Effect of flow-obstruction geometry on pressure drops in horizontal air-water flow

Experiments were carried out to investigate the pressure drop due to flow obstructions in horizontal air-water flow. The axial pressure distribution along a 25.4 mm inside diameter tube, with and without flow obstructions was measured using multi-tube manometers. Various obstruction shapes and sizes were investigated. Pressure-loss coefficients and two-phase multipliers were derived for twelve different flow obstructions.Estimates of the kinetic energy and momentum of the flow were also obtained from radial void distribution measurements. The pressure drop through the obstructions in two-phase flow was found to depend strongly on the kinetic energy and momentum of the liquid intercepted by the flow obstruction. Buoyancy-induced flow stratification caused a strongly non-symmetrical effect, and resulted in large pressure drops for flow obstructions located in the bottom part of the channel.