Countercurrent exchange

About: Countercurrent exchange is a research topic. Over the lifetime, 2255 publications have been published within this topic receiving 28687 citations. The topic is also known as: Countercurrent exchange.

Probability Density Function Modeling of Multi-Phase Flow in Porous Media with Density-Driven Gravity Currents

Abstract: A probability density function (PDF) based approach is employed to model multi-phase flow with interfacial mass transfer (dissolution) in porous media The joint flow statistics is represented by a mass density function (MDF), which is transported in the physical and probability spaces via Fokker–Planck equation This MDF-equation requires Lagrangian evolutions of the random flow variables; these evolutions are stochastic processes honoring the micro-scale flow physics To demonstrate the concept, we consider an example of immiscible two-phase flow with the non-equilibrium dissolution of single component from one phase into the other-a model for solubility trapping during CO2 storage in brine aquifer Since CO2-rich brine is denser than pure brine, density-driven countercurrent flow is set up in the brine phase The stochastic models mimicking the physics of countercurrent flow lead to a modeled MDF-equation, which is solved using our recently developed stochastic particle method for multi-phase flow (Tyagi et al J Comput Phys 227:6696–6714, 2008) In addition, we derive Eulerian equations for stochastic moments (mean, variance, etc) and show that unlike the MDF-equation the system of moment equations is not closed In classical Darcy formulation, for example, the mean concentration equation is closed by neglecting variance However, with several one- and two-dimensional simulations, it is demonstrated that the PDF and Darcy modeling approaches give significantly different results While the PDF-approach properly accounts for the long correlation length scales and the concentration variance in density-driven countercurrent flow, the same phenomenon cannot be captured accurately with a standard Darcy model

Hydrodynamics of the tridimensional rotational flow sieve tray in a countercurrent gas-liquid column

Abstract: The hydrodynamic performance of the TRST in a gas-liquid countercurrent flow column was investigated experimentally in this article. The results show that the operating field can be divided into low and high loading areas according to the increasing rate of the pressure drop. The space utilization of the tray is low, and the flow patterns are mainly droplet-column and continuous film flows. The pressure drops of the tray at each installed locations are different, indicating that the gas-liquid load of each tray is unbalanced. Compared with concurrent flow operation, the range of gas flux is at least 45% less, and the liquid flux range is at least 37.5% less. Compared with other new tray types under countercurrent flow operation, the pressure drop of the TRST is smaller, less than 300 Pa, but the range of gas-liquid flux is also narrow. The empirical models of the pressure drops, loading curve, and flooding curve agree well with the experimental data.

High efficiency column crystallizer

Abstract: An improved countercurrent solid-liquid contacting apparatus, and more particularly an improved counter-current crystallizer column is disclosed. The present invention embraces the discover that column efficiency and product purity can be substantially enhanced by reducing axial liquid back-mixing by using stationary solid beds and transport means at spaced intervals along the column length.