RU2355969C2 - Heat exchanger - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: invention relates to the devices aimed at increasing convective heat exchange intensity and can be used in heating engineering. The aim of the invention consists in increasing heat exchange between the cooling medium and the medium being cooled, increasing cost effectiveness and reliability of the heat exchangers performance. The above aim is achieved in a heat exchanger having cavities for the passage of the cooling and cooled liquids which are formed by baffles fitted with the elements making the liquids flow turbulised; the elements are made as alternating valleys and tops in the form of truncated cones set in lines or chequerwise and opposite to each other on the adjacent baffles complying with their total coaxiality; the elements making the liquids flow turbulised are fitted with projections which are hollow or solid, set inside the truncated cones on their smaller base and the height of the projections is greater than that of the cones by the specified value. According to the second version of the invention the elements making the flow turbulised are fitted with tubes which are set along the axis of the truncated cones, pierced through the baffles and used as cavities for the passage of the liquid being cooled; and the cavities for the passage of the cooling liquid are formed by the adjacent baffles.

EFFECT: increasing heat exchange between the cooling medium and the medium being cooled, increasing cost effectiveness and reliability of the heat exchangers performance.

2 cl, 5 dwg

Description

The invention relates to devices designed to increase the intensity of convective heat transfer, and can be used in thermal power, utilities, transport and other sectors of the economy.

In these sectors of the national economy, the use of devices using convective heat transfer for heating and cooling liquids and gases, to prevent thermal pollution of the environment, is of great importance. The main indicator of the operation of these devices is the intensification of heat transfer.

In known devices made in the form of tubular heat exchangers, radiators, to increase the heat transfer intensification, parallel tubes are located most rationally - corridor or staggered [1, p.173-177].

The use of elements in tubing devices that turbulent the flows of both cooled and cooling liquids and gases leads to a certain increase in heat transfer intensification. In one of these devices [1, p.135 and p.285], tubes made of elements turbulent in the form of protrusions of artificial roughness of a triangular or rectangular shape located on the inside of the tubes are used as cavities for passing cooled and cooling liquid (see figure 1).

The disadvantage of this device is the relatively low efficiency for turbulent flows due to the tear-off liquid flow around the protrusions on the inner side of the tubes.

As a prototype, a plate air heater according to A.S. No. 1575062, containing as turbulators, recesses and oblong protrusions in an alternating manner. On the partitions, in addition to them, there are supporting protrusions for the formation between the sheets of the desired gap and which are not turbulators. This type of turbulizer has the disadvantage that when flowing around the protrusions, vortices are formed only in the stern part and do not have high efficiency.

The objective of the invention is to increase the efficiency and reliability of the operation of the heat exchanger by increasing the intensity of convective heat transfer, which is achieved by increasing the degree of turbulization of the flows of both cooled and cooling liquids and gases.

To achieve this technical result, in the heat exchanger, including the cavity for the passage of the cooled and cooling liquids, partitions are used for the formation of the cavity for the passage of the liquid, made with elements turbulent flow, in the form of alternating hollows and elevations in the form of truncated cones located corridor or staggered on the partitions installed with the location of truncated cones on adjacent ones opposite to each other and in compliance with their general alignment, in addition, the elements are turbulizing the liquid flow is provided with protrusions made hollow or solid, which are installed inside the truncated cones on their small bases, and the height of the protrusions is greater than the height of the cone by an amount determined in accordance with the expression h = (0,1 ÷ 0,3) · r, where r is the radius of the small base, while the adjacent partitions form cavities with alternation to pass the cooled fluid, then to pass the coolant.

According to the second option, in the heat exchanger, which includes cavities for passing cooled and cooling liquids, formed by partitions made with elements that turbulent the fluid flow in the form of alternating depressions and elevations in the form of truncated cones located corridor or staggered, and opposite to each other on adjacent partitions, observing their general alignment, the elements that turbulent the flow are equipped with tubes installed along the axis of the truncated cones and passing through the partitions, and the tube and used as cavities for passing coolant, and cavities for passing coolant are formed by each adjacent partition.

The use of a heat exchanger with the proposed design of elements that turbulent the flow makes it possible to purposefully induce a lot of quasi-ordered vortices in the fluid flow, including horseshoe-shaped ones with increased intensity, which leads to an increase in the heat exchange intensity between adjacent alternating cavities through which cooled and cooling liquids (gases) pass ) The supply of flow turbulization elements with hollow and solid protrusions or tubes passing through the partitions increases the heat transfer intensification, which is achieved due to the contact of many horseshoe-shaped vortices with each protrusion and with each tube along its entire length.

The authors are not aware of the use in other technical solutions of the proposed combination of distinctive features to increase the efficiency, reliability, efficiency of heat exchangers. Therefore, we can conclude: the proposed design of the heat exchanger is new and meets the criterion of "inventive step".

The invention is industrially applicable and can be used in the mass production of heat exchangers.

The proposed invention is illustrated by the drawings presented in figure 2-5.

Figure 2 presents a longitudinal section of a heat exchanger, in which the cavity for the passage of water is formed by partitions.

Figure 3 is a view along aa.

Figure 4 presents a longitudinal section of the walls of the heat exchanger with the contact diagram of the horseshoe-shaped vortices with the inner surface of the cavities for the passage of fluid, equipped with additional elements, turbulent flow in the form of protrusions.

Figure 5 presents a longitudinal section of a heat exchanger, where the cavity for the passage of cooled water and additional elements, turbulent flow, made in the form of tubes.

In the proposed heat exchanger, the cavities for passing the cooled and cooling liquids are formed by partitions 1 (see FIG. 2) made with alternating depressions 2 and elevations 3 in the form of truncated cones with a generatrix 4 and a small base 5. The truncated cones serve as elements turbulent fluid flow (see figure 3). Additional elements, turbulent flow, made in the form of protrusions 6 hollow or solid. The protrusions 6 are installed inside the truncated cones on small bases 5. The height of the protrusions 6 h is determined in accordance with the expression h = (0.1 ÷ 0.3) · r, where r is the radius of the small base 5 of the truncated cone. Partitions 1 (see Fig. 3) in the heat exchanger are installed with the arrangement of truncated cones on adjacent partitions opposite to each other in compliance with their general alignment along the common axis 7, while adjacent partitions 1 form cavities with alternation for passing the cooled liquid, then for passing coolant, and fluid flows in adjacent cavities are directed counter to each other.

It is possible to perform additional elements that turbulent the flow in the form of tubes 8 (see Fig. 5) installed along the axis 7 of truncated cones and passing through the walls 1. The tubes 8 are installed in the tube board 9. The cooled liquid is supplied through tubes 8, the outer surface which plays the role of additional elements that turbulize the fluid flow. Cavity passages are formed by each adjacent partition 1.

The work of the proposed heat exchanger.

The device operates as follows. The fluid flow during movement between the two partitions 1 and the flow around the elements turbulizing the fluid flow forms a stable horseshoe-shaped vortex at the base of each of them, covering the element, turbulating the fluid flow and having a high intensity. The latter leads to enhanced heat removal both from the partition 1 and from the depressions 2 and the elevations in the form of a truncated cone 3. In the horseshoe-shaped vortex, a continuous renewal of fluid occurs, which enhances the development of convection currents. When the elements turbulizing the fluid flow are supplied with hollow or solid protrusions, vortices also develop inside them, which additionally enhance the heat transfer intensity. In the case of continuous protrusions, part of the heat transfer is carried out by complex heat transfer.

The second variant of the proposed device is presented in figure 5, which shows the tubes 8, through which the cooled liquid is supplied, united by the tube board 9. In this case, the cooling liquid is supplied through the channels 10. Horseshoe vortices are formed in the recesses, in a set covering each of the tubes in length, which leads to a sharp increase in heat transfer processes.

Technical and economic effect of using a heat exchanger

The expected increase in the efficiency of cooling liquids will lead not only to an intensification of the cooling process, but also to a decrease in the metal consumption of heat exchangers, which, when applied massively, will lead to a significant economic effect.

Information sources

1. Heat and mass transfer. Thermotechnical experiment. Directory. M .: Energoizdat. 1982 / Ed. V.A. Grigoriev and V. M. Zorin. S.135, 173-177, 285.

Claims (2)

1. A heat exchanger, including cavities for cooled and cooling liquids, formed by partitions made with elements that turbulent the fluid flow in the form of alternating cavities and elevations in the form of truncated cones located corridor or staggered and opposite to each other on adjacent partitions in compliance with their general alignment, characterized in that the elements that turbulent the flow are provided with protrusions made hollow or solid, mounted inside truncated cones on their small bases, and the height of the protrusions is greater than the height of the cones by an amount determined in accordance with the expression h = (0.1 ÷ 0.3) · r, where r is the radius of the small base, while the adjacent partitions form cavities with alternation for passing the cooled liquid, then for pass coolant. 2. A heat exchanger, including cavities for passing cooled and cooling liquids, formed by partitions made with elements turbulating the fluid flow in the form of alternating cavities and elevations in the form of truncated cones located corridor or staggered and opposite to each other on adjacent partitions in compliance with their general alignment characterized in that the elements turbulizing the flow are provided with tubes installed along the axis of the truncated cones and passing through the partitions, the tube and used as cavities for passing coolant, and cavities for passing coolant are formed by each adjacent partition.

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