EFFECT OF SEMI-CIRCLE RIB ON HEAT TRANSFER COEFFICIENT IN A RECTANGULAR CHANNEL

In this paper an experimental and numerical analysis has been conducted to study the effect of heat transfer and filed flow of two-phase flow (water and air) through a rectangular ribbed channel. The study has involved the several values of heat flux (120,140,160 Watts), air and water superficial velocity (1.096, 1.425, 1.644, 1.864, and 2.193 m/s) and (0.0421, 0.0842, and 0.1474 m/s), respectively. The distribution of temperature along the channel was photographed using thermal camera and compared with numerical results . The experimental test system was fabricated of vertical rectangular channel with cross section of (0.08m × 0.03m) and a length (0.7 m) to analyze the behavior of the mixture (water-air) over the heated plate (semi-circle ribs ). The computational fluid dynamics CFD software was utilized to simulate the governing equations with initial and boundary conditions. Results found that the ribbed channel give the high heat transfer rate compared to the smooth channel. The percentage deviation between the experimental and numerical data is (1.0% 6.0% ). The results proved that the flow is growing to become turbulent, eddies develop about the heated plate (rib), the temperature at the outlet decreases and heat transfer coefficient improved by adding ribs, it also improved when the velocities of the flow increased.