The hydrodynamics of cocurrent gas‐liquid flow in packed beds is analyzed by extending the concept of relative permeability to the inertial regime.
The relative permeabilities of the gas and liquid phases are functions of the saturation of the liquid phase. These functions are found from an analysis of experimental data. The relations obtained are used to develop empirical correlations for predicting liquid holdup and pressure drop in gas‐liquid cocurrent downflow in packed beds over a wide range of operating conditions. The correlations proposed give very good results when compared to experimental data yielding, in general, mean relative deviations lower than existing correlations. In addition, a new equation is proposed for predicting static holdup in packed beds which is based on a more physically realistic characteristic length than that used in previous studies.
Atmospheric particulate have deleterious impacts on human health. Predicting dust and aerosol emission and transport would be helpful to reduce harmful impacts but, despite numerous studies, prediction of dust events and contaminant transport in dust remains challenging. In this work, we show that relative humidity and wind speed are both determinants in atmospheric dust concentration. Observations of atmospheric dust concentrations in Green Valley, AZ, USA, and Juárez, Chihuahua, México, show that PM10 concentrations are not directly correlated with wind speed or relative humidity separately. However, selecting the data for high wind speeds (> 4 m/s at 10 m elevation), a definite trend is observed between dust concentration and relative humidity: dust concentration increases with relative humidity, reaching a maximum around 25% and it subsequently decreases with relative humidity. Models for dust storm forecasting may be improved by utilizing atmospheric humidity and wind speed as main drivers for dust generation and transport.
dynamic behavior has resulted in correlations that are valid only over limited ranges of experimental conditions.The main objective of this work is to present a detailed experimental study of the hydrodynamics of trickling flow in packed beds. This study deals with the experimental evaluation of liquid holdups and pressure drops for a wide range of operating conditions, giving special attention to the dependence of these parameters on the history of the process, i.e., to the presence of hydrodynamic hysteresis.
Vol. 32, No. 3 370 March 1986 approaches have been used to predict pressure drops ir. gas-liquid uxurrent flow through packed beds: 1. The two-phase flow pressure drop has been expressed as a function of the pressure drops of gas and liquid in one-phase flow through the packed bed. The correlation is of the same form as those used to predict pressure drops in two-phase flow through tubes. This approach was developed by Larkins (1959) and it has subsequently been used in most of the investigations performed in the field (Weekman, 1963; Reiss, 1967; Charpentier et al., 1968; and Midoux et al., 1976).2. The pressure drop has been correlated to the liquid and gas
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.