A shell and tube heat exchanger among a variety of heat exchangers is still widely used in many industrial applications as it has several advantages like a long working life, simple manufacture and wide operation range.
In multi-channel systems like the shell and tube heat exchanger, flow distributions significantly affect their performance and lifetime. Uniform distribution is commonly assumed in designing conventional heat exchangers, but flow maldistribution may be an inevitable occurrence in practice. In particular, flow distribution in the tube-side of the SSTHX with axial connections of bonnet nozzles is extremely non-uniform.
Therefore, numerical and experimental studies on flow distributions of the shell and tube heat exchangers have been widely carried out.
In particular, many attempts have been made for flow uniformity in multi-channel systems by means of different geometry of headers or manifolds. Most studies tended to be focused on shell-side flows due to their complexity in shell and tube heat exchangers. What is difficult in numerical studies on heat exchangers is that their geometries with lots of channels cannot be modeled as it is. One way to solve it is to model tube bundles as porous media. The most important problem is to determine porous medium parameters accurately. In most references, they were obtained by empirical correlations.
Various baffles have been proposed to improve velocity distributions and heat transfers of heat exchangers.
However, few researchers have addressed the problems concerning the tube-side flow of the shell and tube heat exchanger.
It should be noted that most studies have been focused on limited regime like laminar flow or turbulent flow.
Pak Sin Myong, a researcher at the Faculty of Heat Engineering, has clarified that introduction of new header baffles makes it possible to uniformalize dramatically flow distribution in the tube-side of SSTHX. He has also modeled tube bundles as porous media as they have lots of tubes, and he has obtained porous media parameters through CFD simulation for one isolated channel.
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