Numerical simulation and experimental investigation of bubble behaviour during pool boiling in the coiled wire

Abstract

Under the computational fluid dynamics (CFD) framework, an interface tracking method has been used to perform several multiple simulations of coiled wire boiling in a pool. This study includes simulations of the boiling regime, including the Critical Heat Flux (CHF), ranging from nucleate boiling to film boiling. The purpose of this research was to investigate using coiled wire to increase the rate of heat transfer under constant heat flux conditions. The range of the applied heat flux is 130–1075 kW/m2. This research delves into the formation of bubble shapes, bubble diameter, and bubble departure frequency. The vapour bubble grows in size as the heat flux increases; with a heat flux of q'' = 600 kW/m2, it reaches its maximum measured diameter of about 9 mm. Additionally, the heat transfer coefficients and wall temperature distribution were determined using the simulation findings. The heat flux was gradually increased in the critical heat flux investigation until burnout of the coiled wire was observed and a bubble layer formed. This led to the conclusion that q'' = 1075 kW/m2 represents the CHF for this particular geometry. It was observed that the CHF conditions occur in the coil portion, which emphasises the importance of considering the critical heat flux more carefully while designing this geometry.