JPS6235046A - Heat exchanger for stirling engine - Google Patents

Abstract

PURPOSE:To uniformalize thermal stress and improve heat conductivity by providing an annular clearance around an expansion chamber at the upper portion cylinder of of a stirling engine to provide a operative gas chamber. CONSTITUTION:An outside head 15 is provided on the outer periphery of a cylinder 16 constituting an expansion chamber 1a of a stirling engine through a fine annular clearance 18. The expansion chamber 1a communicates to the annular clearance 18 through a gas path of a heater tube constituted from an inner pipe 17b and an outer pipe 17a. The annular clearance 18 communicates to a regenerator 5. Since the cylinder 16 receives heat of an outside combustion chamber through the annular clearance 18, thermal stress is uniformalized and heat conductivity is improved since the cylinder receives heat on the whole surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a cylinder head constituting a heat exchanger for a Stirling engine.

[Conventional technology]

Fig. 3 is a sectional view showing a heat exchanger for a displacer type Stirling engine described in Japanese Patent Application Laid-Open No. 52-25952. In Fig. 0, 1 is a high temperature cylinder, 1a is an expansion chamber, and 2 is a high temperature cylinder 1. A regenerator housing configured in a concentric ring shape around the periphery, 2a is a regenerator chamber, 3 is a low temperature cylinder sealed and fixed to the regenerator housing 2 by an O-ring seal 3b and a fixing bolt 102, 3a is a compression chamber. be. Reference numeral 4 designates a plurality of heater tubes radially piped from the head surface of the high temperature cylinder 1 to the head portion of the regenerator housing 2, and 5 designates the inside of a concentric ring-shaped regenerator chamber made of wire mesh or the like. Reference numeral 6 denotes a concentric annular cooler disposed below the recycled image filling material 5, 6a a cooling pipe assembled to the concentric annular cooler 6 by brazing or the like, and 6b and 6c sealing the concentric annular cooler 6 from the outside air. This is an O-ring seal for. 7.8 is a cooling water inlet pipe and a cooling water outlet pipe for cooling the cooler 6.

Further, 9 is a displacer with a hollow sealed structure, 10 is a gas seal ring attached to the displacer 9, 1) is a power piston, and 101 is provided at the center shaft of the power piston 1) to seal the displacer rod 13. The rod seal 14 is a power piston rod fixed to the power piston 1). The lower part of the low-temperature cylinder 3 is a crank case equipped with a crank mechanism that reciprocates the displacer 9 and the power piston 1) with a predetermined phase difference, and each connecting rod.

Next, the operation will be explained.

In the displacer type schooling engine, the heater pipe 4,
By continuously heating and cooling each of the coolers 6, the working fluid is expanded and compressed, and the working fluid is caused to flow back and forth within the heat exchanger. That is, the working fluid flows from the heater tube 4 to the cooler 6 through the regeneration fill 5 filled inside the regenerator chamber, or vice versa. The heating energy applied to the heater tube 4 is converted into the rotational energy of the rotating shaft of the crankshaft through the reciprocating motion of each piston.

[Problem that the invention seeks to solve]

However, the conventional heat exchanger for a displacer type cooling engine has the following problems. That is,
In the configuration of the high temperature cylinder 1 and the regenerator housing 2,
The necessity for them to withstand an internal pressure of 10 to 60 atmospheres increases the wall thickness of each wall by design, resulting in heat transfer losses from the high-temperature cylinder 1 to the cooler 6 via the regenerator housing 2. In addition, there is a large change in cross-sectional area at the joint between the high-temperature cylinder 1 and the regenerator housing 2, which causes a large concentration of thermal stress in addition to welding stress. There was a problem that it was easy to cause damage.

This invention was made to solve the above-mentioned problems, and reduces heat conduction loss from the high-temperature cylinder to the cooler and thermal stress concentration at the joint between the high-temperature cylinder and the regenerator housing. An object of the present invention is to provide a heat exchanger for a Stirling engine that can improve thermal efficiency and durability.

[Means for solving problems]

A heat exchanger for a Stirling engine according to the present invention has a cylinder head that becomes high temperature in a dome shape, and a dome-shaped split liner for partitioning an expansion chamber and a regenerator chamber into the dome-shaped cylinder head. At the same time, the heater tube is formed into an annular shape, and one end of the inner tube constituting the heater tube is connected to the split liner, and the outer tube is connected to the cylinder head.

[Effect]

In this invention, the cylinder head has a shape with little change in cross-sectional area, which reduces the thermal stress generated in the cylinder head, making it possible to make the cylinder head thinner, reducing heat conduction loss, and reducing the heater tube. The annular shape reduces thermal stress acting on the heater tube, extending its life.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a sectional view showing one embodiment of the present invention. In the figure, the second
The same reference numerals as in the figure indicate the same parts.

15 is a cylinder head formed in a dome shape, and its cylindrical portion 15b serves as a regenerator housing. 16
is a dome-shaped split liner that is fitted into the dome of the cylinder head 15 in a substantially tight state so that a predetermined gap, that is, an annular gas passage 18 is formed. A chamber 1a is formed. In other words, this split liner 16 allows the expansion chamber 1
A and a regenerator chamber 2a are separated. Further, a projection 16a is formed on the top of the split liner 16, and the projection 16a is fitted into a hole 15a provided in the central shaft portion of the cylinder head 15, and the fitting portion is joined by brazing or welding. has been done.

Further, 17 is an annular heater tube composed of an outer tube 17a and an inner tube 17b, one end of the outer tube 17a is closed, the other end is brazed or welded to the dome-shaped cylinder head 15, and the inner The space communicates with the gas passage 18. Further, the inner tube 17b is fitted into the outer tube 17a with an annular gap 17c, one end of which is open, and the other end is joined to the split liner 16 by brazing or welding and communicates with the expansion chamber 1a. are doing.

In this embodiment configured as described above, the working fluid in the expansion chamber la is transferred to the inside of the inner pipe 17b, similar to the conventional example shown in FIG.
Annie error gap 1 between outer tube 17a and inner tube 17b
It is possible to flow into and out of the regenerator section via the 7c1 annular gas passage 18, and the basic configuration of the engine is maintained. Therefore, it goes without saying that even such a cylinder head configuration can function satisfactorily as a Stirling engine.

In addition, in such a cylinder head configuration, the shape of the dome-shaped cylinder head 15 serving as a pressure-resistant container has a smooth cross-sectional shape with little change in cross-sectional area, and the cylinder head 15 has a smooth cross-sectional shape with little change in cross-sectional area.
The temperature distribution in the vertical axis direction near the contact point between the spherical part and the cylindrical part in No. 5 is as follows:
The annular gas passage 18 makes it almost uniform and can be almost ignored. Because of this, the cylinder head 15
No large thermal stress is generated in the structure, and the wall thickness of this member can be reduced. As a result, heat conduction loss can be reduced compared to the conventional technology, and the thermal efficiency of the engine can be improved.

On the other hand, since the configuration of the heater tube is an annular shape, it has the great feature that the thermal stress acting on the heater tube can be halved.

Fig. 2 shows another embodiment of the present invention, in which a dome-shaped divided pipe 150 and a cylindrical part can be separated into two parts. It is fitted with the passage 18 with a clearance fit at normal temperature (when not in operation), and is in close contact at high temperature. For this reason, the split liner 19 is formed of a material having a coefficient of linear expansion larger than that of the material constituting the dome-shaped split liner.

It goes without saying that this embodiment also has the same functions and effects as the embodiment shown in FIG. 1 above.

〔Effect of the invention〕

As described above, according to the present invention, the cylinder head is formed into a dome shape with little change in cross-sectional area, and a dome-shaped split liner is fitted into the dome-shaped cylinder head, and a heat exchanger is constructed between them. As a result, the temperature distribution near the head and heater pipe is uniform, reducing the occurrence of thermal stress, making the cylinder head thinner, and reducing heat conduction loss, improving the engine's thermal efficiency. effective. Further, since the heater tube is shaped like an annular shape, the thermal stress acting on the heater tube can be reduced, and the life of the heater tube can be extended.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional configuration diagram of essential parts of a heat exchanger for a Stirling engine according to an embodiment of the present invention, Fig. 2- is a diagram showing another embodiment of the invention, and Fig. 3 is a conventional heat exchanger for a Stirling engine. It is a sectional view of a container. 1a... Expansion chamber, 2a... Regenerator chamber, 15... Dome-shaped cylinder head, 16... Dome-shaped split liner, 17... Annular heater tube, 17a... Outer tube, Fb...Inner pipe, 17c... Annular shaped gap, 18... Annular shaped gas passage. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A dome-shaped cylinder head whose cylindrical portion serves as a regenerator housing, and a regenerator chamber inside the dome-shaped cylinder head between the inner wall of the cylinder head and a gas communicating with the regenerator chamber above the regenerator chamber. A dome-shaped split liner is fitted to form a passage and partitions the expansion chamber and the regenerator chamber, and a plurality of dome-shaped split liners are provided at appropriate locations on the dome-shaped cylinder head, and each liner is provided with a dome-shaped split liner at an appropriate location in the outer tube and the inner tube. an annular heater tube consisting of an inner tube fitted with the inner tube, the outer tube having one end closed and the other end connected to the dome-shaped cylinder head so as to communicate with the gas passage; A heat exchanger for a Stirling engine, characterized in that one end is open and the other end is connected to the dome-shaped split liner to communicate with the expansion chamber. (2) The heat exchanger for a Stirling engine according to claim 1, wherein the dome-shaped split liner has a cylindrical portion and a spherical portion that are separate structures.