Local enhancement of heat transfer in a particulate cross flow—II Experimental data and predicted trends

Abstract

Results from an experimental investigation of the effect of solid particles on heat transfer at the first row of a staggered tube array in cross flow are compared with those determined for equivalent conditions from correlations derived previously by the author. Comparison of the experimental data with the predicted levels of heat transfer enhancement from a range of heat transfer mechanisms suggests that the transport of thermal energy by rebounding particles is responsible for much of the measured increase in heat transfer. The total enhancement based on this model of the suspension flow compares well with the experimental data for particles of 46 and 58 μ m dia, although the agreement is not as good for 127 μm dia particles. The fine particle model of suspension flow gives levels of enhancement of the correct order for some flow conditions but fails to predict the effect of Reynolds number and particle size. In the light of these results, the suspension heat transfer mechanisms for tubes in cross flow are re-assessed and the dominant effects on enhancement are identified for specific flow conditions.