Investigation of thermo hydraulic performance of various ribs mounted in a duct

Abstract

The present research focuses on investigation of the Thermo Hydraulic Performance (THP) of Solar Air Heater (SAH) by implementing artificial rough surfaces in the absorber plate. The study was conducted in numerical and experimental approaches to ascertain the enhancement in convective heat transfer rate and it was compared with smooth surface. Besides, Phase Change Material (PCM) was integrated with solar air heater as a latent heat storage system to increase heat discharge duration during OFF radiation. After an extensive literature review it is inferred that the sharp edge and tip angle are playing significant role in the selection of rib geometries. In that basis, the polygonal transfer rib, forward trapezoidal rib and backward trapezoidal rib has proposed for the investigation. The characterization of heat transfer rate and pressure drop were analyzed for proposed rough surfaces by varying relative pitch distances and relative roughness height. newlineIn first part of the thesis, numerical analysis was performed using ANSYS Fluent version - 13.0 to simulate fluid flow and heat transfer for proposed rough surface to investigate the average Nusselt number, friction factor and thermo hydraulic performances. For the proposed ribbed surfaces, the relative pitch distance (p/e) varied from 3.33 to 20 and relative roughness height (e/D) is varied from 0.03 to 0.09. The velocity of the working fluid is assumed to be in Reynolds number ranging from 3800 to18000 and Renormalization k-and#1013; turbulent model was selected for the investigation. The empirical correlations, Dittus Boelter (1942) and Blasius equation were used to validate the Nusselt number and friction factor for smooth surface to ascertain augmentation of heat transfer. The research gave the result that polygonal ribbed absorber plate at relative pitch distance p/e = 3.33 yields higher Nusselt number and lower friction factor at Reynolds number equals to 18000. newline