Abstract— with the extinction of conventional sources of energy and with the emergence of renewable energy, the study of different mechanical devices to extract energy from these renewable sources has been increased drastically in recent era. In this context, to extract the kinetic energy of the flowing water, hydrokinetic turbines have become popular in these days. There are several turbines which are used as hydrokinetic turbine, like Savonius turbine, Darrieus turbine and Axial flow turbine. Among these turbines, Axial flow turbine draws special attention due to its high co-efficient of power (C P ). In spite of higher C P , this turbine is not explored much like Darrieus and Savonius turbine. So, in present study, it is decided to evaluate performance of turbine by experimental investigations. The aim of the present investigation is to investigate performance evaluation of turbine in various depth of submersion. In this regard, experimental setup with 5 blades and 360 mm diameter impeller is prepared. Experimental results are represented by non-dimensional parameters Co- efficient of power (Cp) and Tip Speed Ratio (TSR). Results indicates that with 50% raise in submersion depth, 65% enhancement in maximum power output is observed, However, there is only 19% enhancement in coefficient of power recorded, based on fully submerged rotor case. Index Terms— Axial flow turbine, Hydrokinetic Turbine, Propeller Turbine, Zero head turbine I. INTRODUCTION YDROKINETIC turbines, also called free-flow turbines, generates electricity from the kinetic energy present in flowing water, rather than the potential energy from the head. The prime advantage of these type of turbine is, it doesn’t require heavy structure dam, and it provides power output directly from kinetic energy from flowing water. Hydrokinetic turbines can be categorized into two main groups, namely the axial flow turbine and the cross flow turbine. The propeller type turbine is an example of an axial Manuscript received March 18, 2016; revised March 31, 2016. This work was supported in part by the Sardar Vallabhbhai National Institute of Technology, Surat, INDIA, under the Institute Research Grant (IRG). Authors would like to thank SVNIT, Surat to provide financial help for preparation of experimental set up. Vimal Patel is with the Sardar Vallabhbhai National Institute of Technology, Surat. 395007, INDIA. (Corresponding Author, phone: +91- 9099573650; e-mail: vkp@med.svnit.ac.in ) Dixit Savalia is with the Sardar Vallabhbhai National Institute of Technology, Surat. 395007, INDIA. (e-mail: savaliadixit@gmail.com). Mohit Panchal is with the Sardar Vallabhbhai National Institute of Technology, Surat. 395007,INDIA.(e-mail: mohit_panchal15@yahoo.com) Nisarg Rathod is with the Sardar Vallabhbhai National Institute of Technology, Surat. 395007, INDIA. (e-mail: rathodnisarg19@gmail.com) flow turbine. Darrieus and Savonius turbines belong to the cross flow category. A Darrieus turbine is a high speed, low torque machine suitable for generating electricity. Darrieus turbine has poor starting characteristics therefore some external power source requires. Darrieus has vertically oriented blades revolving around a vertical shaft. Fig. 1 indicates H-type lift driven vertical axis Darrieus turbine rotor. A Savonius vertical-axis turbine is a slow rotating, high torque machine with two or more vanes. Most wind turbines use lift generated by aerofoil-shaped blades to drive a rotor, the Savonius uses drag and therefore cannot rotate faster than the approaching fluid speed. Fig. 2 indicates conceptual diagram of Savonius turbine rotor. An axial flow propeller turbine is basically combined lift and drag force driven horizontal axis turbine. The conceptual representation of this turbine rotor is shown in Fig. 3. These type of turbine rotor is extensively used in low head high flow type of conventional turbine, like Kaplan turbine rotor. However, its performance as a hydrokinetic turbine, i.e. as a zero head condition, is still not explored. Major drawbacks for the early designs (Savonius and Darrieus) included the significant torque variation during each revolution, and lower power coefficients. Fig. 1 Darrieus Turbine Rotor Experimental Investigations of Hydrokinetic Axial Flow Turbine Vimal Patel, Dixit Savalia, Mohit Panchal and Nisarg Rathod H Proceedings of the World Congress on Engineering 2016 Vol II WCE 2016, June 29 - July 1, 2016, London, U.K. ISBN: 978-988-14048-0-0 ISSN: 2078-0958 (Print); ISSN: 2078-0966 (Online) WCE 2016