| Wind power,as the main force of new energy to achieve the“ Double carbon” target in China,its importance and development trend are self-evident.The desert,Gobi,desert areas(Sand desert)are rich in wind resources,wind power is to achieve large-scale and high-quality development of an important direction.The northwest of China is the main distribution area of sand desert,and also the frequent sand storm area.Wind turbines operating in wind and sand environment for a long time will inevitably interact with sand and dust particles,which will affect the transport of sand and dust and the surrounding environment of wind turbines(wind farms).Therefore,it is of great significance to study the influence of wind turbines on dust transport and reveal the interaction mechanism between wind turbines under wind and sand environment,it will bring environment-friendly and efficient development to the wind power industry.Based on the MPPICFOAM solver in Open FOAM,the Multiphase Particle-in-cell(MP-PIC)model is coupled with the actuator model.A wind turbine model designed by ourselves is taken as the research object.Based on the solver,the wind turbine operating at tip speed ratios of 4,5 and 6.4 in sand and dust environment is simulated.Based on the analysis of wind turbine wake,the wind turbine wake characteristics under wind and sand environment are summarized as follows:(1)Dust promotes turbulent mixing process.Wind turbine wake recovers more quickly in wind and sand environment,and the wake evolves in accordance with the clean air when the wind turbine operates at different blade tip speed ratios;(2)In wind-sand environment,the axial velocity of wake is still “W” shaped,but the presence of sand and dust will accelerate the wind velocity in the outer flow field,and also aggravate the velocity deficit;(3)Within the range of radial rotation,the radial velocity deficit was aggravated by the presence of dust,and the influence of blade tip on velocity lasted to ± 1.5 R.the location of dust accumulation affected the height of the minimum velocity.The influence of wind turbine operation on dust transport was studied by combining numerical simulation and wind tunnel test:(1)The dust accumulates at the position of blade tip vortex and center vortex,forming the “Arc zone”.The dust particles change regularly in the height ± 0.4 m ～ ± 0.2 m,0.1 m ～-0.1 m.(2)At low blade tip velocity ratio,the dust accumulation takes on a spiral shape with the development of Wake Vortex,and the spiral shape becomes more obvious with the increase of axial distance.The aggregation effect of Wake Vortex is stronger at high blade tip velocity than that at low blade tip velocity,and the dispersion of dust particles in the cross section is more obvious.(3)The response of dust particles with different Stokes number to wake structure is different.30μm particles(St = 0.118)are dispersed uniformly and have strong diffusivity in the flow field.70 μm dust particles(St = 0.642)were selectively accumulated in the flow field.115 μm dust particles(St = 1.731)settle rapidly under the influence of gravity in the flow field.(4)The average particle size of cross-section dust particles is smaller than the initial particle size,and with the increase of the axial distance,the particle size decreases gradually,and the large particle size particles settle preferentially in the flow field.The influence of wind turbine on particle size deviation extends to 12 days after wake.(5)the sand-dust on the ground shows the characteristics of intermittent settlement,and the bigger the tip velocity ratio is,the more significant the settlement is.(6)The wind turbine operation promotes the sand-dust settlement,and the sand-dust settlement in the position of 6d after the wind turbine.(7)combined with the wind tunnel test,it is found that there is the phenomenon of blowing sand in the upper blade tip.The larger the tip velocity ratio is,the more obvious the blowing dust is,and the more significant the sand-blocking effect of the wind turbine is. |
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