Dependency of pure liquid pool boiling heat transfer coefficient to bubble contact angle on roughened Brass heater in new model

mohammad hayavi

Abstract

Heat transfer coefficient of nucleate pool boiling Nucleation is a basic part of phase transformations, which plays an important role in understanding and describing any phase change processes. For a boiling process, nucleation appears in the initial stage, and directly affects bubble formation and boiling intensity. According to the heterophase fluctuations which induce phase transition, the phase change has two main types. Classically, phase change caused by the fluctuation with large range and small region is namedphase change of nucleation, for example as normal boiling process. The bubble departure diameter is an important feature of heterogeneous boiling, since it impacts the rate of heat transfer. One of the most important parameters in the design of heat exchangers is heat transfer coefficient. The reciprocal of thermal insurance is the heat transfer coefficient. There are multiple techniques for estimating the heat transfer coefficient in various thermohydraulic situations, fluids, flow regimes, and heat transfer modes.This study examined the pure water and pure ethanol pool boiling heat transfer coefficients on the brass rod heater. examined the variations in the heat transfer coefficient for pool boiling while measuring thedynamic contact angle for each heat flow. The heat flow ranges from 0 to 120 KW. The new model is created using dimensionless quantities representing the liquid thermophysical characteristics and theroughnesses of Brass heaters. .this model obtained by Buckingham theory and genetic algorithm Technique. In a novel paradigm, the genetic algorithm provides the link between dimensionless numbers. The dimensionless capillary number is where the contact angle originates. This model's absolute error is under 11%.