Gravity effects on the dynamics of evaporating droplets in a heated jet

T. Park, S. Aggarwal, V. Katta
1994 32nd Aerospace Sciences Meeting and Exhibit   unpublished
Dispersion and vaporization behavior of liquid fuel droplets in a heated axisymmetric jet is studied using detailed flow visualization based on numerical simulations. Results show that the gravity has a strong effect on the dynamics of jet shear layer and droplets. The presence of gravity introduces the buoyancy-induced hydrodynamic instability, causing the large vortical structures to appear without any external perturbation. The droplet dispersion and vaporization behavior is influenced by
more » ... is influenced by both the vortex structures and the gravity. Three regimes, distinguished by the Stokes number St and the ratio of droplet terminal velocity to characteristic gas velocity Vr, are identified to characterize the effects of vortex structures and gravity on droplet dispersion. At low S/ and Vr, the droplets behave like gas particles. In the second regime, 0.1 < St < 0.64 and 0.04 < Vr < 0.3, due to the centrifugal action of the vortex structures the droplets are dispersed more than the gas particles. At the lower end of the third regime, the droplet motion is affected by both the vortex structures and the gravity, whereas at the higher end it is affected more by gravity. The effect of vaporization is to shift the Stokes number range for the three regimes.
doi:10.2514/6.1994-684 fatcat:wds4awqjsjezfdhyhm4jmtwk7y