Multi-physics Modeling of Technological Systems

8Heat Power Transmission

Summary

This chapter focuses on modeling systems for heat power transfer by fluid media and particularly on heat exchangers. The models presented here have various degrees of complexity, but all of them can be used within a system approach. The usage of these models is illustrated on an example of estimation of automotive radiator performances.

Learning outcomes

On completing this chapter, the reader is expected to be able to:

• – Model the heat power transfer in a heat exchanger using either constant or variable effectiveness;
• – Find the expression of effectiveness as a function of the configuration of the heat exchanger and of its operating parameters;
• – Calculate the heat transfer coefficient of a heat exchanger with or without fins. Calculate the pressure drop in a heat exchanger.

8.1. Heat exchangers

Many applications used in daily life and in various industrial processes involve heat power transfer between two fluids, without mixing them. Heat exchangers are the technical devices that accomplish this task. In some fields of application this equipment is used on a regular basis:

• – Air conditioning used in buildings and means of transport for air heating, cooling and dehumidification;
• – Automotive field for cooling the engine, oil, charge air, exhaust gas recirculation (EGR) or the batteries and the motor in electrical and hybrid vehicles;
• – Thermal power plants for vapor generation and condensation or for cooling the water in condensers; ...