Issues Concerning the Rate of Heat Transfer from a Spinline

Abstract

Abstract Two-dimensional convective heat transfer in a non-isothermal spinline is analyzed. A rigorous derivation of the macroscopic, one-dimensional energy balance describing the cooling of a spinline leads to an equation that differs subtly from the commonly used one-dimensional equation; this difference has practical implications for the correct computation of convective heat transfer coefficients from experimental data obtained from spinlines exhibiting significant radial temperature gradients and, in turn, for the prediction of correct spinline temperature profiles. The errors involved are illustrated with computed results and a method is proposed for the determination of the correct heat transfer coefficients in the presence of radial temperature gradients. Further, it is shown that the radial convective heat flux resulting from the inward radial velocity of an attenuating spinline is important and its omission can lead to significant errors in the computed temperature.