Main Article Content
Periodic laminar flow and heat transfer characteristics in a three–dimensional (3D) isothermal square channel walls with 45° U-shaped rib turbulators, URT, were investigated numerically. The computations are based on the finite volume method (FVM), and the SIMPLE algorithm has been implemented. The fluid flow and heat transfer characteristics are shown for Reynolds numbers based on the hydraulic diameter of the square channel, Re = 100 to 1000. To generate main longitudinal vortices flows through the tested section, URT with an attack angle of 45° are inserted in the tested square channel. Effects of different blockage ratio (b/H, BR) with a single pitch ratio (P/H, PR) of 1 on heat transfer and pressure loss in the channel are studied. It is apparent that in each of the main vortex flows, longitudinal twisted vortex flows can induce impinging flows on a wall of the interbaffle cavity leading to a drastic increase in heat transfer rate over the channel. In addition, the rise in the URT height results in the increase in the Nusselt number and friction factor values. The flow structures with common–flow–down are appeared by using URT. The computational results show that the optimum thermal enhancement factor is around 2.5 at BR = 0.25 and, Re = 1000.
Copyright @2021 Engineering Transactions
Faculty of Engineering and Technology
Mahanakorn University of Technology
P. Promvonge, W. Jedsadaratanachai, S. Kwankaomeng and C. Thianpong, 3D simulation of laminar flow and heat transfer in V–baffled square channel, Int. Commun. Heat Mass Transfer 39 (2012) 85–93.
P. Promvonge, W. Jedsadaratanachai and S. Kwankaomeng, Numerical study of laminar flow and heat transfer in square channel with 30o inline angled baffle turbulators, Applied Thermal Engineering 30 (2010) 1292–1303.
J.C. Han and Y.M. Zhang, High performance heat transfer ducts with parallel and V-shaped interrupted ribs, Int. J. Heat Mass Transfer 35 (2) (1992) 513-523.
M.E. Taslim, T. Li and D.M. Kercher, Experimental heat transfer and friction in channels roughened with angled, V-shaped, and discrete ribs on two opposite walls, Journal of Turbomachinery 8 (1) (1996) 20-28.
T. Giovanni, Heat transfer in rectangular channels with transverse and V-shaped interrupted ribs, Int. J. Heat Mass Transfer 47 (2004) 229-243.
E. Lee, L.M. Wright and J.C. Han, Heat transfer in rotating rectangular channels with V-shaped and angled ribs, Journal of Thermophysics and Heat Transfer 19 (1) (2005) 48-56.
W.L. Fu, L.M. Wright and J.C. Han, Heat transfer in two-pass rotating rectangular channels (AR = 2:1) with discrete ribs, Journal of Thermophysics and Heat Transfer 20 (3) (2006) 569-582.
W. Peng, P.X. Jiang , Y. P. Wang and B. Y. Wei, Experimental and numerical investigation of convection heat transfer in channels with different types of ribs, Applied Thermal Engineering, 31 (2011) 2702-2708.
K.B. Muluwork, Investigations on fluid flow and heat transfer in roughened absorber solar heaters, Ph.D. Dissertation; IIT, Roorkee (2000).
A.M.E. Momin, J.S. Saini and S.C. Solanki, Heat transfer and friction in solar air heater duct with V-shaped rib roughness on absorber plate, Int. J. Heat Mass Transfer 45(2002) 3383–3396.
S. W. Chang, T. L. Yang, T. M. Liou and G. F. Hong, Heat transfer of rotating rectangular duct with compound scaled roughness and V-ribs at high rotation numbers, International Journal of Thermal Sciences 48 (2009) 174–187.
S.W. Chang, T.M. Liou, K.F. Chiang, G.F. Hong, Heat transfer and pressure drop in rectangular channel with compound roughness of V-shaped ribs and deepened scales, International Journal of Heat and Mass Transfer, 51 (2008) 457–468.
R. Karwa and G. Chitoshiya, Performance study of solar air heater having v-down discrete ribs on absorber plate, Energy, 55 (2013) 939-955.
S. Singh, S. Chander and J.S. Saini, Investigations on thermo-hydraulic performance due to flow-attack-angle in V-down rib with gap in a rectangular duct of solar air heater, Applied Energy, 97 (2012) 907–912.
S.V. Patankar, C.H. Liu, E.M. Sparrow, Fully developed flow and heat transfer in ducts having streamwise-periodic variations of cross–sectional area, ASME J. Heat Transfer, 99 (1977) 180-186.
S.V. Patankar, Numerical heat transfer and fluid flow, McGraw-Hill, New York, 1980.
P.J. Roache, Verification and Validation in Computational Science and Engineering, Hermosa Publishers, Albuquerque, NM, 1998, ISBN 0913478083.
F. Incropera, P.D. Dewitt, Introduction to heat transfer, 5rd edition John Wiley & Sons Inc, 2006.