期刊名称：International Journal of Innovative Research in Science, Engineering and Technology
印刷版ISSN：2347-6710
电子版ISSN：2319-8753
出版年度：2017
卷号：6
期号：10
页码：19711
DOI：10.15680/IJIRSET.2017.0610082
出版社：S&S Publications
摘要：The use of an artificial roughness on a surface is an effective technique to enhance the rate of heattransfer to fluid flow in the duct of a solar air heater. This paper presents a comparison of thermo-hydraulicperformance of solar air heaters having different types of geometry of roughness elements (continuous ribs) on theabsorber plate. Analysis shows that solar energy can be efficiently used for process heating in industries, dryingagriculture products etc. The poor thermal efficiency of solar air heaters is generally due to the low heat transfercoefficient between absorber plate and fluid flowing through the duct. The low heat transfer coefficient is due toexistence of thin boundary layer known as the viscous sub-layer which cause to make the insulate situation betweenheated surface and heat convicting fluid. In the last few years, there has been a growing interest in use of roughnessunderside the absorber plate which is a very effective method for improving the heat transfer coefficient. Inparticularly, using the roughness causes to break the viscous sub-layer which results into the high thermal performanceof the solar air heaters. However, the major drawback of this approach is accompanied by higher friction factor thatcauses excessive pumping power for propelling the forced air through the duct. In view a designer needs to carefullyexamine shape and orientation of roughness elements in order to choose the best fit roughness geometry for intendedapplication. Different roughness geometries have been compared on the basis of heat transfer enrichment and thermohydraulicperformance to draw attention towards their usefulness. Thus there is scope of further enhancement ofthermo-hydraulic performance.
