MEASUREMENT AND CALCULATION OF PROPERTIES OF GAS-SOLID TWO-PHASE JETS

An optical technique was developed to measure particle concentration profiles in a two-phase axisymmetric jet. The steady-state mean gas velocity profiles of the single-phase and two-phase jets were measured by a pitot tube. Particle size distribution across the jet was measured with isokinetic particle sampling probes. Schlieren photographs of shock waves in the jet were taken to study the influence of particles on shock wave structure near the exit of the nozzle. The steady-state mean gas phase temperature profiles of the single-phase and two-phase jets were measured by a thermocouple. The effect of the nozzle configurations (subsonic short, subsonic long, converging-diverging, and supersonic nozzles) on the two-phase jet flow was also studied. The measurements were made by seeding 1, 3 and 5% by weight of 1 and 83.6 (mu)m mean diameter alumina particles and 24 (mu)m mean diameter spherical fly ash particles into jets at Mach numbers of 0.2, 0.8, 1.0, and 1.17.; The particle concentration profiles showed that particles concentrate on the axis of the jet at the exit of the nozzle and the profiles and modified Schmidt numbers were influenced by the particle size, particle feeding rate, the velocity of the jet, and nozzle configuration. The particle size distribution was homogeneous in the jet. Schlieren pictures of shock waves in the jet showed that the normal shock wave front near the exit of a nozzle was convexly curved with the addition of a suspension of particles in the jet flow. Temperature profiles and turbulent Prandtl numbers were influenced by the velocity profiles and turbulent Prandtl numbers were influenced by the velocity of the jet and particle feeding rate.; Some aspects of turbulent two-phase flow were investigated and used in interpretation of the experimental data obtained in the study. The eddy-particle interaction was discussed and shown to have an important effect in two-phase flow. The Schmidt number, Prandtl number, and Lewis number were defined for two-phase flow and these dimensionless numbers were calculated from the data obtained from the experimental results.; Oblique shock waves in two-phase flow were studied and the relation between gas-particle flow properties ahead of an oblique shock wave and gas-particle flow properties behind the shock wave were derived by a solution of the steady-state conservation equations of mass, momentum and energy for the mixture-phase. Some of the important assumptions made were that the particles are uniform in size, uniformly distributed and in thermal equilibrium with the gas ahead of the oblique shock wave. Large particles (> 10 (mu)m) do not change direction immediately after passing through the shock wave. Particle drag coefficients in two-phase flow were reviewed and the data used in this study were obtained from aero-ballistic range measurements.; Results of the oblique shock wave calculations are presented as the relation between the incident angle (beta) of the two-phase flow and the deflection angle (theta) considering the effects of the shock wave Mach number, particle velocity lag, feeding rate, and particle size. The shock wave reactions are presented for a range of shock Mach number, particle feeding rate, particle size and particle velocity lag ahead of the shock wave. A comparison of the calculations to the experimental data of Morgenthaler (1962) was used as a guide to selection of a drag coefficient and gave good agreement between theory and experiment for the available data. It was found that the shock wave was influenced by shock Mach number, particle feeding rate, and particle velocity lag.