Effect of addition of calming section on the Heat Transfer process in Semicircular Duct

Experimental study has been carried out to examine the heat transfer characteristics by combined free and forced convection for the fully developed laminar air flow in an inclined semicircular duct having a flat wall at the top. The ranges of Rayleigh number, Reynolds number, and Richardson number were 2.4×105 ≤ 𝑅𝑎 ≤ 3.9×105, 500 ≤ 𝑅𝑒 ≤ 2041, and 0.08≤ 𝑅𝑖 ≤2.5; respectively. The study covered different angles of inclination for both opposing and aiding flows. Empirical equations were deduced for the average Nusselt number as a function of Reynolds number and Rayleigh number for all angles of duct inclination. Results show that the average heat transfer process enhances with decreasing of Richardson number and increasing of Peclet number.