Abstract: - When any fluid flows through rectangular duct with heated object placed inside it, a respective pattern of flow carries heat through convection and radiation. Also the rate of heat transfer depends on the flow velocity, area of exposure and other parameters. Different profiled objects may give different rate of heat transfer. Hence the objects like pin fin with enhanced surface areas (Perforated) placed inside the duct, the heat transfer rate will be maximum. In this experimental paper, the study of different author’s research and their papers is carried out to understand the flow through the rectangular duct. Rate of heat transfer, mass flow rate, inside velocity, pressure and other associated parameters are studied and explained.Keywords: Optimum heat transfer, thermal analysis, geometry, Fluid Flow