Please use this identifier to cite or link to this item: http://idr.iitp.ac.in/jspui/handle/123456789/529
Title: Thermo-Hydraulic Performance of Solar Air Heater with Absorber Plate having Novel Hyperbolic Ribs
Authors: Thakur, D. S.
Keywords: Mechanical Engineering
Issue Date: 2016
Series/Report no.: DI-96;
Abstract: The intent of the present work is to evaluate the thermo-hydraulic performance of artificially roughened solar air heater. In fact, solar air heater ducts with rib geometries such as rectangular, triangular, semi-circular and hyperbolic have been numerically investigated. A 2D CFD simulation using ANSYS FLUENT has been performed for all geometries. Simulations are run for the turbulent flow of air through each type of roughened duct with Re varied from 4000 to 15000, rib height from 0.5 mm to 2.0 mm and pitch from 10 mm to 20 mm. The use of ribs causes laminar sublayer to break, which in turn promotes intense mixing of different fluid layers. Consequently, there is an increase in heat transfer rate. Nevertheless, in the process frictional pressure drop is also increased. The validation of the code is done for smooth duct using (a) Blasius correlation for frictional pressure drop and (b) Dittus-Boelter Nusselt number correlation for convective heat transfer. In addition, Chaube et al. [6] and Yadav and Bhagoria et al. [32] numerical data have been used for the validation of the present code for roughened duct. In this report, a parametric study of novel rib geometries i.e. hyperbolic rib with parabolic tip, hyperbolic rib with a flat tip and parabolic rib has been presented. The range of relative roughness e/Dh is 0.03 – 0.06, pitch to rib height ratio p/e is 10 – 20 and Reynolds number Re is 4000 – 15000. It has been found that the hyperbolic ribs give the best thermo-hydraulic performance, which is 2.173 at Re = 6000. Experimental investigation of optimum geometry has been performed for Nusselt number. The experimental results for smooth duct are compared with Dittus-Boelter Nusselt number correlation for convective heat transfer. 3D simulation of optimum novel geometry has been carried out for different rib inclination angle and configuration (V-shaped and W-shaped). 3D simulation results are validated with experimental results obtained and found to be in good agreement. The range of rib inclination angle is 30º - 90º and Reynolds number Re is 4000 – 15000. It has been found that the hyperbolic ribs with V-shaped configuration give the best thermo-hydraulic performance, which is 2.30 at Re = 6000 and rib inclination angle = 60º.
URI: http://idr.iitp.ac.in:8080/jspui/handle/123456789/529
Appears in Collections:02. ME



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