Effect of nozzle length on gas entrainment characteristics of vertical liquid jet.

Abstract

For a vertical plunging liquid jet system using nozzles which had various values of the length-to-diameter ratio LJDn, characteristics such as the bubble penetration depth Z and the gas entrainment rate Qg were studied experimentally in an air-water system. Whennozzles of an LJDnratio exceeding 15 were employed,the values of Z and Qg were confirmed to be almost independent of LJDn. Empirical correlations for predicting Z and Qg are also presented.

Oxygen Transfer in the Water-Jet Vessel

“…The volumetric mass transfer coefficient kLa, was obtained by analyzing the response curves and Eq. (16).…”

“…1987; Kumagai et ai. 1983;Ohkawa et al 1987b] and the penetration depth of the bubbles produced by a vertical jet [Ohkawa et ai. 1986a] have attracted attention.…”

Experimental and Theoretical Study of the Characteristics of Submerged Horizontal Gas Jets and Vertical Plunging Water Jets in Water Ambient

“…The values of c 1 , c 2 , c 3 , and c 4 were found to be 10.5, 0.54, -0.56, and 1.39, respectively, for two inclined plunging jets and 5.5, 0.73, -0.26, and 1.11 respectively for one inclined plunging jet by given Ohkawa et al (1986). Ohkawa et al, (1987) studied the vertical water jets and suggested for the dimensionless bubble penetration depth, H p /d N , the following expression:…”

“…This second technique is involved in the devices used by Ciborowski and Bin (1972b), Ahmed (1974), Ohkawa et al (1987), Evans (1990) and Kusabiraki et al (1990a). However, each of the above-mentioned techniques has its own shortcomings.…”

“…In an attempt to clarify the effect of different parameters such as: nozzle geometry, jet length, and physical properties of the liquid phase on the entrainment rate, many studies are available in the open literature (e. g. Mahad 2012, Martim 2009, Tamer and Nusret 2003, Ohkawa et al 1987, Iguchi, 1998, and Kusabiraki et al 1990). Theses authors established three regions of the entrainment rate curve as shown in Figure (2.13), thus, a typical S-shaped Figure (2.12): Gas removal measuring apparatus (Kusabiraki et al 1990) entrainment rate curve is observed for the whole region of the jet velocities, that it was divided into three regions as follows:…”