Heat transfer and friction factor characteristics of pipe-in-pipe heat exchanger fitted with varient plain tape insert

摘要

The heat exchanger is used to transfer heat between the fluids without mixing them for both cooling and heating processes. Normally the fluids are separated by a solid wall or tube that is made of different materials in order to avoid mixing. The performance of a heat exchanger is predicted on the basis of heat transfer rate. Many new techniques are being explored by industries to improve the heat transfer rate of heat exchangers. In this work, a double tube heat exchanger is used for studying the variation in heat exchange by inserting a flat tape with different geometries: plain tape, plain tape step cut arc, and plain tape step cut rectangle. Experiments are carried out by varying pressure of hot water and the evaluation is done for different mass-flow rates with inlet temperatures of hot and cold water at 53°C and 30°C, respectively, under counter-flow arrangements. The experimental results revealed that the plain tape inserts in counter-flow arrangements enhance heat transfer rate substantially thereby increasing the effectiveness of the system for a marginal increase in pressure drop.