Analysis of basic parameters of radial types of pulsed rotary equipment

Abstract

Parameters of radial types of pulsed rotary equipment for the treatment of liquids are examined, and computational relationships and analysis criteria are described. Results are presented for experimental investigations confirming the adequacy of the proposed computational procedure.Pulsed rotary equipment (PRE) is used to produce stable highly disperse emulsions and suspensions, intensify the solution and extraction of substances, change the physicochemical parameters of liquids, break down molecular compounds by multifactorial pulsed action on liquid-liquid, liquid-solid, and gas-liquid systems, including: 1) mechanical action on particles of a heterogeneous medium (impact, shear, and pulverizing loads and contacts with working parts of PRE);2) hydrodynamic effect (large shear stresses in a liquid, developed turbulence, and pressure and velocity pulsations in a liquid flow); and3) hydroacoustic effect on a liquid (small-scale pressure pulsations, heavy cavitation, shock waves, and nonlinear acoustic effects) [1-7].One of the basic design features of PRE is the use of a rotor and stator in the form of disks (axial type of PRE), or cylinders (radial type of PRE). In the first case, channels for the passage of liquid are coaxial with the axis of rotation of the rotor, and in the second, they are located in the cylindrical walls of the rotor and stator, and the flow of liquid takes place in the radial direction. The development of centrifugal forces acting on the liquid within the recess of the rotor is an advantage of radial over axial types of PRE. Figure 1 shows a typical schematic of a radial type of PRE. The liquid to be treated is delivered under pressure, or gravity flow through an inlet pipe into the rotor recess, proceeds through the channels of the rotor and stator, and effective chamber formed by the housing and cover, and exits from the apparatus via a discharge pipe.During rotation, the rotor channels become periodically aligned with the stator channels. If the rotor channels are covered by the stator wall, the pressure increases in the rotor recess. When a rotor channel is aligned with a stator channel, the pressure is reduced for a short time interval, as a result of which a pulse of excess pressure develops in the stator channel. A short-lived pulse of reduced ("negative") pressure develops behind it, since alignment of the rotor and stator channels has been concluded, and the feed of liquid into the stator channel is accomplished only by a "transit" flow from the radial gap between the rotor and stator. The volume of liquid in the stator channel tends to exit from the latter, and tensile stresses are created in the liquid under inertial forces; this will result in cavitation. Cavitation bubbles will grow as the pressure drops to that of the saturated vapors of the liquid being treated at a given temperature, and collapse or surge into the stator channel as the pressure increases.In analyzing PRE, it is necessary to isolate the following two problems: analysis and design of universal equipment inten...

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