The Experimental Study Of Effective Drag On Spheres By Shock Wave Loading

One of the important subjects of two-phase flows is the gas-particle flows.The study of thelaw between the gas and solid is very important not only in academic but also in industry．In this paper, the effective drag and drag coefficient of the single sphere and two sphereswere studied experimentally．The experiment was conducted in experimental section which istransparent and is connected to the driven-section of the horizontal shock tube. The single sphereor two spheres whose spacing is adjustable is fixed in the experimental section by fine wire.Thedynamic pressure signal P which is come from the effective drag on single sphere or spheres iscollected by the high-speed data collection system, dynamic test analyze, computer and fixingdevice for sensor. Formula is deduced to convert the dynamic pressure signal P to effective dragon the fixed spheres. For single sphere, the law between the drag coefficient on single sphere andRe was got in different working condition for shock Mach number. For two spheres, the lawbetween the drag coefficient on spheres and distance between the two spheres is discussedmainly. Based on the analysis and comparison of the experimental data, some importantconclusions were obtained.(1) The experimental facility which used to get the dynamic pressure signal P which iscome from the effective drag on single sphere or spheres is designed. Besides, the formula isdeduced to convert the dynamic pressure signal P to effective drag.(2) For single sphere, the drag coefficient is decrescent with the increase of the Re, when theshock Mach number is bigger.(3) While the dimensionless distance H is increasing, the drag coefficient on one of the twospheres increased first, and then decreased.(4) The gap of the drag coefficient on the single sphere and one of the two spheres is great.So, it is not appropriate to apply the drag coefficient on single sphere to the spheres’s.First, the dynamic pressure signal P which is come from the effective drag on single sphereor spheres is gotten by experimental facility which is designed by us. Then, the dynamic pressuresignal P is converted to effective drag on the fixed spheres by formula which is deduced basedon the experimental facility. At last, the effective drag on spheres is gotten. These are the maininnovative points in this research field. The investigation in this paper conquers the key problem for the study of interaction of shock wave and spheres and of the building for drag coefficientmodel of spheres.