KEYNOTE SPEAKER

Constructal Size of Heat Exchangers

Prof. Josua Meyer
University of Pretoria, South Africa

Abstract

A lot of work has been done on predicting the heat transfer and pressure drop characteristics of different types of heat exchangers. Usually the heat transfer coefficient coefficients and friction factors are obtained from empirical equations and/or graphs after which simulations are conducted to determine an optimum on different geometry sizes and different types of heat exchangers. Furthermore, different types of methods have been developed such as the LMTD, effectiveness-NTU, effectiveness–thermal resistance, etc., which can also be used and/or can be incorporates into heat exchanger simulations. The fundamental question is still what the size and geometrical features of a heat exchanger should be given the required heat transfer rate and operating conditions. It is the purpose of this paper to address this question by considering the trade-off between three elements; pumping power, the entropy generation rate, the power loss associated with carrying the heat exchanger on the horizontal landscape at a specific speed. The trade-off was determined and is valid for a wide variety of heat exchangers from boats to aerospace that moves at different velocities. The results are presented for single- and multi-channel heat exchangers. It has been found that each application has an optimum heat flux; the specified mass flow rate determines the cross-sectional area of heat exchangers and the heat transfer rate the longitudinal length. These results are fundamental results and will make a significant contribution in future to the design of heat exchangers.

Biography of the Keynote Speaker

Prof Josua P Meyer obtained his B.Eng. (cum laude) 1984, MEng. (Cum laude) 1986, and his Ph.D. (1988) all in Mechanical Engineering from the University of Pretoria. He is registered as a Professional Engineer and he completed his military service at the Faculty of Military Science, University of Stellenbosch where he lectured aerodynamics for pilots in the South African Air Force. After his two years of military service (1988 – 1989), he accepted a position as Associate Professor in the Department of Mechanical Engineering at North-West University in 1990. He was Acting Head and Professor in Mechanical Engineering before accepting a position as professor in the Department of Mechanical and Manufacturing Engineering at the University of Johannesburg in 1994. He was the Chairperson of Mechanical Engineering from 1999 until the end of June 2002 after which he was appointed as Professor and Head of the Department of Mechanical and Aeronautical Engineering of the University of Pretoria from 1 July 2002. He is Chairperson of the School of Engineering since 1 January 2004. He is currently the Head of the Department of Mechanical and Aeronautical Engineering. He teaches and conducts research in heat transfer, fluid mechanics and thermodynamics.