Performance of the contrarotating Wells turbine

This paper describes an experimental investigation of the contrarotating Wells turbine for a wave power plant. The tests were conducted in a unidirectional steady air flow rig. Measurements taken included the overall performance of the turbine as well as detailed measurements of the radial distribution of velocity and pressure, upstream, downstream and between the rotor planes, for two different solidity turbine models and different rotor speed ratios. Experimental results show that the use of two twin rotors rotating in the opposite direction to each other is an efficient means of recovering the swirl kinetic energy without the use of guide vanes. Also, it was shown that the stall could be postponed by increasing the velocity of the downstream rotor relative to that of the upstream rotor.