RU2296930C1 - Method for cooling of frame of rotary plate heat exchanger and device for its realization - Google Patents

Abstract

FIELD: heat power engineering, mainly for gas-turbine engines, for example, automobile engines.

SUBSTANCE: the offered method consists in extraction of part of the flow of heat exchange medium and direction of it along the frame wall, in this case the extracted part of the flow of hot medium is directed along the frame wall after a preliminary cooling which prevents flow about of the frame wall by hot medium and, consequently, provides for reduction of thermal deformations of the flame. The cooling system realizing this method represents cooling ducts located along the frame wall: the main and the additional duct with a guide case. The main duct is formed by two shells enveloping the heat exchange matrix, it is U-shaped and has a bottom positioned on the heat check. The inner shell is installed in cantilever on the hot cheek and may be made in the form of a heat-insulating wall separating the additional cooling duct from the main one. The outer shell divides the main duct into two bends, one of which communicates with the additional duct, and together with the cover serving at the same time as the bottom of the additional duct, this shell makes up the system guide case. The additional cooling duct, depending on the structural features of the heat exchange matrix and operating parameters of the heat exchanger, is formed by the inner shell and either by slotted ducts of the matrix, at least by one, or by a special duct (slotted or some other) newly introduced in the device, at least by one, or by a part of the porous packing of the matrix, insulated or non-insulated from the main space of the packing.

EFFECT: enhanced efficiency of cooling of the heat exchanger frame and, respectively, reduced its thermal deformations and stresses in it at a structural simplification of the cooling system.

6 cl, 6 dwg

Description

The invention relates to the field of power engineering, and more specifically to methods and devices for heat exchange of gaseous media, for example, hot gas and air in rotary heat exchangers, and relates mainly to rotary disk heat exchangers of regenerative transport gas turbine engines, for example, automobile ones.

Currently, a regenerative gas turbine engine (GTE) is considered as a promising engine for various types of vehicles due to its well-known properties: a wide range of used fuel and low toxicity of exhaust gases. An acute problem that developers of gas turbine engines continue to deal with is the creation of a heat exchanger with high performance characteristics, the stability of which depends largely on the scale of thermal deformations of the rotor frame.

The problem solved by the proposed group of inventions is aimed at reducing thermal deformations of the rotor frame due to its effective cooling.

A known method of cooling the frame of a rotating disk heat exchanger (AS USSR No. 1070422, F28D 19/00), in which a part of the stream is separated from each flow of heat-exchanging gaseous media and directed into the channel between the frame wall and the heat-transfer matrix, and this flow is redistributed so so that when supplying hot gas along the wall of the frame, its minimum flow passes, and when air is supplied, its maximum flow. This method is inefficient, because does not prevent the heating of the frame wall with hot gas.

A known method of cooling the frame of a rotating disk heat exchanger due to the ejection pumping of air and chilled gas through the cooling channel near the surface of the frame (AS USSR No. 792067, F28D 19/00), in which the frame is not sufficiently cooled due to the low costs of the ejected media .

The closest analogue of the proposed method and, therefore, the prototype, is a method of cooling the frame of a rotating disk heat exchanger, in which part of the stream in a given volume is taken from each flow of heat-exchanging gaseous media alternately supplied to a heat-exchange matrix, for example hot gas and air, and sent to a cooling channel formed along the wall of the frame between the hot and cold cheeks (AS USSR No. 552501, F28D 19/00).

For effective cooling in the prototype, the separated part of the hot gas stream at the inlet to the cooling channel is twisted using a guide apparatus to partially reduce its temperature, and the speed of the separated part of the air stream is increased by narrowing the passage section of the channel. However, due to the fact that the separated stream of hot gas is supplied to the cooling channel from the hot side and is almost slightly cooled, the wall temperature in the initial section does not change due to the small temperature and gas temperature difference, and in the final section the wall and the back side of the cheek are heated . The frame is cooled only when an oncoming flow of a cold stream of air-air flows along its wall.

Such a scheme does not provide sufficiently effective cooling; moreover, it causes constructive complication of the cooling system implementing this method and, as a result, of the heat exchanger as a whole.

Known cooling systems for the frame of a rotating disk heat exchanger (USSR author's certificate No. 552501, 792067 and 1070422 all F28D 19/00) are a cooling channel located along the frame wall, a guiding apparatus through which part of the heat-exchange medium separated from the general flow is fed into the channel : hot gas or air, and additional means for ejection, swirling and / or acceleration of the flow.

Of these, the closest analogue and, accordingly, the prototype of the proposed system is a cooling system for the frame of a rotating disk heat exchanger in accordance with USSR No. 552501, containing a cooling channel located along the frame wall between its hot and cold cheeks, formed by two cylindrical shells enclosing the heat exchange matrix, of which the inner cantilever is mounted on the hot cheek, and a guide apparatus made in the form of spacers installed on the side of the hot cheek, twisting flow.

The prototype system implements an insufficiently effective cooling method, because hot gas passes almost uncooled along the frame wall, and the presence of spacers, the curved shape of one of the shells and the interconnection of elements complicate the design of the system.

The technical result obtained from the use of the proposed method and cooling system is to constructively simplify the system and increase the cooling efficiency by eliminating contact during the cooling of hot gas with the wall and cheeks of the frame.

The technical result is achieved by the fact that in the method of cooling the frame of a rotating heat exchanger, in which part of the stream in a given volume is taken from each flow of heat-exchanging gaseous media, for example hot gas and air, alternately supplied to the heat transfer matrix and sent to a cooling channel formed along the frame wall between the hot and cold cheeks, in contrast to analogues, the cooling channel is closed from the side of the hot cheek and the separated part of the hot gas flow into the cooling channel ny cold side cheeks after precooling.

-образной формы с дном, размещенным на горячей щеке, одно его колено открыто в сторону холодной щеки, а другое сообщается с дополнительным каналом со стороны холодной щеки, и направляющий аппарат образован наружной обечайкой и закрепленной на ней крышкой, являющейся одновременно дном дополнительного канала.In a cooling system containing a cooling channel located along the frame wall between its hot and cold cheeks, formed by two shells enclosing the heat exchange matrix, of which the inner cantilever is mounted on the hot cheek, and a guiding apparatus, the technical result is achieved by the fact that, unlike analogues, it has an additional cooling channel located parallel to the main one and closed from the side of the cold cheek, the main channel is made of a two-knee

-shaped with a bottom placed on the hot cheek, one of its knees is open towards the cold cheek, and the other communicates with the additional channel from the side of the cold cheek, and the guiding apparatus is formed by the outer shell and the lid attached to it, which is also the bottom of the additional channel.

In particular types of system execution, additional differences are in the execution of the inner shell in the form of a heat insulating wall and in various forms of formation of an additional cooling channel:

- the inner shell and at least one slotted channel of the matrix;

- the inner shell and part of the porous packing of the matrix, separated from the main volume of the packing or not separated;

- the inner shell and at least one channel newly introduced into the device.

Figure 1 shows a General view of a rotating disk heat exchanger (top view from the side of the cold cheek); figure 2, 3, 4 - embodiments of the frame cooling system (section aa in figure 1), figure 5 is a flow diagram in the matrix and cooling system when passing through it a hot coolant; Fig.6 is a flow diagram in the matrix and cooling system during the passage of cold coolant.

The rotating disk regenerative heat exchanger comprises a frame 1 with openings 2 for the passage of heat-exchanging media (for example, gas and air). In the holes 2 are placed heat transfer matrices 3, for example:

- from a metal tape with distance stampings obtained by winding in rolls;

- from metal mesh or from porous ceramics.

The essence of the proposed method for cooling the frame of the heat exchanger is that from each flow of heat-exchanging gaseous media alternately supplied to the matrix, for example hot gas and air (Figs. 5, 6), at the inlet to the heat exchanger, a part of the flow is taken in a given volume, determined based on required operational parameters of a particular heat exchanger. Then, the selected part of the flow is directed along the wall of the frame into the formed cooling channel, closed on the hot side, and the hot stream is fed into this channel from the side of the cold cheek and previously cooled.

In this way, washing the frame wall with a hot medium is eliminated and it is possible to vary the configuration of the channels to more efficiently cool the frame and reduce thermal deformations in it, while simplifying the design of the cooling system.

Pre-cooling of the selected stream of hot medium and its supply to the cooling channel can be carried out by various known means, expedient structurally and technologically, or, as in the proposed system, using an additional cooling channel parallel to the main channel and communicating with it from the side of the cold cheek.

The volume of the separated parts of the media flows is provided due to the calculated input section and the channel volume based on the real heat transfer parameters, in particular the hot gas flow due to the cross section, volume and type of execution of the additional cooling channel.

-образной формы с дном, размещенным на горячей щеке каркаса 1, и дополнительный канал охлаждения 5. Канал 4 образован двумя, охватывающими теппообменную матрицу 3, обечайками 6 и 7, из которых внутренняя 6 закреплена консольно на горячей щеке и может быть выполнена теплоизолирующей, и каркасом 1. Дополнительный канал охлаждения 5 расположен параллельно основному 4 и закрыт со стороны холодной щеки крышкой 8, которая одновременно связывает его с основным каналом 4.The cooling system of the frame 1 of the rotating disk heat exchanger contains located along the wall of the frame between its hot and cold cheeks cooling channel 4, made

-shaped with a bottom placed on the hot cheek of the frame 1, and an additional cooling channel 5. Channel 4 is formed by two, covering the heat exchange matrix 3, shells 6 and 7, of which the inner 6 is mounted cantilever on the hot cheek and can be insulated, and frame 1. An additional cooling channel 5 is located parallel to the main 4 and is closed on the cold cheek side by a lid 8, which simultaneously connects it with the main channel 4.

The following design options for the frame cooling system are provided:

- an additional cooling channel 5 is formed by an inner shell 6, which can be made insulating, and at least one slotted channel, technologically made integral with the main slotted matrix 3 (figure 2);

- an additional cooling channel 5 is formed by an inner shell 6, which can be heat insulating, and a porous packing 5, technologically performed separately from the main part of the porous packing of the matrix 3, as in figure 3 on the left, or along with it, as in figure 3 on the right ;

- an additional cooling channel 5 is formed by an inner shell 6, which can be made insulating, and at least one slotted channel, technologically separate from the main slotted matrix 3 (figure 4).

At the moment when the matrix is in the hot cavity of the engine and hot coolant (for example, hot exhaust gas) passes through it from the side of the hot cheek, it is divided into two streams (Fig. 5).

The first stream (main) passes through the main channels of the matrix 3 and is cooled in them, while heating the matrix material.

The second stream (separated) passes into the additional cooling channel 5 and is also cooled in it. Then this flow through the lid 8 is directed to the cooling channel 4. Passes through it, cooling the frame 1, and goes into the same hole on the cold cheek as the main stream of cold gas, and then mixes with it.

At the moment when the matrix is in the cold cavity of the engine and cold coolant (for example, compressed air in the compressor) passes through it from the side of the cold cheek, it is also divided into two flows (Fig. 6).

The first stream (main) passes through the main channels of the matrix 3 and is heated in them, while cooling the matrix material.

The second stream (separated) passes into the cooling channel 4, passes through it, cooling the frame 1. Then this stream through the lid 8 is directed to an additional cooling channel 5, where it is heated, while cooling the matrix material. And it goes into the same hole on the hot cheek as the main stream, and then mixes with it.

Claims (6)

1. The method of cooling the frame of a rotating disk heat exchanger, in which part of the flow in a given volume is taken from each flow of heat-exchanging gaseous media, for example hot gas and air, alternately supplied to the matrix and sent to a cooling channel formed along the frame wall between the hot and cold cheeks a heat exchanger, characterized in that the cooling channel is closed from the side of the hot cheek and said part of the hot gas stream is introduced into the cooling channel from the side of the cold cheek after its pre-cooling. 2. The cooling system of the frame of a rotating disk heat exchanger, comprising a cooling channel located along the frame wall between its hot and cold cheeks, formed by two shells enclosing the heat exchange matrix, of which the inside is fixed cantilever to the hot cheek, and a guide apparatus, characterized in that it has additional cooling channel located parallel to the main one and closed from the side of the cold cheek, the main channel is made of two-knee

-shaped with a bottom placed on the hot cheek, one knee is open towards the cold cheek, and the other communicates with an additional channel from the side of the cold cheek, and the guiding apparatus is formed by an outer shell and a lid fixed to it from the side of the cold cheek, which is also the bottom additional channel. 3. The system according to claim 2, characterized in that the additional cooling channel is formed by the inner shell and at least one slotted channel of the matrix packing. 4. The system according to claim 2, characterized in that for the formation of an additional channel is part of the porous packing of the matrix. 5. The system according to claim 2, characterized in that the additional channel is formed by an inner shell and at least one channel newly introduced into the device. 6. The system according to any one of paragraphs.2-5, characterized in that the inner shell is made in the form of a heat-insulating wall between the main and additional channels.

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