Method of measuring void fraction in a channel with porous media
- PDF / 266,563 Bytes
- 4 Pages / 595.32 x 842.04 pts (A4) Page_size
- 79 Downloads / 140 Views
DOI: 10.1134/S0869864320020134
Method of measuring void fraction in a channel with porous media * E.A. Tairov L.A. Melentiev Energy Systems Institute SB RAS, Irkutsk, Russia E-mail: [email protected] (Received July 2, 2019; revised September 15, 2019; accepted for publication November 6, 2019) A new method is described for measuring the average void fraction of a one-component two-phase flow moving in a channel with a fixed porous aggregate. The known method of cutting off the flow is used but, in contrast, the vapor phase in the cut-off volume is transferred to the condensed state, and the released space is filled with the measured amount of additional fluid. The result of verification using this method is presented for the previously proposed formula for calculating the void fraction of the adiabatic steam-water flow in a channel with a fixed bed of spherical particles. Keywords: steam-water flow, granular layer, measurement of void fraction.
To date, quite a large number of methods for measuring the void fraction in flows based on the use of various physical principles have been proposed. The monograph [1] offers the following main methods: cutting-off, the dynamic weights method, gamma- and beta- radiography, the method of electrical conductivity, the optical method, the photographic method, the method of thermocouples and hot-wire method. Their implementation requires special, sometimes quite complex equipment for measuring the local, cross-section or beam averaged, as well as cut-off volume averaged void fraction. Based on the results of experimental studies, generalizing formulas have been obtained for calculating the void fraction in the flow in pipes, ring channels, and rod assemblies [2]. The two-phase flow through porous media has not been sufficiently studied. In [3], examples of attempts to use penetrating radiation of various nature for determining the proportion of liquid in a mixture are given and it is noted that they require huge resources and reinforced safety procedures. A relatively simple weighing method was used in experiments of [4] with air passing through a layer of spherical particles saturated with stationary water. The authors of paper [3] applied the patent-protected technique of a capacitive probe to measure the average * The work was carried out in the framework of the scientific project III.17.1.3 of the Basic Research Programs of SB RAS, reg. No. AAAAA 17-117030310443-5 at the L.A. Melentiev Energy Systems Institute SB RAS on CCU “High-Temperature Contour”.
E.A. Tairov, 2020
313
E.A. Tairov
void fraction in an air-water flow through a layer of glass balls at atmospheric pressure. To test the method, the mentioned weighing technique was used [4]. Weighing is one of the ways to find the volume ratio of the liquid and gas phases in a pre-selected control volume. A long-known and well-proven method for selecting the control volume in gas-liquid flows is the flow cut-off method. A number of authors [5, 6] note that the flow cut-off method allows obtaining very accurate and rep
Data Loading...
