Experimental Determinationof The Drag Coefficient Of ASingle Sphere In Static Liquid

The research of liquid-solid two phase flow of particles is a hot research topic in recent years.It has a wide range of applications in the areas of the granular sedimentationin the tube and channel, grain sorting, hydraulic transmission.Becausethe experiment research for a single particle whose diameter is below1mm settled in the static liquid is not enough, the micro particle dynamics experiment systemin the static liquid is built with the liquid-solid two phase flowof particles as the background.The experiment system can be used to study the state of a single tiny particlesettle in the static liquid.A technology of camera measurement and image processing is used in the experiment. It studies the force when the glass beads and solder beads of different particle size settled in the different stationary liquids.Conclusions are as follows:(1) In the experimental section within the scope of Reynolds number, the drag coefficient CD decreases with the increase of Reynolds number Re. In0.1<Re<10section, the drag coefficient CD decreasesdrastically, and in10<Re<140segments, the drag coefficient CD shows a leveling-off.(2) For the dimensionless diameter d*and dimensionless particle settling velocityv*,the drag coefficient CD decreases with the increase of d.andv*in the scope of their respective experimental section. In0<d*<5and0<v*<10section,the drag coefficient CD decreasesdrastically, and in5<d*<25and10<v*<110segments, the drag coefficient CD shows a leveling-off.(3) The standard drag coefficient curve can be applied to motion state of the single tiny particles with the diameter of which is more than0.1mm.(4) For the experiment data pointsof the CD-Re,CD-d*and CD-v*under various experiment condition,their distribution lawsare analyzed, and fitted correspondingly to get their fitting formula and curve fitting.