In this paper, the influence of temperature-dependent thermo-physical properties is investigated on the decay of swirl in a laminar swirling flow of liquid through a heated microtube. The conservation equations for mass, momentum, and energy are numerically solved to obtain the velocity and temperature fields. The decay of swirl is quantified by the variation of the ratio of swirl number at a section to that at the inlet (S/S0) along the flow. The results reveal that constant property simulations result in faster swirl decay as compared to the variable-property simulations. Further, the implications of slip length, inlet swirl number, inlet swirl velocity profile, and Reynolds number on the swirl decay are presented. The results of the present analysis bear significant technological consequences in the design of micro-heat exchangers with intrinsic rotationalities.
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