DETERMINATION of CONVECTIVE HEAT TRANSFER COEFFICIENT BETWEEN FLUID and CUBIC PARTICLES IN CONTINUOUS TUBE FLOW USING NONINVASIVE EXPERIMENTAL TECHNIQUES1

Convective heat transfer coefficients (hfp) between fluids and cubic particles in continuous flow were investigated with respect to flow rate, viscosity, particle size, and radial location using noninvasive methods: (1) liquid crystal color change, and (2) measurements of relative velocity via flow visualization (for verification of liquid crystal results). All tests were conducted using sodium carboxymethyl cellulose (CMC) as the carrier fluid. Results indicate that hfp increases with decreasing particle size, increasing flow rates and (as expected) decreasing viscosity. Radial location affects hfp values: changing the particle position from the center to the bottom of the tube increases the convective heat transfer coefficient. Comparison between the methods indicates good agreement, providing a means of verification for the liquid crystal method.