JPH01187350A - Regenerator for heat engine - Google Patents

Abstract

PURPOSE:To make such manufacture that dispenses with any brazing work performable by forming a lot of grooves on the inner circumferential surface of a thick-wall pipe excellent in thermal conductivity and a fin for cooling fluid on the outer circumferential surface, respectively, while press-fitting a liner in this pipe, and forming a minute flow passage for working fluid with this groove. CONSTITUTION:When applying to a regenerator at the low temperature side of a Stirling cycle engine, a cylindrical regenerator body 24 is made up of materials of a copper alloy, titanium or the like higher in thermal conductivity than steel material and smaller in specific gravity than the steel material, and a lot of minute grooves are formed on the inner circumferential surface along the axial direction, while a fin 23 constituting a flow passage for cooling water is formed on the outer circumferential surface. In addition, a cast iron liner 25 is pressed in the inner part of this regenerator body 24, and a minute flow passage 26 is formed in a gap with the groove of the inner circumferential surface of the regenerator body 24. Then, helium high in temperature or regenerating fluid is made to flow in this flow passage 26, and during this while, it is made so as to be cooled by cooling water taken in from a cooling water inlet 21 and discharged out of a cooling water outlet 22.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat exchanger for a heat engine, and particularly to a low-temperature side heat exchanger for a hot gas engine such as a Stirling engine.

[Conventional technology]

FIG. 4 is a cross-sectional view showing a conventional Stirling engine disclosed in, for example, Japanese Utility Model Application Publication No. 61-55147. In the figure, 1 is a heater tube attached to the regenerator housing 2, and 3 is a stainless steel metal 4 is a cooler which is a low temperature side heat exchanger, 5 is a block into which the cooler is inserted, and 6 is a passage guide member.

FIG. 5 is a detailed sectional view of the low-temperature side heat exchanger, where 7 is a cooling water inlet flange into which water, which is the cooling fluid of the shell & tube heat exchanger, flows in, and 8 is a cooling water inlet flange through which the cooling water flows out. Cold water outlet flange.

9 is He where He (helium), a heat exchange fluid, flows.
The inlet flange 10 is a He outlet flange through which He flows out. 1) is a heat exchange pipe disposed between the He inlet flange 9 and the He outlet flange 1O, both ends of which are brazed to each flange, and allows He, which is a heat exchange medium, to flow; 12 is a heat exchange pipe for water heat exchange; A baffle plate 13 is a body corresponding to the shell part of the shell & tube.

Next, the operation will be explained. The fluid (He) heated in the first part of the heater tube flows into the regenerator 3 and is gradually cooled, and its temperature is lowered from 650°C to 80°C. The fluid then enters the cooler 4 and is cooled, reducing its temperature to 25°C.

Next, the operation of the cooler 4 will be explained in detail. Fifth
In the figure, high-temperature He, which is a heat exchange fluid (approximately 80
°C) enters from the He inlet flange 9, and the heat exchange pipe 1)
flows inside. Further, water (approximately 10° C.), which is a cooling fluid, enters from the cooling water inlet flange 7 and flows outside the heat exchange pipe 1) to cool He in the heat exchange pipe 1) by heat transfer.

He cooled while passing through the heat exchange pipe 1) (approximately 25°C
) flows out from the He outlet flange lO.

In addition, water, which is a cooling fluid, absorbs heat from (e) and flows out from the cooling water outlet flange 8. The temporary jammer 12 disturbs the flow of cooling water and cools the water whose temperature has risen on the pipe surface by forced convection. and improve heat exchange efficiency.

[Problem to be solved by the invention]

Since the conventional low-temperature side heat exchanger is configured as described above, the He inlet flange 9. The He outlet flange 10 and the heat exchange pipe 1) must be brazed.

However, when this brazing is performed, distortion due to thermal stress generated during brazing and clogging and leakage of heat exchange pipes due to poor brazing may occur, and in order to eliminate these problems, complicated processing methods are required. Therefore, the processing cost is also high. In addition, although the conventional structure described above requires a large number of pipes, there is a limit to reducing the pipe pitch due to constraints during brazing, resulting in problems such as the device being large and heavy.

This invention was made to solve the above-mentioned problems, and it eliminates brazing from the manufacturing process, simplifies the processing method, reduces processing costs, and allows for lighter and smaller heat engines. The purpose is to obtain a heat exchanger.

[Means to solve the problem]

The heat exchanger for a heat engine according to the present invention has many minute grooves along the axial direction on the inner circumferential surface of a thick-walled pipe made of a material with higher thermal conductivity and lower specific gravity than steel materials. A liner is press-fitted into the thick-walled pipe to make the minute groove a flow path for the heat exchange fluid, and fins are provided on the outer peripheral surface of the thick-walled pipe to cool the heat exchange fluid from around the pipe. be.

[Effect]

In this invention, a large number of minute grooves parallel to the axial direction are provided on the inner peripheral surface of a thick-walled tube made of a material with higher thermal conductivity and lower specific gravity than steel materials, and a liner is installed inside the thick-walled tube. By press-fitting, we created a flow path for the heat exchange fluid, so we only needed press-fitting, and most of the materials have a higher thermal conductivity than steel and a lower specific gravity than steel. Since it becomes a container, the weight can be significantly reduced and the thermal conductivity of each part can be improved, thereby making the entire device lighter and smaller.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 (al is a plan view of the low-temperature side heat exchanger of a Stirling engine according to the first embodiment of the present invention, the same figure is a fake) is a partially enlarged view thereof, and FIG. FIG. In these figures, 24 is a heat exchanger main body made of a thick-walled pipe made of a material such as copper alloy or titanium (Ti), which has a higher thermal conductivity than steel materials and a lower specific gravity than steel materials, and has a heat exchanger body on its inner peripheral surface. For example, the width is 0.5m, the height is 2
Tiny grooves are formed along the axial direction.

Furthermore, fins 23 are formed on the outer circumferential surface of the fins 23 to increase cooling efficiency and to form a flow path for cooling water. 25 is a cast iron liner press-fitted into the heat exchanger body 24; 26 is a groove on the inner peripheral surface of the heat exchanger body 24 and the liner 25;
This is a minute He channel formed between the two. Also, 21
22 is a cooling water inlet through which water as a cooling fluid flows in, and a cooling water outlet through which the cooling water flows out.

Next, the operation will be explained.

High-temperature He (approximately 80° C.), which is a heat exchange fluid, enters from the entrance (upper side) of the He channel 26 and flows through the He channel 26 at high speed. Further, water (approximately 10° C.), which is a cooling fluid, enters from the cooling water port 21, flows around the fins 23, and cools the He flowing through the He flow path 26 by heat transfer.

The He (approximately 25° C.) cooled while passing through the He channel 26 flows out from the outlet of the He channel 26 . Further, water, which is a cooling fluid, removes heat from He and flows out from the cooling water outlet 22. The fins 23 increase the heat transfer surface area on the water side and improve heat exchange efficiency.

In this embodiment, while keeping the contact heat transfer area similar to that of the conventional device, the He flow path 26 can be made smaller than before, and the flow velocity can be increased to improve the heat transfer coefficient.
e The number of 26 channels may be small, and the diameter of the heat exchanger can be reduced. In addition, most of the heat exchanger is made of materials that have higher thermal conductivity than steel materials and lower specific gravity than steel materials, so not only can the weight be significantly reduced, but the thermal conductivity can be further improved, making the entire device more efficient. Can be made lighter and smaller.

In addition, the dead volume of the low-temperature side heat exchanger is smaller than that of the conventional shell &
It is smaller than a tube-type heat exchanger and has higher engine efficiency.

FIG. 2 shows a low-temperature heat exchanger according to a second embodiment of the present invention. Instead of providing a housing, the hot side heat exchanger wall 29 of the engine is shown. is used as the housing, and in this case, the low temperature side heat exchanger can be further downsized (reduced in diameter). Note that in FIG. 2, the same reference numerals as in FIG. 1 indicate the same parts, and 27 is an O-ring for preventing leakage of cooling water.

FIG. 3 shows a third embodiment of the present invention. Here, in addition to the structure of the first and second embodiments, a heat exchanger main body 24 is provided on the outer peripheral surface of the liner 28, as shown in the figure. A protrusion 28a is formed to be fitted into the groove of the heat exchanger body, and is combined with the micro groove of the heat exchanger body to form a He flow path. The groove can be made wider, making it easier to process the groove.

In each of the above embodiments, the liner is fixed to the heat exchanger body by press fitting, but this may be fixed by shrink fitting or cold fitting. The width, pitch, height, etc. of the grooves on the inner circumferential side of the container body are not specified, and any shape may be used as long as it has a high heat transfer efficiency. Furthermore, although cast iron was used as the liner material in each of the above embodiments, it could also be an Al liner (the material is not specified, and in these embodiments, copper alloy or titanium was used as the material). Any material may be used as long as the thermal conductivity is higher than that of steel and the specific gravity is smaller than that of steel.

Furthermore, in each of the above embodiments, the case where the heat exchanger of the present invention is applied to a Stirling engine has been described, but heat engines using the Stirling cycle, such as Stirling refrigerators, Bellmeyer cycle engines (refrigerators or heat pumps), G , M cycle engine, etc., and other heat engines. Further, the working fluid (heat exchange fluid) is not limited to He.

〔Effect of the invention〕

As described above, according to the present invention, a large number of minute grooves are provided on the inner circumferential surface of a thick-walled pipe whose constituent materials have a higher thermal conductivity than steel and a specific gravity smaller than that of steel, and A liner is press-fitted into the pipe to make the micro groove a flow path for the heat exchange fluid, and cooling fins are provided on the outer circumferential surface of the thick-walled pipe to form a heat exchanger. Many steps have been eliminated, making the work much easier.
The device can be made at low cost. In addition, most of the materials are made of materials with lower specific gravity and higher thermal conductivity than steel materials, so
It is extremely lightweight and has good thermal conductivity in each part (in addition, the contact heat transfer area remains the same as before, but the flow path is made smaller to allow the heat exchange fluid to flow at high speed, greatly improving thermal conductivity. As a result, the number of grooves can be reduced and a compact heat exchanger can be obtained.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view of a low-temperature side heat exchanger according to a first embodiment of the present invention, FIG. 1(b) is a partially enlarged view thereof, and FIG.
Figure (C) is a cross-sectional configuration diagram of the low temperature side heat exchanger, Figure 2fa
) is a plan view of a low-temperature side heat exchanger according to a second embodiment of the present invention, FIG. 2(b) is a partially enlarged view thereof, and FIG. 2(C) is a cross-sectional configuration diagram of the low-temperature side heat exchanger. , FIG. 3(a) is a plan view of a low temperature side heat exchanger according to a third embodiment of the present invention.
Figure 3(C) is a cross-sectional configuration diagram of the low-temperature side heat exchanger, Figure 4 is a cross-sectional configuration diagram showing the heat exchanger section of a conventional Stirling engine, and Figure 5(C) is a partially enlarged view of the same. The figure is a cross-sectional configuration diagram of a conventional shell four-tube type low-temperature side heat exchanger. 21...Cooling water inlet, 22...Cooling water outlet, 23.
... Fin, 24 ... Heat exchanger main body, 25 ... Liner, 26 ... He channel, 27 ... O-ring, 28
...Liner with protrusions, 29...High temperature heat exchanger wall. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A heat exchanger for exchanging heat with the working fluid of a heat engine, which has minute grooves along the axial direction on its inner periphery and fins for cooling fluid on its outer periphery to conduct heat transfer. A cylindrical heat exchanger body made of a material other than aluminum, which has a higher specific gravity than steel materials and a specific gravity smaller than that of steel materials, and is press-fitted into the heat exchanger body, and the grooves are made into flow paths for the working fluid. A heat exchanger for a heat engine, characterized in that it is equipped with a liner for.