A resistance wire technique applied to heat transfer measurements in high aspect ratio fluidized beds

The purpose of this investigation is to determine convection coefficients in high aspect ratio fluidized beds. High aspect beds, which have recently been used to improve load turndown in fluidized bed combustors, are under consideration for immersion cooling of electronic equipment. Bed-to-wall convection coefficients are obtained by using a heated-wire technique. Resistance wire is wound around the wall and the wall is immersed in a fluidized bed. Convection coefficients are determined by plotting power dissipated in the bed versus the temperature of the resistance wire. Two systematic errors are inherent to this heated-wire technique: temperature gradients between wires and heat conducted by using a finite-difference numerical model of the wire-wrapped surface. The purpose of this paper is to demonstrate how we can correct these systematic errors while retaining the usefulness of the technique for heat transfer measurements in fluidized beds