Turbulent Convective Heat Research Articles

Turbulent convective heat and mass transfer from accelerating particles

AbstractThe rate of evaporation of acetone from single particles accelerating freely in a downward concurrent turbulent air stream was studied over a range of air velocities from 40 to 70 ft./sec. and at a constant air temperature of 410°F. The particles consisted of celite in the shape of spheres, cubes, disks and cylinders, varying in size from 0.15 to 0.40 in. Accurate particle velocity data were obtained with a new radioactive tracer technique, and high‐speed photography at two positions along the column permitted measurement of the rate of rotation and showed that the particles rotated in a random manner.Adequate prediction of the observed heat and mass transfer data could be obtained from the integration of a rate eequation previously reported for stationary particles. The concept of a new characteristic dimension, developed for the latter case, was found to be applicable to randomly rotating shapes and to account satisfactorily for the behaviour of nonspherical particles.

Analysis of the Aerodynamic Heating for a Re-Entrant Space Vehicle

An analysis of the aerodynamic heating is presented through the trajectory and over the surface of a re-entrant hypersonic space vehicle. Bodies exhibiting zero and high lift over drag ratios are considered. The turbulent and laminar convective heat inputs are specified as functions of the trajectory and space vehicle parameters. The maximum heating rates and time integrated heat fluxes are given as functions of the local pressure distribution, body geometry, and wall temperature. Examples are presented to illustrate the application of this analysis.