TEST STUDY ON THE FLOWING BEHAVIOR OF SINGLE-PHASE FLOW IN THE VERTICAL CONCENTRIC ANNULAR PIPE WITH ROTATING INNER PIPE

Using air, oil, and water as working medium, a test study is conducted to discover the flowing behavior of the single-phase flow in the vertical concentric annular pipe, which contains rotating inner pipe. The frictional resistance in the annular pipe is firstly measured, with the static inner pipe, when 100 Re 70000; and then compared with several other frictional resistance formulas. It is concluded that frictional coefficient of turbulence is about larger 6%~10% than laminar in a concentric annular pipe. By measuring the axial frictional pressure drop, the centrifugal instability and the frictional resistance in the annular pipe is investigated, when the inner pipe is rotating. The converting boundary from laminar flow to laminar plus Taylor vortex, and turbulence plus Taylor vortex to turbulent flow is obtained when the diameter ratio is lower than 0.8, and a new frictional resistance formula is also presented for different flowing type in the concentric pipe of larger annular.