JFET_V6_N3_RP2 V.N. Mawal A.K. Goswami S.N. Jain K.L. Wasewar Journal on Future Engineering and Technology 2230 – 7184 6 3 35 40 Helical Coils, Natural Convection, Heat Transfer Coefficient Tube coils afford one of the cheapest means of obtaining heat transfer surface. Helical coils are frequently installed in vertical cylindrical vessel with or without an agitator, although free space is provided between the coil and vessel wall for circulation. Heating of viscous liquids and suspensions of particulate matter are important considerations in several industrial equipment including reactors. Several studies with mixing of suspension and with circulating coolant in a coil are available in literature. In this study, the overall heat transfer coefficients with natural convection between the coil surface and the liquid bath were investigated. The behaviour of overall heat transfer coefficient and coolant side heat transfer coefficients were observed for water (Newtonian), 3% soap and 1.5% starch solution (non-Newtonian) as hot bath liquids in the cylindrical vessel of a known dimension. Water as a coolant was supplied through helical coil immersed in the hot bath for batch cooling. February - April 2011 Copyright © 2011 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=1411