Author(s)

C.J. Bolinder & B. Sunden

Abstract

Laminar flow forced convective heat transfer in a helical square duct with a finite pitch C.J. Bolinder & B. Sunden Division of Heat Transfer, Lund Institute of Technology, Box 118, 221 00 Lund, Sweden ABSTRACT The effect of a finite pitch or torsion on the temperature field and the Nusselt number for laminar flow in a helical square duct is presented. Fully developed conditions are assumed. As thermal boundary condition is used constant axial wall heat flux with constant peripheral wall temperature. For ducts of small and moderate pitch, the flow and heat transfer characteristics are found to be very similar to those for a toroidal duct with the same dimensionless curvature £. INTRODUCTION Curved ducts frequently appear in heat transfer applications, and are often advantageous. The mean heat transfer rate for laminar flow is increased com- pared to straight ducts. This is due to the so-called secondary flow, which is set up in the curved duct. By applying curv

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