Experimental Study on Conversion Characteristics of a Hexagonal BBDB System with a Check Valve

A new type of Backward Bent Duct Buoy(BBDB) system is introduced, and energy conversion experiments of a model and a small generating prototype are carried out. The experimental model in the wave flume is 1.2 meters long and 0.51 meters wide, and the cross-section of the horizontal pipe of the model is hexagonal. The experimental results in the wave flume show that the Capture Width Ratio (CWR) can reach up to 144.0% with the the check valve under regular waves. A small scale generating prototype, which is 3.14 times the size of the flume experimental model, was made. The generating prototype is 3.8 meters in length, 1.6 meters in width and 1.9 tons in weight, equipped with a unidirectional impulse air turbine and a 450W alternator. The basin experimental results of the prototype show that the peak of the CWR is 198.3%, the second conversion efficiency from pneumatic energy to electricity is as high as 31.0%, and the maximum of the conversion efficiency from wave to wire is 50.67%, under battery loads and regular waves, which is superior to that of the historical documents. The energy conversion characteristics of the new BBDB system present good development prospects. It is expected to make the wave-to-wire efficiency exceed 100% for optimization research in the further.