Numerical Simulation on Atomizing Performance of Pressure Swirl Nozzles in Ethoxylation Reactors

Abstract

AbstractInitial breakup model(IBM) approach in conjunction with Volume of fluid(VOF) is developed to model the special nozzle in ethoxylation reactors, which has to meet the requirement of low pressure drop, high volume flow rate, little droplets size and large field. For the VOF model, Realizedk-εis selected and has higher accuracy of simulation for swirling flows by comparing with Standard and RNGk-εmodels. IBM is written as a user defined function(UDF) and embedded to study the extra breakup from ligaments to droplets and forecast the droplets size distribution. As the experiments have been conducted already, the simulation results have a good agreement with the experimental results in flow rate, spray cone angle and droplets size distribution. At the same time, the atomization process and atomization mechanism of the ethoxylation reaction nozzle were analyzed. Then the VOF-IBM methodology can be used to predict the spray characteristics of the nozzles with different structure and the optimal structure for ethoxylation reaction was found by orthogonal test and fuzzy comprehensive evaluation. In addition, the primary and secondary order of the influencing factors for discharge coefficient, spray cone angle and Sauter mean diameter are respectively gained. The VOF-IBM is instructive for the optimization design of ethoxylation reaction.