Forced convective heat transfer in a straight pipe rotating around a parallel axis

Abstract

Turbulent heat transfer in a pipe rotating around a parallel axis with large angular velocity is studied theoretically by assuming an effective secondary flow due to density difference in a centrifugal field. Flow and temperature fields, fully developed under the condition of constant wall temperature gradient, are analyzed by dividing them into a flow core region and a thin boundary layer along the wall. The analysis consists of two parts in this paper. One is common to different secondary flow problems, and the other in which the body force terms appear explicitly is particular for the present problem. The formulae for the resistance coefficient λ and the Nusselt number Nu are obtained in terms of Re and Δ ( Re = Reynolds number, Δ = inertia force/ body force). It is shown that the increases in the values of λ and Nu due to secondary flow can be expressed in terms of the parameter Re/Γ m 2 (m = 1 for laminar flow, m = 4 or 5 for turbulent flow) which is found to be a general parameter for various secondary flow problems. The effect of Cariolis force due to secondary flow is shown to be negligibly small.