Experimental studies have been carried out on isothermal pressure drop and convective heat transfer to servotherm medium grade oil in laminar flow in one smooth tube and seven wire coil-inserted tubes of varying wire diameter and pitch of wire coil. The performance of these wire coil inserted tubes has been evaluated by two different criteria based on the objective of either maximizing heat transfer rate or minimizing exchanger size. The results indicated that as much as fourfold improvement can be obtained in laminar flow heat transfer coefficient using these tubes.
The effect of liquid solidification at the inner surface of a circular tube upon laminar-flow heat transfer and pressure drop is investigated. Steady-state conditions and a uniform wall temperature, which is lower than the liquid freezing temperature, are assumed. Theoretical solutions for heat transfer, radius of the liquid-solid interface, and pressure drop are determined assuming negligible free convection. Experimentation shows that free convection may produce considerable deviations between theoretical and observed results. A semiempirical method for obtaining approximate solutions is developed. A numerical example which demonstrates how free convection affects the solid-phase shell profile is presented.
Closure to “Discussion of ‘The Effect of Liquid Solidification in a Tube Upon Laminar-Flow Heat Transfer and Pressure Drop’” (1968, ASME J. Heat Transfer, 90, p. 190)
