Mass transfer in a low-pressure vortex tube

Analysis and calculation have been conducted of the process of low-pressure reverse osmosis in the membrane apparatus of the system for recycling hygiene water for the space station. The paper describes the physics of the reverse osmosis treatment and determines the motive force of the process, which is the difference of effective pressures (operating pressure minus osmotic pressure) in the solution near the surface of the membrane and in the purified water. It is demonstrated that the membrane scrubbing action is accompanied by diffusion outflow of the cleaning agent components away from the membrane. The mass transfer coefficient and the difference of concentrations (and, accordingly, the difference of osmotic pressures) in the boundary layer of the pressure channel can be determined using an extended analogy between mass transfer and heat transfer. A procedure has been proposed and proven in an experiment for calculating the throughput of a reverse osmosis apparatus purifying the hygiene water obtained through the use of a cleaning agent used in sanitation and housekeeping procedures on Earth. Key words: life support system, hygiene water, water processing, low-pressure reverse osmosis, space station.

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Heat and Mass Transfer Between Cold and Hot Vortex Cores inside Ranque-Hilsch Vortex Tube-Optimization of Hot Tube Length

International Journal of Heat and Technology ◽

10.18280/ijht.340105 ◽

2016 ◽

Vol 34 (1) ◽

pp. 31-38 ◽

Cited By ~ 16

Author(s):

Seyed Rafiee ◽

M. Sadeghiazad

Keyword(s):

Mass Transfer ◽

Heat And Mass Transfer ◽

Vortex Tube ◽

Tube Length

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Mass transfer coefficient and retention of PEGs in low pressure cross-flow ultrafiltration through asymmetric membranes

Journal of Membrane Science ◽

10.1016/0376-7388(94)00197-7 ◽

1995 ◽

Vol 99 (1) ◽

pp. 1-20 ◽

Cited By ~ 53

Author(s):

P. Prádanos ◽

J.I. Arribas ◽

A. Hernández

Keyword(s):

Mass Transfer ◽

Transfer Coefficient ◽

Mass Transfer Coefficient ◽

Cross Flow ◽

Low Pressure ◽

Asymmetric Membranes

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Research on the heat and mass transfer characteristics of fin-tube exchanger under low pressure environment

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2017.01.012 ◽

2017 ◽

Vol 115 ◽

pp. 692-701 ◽

Cited By ~ 4

Author(s):

Run-ze Jia ◽

Yi-chun Wang ◽

Xi-long Zhang ◽

Rui Wan

Keyword(s):

Mass Transfer ◽

Heat And Mass Transfer ◽

Low Pressure ◽

Transfer Characteristics ◽

Fin Tube

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Vortex Tube Applications in Micro-Power Generation

2002 International Joint Power Generation Conference ◽

10.1115/ijpgc2002-26056 ◽

2002 ◽

Author(s):

Selin Arslan ◽

Bojan Mitrovic ◽

Michael R. Muller

Keyword(s):

Pressure Drop ◽

Power Systems ◽

Steam Turbine ◽

Vortex Tube ◽

Low Pressure ◽

Total Efficiency ◽

Pressure Drops ◽

Large Pressure ◽

Micro Power ◽

Vortex Tubes

The purpose of this paper is to study vortex tube performance characteristics and the use of vortex tubes to increase the total efficiency of power systems, especially micropower systems. A vortex tube is a device in which compressed air is made to swirl and separate into two low-pressure streams, one with higher temperature than the entry and the other lower. The lack of moving parts and electricity make the vortex tube attractive for a number of specialized applications where simplicity, robustness and reliability are desired. Vortex tubes are currently used for industrial cooling applications, separation technologies, and chemical analysis. It is well known that the temperature difference between the hot and cold sides of the vortex tube scales with the pressure drop. Also, at any pressure drop, the temperatures and flow rates are dependent on the flow fractions between the hot and cold sides. Data is available for large pressure drops, but this paper presents experimental results at low-pressure drops optimizing the operational modes for various applications. The micro-power systems under consideration include micro-turbines, which evolved out of automotive turbocharger technology. The use of vortex tubes in power systems has received some attention but the use of both the hot and cold streams has never been considered. In this work, we consider such dual use. As an example of an application, the vortex tube is considered in conjunction with a heat recovery steam generator (HRSG). The vortex tube splits the turbine exhaust flow into hotter and cooler streams. The cooler stream is still hot enough to supply all needed heat in the economizer section, leaving the hotter stream to increase the exit temperature from the superheater. In this way both the air leaving the HRSG and going to the steam turbine will have an increased enthalpy and cycle efficiencies are improved. In addition, steam turbine exit quality is increased.

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