical Volume Flow Rate In Rotating Liquid Film Reactor

A rotating liquid film reactor(RLF R)is a truncated cone reactor composed of a rotor and a stator for preparing nano materials.Compared with traditional reactor,it provides material with smaller crystal size and narrower crystal size distribution.Experiments show that,when there has no air bubbles enter the reactor and no fluid overflow the reactor,each speed and gap size will correspond to the only maximum and constant flow rate which is defined as the critical volume flow rate(CVFR).All precipitation experiments and the calculation of average particle size are performed at the CVFR.So it is important to look for a method to calculate the CVFR.In this paper,a numerical method for computation of CVFR is presented based on the computational fluid dynamics technique and the Navier-Stokes equations.The Realizable k-? turbulence model is selected for the calculation according to the number of swirls.The CVFR is calculated by introducing a boundary layer mesh with the climbable wall function and using an adaptive time step method and a mesh adaptive method.The paper simulates the CVFR of two different reactors in the laboratory numerically.By comparing the calculation results with the experimental ones of several sets of parameters,it is found that the two have good agreement,and this shows that the algorithm has certain reliability.On the basis of the reliability of the algorithm,the dependence of the CVFR on the height,the gap width and the rotor speed is studied.The sensitivity of the CVFR to the parameters of the reactor is also examined by introducing the concept of the partial elasticity.The calculation results show that the partial elasticity of the CVFR to the rotor speed is bigger than that to the gap width,this indicates that CVFR is more sensitive to rotor speed.The sensitivity is gradually reduced as the rotational speed increases.The partial elasticity of the CVFR to the reactor height is bigger than that to the rotor speed,but the sensitivity gradually decreases as the speed and height increase.