JPH0692773B2 - Heat exchanger for displacer type Stirling engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat exchanger for a displacer type Stirling engine, and more particularly to a heat exchanger for a displacer type Stirling engine capable of improving thermal efficiency and durability as compared with conventional heat exchangers. It relates to a heat exchanger.

[Prior Art] FIG. 3 is a cross-sectional view showing a structure of a heat exchanger of a conventional displacer type Stirling engine described in JP-A-52-25952, in which 1 is a high temperature cylinder and 1a is a The expansion chamber 2 is a regenerator housing formed in a concentric annular shape around the high temperature cylinder 1, and 3 is a low temperature cylinder 3a which is hermetically fixed to the regenerator housing 2 by an O-ring seal 3b and a fixing bolt 102. Is a compression chamber, 4 is the head portion of the high temperature cylinder 1 to the regenerator housing 2
, A plurality of heater pipes radially arranged to the head part, 5 is a concentric annular regenerator filling made of wire mesh, 6 is a concentric annular cooler 6a disposed below the regenerator filling, 6a
Is a cooling pipe assembled to the concentric annular cooler 6 by brazing or the like, 6b and 6c are O-ring seals for sealing the concentric annular cooler 6 with the outside air, and 7 and 8 are cooling water for cooling the cooler 6. Inlet pipe, cooling water outlet pipe, 9 is a hollow hermetic displacer, 10 is a seal ring mounted on the displacer 9, 101 is a rod seal provided on the central shaft of the vertical power piston 11, and seals the displacer rod 13. Reference numeral 14 is a power piston rod fixed to the power piston 11. Here, the lower part of the low temperature cylinder 3 is a crankcase provided with a crank mechanism for reciprocating the displacer 9 and the power piston 11 with a predetermined phase difference and each connecting rod.

Next, the operation will be described.

In the displacer type Stirling engine, the working fluid is expanded and compressed by continuously heating and cooling the heater tube 4 and the cooler 6, respectively, and the working fluid is reciprocated in the heat exchanger. That is, the working fluid flows from the heater tube 4 through the regenerator filling 5 to the cooler 6 or vice versa. Then, the heating energy to the heater pipe 4 is converted into the rotational energy of the crankshaft through the reciprocating motion of each piston.

[Problems to be Solved by the Invention]

However, the heat exchanger of the conventional displacer type Stirling engine has the following problems.

That is, since the high temperature cylinder 1 and the regenerator housing 2 are required to withstand the internal pressure of 10 to 60 atm applied to the expansion chamber 1a of the high temperature cylinder 1, each is designed to have a thick wall thickness, which is a high temperature cylinder. 1 to regenerator housing 2
There is a problem that the heat conduction loss transmitted to the cooler 6 via the engine is increased and the thermal efficiency of the engine is deteriorated. Further, there is a large change in the cross-sectional area at the joint between the high temperature cylinder 1 and the regenerator housing 2, so that a large thermal stress concentration occurs outside the welding stress at the joint, and the joint is easily damaged. There was a problem. In addition, when the engine is assembled, the gas supply piston seal ring (displacer seal ring) 10 is damaged by the gas flow hole 105 under the bottom surface of the cooler, and the sealing performance is deteriorated.

The present invention has been made in order to solve the above problems, and the heat conduction loss between the cylinder and the cooler, in which the working fluid reciprocates from the expansion chamber inside to the cooler,
Also, thermal stress concentration is reduced at the joint between the cylinder and the housing member that is joined to a part of the cylinder and forms a space filled with the regenerator, and damage to the displacer seal ring during engine assembly is prevented. Then, it aims at providing the heat exchanger of the displacer type Stirling engine which can aim at improvement of the thermal efficiency and durability of an engine.

[Means for solving problems]

A heat exchanger for a displacer-type Stirling engine according to the present invention comprises a dome-shaped cylinder having an inner space of the spherical portion serving as an expansion chamber, and an uppermost portion thereof fitted to an inner peripheral surface of the spherical portion of the dome-shaped cylinder. A cylindrical inner liner forming a space filled with a regenerator between the cylindrical portion of the dome-shaped cylinder, a concentric annular regenerator filled in the space, and the inside of the dome-shaped cylinder, A concentric annular regenerator and a concentric annular cooler provided below the inner liner, and a displacer that slides on the inner wall surface of the concentric annular cooler and moves so that the uppermost part of the spherical portion reciprocates in the expansion chamber. A projecting surface is provided between the bottom surface of the concentric annular cooler and the top surface of the compression cylinder below the cooler so as to substantially coincide with the inner wall surface of the concentric annular cooler. The number of projections, provided on the spherical portion of the domed cylinder, in which a heater tube for connecting the space in which the expansion chamber and the regenerator is filled.

[Action]

In the present invention, due to the above configuration, the inner space of the spherical portion of the dome-shaped cylinder located above the cylindrical inner liner becomes an expansion chamber, and the inner wall surface of the cylindrical inner liner always has the outer periphery of the displacer. The surfaces are opposed to each other with a certain distance. Therefore, the pressure acting on the cylindrical inner liner is only the pressure loss (a pressure of about 0.2 atm) generated when the working fluid flows through the regenerator and the cooler, and the wall thickness can be made thin. The heat conduction loss transmitted from the spherical portion of the cylindrical cylinder to the cooler via the heater tube and the regenerator is reduced, and the thermal efficiency of the engine is improved.

In addition, the cylindrical inner liner is joined to the dome-shaped cylinder by fitting the uppermost part thereof to the inner peripheral surface of the spherical portion of the dome-shaped cylinder, and also of the dome-shaped cylinder to which the heater tube is connected. Since the spherical portion has a curved shape with a small change in its cross-sectional area, the concentration of thermal stress applied to the cylinder can be significantly reduced and the durability of the engine can be improved as compared with the conventional device.

Furthermore, the displacer seal ring is located below the bottom of the cooler during engine assembly due to the projection that is provided between the bottom surface of the concentric annular cooler and the top surface of the compression cylinder below the cooler, and the projection that substantially matches the inner wall surface of the concentric annular cooler. Damage to a certain gas flow hole is prevented, and the durability of the engine is further improved.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
1 is a sectional view showing the structure of a heat exchanger of a displacer type Stirling engine according to an embodiment of the present invention. In the drawing, the same reference numerals as those in FIG. 3 indicate the same or corresponding portions.

Reference numeral 15 is a dome-shaped cylinder in which the inner space of the spherical portion is the expansion chamber 1a, and 16 is a space filled with the regenerator filling (concentric annular regenerator) 5 between the dome-shaped cylinder 15 and the upper portion of the cylindrical portion. Is a cylindrical inner liner that forms an inner peripheral surface of the spherical portion of the dome-shaped cylinder 15. Further, 23 is a concentric annular cooler 6 and an inner liner 16
Is an O-ring seal that seals the fitting part of the compression cylinder, and 17 is a compression cylinder whose inner wall surface is the sliding surface of the power piston 11 and is provided below the concentric annular cooler 6. , 19 are cooling water inlet and outlet pipes for cooling the compression cylinder 17, 20 is an upper flange portion of the crankcase, and the crankcase is the displacer 9 and the power piston. A crank mechanism (not shown) for driving 11 with a predetermined phase difference is provided. Reference numeral 21 is a bolt that connects both flange portions of the dome-shaped cylinder 15 and the crankcase that form the heat exchanger, and 22 is an O-ring seal for airtightness.

FIG. 2 is a perspective view of the concentric annular cooler 6, in which 106 are projections arranged at eight positions in the circumferential direction on the bottom surface of the cooler 6, and each projection 106 has a projecting surface on the seal ring of the displacer. The sliding surface 107 (the inner wall surface of the concentric annular cooler 6) is provided so as to substantially coincide therewith.

In the device of this embodiment, as described above, the dome-shaped cylinder 15
The space formed between the upper part of the cylindrical part of the above and the cylindrical inner liner 16 is filled with the regenerator filling (concentric annular regenerator) 5. The concentric annular cooler 6 is arranged below the regenerator filling (concentric annular regenerator) 5 and the inner liner 16, and the lower part of the inner liner 16 is fitted on the upper part thereof, and the inner wall surface of the concentric annular cooler 6 seals the displacer 9. It becomes the moving surface 107. In addition, the displacer 9 has an upper portion formed in a spherical shape here, and moves in the dome-shaped cylinder 15 so that the uppermost surface of the spherical portion reciprocates in the expansion chamber 1a. A plurality of heater tubes 4 connecting the expansion chamber 1a and the space filled with the regenerator filling (concentric annular regenerator) 5 are provided in the spherical portion of the dome-shaped cylinder 15.

Here, comparing the configuration of the device of the present embodiment with that of the conventional device, the spherical portion of the dome-shaped cylinder 15 of the device of the present embodiment,
The inner space of the conventional device corresponds to the upper part of the high temperature cylinder 1 in which the expansion chamber 1a is formed.
The inner wall surface of the concentric annular cooler 6 of the apparatus of this embodiment corresponds to the inner wall surface of the lower portion of the high temperature cylinder 1 which is the displacer sliding surface of the conventional apparatus.

Next, the operation and effects will be described.

The operation of the device of this embodiment is basically the same as that of the conventional device, and the working fluid is compressed from the expansion chamber 1a through the heater tube 4, the regenerator filling (concentric annular regenerator) 5, and the cooler 6. It reciprocates to 3 and vice versa, and operates as a displacer type Stirling engine. In such an operation, the pressure acting on the inner liner 16 does not serve as an expansion chamber in its inner space, and therefore the flow of the working fluid accompanying the reciprocating movement of the displacer 9 causes the regenerator filling (concentric annular regenerator) 5 and the concentric annular cooler. The pressure loss (approx. 0.2 atm) generated in 6 is about. Therefore, the thickness of the cylindrical inner liner 16 can be made extremely thin as compared with the thickness of the side wall of the high temperature cylinder 1 of the conventional apparatus.
The heat conduction loss from 15 to the cooler 6 can be reduced, and the thermal efficiency of the engine can be improved. In addition, the heater tube 4 is provided in the spherical portion of the dome-shaped cylinder 15 whose cross-sectional area changes little,
Since the inner liner 16 is fitted to the inner peripheral surface of the spherical portion, the concentration of thermal stress in the cylinder can be reduced as compared with the conventional device, and the durability of the engine is improved. Further, since the protrusion 106 is provided on the bottom surface of the cooler 6, the displacer seal ring 10 is not damaged by the gas flow hole 105 under the bottom surface of the cooler 6, and it is possible to prevent the sealing performance of the seal ring 10 from being deteriorated. . This also allows
The thickness of the seal ring 10 can be made extremely thin, and the friction loss between the seal ring 10 and the inner liner 16 can be reduced.

Although the projection is provided on the bottom surface of the cooler in the above embodiment, the projection may be provided on the top surface of the compression cylinder and facing the sliding surface of the seal ring of the power piston, and the same effect as in the above embodiment can be obtained. To be

Further, in the above-described embodiment, the case where eight protrusions are provided has been shown, but depending on the shape of the seal ring, the number of protrusions provided may be two or more, and the same effect as in the above-described embodiment is obtained. .

〔The invention's effect〕

As described above, according to the heat exchanger of the displacer type Stirling engine according to the present invention, the inner space of the spherical portion serves as an expansion chamber, and the uppermost portion of the spherical portion in the dome shaped cylinder. A cylindrical inner liner fitted to the inner peripheral surface to form a space filled with the regenerator between the cylindrical portion of the dome-shaped cylinder, a concentric annular regenerator filled in the space, and the dome. Inside the cylindrical cylinder, slides on the concentric annular cooler provided below the concentric annular regenerator and the inner liner, and the inner wall surface of the concentric annular cooler, and the top of the spherical portion reciprocates in the expansion chamber. Between the displacer that moves so as to move, the bottom surface of the concentric annular cooler and the top surface of the compression cylinder below the cooler, the protruding surface is on the inner wall surface of the concentric annular cooler. A plurality of projections provided in agreement,
Since it is provided in the spherical portion of the dome-shaped cylinder and is provided with a heater tube that connects the expansion chamber and the space filled with the regenerator, heat conduction loss from the cylinder to the cooler and thermal stress in the cylinder. Concentration is reduced, and
The displacer seal ring is prevented from being damaged by the gas flow holes below the bottom surface of the cooler, and as a result, the thermal efficiency and durability of the engine can be significantly improved.

[Brief description of drawings]

1 is a sectional view of a displacer type Stirling engine according to an embodiment of the present invention, FIG. 2 is a perspective view of the concentric annular cooler shown in FIG. 1, and FIG. 3 is a sectional view of a conventional displacer type Stirling engine. . 1 ... High temperature cylinder, 2 ... Regenerator housing, 4 ...
Heater tube, 5 ... Concentric annular regenerator filling, 6 ... Concentric annular cooler, 10 ... Seal ring (displacer seal ring), 15 ... Dome cylinder, 16 ... Inner liner, 17 ... Compression cylinder, 107 ...... Displacer sliding surface (inner wall surface of concentric annular cooler). The same reference numerals in the drawings indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuhiko Kawajiri 8-1-1 Tsukaguchi Honcho, Amagasaki City, Hyogo Prefecture Sanryu Electric Co., Ltd. Applied Equipment Research Laboratory (72) Inventor Nomaguchi Yu 8-chome, Tsukaguchi Honmachi, Amagasaki City, Hyogo Prefecture No. 1-1 Sanryo Electric Co., Ltd. Applied Equipment Research Laboratory

Claims (1)

[Claims] 1. In a heat exchanger of a displacer type Stirling engine, a dome-shaped cylinder whose inner space of the spherical part is an expansion chamber, and an uppermost part of which is fitted to an inner peripheral surface of the spherical part of the dome-shaped cylinder. Then, a cylindrical inner liner forming a space filled with a regenerator between the cylindrical portion of the dome-shaped cylinder, a concentric annular regenerator filled in the space, and in the dome-shaped cylinder, A concentric annular cooler provided below the concentric annular regenerator and the inner liner, and a displacer that slides on the inner wall surface of the concentric annular cooler so that the uppermost part of the spherical portion reciprocates in the expansion chamber. A projecting surface is provided between the bottom surface of the concentric annular cooler and the top surface of the compression cylinder below the cooler so as to substantially coincide with the inner wall surface of the concentric annular cooler. Heat of a displacer-type Stirling engine, comprising: a plurality of protrusions, and a heater tube provided in the spherical portion of the dome-shaped cylinder and connecting the expansion chamber and a space filled with the regenerator. Exchanger.