Document Type : Research Paper

Authors

1 department of mechanical engineering, university of technology, Baghdad, Iraq

2 mechanical engineering department, university of technology, Baghdad, Iraq

3 Mechanical Engineering Dept., University of Technology-Iraq, Alsina’a street,10066 Baghdad, Iraq.

Abstract

The printed circuit heat exchanger is one of the most recent important heat exchangers, especially in the nuclear power plant and aerospace applications, due to its very compact geometry and small print foot. This paper presents a 3D numerical investigation of the thermo-hydraulic performance of PCHE with a new non-uniform channel design configuration. The new channel design consists of two different fins and shape inserts: the diamond and biconvex shapes. The influence of two design parameters on the heat exchanger performance was studied and optimized, the longitudinal and transverse pitch length (Pl) and (Pt). Air with constant properties as the working fluid with constant heat flux at the walls envelope. The Reynolds number varied from 200 to 2000. Different Pitch lengths were used (Pl=20, 30, 40, and 50) mm and (Pt=3, 4, and 5) mm. Three performance parameters were studied the Nusselt number, friction factor, and the overall performance evaluation factor. Results show that the thermal performance enhanced with decreasing the pitch lengths, and it was shown that this enhancement was found only at high Reynolds numbers above 1400. The higher enhancement factor was with NACA 0020 airfoil fins at pt=3 mm and pl=20mm of η=2.75 at Re=2000, while the worst performance was obtained with biconvex fins. The main reason behind the enhancement is the disruption of the boundary layer and the good mixing induced in the fluid flow.

Graphical Abstract

Highlights

  • Numerical thermal and hydraulic analysis for a novel channel for mini channels printed circuit heat exchanger were done.
  • Fins inserts of two different shapes have employed the diamond and biconvex shape fins
  • The influence of two geometrical parameters was studied: the longitudinal and transverse pitch lengths.
  • The results show a good enhancement in heat transfer indicated by the Nusselt number, but a fall in hydraulic performance indicated by the friction factor
  • The overall performance factor criteria were employed to make the comparison with the straight rectangular channel depending on the same power input
  • The new channels show a very good enhancement depending on the criteria

Keywords

Main Subjects

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