RU2455056C2 - Method of fluid dispersion and device to this end - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to mixing flows of liquid-phase media and may be used in, for example, power engineering for preparation of fuel oil containing water for combustion. Proposed method comprises accelerating and swirling fluid flow, uniform distribution of fluid flow into several flows, bringing flow parameters to cavitation and mixing of said flows with simultaneous increase in flow total cross-section. Besides, fluid flow is divided into concentric flows. Note here that adjacent concentric flows are spun in different directions and divided into several flows to be accelerated by their contraction and to be mixed. Proposed device comprises casing made up of solid of revolution housing central solid of revolution and jet-forming channels to swirl the flow. Said jet-forming channels are made up of set of thin plates with openings turned relative to each other with respect to casing axis. Plate opening edges are sharp.

EFFECT: power savings, higher efficiency.

4 cl, 4 dwg

Description

The present invention relates to techniques for mixing flows of liquid-phase media and can be used, for example, in the energy industry in the development and manufacture of dispersants (cavitators, emulsifiers) intended for preparation for burning various fuel mixtures (obtaining emulsions of fuel mixtures), in particular fuel oil containing water .

A known method of dispersing liquids, including bringing the parameters of the fluid flow to the occurrence of cavitation by reducing the flow cross section and the subsequent expansion of the flow cross section (RF patent No. 2040320, publ. 25.07.95).

The disadvantage of this dispersion method is the large unevenness of dispersion in the cross section of the flow and the high energy intensity of the process.

There is also known a method of dispersing liquids, including distributing a fluid stream into several streams, accelerating the streams by reducing their cross-section before cavitation occurs, and then mixing these streams while increasing the cross-section of the stream. Reducing the flow cross section in this technical solution is done by installing rods on which cavitation occurs. This method is implemented in the invention according to the patent of the Russian Federation No. 2239491, publ. 11/10/2004. The implementation of the invention allows to achieve a more uniform dispersion across the cross section of the stream, since the rods, during the flow of which cavitation occurs, are uniformly distributed over the stream.

The disadvantage of this method is the high energy intensity of the process and low mixing efficiency of the liquids forming the mixture.

Closest to the proposed one is a method implemented in a device for dispersion (RF patent No. 2215203, publ. 10/27/2003), including the distribution of the fluid flow into several flows, accelerating the flows by reducing their cross-section before cavitation occurs, and then mixing these flows with simultaneous an increase in the cross section of the flow along which the fluid flow is pre-twisted. Swirling the flow improves fluid mixing.

The disadvantage of this method is the high energy intensity of the process and the difficulty of regulating the optimal operating modes of devices that implement the method.

A device for dispersing a liquid is also known (see RF patent No. 2239491, publ. November 10, 2004), comprising a housing in which at least one baffle is installed to separate the flow and devices that cause cavitation when they are surrounded by a mixture of liquids.

The disadvantage of this device is the low efficiency of mixing liquids due to the lack of elements in the device that ensure swirling flow, and a large energy intensity of the process.

The closest in technical essence to the proposed invention (prototype) is the dispersant according to the patent of the Russian Federation No. 2215203, publ. October 27, 2003. This known device comprises a housing with an inner surface in the form of a body of revolution, mounted profiled central body in the form of a body of revolution (central cowling) and stream forming channels coaxially with the axis of the inner surface of the body, providing flow swirling. The formation of jets in this case is carried out using a scapular crown.

The design of this device is made for specific flow parameters and does not allow changing the minimum flow cross section and the ratio of the tangential and axial components of the flow velocity in the device, therefore, when changing the flow parameters, it is necessary to replace the entire device or its individual parts.

The objective of the invention is to reduce the energy intensity of the process and increase the efficiency of mixing the liquids forming the mixture, as well as achieving the ability to control the parameters of the fluid flows without changing the design of the device or its parts.

To obtain such a technical result in the proposed method of dispersing a fluid, including accelerating and swirling the fluid flow, uniform distribution of the fluid flow over a number of flows, bringing the parameters of the fluid flow to the occurrence of cavitation and mixing the flows while expanding the flow cross section, additionally the liquid flow is separated, at least , into two concentric streams, while adjacent concentric streams give rotation in different directions and are divided into a number of separate streams each from concentric streams and additionally accelerate each of the individual streams by narrowing them, and then mix all the streams.

Distinctive features of the proposed method are the additional separation of the fluid flow into at least two concentric streams, while adjacent concentric streams are rotated in different directions and each concentric stream is divided into a number of separate streams and additionally accelerate each of the individual streams by narrowing them , and then mix all these streams.

When mixing concentric and swirling flows in different directions, not only a zone of effective mixing of flows is formed, but also a zone of cavitation vortices is formed, and due to the addition of velocities of swirling flows in opposite directions, vortices are formed at a lower flow velocity in the most narrowed parts of the dispersant, which reduces the energy consumption process.

It is advisable, when implementing the method, to select the spin parameters of concentric flows from the condition that the total rotation moment is equal to zero, and to adjust the spin parameters by changing the ratio of the tangential and axial velocities and the minimum cross-section of the flows of each of the individual flows.

To achieve the above technical result, a device for dispersing liquids is proposed, which, like the prototype, comprises a body with an inner surface in the form of a body of revolution, a profiled central body in the form of a body of revolution (central cowling) aligned with the axis of the inner surface of the body, and jet-forming channels to ensure twisting flow, as well as devices that cause cavitation when they flow around a mixture of liquids.

In contrast to the known device, there is at least one additional partition made concentrically to the inner surface of the housing, and the jet forming channels separated by a partition have an orientation that provides the opposite direction of the swirl of concentric flows relative to the axis of the device. It is also proposed to form the jet forming channels for swirling the flow of a mixture of liquids from a package of thin plates with windows rotated relative to each other relative to the axis of the housing. In this case, it is advisable to rotate the thin plates relative to each other so that the curve along the edge of the windows along the edges of the windows in the plates is smooth. To facilitate the occurrence of cavitation, it is advisable to edge the windows in the plates with sharp edges, as well as provide additional devices that cause cavitation, such as protrusions in the windows on some of the plates.

The proposed device allows not only efficiently and with less energy to disperse liquid mixtures, but also allows you to adjust the main parameters of the dispersant, namely the minimum flow cross section and the ratio of the tangential and axial components of the flow velocity in the device.

The proposed method is carried out in the following sequence. The fluid flow to be dispersed is accelerated by reducing the flow cross section, then it is divided into at least two concentric flows, while adjacent concentric flows are rotated in opposite directions. Each of the concentric streams is divided into a number of separate streams and additionally accelerate these streams by reducing their cross section, and then mixing these streams with simultaneous expansion of the total cross section of the stream. The parameters of concentric flows are controlled by changing the ratio of the tangential and axial velocity components and the minimum cross-section of each of the individual flows. It is advisable to choose the spin parameters of concentric flows from the condition that the total rotation moment is equal to zero.

When mixing concentric and swirling flows in opposite directions, a zone of high tangential stresses is formed at the boundary of concentric flows, which leads not only to intensive mixing of liquids, but also to the appearance of vortex cavitation, while processes occur at lower energy consumption, since the relative velocities of the swirling flows in different directions, increasing. For example, when the ratio of the tangential and axial velocities in each of the concentric flows before mixing is 1, the relative velocity of the multidirectional flows in the mixing zone reaches 1.4.

The invention is illustrated by drawings, which depict:

figure 1 is a General view of a device for dispersing liquids (dispersant) in section;

figure 2 - section aa the General view of the device;

figure 3 is a view of one of the jet-forming channels formed by windows in thin plates (view B in section AA);

figure 4 - part of one of the plates of the dispersant with protrusions to facilitate the occurrence of cavitation.

The proposed device for implementing the method comprises (Fig. 1) a housing 1 with an inner surface in the form of a body of revolution. Inside the housing 1, packages of thin plates 2 and 3 are installed, tightened together by curly washers 4 and 5 with the help of a central fairing 6 and a bolt 7. Directly to the housing 1, the packages of plates are attached using a threaded sleeve 8. The disperser housing 1 has flanges 9 and 10, with the help of which it is installed in the pipeline rupture and fastened to the flanges of the inlet pipe 11 and the outlet pipe 12. The possible shape of the thin plates 2 and 3 is shown in figure 2 - these are washers in shape, along the outer edge of which trapezoidal windows 13 and 14 are made on the plates 2 and 3 respectively etstvenno. The streamforming channels are formed by sequentially rotating adjacent thin plates in the package with windows relative to each other around the axis of the body (FIG. 2 and FIG. 3), while the orientation of the streamforming channels formed by the windows 13 and 14 should provide the opposite direction of swirling of the concentric fluids relative to device axis. It is advisable the step by which the edges of the windows of adjacent plates are shifted relative to each other, gradually increase from input to output (figure 3), for example, according to arithmetic or geometric progression. Changing the parameters of the progression 7 allows you to change the ratio of the tangential and axial components of the flow velocity and the minimum flow cross section in the jet forming channel, while the curves enveloping the edges of the windows along the flow of the liquids (Fig. 3) have a smooth bend. To improve the mixing of liquids and to facilitate the occurrence of cavitation, the edges of the windows in the plates have sharp edges 15 (Fig. 3), in addition, the edges of some windows can be provided with protrusions 16 (Fig. 4). Concentric to the inner surface of the housing 1, the partition 17 in this device is formed by a package of thin plates 2, and more precisely by jumpers 18 on these plates between the inner circular hole and the windows 13.

The device operates as follows.

The mixture of liquids subjected to dispersion is supplied under pressure to the inside of the housing 1 under pressure, where the fluids smoothly accelerate when moving inside the housing due to the narrowing of the flow using the central fairing 6 and the figured washer 4. Next, the flow is divided into two concentric flows using the baffle 17. The external concentric stream is additionally accelerated and receives rotation relative to the axis of the device as liquids pass through the jet-forming channels formed by a package of thin plates 2, and the inner end ntrichesky additional flow accelerates and receives rotation about the axis of the device during the passage of liquids through the jet forming channels formed package of thin plates 3, the outer and inner concentric stream is opposite the direction of twist. After the passage of the jet forming channels, the external and internal concentric flows merge, and since these flows are twisted in opposite directions, a zone of high tangential stresses forms on their boundary, caverns appear in the centers of the vortices and a zone of vortex cavitation forms. Vortex formation and cavitation also occur on the sharp edges of the edges of the plates, which form the jet-forming channels and on the protrusions 16 on the edges of the windows.

The proposed design of a device for dispersing liquids allows you to change the configuration of the jet forming channels and, accordingly, the main parameters of the device, namely the minimum flow cross section and the ratio of the tangential and axial components of the flow velocity in the device, without changing the design. This allows you to reconfigure the dispersant to the optimal mode of operation when changing the parameters of the fluid flow and to reduce the energy consumption for dispersion.

Claims (4)

1. A method of dispersing a liquid, including dividing the fluid stream into at least two concentric flows, imparting adjacent concentric flows to rotate in different directions, dividing each of the concentric flows into a series of separate flows and additional acceleration of each of the individual flows by narrowing them, bringing parameters of the fluid flow before cavitation and mixing of all flows, characterized in that the mixing of the flows is carried out immediately after swirling, and the swirling parameters are Centric flows are selected from the condition that the total rotation moment be equal to zero. 2. A device for dispersing a liquid, comprising a housing with an inner surface in the form of a body of revolution, mounted coaxially with the axis of the inner surface of the housing, a profiled central body in the form of a body of revolution, at least one partition made concentrically to the inner surface of the housing, stream forming channels providing the opposite direction swirls of concentric flows relative to the axis of the device and the device, causing cavitation when flowing around them with a mixture of liquids, characterized in that rueforming channels for swirling the flow of a mixture of liquids are formed by a package of thin plates with windows rotated relative to each other relative to the axis of the housing. 3. The device for dispersing a liquid according to claim 2, characterized in that the edges of the windows in the plates have sharp edges. 4. A device for dispersing a liquid according to claim 2, characterized in that at least some of the windows in the plates are provided with protrusions.

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