Design And Development Of Aerodynamic Structure For NK-1Movable Wind Erosion Tunnel

The open sources were important for ambient PM, compared with other sources.A certain amounts of ambient are PM are derived from soil via wind erosion dustproduction procedure, especially in northern China. This is an effective way forimprove Urban air quality to control the particulate emission sources. Movable winderosion tunnel is a important and preferred tool to quantitative study on dust emission,migration and transmission caused by soil erosion procedure, with which effective,reliable, and feasible research tool and techniques can be provided for parameterslocalization of wind erosion predictive equations, construction of the wind erosionprediction system, the technological measures to prevent and control soil wind opensource, and so on.Based on the wind erosion theory, principle of wind tunnel design,atmospheric boundary layer similarity theory, some aerodynamic criteria anddesign conditions has been proposed for designing NK-1movable wind erosiontunnel, which was2.456meters high and15.9meters long composed of inlet section,power section, transition section, turning section, stability section, contraction section,working section and diffusing section. The wind erosion tunnel possessedcontraction ratio of2.0and energy ratio of0.414. The wind speed can be adjustedsmoothly by a frequency activator within the range of03～20m/s.The assembly anddisassembly of the tunnel components are easy to perform. It realized the functions ofmoving and transporting while using in the fields.The unique design of the NK-1movable wind erosion tunnel were: firstly，thewind erosion tunnel is a symmetry aerodynamic structure with an elevation of20°degrees, which can reach better energy efficiencies and structure compactness.Secondly, the power section is independently designed and manufactured includingthe design of a fan system, deflector and fairing. The efficiency of the fan system hasbeen verified by choosing a high lift drag ratio fan aerofoil, and determiningoperation point according to the needs of running, and choosing of parameters forrotor and fairing such as boss ratio, solidity, lift coefficient and camber angle etc. Thirdly, Fluent, a kind of CFD(Computational Fluid Dynamics) software, was used tosimulate the mean velocity profiles of atmospheric boundary layer by introducing theporous media model in NK-1movable wind erosion tunnel in order to get th optimaldistribution of stick grid-roughness elements, and the results was validatedsatisfactorily by the wind erosion tunnel experiments. The velocity profiles ofatmospheric boundary layer approach the logarithmic law similar to the groundsurface based the combination of stick grids and roughness elements.Appling the data acquisition and wind speed controlling system, some testswere finished refer to the main characteristic parameters testing of field aerodynamicsflows in the portable wind-tunnel such as turbulence intensity and distribution,airflow stability, air current horizontal homogeneity, pressure gradient on thedirection of axis, wind-tunnel energy ratio. The results show that the flow fieldperformance conforms to the design requirements in wind erosion tunnel. The studyprovides a effective tool for wind erosion studies both in fields and in laboratory. Onthe other hand, the study laid the theoretical foundations for applying the movablewind erosion tunnel.