Heat exchange of a gas-suspension flow under conditions of inertial particle precipitation at a duct wall

Results are reported for an experimental study of local heat exchange between a hot-air flow containing a suspension of aluminum oxide particles and nozzle walls in the subsonic region as well as the walls of a short curved duct under conditions of flow cooling with different power contents. The experimental conditions included nozzle entrance pressures of 2.8 to 3.7 bar, nozzle flow temperatures of 530 to 570 K, nozzle Reynolds numbers of 100,000 to 110,000, a duct entrance pressure of 1 bar, duct flow temperatures of 440 to 520 K, and expended particle concentrations of 0 to 0.5. Heat-transfer coefficients are measured for both the two-phase flow and the pure gas. It is found that heat exchange in the nozzle is intensified in the region where particles are inertially precipitated at the walls and that the presence of solid particles in the duct flow leads to a substantial increase in heat-exchange intensity at the concave duct wall.