The shell and tube heat exchanger among a variety of heat exchangers is widely used in many industrial applications for its advantages of long lifetime, simplicity of manufacture and wide operation range. In multi-channel systems including the shell and tube heat exchanger, flow distribution significantly affects their performance and lifetime. When a heat exchanger is designed, flow distribution is usually assumed to be uniform, but flow maldistribution may be an inevitable occurrence in practice. In particular, flow distribution in the tube-side of a single-pass shell-and-tube heat exchanger (SSTHX) with axial connections of bonnet nozzles is extremely non-uniform.
Generally, flow uniformity in multi-channel systems like heat exchangers has been realized in a limited flow regime (e.g. laminar flow or turbulent flow).
Pak Sin Myong, a section head at the Faculty of Heat Engineering, has proposed an innovative header baffle to effectively uniformalize flow distribution in the tube-side of a single-pass shell-and-tube heat exchanger (SSTHX) with axial connections of bonnet nozzles, even within the extensive range of Reynolds number.
He simulated the flow in the SSTHX using the commercial CFD code-ANSYS Fluent, and modeled the tube bundles as a porous medium. In the new structure of SSTHX, flow distribution was uniformalized ideally from extreme laminar regime to strong turbulent regime (Reynolds number of 40-80 000) although pressure loss was significantly increased (about 35%).
The effects of structural and thermo-hydraulic factors on flow uniformity were very small.