Thermo-hydraulic performance of turbulent flow through ribbed air channel (experimental study).

An experimental investigation of thermo-hydraulic performance for a square cross-section air channel with dimensions of (15cm×15cm) and a length of (1.3 m) is considered in the present work. The experimental rig is fabricated from steel (ASM4120) with rectangular periodic eight ribs with dimensions of (3.75 cm ×7.5cm) along the lower wall of the air channel and its exhibition to constant heat flux (1500 and 3000) W/m2. The range of the Reynold numbers is varied by (6000,8000,1000 and 12000). All results are compared with the smooth channel model, the results showed that the best heat transfers are noted in the case of (Re = 8000 and q" = 3000 W/m2) where the Nusselt is enhanced by 7 % when using the ribbed lower surface of the air channel. Also, the maximum value of the friction factor occurs in the case of a ribbed duct at the condition of (Re = 6000 and 3000 W/m2) where the friction factor is increased by 19 %. Finally, the thermo-hydraulic performance factor was about 1.11 and which indicates the enhancement that occurred by adding the ribs for the smooth channel. [ABSTRACT FROM AUTHOR]