Hydrodynamic drag under conditions of flow of a two-phase mixture in a pebble bed

An experimental investigation is performed of the hydrodynamic drag under conditions of motion of water, air, and steam–water mixture in a pipe $34$ mm in diameter with a bed of pebbles $2$ mm in diameter. The experiments with air and water are performed for Reynolds number values from $100$ to $1770$. Experimental data are obtained for the first time on the resistance of a two-phase mixture in the ranges of pressure from $0.9$ to $3.0$ MPa, mass flow rate in the pebble bed from $108$ to $238$ kg/(m$^2$ s), and steam quality from zero to $0.21$. Theoretical relations are suggested, which generalize the measurement results. Tables of experimental data are given.