Wet gas pressure drop across multi-orifice plate in horizontal pipe in low gas-phase Froude number region

In comparison with the traditional single-orifice plate, as a throttling element, multi-orifice plates exhibit a low pressure loss, low flow-induced noise, and stable pressure difference response, which are advantageous in wet gas measurements. In this study, the pressure drop of wet gas across two multi-orifice plates (one with circular holes and another with slotted holes) in a horizontal pipe was experimentally investigated in the stratified flow region and intermittent flow region. The two regions are different from the flow pattern but can be collectively referred to as a low gas-phase Froude number (Fr-G) region. At the same porosity, there is no significant difference between circular and slotted multi-orifice plates in pressure drop characteristics. As the flow pattern transitions from stratified to intermittent, Phi(G) increases considerably with a decrease in Fr-G and an increase in liquid-phase Froude number (Fr-L); this differs from the well-known wet gas pressure drop characteristics of orifice plates as obtained from common wet gas with annular-mist flow. The prediction accuracies of the available pressure drop models for the gas-liquid flow across the orifice plate were analyzed based on the experimental results. The findings indicate that none of the models can provide accurate predictions in the two low-Fr-G subregions simultaneously. With the modified models, in which Fr-G and Fr-L are correlated simultaneously, new correlations are proposed for the low-Fr-G region. Among these models, the modified Murdock model exhibits the best prediction accuracies, i.e., 15% and 6%, when the upstream is in the flow pattern transition region and stratified flow region, respectively. These results elucidate the mechanism and prediction methods for the application of multi-orifice plates to wet gases as a measuring sensor. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.