Reoxygenation by Free, Wall-Supported, and Plate-Supported Rectangular Jets Plunging into a Quiescent Pool

Abstract

This paper presents the results of oxygen transfer properties of a free, wall-supported, and plate-supported plunging rectangular jet. Consistently, the free jet had the highest values of oxygen transfer coefficient, KLa20; wall-supported and plate-supported jets were typically 0.93 and 0.74 times that of the free jet, respectively. At constant jet height hj and jet velocity vj, KLa20 decreases as the water depth in the pool increases for all types of jets. This is attributed to a decrease in the air/water interface, also known as the contact area, as volume increases. An optimum water depth, hw′, can be inferred for all three supports below which KLa20 decreases due to the bubble plume impinging on the bottom of the pool. For varying hj and vj, KLa20 increases with the former while a power relationship is observed between KLa20 and the latter for all supported jets. Ultimately, for each type of support an empirical equation based on the properties of the jet and the pool is proposed.