Effect of rib roughness pitch on thermal and thermo-hydraulic performance of a solar air heater roughened artificially with arc rib having gap
Article Main
Abstract
This experimental study on a solar air heater having absorber plate roughened artificially by providing roughness in the form of arc ribs having gap was carried out in the Department of Mechanical Engineering, Punjab Agricultural University, Ludhiana, India to study the effect of relative roughness pitch on thermal and thermohydraulic performance as well as to compare the performance of arc rib with gap roughened solar air heater with that of continuous arc rib roughened solar air heater. The roughness geometry parameters included relative roughness height of 0.043, angle of attack of 30 degree, relative gap position of 0.80, gap-width equal to the width of the rib and five values of relative roughness pitch ranging from 4 to 12 for flow Reynolds number range of 2000 to 16,000. The Nusselt number and friction factor were found to be more for relative roughness pitch value of 10 as compared to other values of relative roughness pitch. Thermo-hydraulic performance of solar air heaters roughened by arc with gap and continuous arc roughness geometries were found to be 1.91 times and 1.78 times respectively as compared to that of solar air heater having smooth absorber plate due to generation of turbulence in laminar sublayer region. However, improvement in thermo-hydraulic performance of solar air heater roughened by arc with gap geometry over continuous arc rib roughened solar air heater was attributed to generation of a region of turbulence on downstream side of the gap.
Article Details
Article Details
Artificial roughness, Reynolds number, Solar air heater, Thermal performance, Thermohydraulic performance
Akpinar, E.K. and Koçyig, ?it F. (2010). Energy and exergy analysis of a new flat-plate solar air heater having different obstacles on absorber plates. Appl. Energy. 87: 3438–3450.
Alta, D., Bilgili, E., Ertekin, C. and Yaldiz, O. (2010). Experimental investigation of three different solar air heaters: energy and exergy analyses. Appl. Energy. 87: 2953–2973.
ASHRAE, Standard 93–97, 1977. Method of Testing to determine the thermal performance of solar air heater, American Society for Heating, Refrigeration and Air Conditioning Engineering, NY: 1-34.
Bhushan, B. and Singh, R. (2010). A review on methodology of artificial roughness used in duct of solar air heaters. Energy. 35: 202-212.
Cho, H.H., Kim, Y.Y., Rhee, D.H., Lee, S.Y., Wu S.J. and Choi, C. (2003). The effect of gap position in discrete ribs on local heat mass transfer in a square duct. J. of Enhanc. Heat Transf. 10 (3): 287-300.
Duffie, J.A. and Beckman, W.A. (2006). Solar engineering of thermal processes. John Wiley and Sons, New York.
Eckert, E.R.G. and Webb, R.L. (1972). Application of rough surfaces to heat exchanger design. Int. J. Heat and Mass Transfer. 15: 1647-1658.
El-Sebaii, A.A., Aboul-Enein, S., Ramadan, M.R.I., Shalaby, S.M. and Moharram, B.M. (2011). Thermal performance investigation of double pass-finned plate solar air heater. Appl. Energy. 88: 1727–1239.
Gill, R. S., Singh, S and Singh, P.P. (2012). Low cost solar air heater. Energy Conversion and Management. 57(5): 131–142.
Gupta, D., Solanki, S.C. and Saini, J.S. (1993) Heat and fluid flow in rectangular solar air heater ducts having transverse rib roughness on absorber plates. Solar Energy. 51(1): 31–37
Han, J.C. and Park, J.S. (1988). Developing heat transfer in rectangular channels with rib turbulators. Int. J. Heat and Mass Transfer, 31, 183-195.
Han, J.C., Glicksman, L.R. and Rohsenow, W.M. (1978). An investigation of heat transfer and friction for rib-roughened surfaces. Int. J. Heat and Mass Transfer. 21, 1143-1156.
Hans, V.S., Saini, R.P. and Saini, J.S. (2010). Heat transfer and friction correlations for a solar air heater duct roughened artificially with multiple v-ribs. Solar Energy. 84: 898-911.
Ho, C.D., Yeh, H.M., Cheng, T.W., Chen, T.C. and Wang, R.C. (2009). The influences of recycle on performance of baffled double-pass flat-plate solar air heaters with internal fins attached. Appl. Energy. 86: 1470–1478.
Kline, S.J. and McClintock, F.A. (1953). Describing uncertainties in Single-Sample Experiments. Mechanical Engineering. 75: 3-8.
Kumar, Anil, Saini, R.P. and Saini, J.S. (2012) Experimental investigation on heat transfer and fluid flow characteristics of air flow in a rectangular duct with Multi v-shaped rib with gap roughness on the heated plate. Solar Energy. 86: 1733–1749.
Momin, A.M.E, Saini, J.S. and Solanki, S.C. (2002). Heat transfer and friction in solar air heater duct with V-shaped rib roughness on absorber plate. Int. J. Heat and Mass Transfer 45: 3383-3396.
Omojaro, A.P. and Aldabbagh, L.B.Y. (2010). Experimental performance of single and double pass solar air heater with fins and steel wire mesh as absorber. Appl. Energy. 87: 3759–3765.
Park, J.S., Han, J.C., Huang, Y., Ou, S. and Boyle, R.J. (1992). Heat transfer performance comparisons of five different rectangular channels with parallel angled ribs. Int. J. Heat and Mass Transfer. 35(11): 2891-2903.
Siddhartha, Varun (2010). Thermal performance optimization of a flat plate solar air heater using genetic algorithm. Appl. Energy. 87:1793–1799.
Singh, S., Chander, S. and Saini, J.S. (2011). Heat transfer and friction correlation of a solar air heater ducts artificially roughened with discrete v-down ribs, Energy. 36: 5063-5064.
Singh, S., Singh, B., Hans, V.S.and Gill, R.S. (2015). CFD (computational fluid dynamics) investigation on Nusselt number and friction factor of solar air heater duct roughened with non-uniform cross-section transverse rib. Energy. 84: 509-517.
Wazed, M.A., Nukman, Y., Islam, M.T. (2010) Design and fabrication of a cost effective solar air heater for Bangladesh. Appl. Energy. 87: 3030–2036.
This work is licensed under Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) © Author (s)