Comparative efficiency testing for a newly designed cyclone type sediment trap for wind erosion measurements

摘要

The measurement of eolian sediment transport still remains one of the biggest challenges in eolian research. This paper presents the experimental results on the trap efficiency of a newly designed cyclone-type trap (BEST) and Wilson and Cook trap (WAC) under various wind speeds in the Eremology Wind Tunnel Facility at Gent University, Belgium. The performance of the two traps were tested for four different sediment sizes (<100,100-200,200-300 and 300-500 μm) and under four free-flow wind speeds (12,13,14, and 15 m s~(-1)). The test results showed that the efficiency of the BEST was higher than that of the WAC, and the efficiencies of BEST and WAC varied between 75 and 100% and 12 and 52%, respectively. In addition, the coefficient of variation (CV) indicated that the variability in the efficiency of the BEST was lower with wind speed and particle size. These higher and more consistent efficiencies of the BEST were chiefly attributed to its cyclone design, which provided: i) separation of particles from air (particle settling) by means of the accelerated gravitational force achieved by a rapid air rotation, ii) the reduced stagnation pressure at the catcher inlet by gradually increasing the outlet velocity, and iii) the reduced turbulence within its body by a regular circulating path.