Penetration and Dispersion of Transient Gas Jets and Sprays

Abstract

Results from numerical computations performed to represent the transient behavior of axisymmetric non-vaporizing and vaporizing sprays injected into a constant volume chamber are presented. These results are compared with those from vaporizing spray experiments where, for the same mass and momentum flow rates, the effect of chamber density on spray penetration and dispersion angle was studied. It is shown that with the practical numerical resolution employed here, which appears to be inadequate, the results do not agree. Higher resolution is impractical from a numerical point of view for sprays. Hence, the present work further explores whether gas jets, which may be computed with a high resolution, are comparable to the sprays in terms of penetration and dispersion angle. For each gas jet computation, the injected mass and momentum flow rates and the chamber density in the corresponding gas jet computations are maintained the same as those in the spray experiments. Comparisons show that the gas jet penetration and angles are in agreement with the trends of the spray measurements. In both cases. the penetration decreases with increasing chamber density and the dispersion angle increases.

A Computational Investigation of the Interaction of Pulses in Two-Pulse Jets

“…The RANS model employed in this study has been extensively employed in prior studies of gas jets and sprays [7][8][9][10]. Turbulence is modeled using a twoequation k-e model.…”

Numerical studies of vortex-induced extinction/reignition relevant to the near-field of high-Reynolds number jets

“…The equivalent constant-density gas jet has a diameter ͑d͒ of O͑1 mm͒ and the same injection velocity. 36,37 If a spreading rate of 0.095 is assumed for the jet and the turbulent length scale is assumed to be 0.15 of the jet half-width, 38 the value of the length scale at 30d is about 430 m. Length scales at shorter axial distances will be even smaller. The vortex length scales selected in this work lie in the range of 100-400 m, which represent integral scales at axial locations upstream of 30d.…”

THE k-ε MODEL AND COMPUTED SPREADING RATES IN ROUND AND PLANE JETS

“…Computed values have been quoted in the range of 0.115± 0.128 (Wilcox[1], Wood & Chen[14]). Our work is motivated by our interest in round jets in the context of our general work in the area of diesel engine jets (Abraham & Magi[6], Iyer & Abraham[15], Iyer & Abraham[16], Post et al[17]). In typical diesel engines, the vaporizing diesel spray is similar to a turbulent round jet.…”