Abstract—Aeration by a plunging water jet is an energetically attractive way to effect oxygen-transfer than conventional oxygenation systems. In the present study, a new type of conical shaped plunging aeration device is fabricated to generate hollow inclined plunging jets (jet plunge angle of 3 π ) to investigate its oxygen transfer capacity. The results suggest that the volumetric oxygen-transfer coefficient and oxygen-transfer efficiency of the conical plunging jet aerator are competitive with other types of aeration systems. Relationships of volumetric oxygen-transfer coefficient with jet power per unit volume and jet parameters are also proposed. The suggested relationships predict the volumetric oxygen- transfer coefficient within a scatter of % 15 ± . Further, the application of Support Vector Machines on the experimental data revealed its utility in the prediction of volumetric oxygen-transfer coefficient and development of conical plunging jet aerators. Keywords—Conical plunging jet, oxygen-transfer efficiency, support vector machines, volumetric oxygen-transfer coefficient. I. INTRODUCTION falling water jet, when passes through the surrounding atmosphere and plunges into a pool of water, it entrains into this pool a substantial amount of air and forms a submerged two-phase region with a considerable air-water interfacial area. This process is called plunging water jet entrainment and aeration. It is basically a combination of hydrodynamic and aerodynamic forces interacting between water jet and ambient air [1]. Plunging jet applications include aeration and floatation in water and wastewater treatment, oxygenation of mammalian-cell bio-reactors, biological aerated filter, fermentation, bubble floatation of minerals, plunging columns, cooling system in power plants, stirring of chemicals as well as increasing gas-liquid transfer, plunging breakers and waterfalls [2] – [6]. Aeration by a plunging water jet is an attractive way to effect oxygen-transfer than conventional aeration systems for various reasons [2],[7] – [8]: it is energetically attractive, it does not require an air compressor; it does not require separate stirring device Manuscript received October 25, 2007. Surinder Deswal is with the National Institute of Technology, Kurukshetra -136119, Haryana, India (corresponding author to provide phone: +91-1744- 233356; fax: +91-1744-238050; e-mail: deswal.leo@gmail.com ). D. V. S. Verma, was with National Institute of Technology, Kurukshetra- 136119, Haryana, India. He is now Director/Principal, CDLM Engineering College, Panniwala Mota, Sirsa, Haryana, India (e-mail: dvs_verma@yahoo.co.in). because the plunging jet itself achieves aeration and mixing; it is simple in design, construction and operation; and it is free from operational difficulties such as clogging in air diffusers, limitations on the installation of mechanical aerators by the tank width, etc. Supported by these potential advantages, there has been a growing interest in aeration by plunging jets in the last few years. A substantial number of researchers have studied air-water oxygen transfer by plunging jets. Experimental studies on the oxygen transfer by plunging water jets were carried out by [9] – [17]. These and the other related studies were reviewed in detail by Bin [2]. Some of these researchers have presented their data in the form of empirical relationships. The simplest relationships for single circular water jets plunging vertically (i.e. jet plunge angle, 0 90 = θ ) are recommended by Ahmed and Glover [19] (Eq.1), Bin and Smith [14] (Eq.2) and by Tojo and Miyanami [12] (Eq.3): ( ) 2 3 2 4 20 10 85 . 4 10 1 . 3 j j L d v A K − − × + × = (1) ( ) P A K L 5 20 10 9 − × = (2) ( ) ( ) 65 . 0 20 029 . 0 V P a K L = (3) where ( ) 20 A K L is volumetric oxygen transfer factor at standard conditions (m 3 /h); j v is jet velocity at exit (m/s); j d is jet diameter (m); P is jet power (W); ( ) 20 a K L is volumetric oxygen transfer coefficient at standard conditions (1/s); and V P is jet power per unit volume (kW/m 3 ). Thus much useful information is available on the oxygen transfer characteristics of conventional plunging water jets. These and other researchers have identified jet velocity, jet diameter, jet plunge angle and jet power (which is a function of jet velocity and jet diameter) as the four operating variables affecting the oxygen transfer of a plunging water jet aeration system. However, it is insufficient to investigate or discuss the oxygen transfer by plunging jet aeration system only by these four factors. An important factor that cannot be overlooked is geometry/shape of the jet in the aeration system. Reviewing existing studies on different geometries of plunging jets, most of these works were carried out on conventional shapes of plunging jets. Chanson and Brattberg [20] investigated air entrainment by two-dimensional planner plunging jet; Bagatur et al. [21] investigated entrainment by oval and rectangular (with rounded ends) plunging jets; and Emiroglu and Baylar Performance Evaluation and Modeling of a Conical Plunging Jet Aerator Surinder Deswal, and D. V. S. Verma A World Academy of Science, Engineering and Technology International Journal of Aerospace and Mechanical Engineering Vol:1, No:11, 2007 616 International Scholarly and Scientific Research & Innovation 1(11) 2007 scholar.waset.org/1307-6892/9633 International Science Index, Aerospace and Mechanical Engineering Vol:1, No:11, 2007 waset.org/Publication/9633