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.

An analysis of a countercurrent adsorber

Abstract: The steady-state behavior of an isothermal countercurrent moving bed adsorber is analysed with the assumption that only one component is appreciably adsorbed, and adsorption can be described by a Langmuir isotherm. The behavior of the system is observed to depend critically on the parameter a, which is the ratio of the flux of matter in the solid phase to that in the fluid when the two phases are at equilibrium at low concentrations. When 0< a< 1 the qualitative behavior of the system is the same as that of a fixed bed (σ = 0). It is when σ ≥ 1 that the true countercurrent nature of the adsorber comes into play. When the adsorption-desorption rate is finite the dimensionless length of the adsorber can be readily expressed in terms of an integral, whose evaluation is performed for physically meaningful conditions of the inlet streams. When adsorption-desorption equilibrium is instantaneously achieved the problem is overdetermined and one or more discontinuities have to be introduced in the concentration pr...

Pure countercurrent compact type pipe folding economizer

Abstract: The invention discloses a pure countercurrent compact type pipe folding economizer. The economizer comprises a shell, wherein the two ends of the shell are respectively closed by a first pipe plate and a second pipe plate to form an accommodating space; multiple heat exchange tubes are mounted in the shell, and comprise a heat transfer pipe and first and second round pipes connected to the two ends of the heat transfer pipe; the first round pipe, the heat transfer pipe and the second round pipe are integrally molded, and are equal in perimeters of cross sections; the adjacent heat exchange tubes realize the point contact through projection parts on the heat transfer pipe to form a self-support structure; and gaps are correspondingly formed between adjacent two contact points of the adjacent heat exchange tubes to form a netty channel in the accommodating space. The economizer achieves effective size control of a tube shell pass space through changing the flattening rate and the twisting rate of the deformed heat exchange tubes, so that the shell pass space is more compact, the flowing speed of shell pass refrigerant liquid is accelerated, the tube shell pass heat exchange process is more matched, and the volume of the economizer is reduced.

Function of Thin Segments of Henle’s Loop

Abstract: It is well known that the renal medulla plays an important role in the generation of concentrated urine, which is critical in the maintenance of body fluid osmolality. Since the proposal of the operation of countercurrent systems in the renal medulla by Kuhn and his associates [1–3], it has been widely accepted that the loop structures of the nephron in the renal medulla are essential for the generation and maintenance of a steep osmotic gradient along the axis of the renal medulla. However, the detailed mechanisms by which a steep osmotic gradient is generated by the countercurrent multiplication system remain to be established.

Countercurrent Flow Limitation Calculation of Hot Leg Based On System Program

Abstract: In the event of a Loss of Coolant Accident, a large amount of coolant is released from the reactor, and steam is generated inside the reactor, and then flows down the heat pipe into the steam generator. When a natural circulation is not established in a loop, the condensed liquid in the steam generator is returned to the core by gravity of the wall of the pipe through the hot leg. This countercurrent flow has important influence on reactor safety analysis. At present, many researches have been carried out in this field, but most of them focus on the study of the countercurrent flow characteristics of two-phase flow in vertical or horizontal pipes, there are few researches on the countercurrent flow in a complex. In this paper, the countercurrent flow of two-phase flow in the hot leg under the condition of Loss of Coolant Accident (LOCA) is modeled and calculated. The experimental loop is composed of vertical pipe, inclined pipe and horizontal pipe. It is found that the shape of the hot leg has a significant effect on the injection limit, and the data based on dimensionless square root of velocity is compared with Wallis’ vertical tube results. The effects of liquid viscosity, density of liquid phase and gas, and geometry of pipeline on flooding were also studied.