Atomization and Sprays Journal of the International Institutes for Liquid Atomization and Spray Systems

ISSN for PRINT: 1045-5110

For Online Access

Best Paper Award Selection - Editorial Board Site

1993, Volume3

Issue 4

134 pages

Issue price - $75.00

Vincent G. McDonell
Department of Mechanical and Aerospace Engineering, University of California, Irvine, California, USA

M. Adachi
UCI Combustion Laboratory, University of California, Irvine, California 92717

G. S. Samuelsen
UCI Combustion Laboratory, University of California, Irvine, California 92717

A detailed characterization of the continuous and dispersed phases present in a methanol spray produced by a nonswirling air-assist atomizer operated in a down-fired orientation under reacting and nonreacting conditions is presented. This study is the second in a series of ongoing efforts to understand the behavior of sprays under a variety of conditions. Measurements of continuous-phase mean and fluctuating velocities, dispersed-phase size and velocity distributions, and local dispersed-phase volume flux are obtained using phase Doppler interferometry. The mean concentration of hydrocarbons in the continuous phase are measured using a two-wavelength extinction/absorption technique. Part I of the present article focuses on results from the gas-phase measurements. The results indicate that the presence of droplets can increase or reduce the fluctuating velocities and shear stress in the gas phase, depending on the local concentration, size, and relative velocities of the drops. The presence of reaction (I) expands and accelerates the gas phase, (2) increases the amount of hydrocarbon vapor present near the centerline, and (3) increases the anisotropy of the gas-phase turbulence compared to the nonreacting case. The measurements indicate the existence of two regions in the reacting spray: (1) a relatively coot central region that features high vapor concentrations; and (2) a surrounding high-temperature reaction zone in which vapor is consumed. It is observed that, in the far field, the velocity profiles of the single-phase jet and of the gas phase in the nonreacting spray are self-similar. This behavior is also observed for previous data sets with one exception, and that case featured a much higher liquid-to-air mass loading ratio. The presence of reaction does not significantly alter the self-similar behavior, although the profiles do narrow. The concentration profiles do not exhibit self-similar behavior, as expected, due to the presence of vapor sources (i.e., drops).

Download article, 389-410 pages

Article price - $35.00

<< Previous article   Next article >>