MASS TRANSFER IN COUNTER-CURRENT LIQUID AND GAS FLOW IN A VERTICAL PIPE
Keywords:heat transfer, mass transfer, contact heat and mass transfer devices, flooding mode
Background. Contact heat and mass exchangers are used in many technological processes: cooling of circulating water or fume gases, air humidification in air conditioning systems, etc. In the most common types of these devices, the main elements are vertical pipes in which a film of liquid flows down under the pull of gravity against the gas flow. However, there is no universal dependence for the calculation of such processes.
Objective. The purpose of the paper is to investigate the process of mass transfer for the case of counter-current interaction of a film of water and air in a vertical pipe before the onset of the flooding regime.
Methods. An experimental stand was created, a pipe with an inner diameter of 34 mm and a length of 1.4 m was used as a working area. Air and water flow rates, dry and wet bulb temperatures at the inlet and outlet of the apparatus were measured. The control over the complete wetting of the irrigation surface took place visually through the holes in the exit of the vapour-gas mixture in the upper part of the experimental setup. According to the developed method, the mass transfer coefficient was determined.
Results. Experimental dependences for determining the mass transfer coefficient are obtained. The presence of the influence of water consumption on the mass transfer coefficient is shown. The limits of application of the analogy between heat and mass transfer are analysed.
Conclusions. An empirical dependence convenient for engineering calculations is proposed. The reliability of the experimental technique and processing of its results is confirmed, which allows using the technique for experimental research of more complex systems. In future studies, it is planned to investigate in more detail the effect of fluid flow on the mass transfer process.
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