Study of Pool Boiling Through Numerical Approach Vinod Pandey, Gautam Biswas and Amaresh Dalal 1 Introduction The processes involving high heat fluxes over a heated surface result in the vapor generation from the cavities and this phenomenon is termed as boiling. In the presence of gravity with the increase in superheat as shown in the boiling curve (Fig. 1), heat transfer prevails through natural convection which subsequently leads to the generation of vapor bubbles at some preferred cavity sites (onset of nucleate boiling). Depending on the heat flux or the superheat at the heated surface, the mode of boiling transforms from nucleate to film boiling with an intermediate stage of transition between the two modes. The nucleate boiling is influenced effectively by various factors like surface superheat, wettability, roughness, liquid-subcooling, etc. As the superheat increases the adjacent bubbles interact and merge to form an enlarged dry- out region resulting in vapor slugs and columns [1]. It is called as the boiling crisis where a sudden drop in heat transfer efficiency is experienced. Contrary to the vapor column theory, an alternative theory of vapor recoil has also been established recently [2] which explains the boiling crisis even under microgravity. The transition mode continues with increase in superheat to ultimately establish a continuous thin layer of vapor film which corresponds to the minimum heat flux point or the Leidenfrost point in the boiling curve. Thereafter, the film boiling regime continues which is dominated by the instabilities at the liquid-vapor interface. Before approaching to the numerical aspects of boiling study, the following section discusses the overall development in the boiling-research. V. Pandey · A. Dalal Department of Mechanical Engineering, Indian Institute of Technology, Guwahati 781039, India e-mail: amaresh@iitg.ac.in G. Biswas (B ) Department of Mechanical Engineering, Indian Institute of Technology, Kanpur 208016, India e-mail: gtm@iitk.ac.in © Springer Nature Singapore Pte Ltd. 2020 A. Runchal (ed.), 50 Years of CFD in Engineering Sciences, https://doi.org/10.1007/978-981-15-2670-1_17 607