Experimental Investigation and Heat Transfer Process in Concentric Tubes Fitted with Extended Surfaces

Abstract

In the present age of industrialization, heat exchangers play a major role in energy newlineexhaustion which is been used extensively in mechanical and chemical industries. A newlinedouble-pipe heat exchanger (DPHE) is the most versatile equipment which is used to newlinetransfer energy between hot and cold fluids. Because of their simple construction and ease newlineof maintenance, these are widely used in industrial applications like chemical, food newlineprocessing, and power plants, etc., further improving the performance of existing heat newlineexchangers to meet the increasing demand in heat transfer can be achieved by using heat newlinetransfer augmentation approaches (Passive and Active methods). The use of extended newlinesurfaces is found to be the most effective heat transfer enhancement technique than other newlinepassive methods. Increased surface area and more fluid interaction with the extended newlinesurfaces will enhance the exchange of heat between hot and cold fluids. newlineThis research work proposes experiments on increasing the heat transfer newlineperformance by considering various enhancement parameters like heat transfer newlinecoefficient in the form of Nusselt No., overall heat transfer coefficient (U), friction newlinefactor(f), Pressure drop and#8710;and#119875;, n effectiveness(and#951;), efficiency(and#603;), Pumping power(P) and newlineThermo-hydraulic performance index(THPI) in the double-pipe heat exchanger(DPHE) newlineby introducing helical fins of the varying pitch of 25,50,75 and 100 mm with increasing newlinein fin height of 6,8 and 10 mm along the length of 1500 mm pipe. It uses the water as newlineboth hot and cold fluid, hot water flows inside the inner pipe and cold water is allowed newlinethrough the annulus side of DPHE. The experiment is conducted by varying the mass flow newlineof cold fluids in terms of Reynolds number ranging from 2500 to 9500 at an interval of newline1000, by keeping the flow rate of hot water constant throughout the analysis for both newlinehelical finned and plain DPHE. The usage of helical fins in the flow path of cold liquid newlinereduces the flow passage area and creates turbulence which results in enhanced h