Numerical heat transfer analysis in a two-phase microorganism malodor removing system with the effect of internal structures

Malodorous emissions from industrial and household sewage systems cause harmful effects on nearby human populations and the environment. Eco-friendly malodor removing systems utilize bacteria to control unpleasant odors from sewage systems. Heat transfer is a vital factor in industrial system designs because microorganisms require an optimum water temperature to function efficiently. A numerical study was conducted to estimate the heat transfer rate in the water basin of a malodor removing system. Flow-deflecting baffles were utilized to reduce heat loss in the basin. Heat transfer was reduced by installing a rotating drum to increase gas dissolution by an improved liquid circulation. The average and local heat transfer coefficients, Nusselt number, and temperature distribution were evaluated to estimate heat loss in the water basin. This study proposes an empirical relation to generalize the numerical results for calculating heat transfer rates. Results showed that using baffles and rotating drum reduced heat transfer in the basin. Furthermore, the heat transfer coefficient was increased by raising the superficial gas velocity and bubble size.