| Tidal energy occupies the important position in the development and utilization of renewable energy,which is a huge potential of clean and renewable energy. Now some tidal power stations have been completed all over the world, its carrier structure types mainly in three forms—floating moored system, pile mounted system and gravity based system.Floating moored system is popular due to its wide application of water depth and convenient installation. Nevertheless, the hydrodynamic and motions of the floating tide power station carrier is very complex. It may be inaccurate if the design of tide power station is fully designed as general marine structures without considering the water turbine flow field and the carrier interference with each other, or adding turbine damping to the carrier as a certain proportional. And there has no studies were found yet. Therefore, research about hydrodynamic and motion characteristics of floating carrier in the waves and currents is one of the key problems of tide power station design.In this paper, the hydrodynamic problems of floating carrier with vertical axis tidal water turbine were studied. In the basis of potential flow theory, the motion equation of floating carrier with turbines was derived, the hydrodynamic and motion of carrier plus water turbine was studied, and the influence of hydrodynamic and motion of water turbine on its carrier was also investigated.First of all, the use of tidal current energy and the development situation of tide power station were summarized. Review the vertical water turbine hydrodynamic theory and motions of general floating body in waves. Second of all, According to general equation of motion of floating body theory, the turbine fluid force as an additional load added to the equation of motion of carrier relating some theoretical assumptions in order to get the general motion equation of the floating body with a turbine. For a slight wave condition, of a cylindrical carrier were solved according to the definite condition. The expression of potential hydrodynamic coefficients in the frequency domain and differential equations of motion of the carrier were derived by means of dividing the floating body six freedom degrees motion into radiation and diffraction problems. To force the issue with the vertical water turbine move with its carrier in wave, hydrodynamic model was established in the basis of slice theory.As this paper, application of the floating body hydrodynamic model and the method of solving six freedom degrees in frequency domain solved problems. Without loss of generality,taking typical disk-type floating carrier with surging and pitching motions in regular waves into research. First,the force expressions of the vertical water turbine for surging and pitching motion in the water were listed, and then export the two freedom degrees of motion equations of the carrier add a turbine. Taking turbine rotation speed is zero and considering the blades of the turbine stay at 0 degree, 45 degree and 90 degree angle as research examples in the numerical calculation. The force of the turbine in uniform flow was simulated by hydrodynamic coefficients with each impeller angel. Taking advantage of MATLAB software to solve the motion equations to obtain the hydrodynamic and movement amplitude results of surge and pitch motion both the carrier and carrier with the turbine. Studying the different level influence regularity of hydrodynamic and movement of the carrier which was affected by different angels of the turbine blades. |
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