As a continuation of the first set of tests to provide further detailed design information and validation date for numerical models a new experimental test rig was developed. This test rig has been designed, built and successfully used to measure power and thrust on model tidal turbines under various configurations and flow conditions. The setup in the cavitation tunnel at QinetiQ in Hampshire and typical performance measurements from this phase of tests are shown below. Similar data sets were also obtained for thrust measurements, addition hub pitch angles, and other yaw angles.
Figure below demonstrates cavitation experiments on the turbine blades. Cavitation is water vapour produced in regions of low pressures behind the blade. The collapse of cavitation bubbles result in erosion which can lead to eventual failure of the device. This is a common problem on ship propellers.
Tests have also been carried out in towing tank at the University of the Solent, Southampton (see figure below.) These tests also encompassed the effects rotor yaw, rotor tip emersion and complex dual rotor studies.
Full details of the results and detailed discussion have been published in:
Bahaj A.S., Molland A.F., Chaplin J.R. and Batten W.M.J. (2007) Power and thrust measurements of marine current turbines under various hydrodynamic flow conditions in a cavitation tunnel and a towing tank.Renewable Energy, Volume 32, Issue 3, March 2007, pp 407-426.
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