Publication

Abstract : The design, manufacturing and selection of ribs is tedious task. The different types of ribs are manufactured and used in various heat transfer enhancement applications. These ribs have different geometries and its application results in different amounts of heat transfer. A two-dimensional numerical analysis of the forced convective heat transfer of air with different rib thickness is performed. Rib thickness can affect the thermo-physical behaviour of the fluid flowing over the ribbed surface in addition to the types and orientation. Therefore, its effect on the thermal and flow structures is studied with ANSYS-Fluent. This numerical tool has been a proven method for varieties of flow problems and produces acceptable results without involving time consuming experimentations. The design variables in the form of relative roughness height (0.11), relative roughness pitch (6.67), Reynolds number (5000–24,000) under a constant heat flux of 1000 W/m2 is considered. The mass flow rate (𝑚)˙ 0.0893–0.429 kg/sec and rib thickness from 0.5 to 6 mm is considered. The results demonstrate that the thin ribs show better heat transfer characteristics, but also higher frictional losses. The maximum Nusselt and friction factor ratio obtained for the thin and square ribs are 2.30, 5.03 and 2.17, 4.2 respectively, which encourages its usage for various applications. The average thermohydraulic performance parameter of 1.069 for thin and 1.032 for thick rib is obtained.