The formation of air bubbles at constant pressure at submerged orifices was investigated for several liquids. The frequency of formation of the bubbles was determined by the use of a stroboscope, and the rate of gas flow was measured with conventional rotameters. Several orifices having diameters ranging from 0.0794 to 0.397 em. were employed, and the gas flow rate was varied from about 0.1 cc. (at standard conditions)/sec. to about 150 cc./sec. It was found that the formation of bubbles could be correlated with the physical variables of the system by the application of Newton's second law of motion to the bubble at the instant just prior to its release from the orifice.Gas, as a dispersed phase, plays a significant role in numerous physical and chemical processes. This is reflected by the attention given in the literature to the formation of gas bubbles at capillary tubes, orifices, and other devices submerged beneath liquid surfaces (1, 2, 4, 5, 6). I n the experiments described herein the bubbles were formed a t approximately constant pressure within the gas chamber (Figure 1) by passing air through orifices each of which was submerged in several liquids in turn. Correlat>ion of the physical variables involved was achieved through the application of Newton's second law of motion.It his been established that a t very low rates of air flow the kiae of the bubble is nearly independent of the flow rate and is determined primarily by the orifice diameter, the surface tension, and the liquid density. A t higher or intermediate rates of gas flow the size of the bubble becomes dependent upon the rate of gas flow through the orifice, as shown by Davidson et al. (1). A t very high rates of gas flow Leibson et al. (6) demonstrated that the apparent jet of air issuing from the orifice is actuaIly a series of closely spaced, irregular bubbles which undergo further separation upon rising through the liquid.The influence of the volume of the gas chamber (Figure 2) and other physical dimensions of the apparatus on the formation of bubbles has been pointed out by Hughes et al. (4), who also observed that the effect of the chamber volume was not considered in the treatment of many of the data in the literature. Davidson et al. (1) demonstrated that as long as the volume of the gas chamber was less than a critical size it did not affect the formation of bubbles. For a given orifice diameter and gas flow rate the volume of the bubbles formed increased as the chamber volume was increased until approximately constant pressure within the gas chamber was approached. Most of the experiments reported in the literature were carried out with both capillary tubes and relatively small gas-chamber volumes; however in some instances Davidson (1) and Leibson (6) did use chamber volumes large enough to insure the formation a t constant pressure within the gas chamber.Since the majority of the bubble type of contactors employed in industrial applications operate at constant gaschamber pressure and since such data are scarce, this investigati...

This paper deals with the dispersion of one immiscible liquid in another (water in kerosene) by means of an orifice mixer. The degree of mixing was determined by measuring the area per unit volume of the dispersed phase. The area was measured with a photoelectric device, which had been calibrated photographically. The interfacial area formed at high Reynolds numbers (10,000 to 45,000, based on the diameter of the orifice) was found to increase with increases in both the volume fraction of water in the water‐kerosene mixture and the change in kinetic energy across the orifice. In addition, other aspects such as the rate of coalescence of the dispersed phase downstream from the orifice are treated.

A series of five experiments examining the effects of a simulated fire fighting water spray introduced into a fully-developed compartment fire were conducted for the Federal Emergency Management Agency by the Center for Fire Research at the National Bureau of Standards per Interagency Agreement (EMW-E-1239) Task Order 4A. Data from these tests were intended to be used as a check of predicted results from the Mission Research Corporation Fire Demand Model. The results illustrate the dynamics of compartment fire suppression using water sprays. and J. Ball, "A Physically Based Fire Suppression Computer Simulation for Post-Flashover Compartment Fires",