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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.


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DOI
01 Jan 2014
TL;DR: In this paper, a model is developed for separation of multicomponent gas mixtures in a countercurrent hollow fiber membrane module, where a proper initial guess is proposed for beginning the calculation and a simple procedure is introduced for correcting the guesses, thereby the CPU time is decreased essentially.
Abstract: A model is developed for separation of multicomponent gas mixtures in a countercurrent hollow fiber membrane module. While the model's solution in countercurrent module usually involves in a time consuming iterative procedure, a proper initial guess is proposed for beginning the calculation and a simple procedure is introduced for correcting the guesses, hereby the CPU time is decreased essentially. The model's predictions are compared with the experimental data and a good agreement is achieved. By using data taken from a LAB unit in Isfahan, the proposed model is applied to investigate the feasibility of membrane process for hydrogen separation in this unit. It is revealed that a high hydrogen purity and recovery could be achieved in the permeate stream, while the required area increases at higher stage cut or higher permeate
Journal ArticleDOI
TL;DR: The tiltpipe liquid thermosiphon (TLT) as mentioned in this paper is a heat transporter with water as the liquid, contained in a steel pipe, maintained in a tilted orientation.
Abstract: A new heat transporter is described, the tiltpipe liquid thermosiphon (TLT). In service, a straight, sealed pipe, filled with liquid, is maintained in a tilted orientation. By means of the contained liquid, heat is received from a heat source at the lower end of the pipe, transported to the elevated end, and delivered to a heat sink. The heat transport rate and the temperature distribution in the TLT were studied over a wide range of tilts, with water as the liquid, contained in a steel pipe. At its optimum tilt the TLT combined a high heat transport rate with virtually no temperature degradation in the water from end-to-end of the pipe. In both of these criteria the TLT far exceeded the performance of the unit in vertical orientation, the only one examined by previous investigators. Another characteristic difference between the tilted and the vertical unit was that at any given pipe cross section in the heat transport region (i.e., between the heat source and the heat sink), the water in the tilted pipe had a higher temperature near the top of the cross-section than near the bottom. With vertical orientation there was no such temperature difference. The experimental results with the TLT, particularly in the region of the optimum tilt, were explainable in terms of a liquid thermosiphon mechanism, but a unique one. It was inferred that there was cyclical countercurrent flow of contiguous streams in a single pipe with a warmer, less dense water stream flowing axially upward through a top segment of the pipe cross-section and, separated by a quiescent interfacial plane, a cooler, more dense water stream flowing axially downward, through a bottom segment. It followed that at the pipe terminals each stream reversed itself, becoming its opposite by virtue of heat receipt/delivery at the heat source/sink. The contiguous, countercurrent flow pattern described above was confirmed visually at the optimum tilt of eleven degrees by observation of water flow inside a clear plastic tube added to the midsection of the steel pipe. The streams were rendered visible by injections of soluble coloring material in the water at the elevated and lowered ends of the pipe.
Journal ArticleDOI
TL;DR: In this article, the authors presented a mathematical description of the process of cooling of ethylene in countercurrent heat exchangers of the double-pipe type, where the ethylene gas is flowing in the inner tube, and water is moving countercurrently in the intertubular space.
Abstract: The authors have presented a mathematical description of the process of cooling of ethylene in countercurrent heat exchangers of the ″double-pipe″ type, where the ethylene gas is flowing in the inner tube, and water is moving countercurrently in the intertubular space. Such a system belongs to the basic cycle of polymerization of ethylene by the high-pressure method. Basic properties of heat-exchange apparatuses of a cooling system and its parameters have been described. The interrelation between such physical quantities as pressure, temperature, flow rates of coolants, and heat-transfer surfaces of circulating water and return ethylene has been determined. The proposed model takes account of the ″sticking″ of a liquid polymer onto interior tube walls.
Journal ArticleDOI
TL;DR: In this article, the conditions of ideal heat exchange, according to which at the given heat load and overall heat transfer coefficient the entropy production in the system attains its lower boundary, can be realized in a set of countercurrent heat exchangers on coordinated selection of temperatures and heat capacities of flows.
Abstract: It is shown that the conditions of ideal heat exchange, according to which at the given heat load and overall heat transfer coefficient the entropy production in the system attains its lower boundary, can be realized in a set of countercurrent heat exchangers on coordinated selection of temperatures and heat capacities of flows. The parameters of flows and the distribution of heat transfer coefficients and heat loads between two-flow heat exchangers for the Newtonian kinetics have been determined. The value of the minimal dissipation and the profile of the distribution of the overall heat transfer coefficient for the case where the temperature profile of one of the flows is fixed have been obtained.
Patent
09 Oct 2017
TL;DR: In this paper, a recuperative countercurrent heat exchanger includes a base made of a heat insulating material and a plurality of heat transfer rods or grids passed through the substrate.
Abstract: FIELD: heating systemSUBSTANCE: core of the recuperative countercurrent heat exchanger includes a base made of a heat insulating material and a plurality of heat transfer rods or grids passed through the substrate, wherein the base with rods or grids is arranged to be housed in the heat exchanger housing, dividing it into two channels for counter flow of coolant therethroughEFFECT: increasing the efficiency of heat exchange while enhancing technical capabilities and simplifying service2 cl, 5 dwg

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202358
2022115
202127
202041
201947
201849