CFD MODELLING OF NUCLEATE POOL BOILING

Abstract

Nucleate boiling is a very significant two phase process and finds wide application in many chemical industries. It is an extremely advantageous mechanism, due to its ability to transfer enormous amount of heat at low temperature gradients. Modelling of nucleate pool boiling is very is desirable in order to avoid overheating or damage of heating material in many industrial applications of it. The main objective of the project work is to develop an effective heat transfer model for calculation of heat transfer coefficient. The set up used for study is taken from BHAUMIK et.al. (2004) literature. The set up consist of a vertical cylinder in which a horizontal heating rod is immersed. Different constant heat flux is given to heating rod made up of stainless steel. For every constant heat flux provided to heating surface heat transfer coefficient is measured at both atmospheric and sub-atmospheric conditions.CFD code ANSYS 13 is used for simulation. Simulations have been carried out in 2D heating system using a transient Eulerian-Eulerian multiphase model. RPI boiling model of Kurul & Podowski is used for simulation process. Simulations have been carried out for benzene & water at atmospheric & sub-atmospheric pressure. Simulated results are obtained for heat transfer coefficients, wall super-heat, quenching heat flux to total flux, convective flux to total flux, evaporative flux to total flux ; heat transfer coefficient obtained for different constant heat flux for both atmospheric and sub-atmospheric conditions are compared. Obtained results are validated with previously reported experimental data.