PRESSURE CHANGES AT A SUDDEN EXPANSION IN GAS-SOLID FLOWS

There is a pressure recovery when a two-phase mixture passes through a pipe enlargement. This paper describes an experimental project for the determination of this pressure recovery in air-solids systems. The solids used are medium size wax and lucite particles. Two pipe diameter ratios were investigated, 0.63 and 0.76. The Reynolds numbers for the experiments varied between 45000 and 72000 and the loading ratios were low to intermediate (up to 6), it was observed that the major part of the pressure recovery in these mixtures was due to the air alone and that only a small part of it (up to 25%) was due to the deceleration of solid particles.