The effect of liquid viscosity on the void fraction in a two-phase gas-liquid flow in narrow mini-channels
Advancing the chemical engineering fundamentals
Multifase Flows (T2-5P)
Keywords: gas-liquid flow, two-phase flow, viscosity, void fraction, narrow channel
Studies on two-phase mixture flow in mini- and micro-channels have become very intensive in the last years. A reason of this increasing interest in two-phase liquid-gas flow in limited spaces is a possibility of intensification of heat and mass transfer processes as well as selectivity and miniaturisation of the processes. This type of flow has found applications in cooling systems for nuclear reactors, space technology, cooling of electronic systems, reactors and bioreactors.
In narrow mini-channels we can observe big differences in two-phase flow hydrodynamics as compared to the flow in pipes of larger diameter. This refers, first of all to flow structures, participation of phases and resistance of flow. In the past decade a number of studies dedicated to this subject were published. The publications were concerned mainly with a description of two-phase water-air flow hydrodynamics. There are no studies dedicated to the flow of two-phase mixtures containing highly-viscosity liquids.
The aim of the present research was to investigate the effect of liquid viscosity on the void fraction in a two-phase liquid-gas flow in narrow mini-channels and to compare the results obtained with relations available in the literature.
The basic element of the constructed experimental set-up was a channel of rectangular cross section. Two 15 mm wide channels with 1.16 mm and 2.40 mm slots were used in the experiments. A liquid phase in the experiments was water and water solutions of saccharose. The values of apparent liquid and gas superficial velocity ranged from 0.028 to 2.30 m/s and from 0.012 to 5,75 m/s, respectively. Liquid and gas streams flowing to the column were measured by precision flowmeters. The two-phase mixture flowing in the channel was filmed by a Photonfocus MV-D752-160 high-speed camera and the image was recorded on a computer hard disk. Next, basing on the recorded image by means of the procedure prepared in the Labview environment, the void fraction in the flowing two-phase mixture was determined. As a result of the research a significant effect of liquid viscosity on the void friction in the flowing two-phase mixture was found.
See the full pdf manuscript of the abstract.
Presented Tuesday 18, 13:30 to 15:00, in session Multifase Flows (T2-5P).
