Effect of Bottom Wall Heating on the Turbulent Fluid Flow in an Asymmetric Rectangular Diffuser: an Experimental Study

Turbulent fluid flow and heat transfer in an asymmetric diffuser are important in the context of the power plant engineering such as gas turbine, aircraft propulsion systems, hydraulic turbine equipment etc. In the present study, an experimental investigation on the forced convective heat transfer considering turbulent air flow in an asymmetric rectangular diffuser duct has been done. The experimental setup considered for the analysis consists of a diffuser at different bottom wall temperatures and inlet conditions. The air enters into the diffuser at a room temperature and flows steadily under turbulent conditions undergoing thermal boundary layer development within the diffuser. Efforts have been focused to determine the effects of bottom wall heating on the recirculation bubble strength, thermal boundary layer, velocity fields, temperature profiles etc. The distribution of the local average Nusselt number and skin friction factor in the whole flow fields have been critically examined to identify the significance of bottom wall heating effects on the overall heat transfer rates.