Experimental and numerical investigations of two phase flow in shock tube

We present an experimental and numerical study of the interaction between a shock wave and a solid particle bed initially at rest. Experiments are conducted in a vertical shock tube with a square cross section. So as to describe precisely our two phase flow, we use several diagnostics: shadowgraph visualization with high speed camera, X-ray densitometry, differential interferometry and pressure gauges. Several types of configurations are studied. We vary the thickness of the bed, the nature and the size of particles as well as the carrier gas. Shadowgraphies allow to obtain the average trajectory of particles cloud while the X-ray densitometry gives access to the distribution of the solid phase in the cloud. The differential interferometry and pressure gauges record the action of particles on the gaseous phase. Our experiments show then a rapid particle displacement as they form a compact bed. We also show a dilution of the solid phase. This dilution is function of contacts between particles (thin beds) or of the non-uniformity of the gaseous phase in the cloud (thick beds). Two numerical codes are employed to help us in the comprehension of our flows. The two models find the main phenomena described by the experiments. Moreover, they demonstrate the preponderance of the drag force and force due to pressure gradient across the particles bed on the dynamic of the flow. We also show the displacement of compaction wave within the solid phase identical to that measured experimentally