E-mail: bomgua@mail.ru
One of the directions of technical progress in transport is development of pipeline transport. A hydraulic transport at which the streams of water or mixture carry friable materials or a homogeneous mixture in pipes is most perspective. Due to the known advantages these types of transport find application at moving minerals (coal, sand, hoggin, oil, solutions of salts, etc) from the place of booty to the user; wastes of concentrating factories; ash and slag of thermal power-stations in dumps; gob to the place of storage, etc. There are vertical or sloping areas in many charts of the hydraulic conveying, for example, getting up of hard material from the underground working or from the bottom of different reservoirs at mining; getting up of tiny liquid (waters, oils and others) on the surface of the earth. As theoretical and experimental researches of the Donetsk national technical university and other scientific centers, and also experiments of exploitation of hydraulic system created by them showed, sometimes it is very expedient to use the airlift pump.
The airlift pump is the device intended for getting up liquid from some depth to the certain height by compressed air. Principle of work of airlift pump consists of the following. If we will introduce air under sufficient pressure in the lower part of the pipe put into water , air emulsion (mixture of water and bubbles of air) appearing in the pipe will rise due to the difference of specific masses of emulsion in the pipe and water in a mining hole. Naturally, the easier is the emulsion the more bubbles of air if will have, but there is the critical limit of the given volume of gas when the pumping of liquid is halted.
Actuality of work is related to the necessity of determination of more exact hydro - dynamic parameters of stream of diphasic mixture in the lifting pipe of airlift pump.
There are six forms of flow of stream at motion of air-water mixture in a vertical pipe: bubble, cork, cork- dispersion, emulsive, pellicle-emulsive, ring and dropping flow. From a number which in the liftings pipes of airlift pump will be mainly realized cork, emulsive, ring. Structure of air-water stream and his description in a great deal is determined by the structural and technological parameters of airlift pump.
Definiteness of scopes of structures of air-water mixtures allows to develop the mathematical models of workings processes of airlift pump. Therefore accepted and considered certain (emulsive) structure of stream and equation characterizing motions in a vertical pipeline is shown in this work. Equation of motion of mixture is shown
where
-mass pumping of mixture;
-air-water mixture density;
-rate of movement of air-water mixture;
-area of transversal section of lifting pipe;
- water density ;
-air density ;
- mass contents of air;
The soeving of the obtained equation will allow to define the values of hydrodynamic parameters of air-water mixture in the set sections of lifting pipe of airlift pump depending on the expense of air. Thus, successive application of methods of mechanics of continuous medium to the modelling of motion of stream air-water mixture is carried out in the presented research, explanation of parameters of mixture is given at the emulsive (foamy) model of stream.