报告内容摘要

Application of heat exchangers is common to almost every industry. In power generation plants, the production of high grade energy strongly depends on the performance of heat exchangers while in food, process and oil industries where high grade energy is consumed for heating/cooling purposes, operating cost of the plant is critically influenced by  the performance of heat exchangers. Hence it is possible to reduce energy consumption through innovative design of heat exchangers.  Thermal science and engineering community faces the challenge of energy crisis and the problem can be mitigated to a large extent by saving energy through heat transfer enhancement techniques. These techniques, classified as active, passive and compound, provide a powerful tool to improve the thermal performance of heat exchangers, including the reduction of its size and cost, and to save and conserve energy.

Passive techniques are more popular in industries, as no external power input for the enhancement of heat transfer is involved. These methods generally use surface or geometrical modifications to the flow channel by incorporating inserts or additional devices. Hence they offer low cost solution to improve heat exchange processes. Active techniques, on the other hand, consume some external power for the enhancement of heat transfer and hence they are confined to biomedical instruments, space and aviation applications etc where performance, not the operating cost is important. In recent times, compounding of two or more above mentioned techniques appears more promising from the energy conservation point of view.

The fact that all the above heat transfer techniques cause an increase of pressure loss across the exchanger, a qualitative comparison for enhanced heat transfer surface is important to evaluate the performance of the enhancement techniques. A great number of evaluation methods have been proposed but the evaluation approach based on the comparison between enhanced and original heat transfer surfaces for identical flow rate; identical pressure drop and identical pumping power are mostly used. In order to strengthen the assessment criteria, many factors like economic, manufacturability, reliability, and safety also need to be considered.

Performance of heat exchanger essentially affects the economy of a nation. Energy can be conserved by improving the performance of heat exchangers using heat transfer enhancement techniques.

报告人简介

Sujoy Kumar Saha is the professor in the Department of Mechanical Engineering at Indian Institute of Engineering Science and Technology (IIEST), Shibpur. He obtained his Ph.D. degree from Indian Institute of Technology, Bombay. His research areas include thermal Engineering, heat power and heat transfer enhancement.