Evaluation And Mechanism Analysis Of A New Energy Saving Device--Hub Vortex Absorbed Wheel

With the rapid development of global trade integration pr ocess, ships as t he main conveyance at sea will play more import ant role, as a consequence the pr oblems of exces sive e nergy consumption and gre enhouse gas emissions bec ome more and more significant. The enforc ing of EEDI index will bring opportunities and challenges t o ship energy saving and reduction. In this paper, the evaluation and mec hanism analysis of a new t ype of energy s aving de vice so called “hub vortex absor bed whe el” is presented.Firstl y, a numerical assessment method of hub vor tex absorbed wheel’s energy saving effect ha s been established and ve rified. Then the energy saving e ffect of a propeller with hub vortex a bsorbed wheel is evaluated by the numerical method. The energy saving mechanism of hub vortex absorbed wheel is analyzed based on the force and fl ow fie ld. It is found that the hub vortex abs orbed whe el can weaken hub vorte x be hind the propeller, and then the pressure on t he t aper of hub vortex absorbed wheel is recovered and the resistance is reduced, so the total thrust of the propeller and hub vortex absorbed wheel as a whole is i ncreased. On the other hand, the t otal torque is declined. So the hub vortex abs or bed wheel c an achieve saving energy.Secondly, the influence of some geometry parame ters of hub vor tex absorbed wheel to the e nergy saving effect is analyzed, such as the diameter of hub vortex absorbed wheel, its length,a nd taper, and the length of the wheel duc t. This can provide reference data for the subsequent de sign of hub vortex absorbed wheel.Two hub vortex absorbed wheel designs were select ed based on the para meter analysis. Their hydrodynamic performance was te sted in t he cavitation tunnel. The test results can ver ify the a ccuracy of the CFD numerical met hods and evaluate the ene rgy saving e ffect of vortex wheel.In addi tion, the flow field behind the hub vortex absorbed wheel is measured by the LDV and P I V. It c an verify the flow field of CFD calculat ion, and al so he lp to explain the energy saving mechanism. Finally, the energy-saving mechanism and the effect of two ene rgy-sa ving devices,propeller boss cap fi n and hub vortex absor bed whe el, were analyzed...