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.

Countercurrent Gas-Liquid Flow in Boiling Channels

Abstract: Countercurrent gas-liquid flow is theoretically and experimentally evaluated for a boiling system simulating a BWR core. In a single channel, flow patterns are determined from the mass balance equations and pressure drop under steady state conditions is calculated for each flow pattern using a drift flux model, where the distribution parameter and drift velocity are correlated as functions of void fraction and hydraulic diameter from void fraction data. The calculated pressure drop shows a similar trend to that of the data for the effects of bypass leak flow rate and heater power. Countercurrent behavior in three boiling channels under slow transient conditions is also predicted from the single channel characteristics and close agreement is obtained between the predicted and experimental results. The results show that steam up-flow or cocurrent up-flow easily occurs in a channel with low pressure drop, namely, with a large entry orifice, high power or low bypass leak flow rate.

Co2 capture processes using rotary wheel configurations

Abstract: The disclosure relates to a continuous or semi-continuous, cyclic, countercurrent sorption-desorption method for enhanced control, separation, and/or purification of CO2 gas from one or more sources of a mixture of gases through integrated use of solid monolithic sorbents having a sorption selectivity for the CO2 gas, wherein liquid phase water is added to increase the heat capacity of the mixed gas source(s) in order to achieve a thermal wave moving through the thickness of the sorbent material faster than the CO2 sorption wave.

Solutions in closed form for a double-spiral heat exchanger

Abstract: The MACSYMA code for symbolic manipulation was used to obtain solutions in closed form for double-spiral heat exchangers of a few turns, both with and without heat losses to the surroundings. The solutions, which are for an equal rate of flow of the same fluid in both directions, reveal the existence of an optimal number of transfer units (an optimal rate of flow) for which the temperature rise for the heated stream is a maximum for a given thermal input or temperature difference. Such anomalous behavior, which is of obvious importance in the design and operation of double-spiral exchangers, has generally been overlooked or misinterpreted in prior experimental work and numerical solutions. For realistic heat losses to the surroundings, double-spiral exchangers of multiple turns are shown to be superior to true countercurrent exchangers in terms of producing a temperature rise