Thermodynamic properties of the bubble growth process in a pool boiling of water-ethanol mixture two-component system

Mohammad Sattari,Leila Mahdavian

doi:10.1515/chem-2019-0010

Mohammad Sattari, Leila Mahdavian

Open Access

https://doi.org/10.1515/chem-2019-0010

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Abstract

AbstractSaturated pool boiling in a two-component water-ethanol solution was studied at a pressure of one atmosphere in a horizontal stainless steel cylinder. Solutions with volumes of 3%, 7%, and 12% of water-ethanol solution were examined at a heat flux of 1.8 to 60 kW/m2. Videos and photos were analyzed and changes in bubble diameter, growth, and departure parameters were recorded. The results showed that the bubble departure diameters increased with increasing heat flux, but diameters decrease with increasing ethanol mass fraction. The experimental data are evaluated with two models of Alavi Fazel and Hamzehkhani’s model, have better fitting with Hamzehkhani’s model.

Highlights

Nuclear boiling is an application of heat transfer that, as the subject of many studies, has led to many empirical results
The bubble formation steps were conducted first for pure water, water-ethanol solutions were prepared at concentrations of 3%, 7%, and 12% by volume, and the test was repeated as for pure water
This study investigated bubble diameter at heat fluxes ranging from 1.8 to 60 kW.m-2

Summary

Introduction

Nuclear boiling is an application of heat transfer that, as the subject of many studies, has led to many empirical results. Boiling is a common issue in complex engineering problems, The process of bubble formation, growth, and movement in the boiling process significantly increases the boiling heat transfer coefficient compared to the convection mechanism without a phase change [4]. Bubble formation occurs when the surface temperature (Tw) is higher than the temperature of liquid at a pressure of saturation (Tsat) and heat is thereby transferred from the solid to liquid. The resulting heat flux depends on the temperature difference between the surface and the saturated liquid. The liquid is stagnant (the flow of liquid is zero) at pool boiling and movement adjacent to the solid surface is caused by the free convection in the growth of the bubble. The departure point of nuclear boiling is attained by increasing the flux to a point referred to as the critical heat flux

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Conclusion