Abstract

For the simultaneous attainment of enhancement and uniformity in temperature distribution in case of quenching performed in transition and nucleate boiling regimes, the heat treatment is performed by adopting thin coolant flow boiling methodology which depicts high replacement rate of vapour and low coolant consumption rate in comparison with the other cooling methodology such as jet and spray cooling.Furthermore, the simultaneous flow over the entire plate reduces the intensity of non-uniformity in cooling. The analysis of experimental results in case of thin film flow boiling clearly indicates significant improvement in initial heat flux (IHF) and critical heat flux (CHF) in comparison with low mass flux jet and spray coolings. Comparative study also ensures that better enhancement and uniformity in cooling are achieved in the current case in comparison with low mass flux spray and jet coolings. Furthermore, the calculation indicates very low coolant consumption characteristic in comparison with the others. The abovementioned parameters (CHF and IHF) alter due to the change in surface tension, viscosity, specific heat and thermal conductivity of the coolant and therefore, the role of above-mentioned coolant properties in case of thin film boiling is monitored. For this,various additives such as Sodium Dodecyl Sulphate (SDS), Polyethylene Glycol (PEG), Polyoxyethylene 20 Sorbitan Monolaurate (Tween 20) and Ethanol were used. In the present work, the analysis discloses that for the better Nusselt number the optimum Reynolds number is 1953 and Ohensorge number and Prandtl number are 0.0032 and 5.85, respectively.

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