Dynamics Analysis Of Flexible Direct Drive Tidal Current Energy Power Turbine

With the consumption of energy, people have to look to the renewable energy, and marine renewable energy because of large reserves, clean and so on the advantages of special attention. These include ocean wave energy, tidal energy, tidal currents, and so on. Based on ocean tidal current energy, a kind of flexible direct drive wave wheel generator is designed. Firstly, the structure of the device and the principle of power generation are introduced, the selection of generator is introduced in the paper,And the main shaft, bearing and other structure of the check. Dynamic analysis mainly consists of two parts.one part is Fluid dynamic analysis of hydraulic turbine. First, the turbine blade is analyzed; the effects of flow rate, blade angle of attack on the performance of turbine are analyzed. The relationship of energy utilization coefficient and tip speed ratio and the torque and resistance of the main shaft are summarized. Finally, the relationship between the energy utilization factor and the flow rate is used. The process of increasing the flow rate by increasing the flow guide cover is analyzed. By comparing the 4 different types of flow guide cover, select the highest profile o f the turbine, thereby increasing the power of the turbine. Another part is the structural dynamics analysis of hydraulic turbine. First, the modal analysis of hydraulic turbine, determine the structure of the natural frequency and vibration type, compared to the frequency of external load, to determine the structure of the resonance can be avoided. Then the harmonic response analysis is carried out, and the steady state forced vibration of the structure is analyzed. At the end, the flume test was carried o ut, and then the experiment was carried out on the sea. The following is the design ideas of this article:(1)Based on marine renewable energy technology, we design a device using ocean energy to generate electricity——Flexible direct drive wave whee l generator. First, the whole structure is introduced. Including the permanent magnet synchronous generator and its advantages, structure checking of Turbine Spindle and bearing etc., ensure the design life.(2)The hydrodynamic performance of hydraulic turbine is studied. Firstly, the force analysis of the turbine blade is carried out, Based on the formula, the relationship between the dimensionless number CP and λ,the tip speed ratio of the impeller is finally determined. Through the research on the performance of the hydraulic turbine, the research shows that with the increase of the flow rate, the wake diffusion is more obvious in the flow field, turbulence intensity enhancement. But it comes with the production of eddy currents. Although it is beneficial to improve the efficiency of the device, but the vortex will produce cavitation, so it is not necessarily to flow faster, the more the better, must take into account the structure design, to increase its capacity to withstand the load flow. Effects of blade angle of attack and blade length on the performance of hydraulic turbine, Final determinate when the installation angle is 0 degree, the flow field of the turbine is stable, the wake area is short and the flow rate is relatively high. Finally, the torque and resistance of the main shaft of the turbine are analyzed, by comparing the torque at different speeds, it is illustrated that the torque increases with the increase of the speed of the hydraulic turbine. As the speed increases, the resistance increases, and showed resistance to change more unstable, so to ensure high speed at the same time, but also take into account the resistance coefficient of hydraulic turbine energy caused by the decrease in the rate of.(3)Increasing the speed of hydraulic turbine by adding the flow guide, and then increase the energy utilization rate of water turbine. This has a very important significance for the low speed power flow region. In this paper, by analyzing the four types of flow, finally, the optimal alignment of the three curves shaped flow guide is determined. In order to make full use of the function of the flow guide, creatively put forward the installation of "diversion elliptical cone", can be based on the increase in the flow rate of about 20%.(4)Structural dynamics analysis first analyst structural modal to analyze the natural mode and frequency of the structure. Calculate the frequency of externa l excitation.After the harmonic response analysis; determine the maximum amplitude of the 4 positions, by observing the displacement amplitude frequency characteristic curve, the displacement at both ends of the blade is obviously larger than the maximum displacement amplitude of the contact position of the blade and the bracket. The maximum displacement appears in the first and second order modes of the 7.5H z, which has a reference value for the subsequent structural optimization.(5)Finally carries on the experiment research, the torque and power of the hydraulic turbine were obtained by flume experiment and sea trial. The energy utilization factor is obtained, which is compared with the previous calculation results, which verifies the rationality of the theoretical calculation.