https://link.springer.com/content/pdf/10.1007%2FBF02558984.pdf

Gas entrainment by plunging liquid jets

One of the most cited water quality parameters in the freshwater hydrosphere is dissolved oxygen. The oxygen concentration in surface waters is a prime indicator of the quality of that water for human use as well as use by the aquatic biota. When a water jet impinges a pool of water at rest, air bubbles may be entrained and carried a way below the pool free surface. This process is called plunging water jet entrainment and aeration. In this paper, air entrainment rate and oxygen transfer efficiency of venturi device with air holes along the length of the convergent-divergent passage was studied experimentally, and in particular, the effect of varying numbers, positions, and open/close status of the air holes. A negative pressure drew air in through holes at the convergent-divergent passage of the venturi device. This phenomenon affected the water jet expansion, the air entrainment rate, and the bubble penetration depth and hence the oxygen transfer efficiency. It was demonstrated that the values of air en...

Study of the influence of air holes along length of convergent-divergent passage of a venturi device on aeration

The dissolved oxygen content is a prime indicator of the quality of water. Water jets can increase dissolved oxygen levels when the jet impact velocity exceeds a critical velocity. In this paper, a...

Air entrainment and oxygen transfer in a venturi

An experimental investigation was made to measure interfacial area, a, and liquid-side volumetric mass transfer coefficient, k L a, in a downflow bubble column by chemical methods viz., absorbing CO 2 in aqueous sodium hydroxide and sodium carbonate/bicarbonate buffer solution respectively. The effect of gas and liquid flowrate and nozzle sizes on a and k L a were investigated. The experimental data obtained in the present system were analyzed and correlations were developed to predict a and k L a in terms of superficial gas velocity. The variation of a and k L a with specific power input were shown in graphical plot and compared with other gas-liquid systems.

Interfacial area and liquid-side volumetric mass transfer coefficient in a downflow bubble column

Despite numerous works reporting on oxygen transfer by plunging jets, few studies have been carried out on multiple plunging jets. In this paper, the volumetric oxygen-transfer coeffi cient and oxygen-transfer effi ciency of multiple plunging jets in a pool of water for different confi gurations in terms of varying numbers of jets and jet diameters were studied experimentally. This research suggests that the volumetric oxygen-transfer coeffi cient and oxygen-transfer effi ciency of the multiple plunging jets for air/water systems were signifi cantly higher than those of a single plunging jet for same fl ow area and other similar conditions. A relationship between the volumetric oxygen-transfer coeffi cient and jet parameters is also proposed. The suggested relationship predicted the volumetric oxygen-transfer coeffi cient for single and multiple plunging jet(s) within a scatter of ±15%.

https://www.cawq.ca/journal/temp/article/359.pdf

Air-Water Oxygen Transfer with Multiple Plunging Jets

This is an investigation of the gas holdup and the volumetric mass transfer coefficient of a plunging water jet in an air-water system. We sound kLa to be directly proportional to gas holdup in two regions. For the first time, this has been clarified in the plunging liquid jet system. The volumetric mass transfer coefficient and the gas holdup have been well correlated in terms of the Froude number, liquid jet length, nozzle diameter and vessel diameter.

Seiichi Sugawa

Papers

Oxygen transfer in the water-jet vessel