Heat transfer and second law analysis of turbulent flow mixed convection condensation inside a vertical channel

Abstract

Abstract Study of condensation is important for effective energy management of many thermal systems like power plant, chemical processing unit, refrigerator, air-conditioner, cold storage unit, desalination and solar stills unit etc. Condensation of air-water vapour system for turbulent flow mixed convective condition is thoroughly analysed here. Pletcher s mixing length model is used to determine turbulent viscosity, thermal conductivity and mass diffusivity. Heat and mass transfer as well as entropy generation analysis of turbulent flow condensation is extensively investigated. Higher Reynolds number condition increases both the overall thermal and condensing Nusselt number. Relative humidity does not significantly influence overall thermal Nusselt number, but it certainly does influence overall condensing Nusselt number. Increased inlet pressure increases overall thermal Nusselt number, whereas it reduces overall condensing Nusselt number. Overall thermal transport entropy generation as well as overall mass transport entropy generation show enhancement with Reynolds number and relative humidity. Both the overall entropy generation reduces with higher inlet pressure condition. Second law efficiency enhances with Reynolds number, but deceases with relative humidity. Higher inlet pressure enhances second law efficiency. Finally correlations of pressure drop, induced velocity, overall Nusselt numbers and overall entropy generations for turbulent flow condensation are reported.