JPS62113851A - Combustor for stirling engine - Google Patents

Abstract

PURPOSE:To easily mount a heat receiving fin to a heater tube, by forming the heat receiving fin, provided in the periphery of the heater tube arranged spacing a distance in a combustion chamber, by a plate unit of bellows shape having penetration holes overlapped with each other in each folded part. CONSTITUTION:A combustor of a Stirling engine, formed by parallelly arranging plural heater tubes 1 spacing a distance in a combustion chamber partitioned in a housing, absorbs heat from combustion gas, generated by a burner provided in the central part of the combustion chamber, through heat receiving fins 2. Here the heat receiving fin 2 is formed by a plate unit made of heat resisting alloy plate and folded in a multi-layer bellows shape. While penetration holes 21, almost coaxially overlapping with each other, are formed in each folded part 20 of said heat receiving fin 2, and after the heater tube 1 is inserted into said penetration holes 21, the both heater tube 1 and heat receiving fin 2 are integrally formed by brazing.

Description

[Detailed description of the invention] [Purpose of the invention] The present invention relates to improvements in combustors for Stirling engines.

[Prior Art] Conventionally, a combustor for a Stirling engine has been provided according to Japanese Unexamined Patent Publication No. 57-0038'05. This Stirling engine combustor has a combustion chamber 1, as shown in FIG.
00, a heater tube 102 held in the housing 101 and arranged in parallel at intervals in the combustion chamber 100, and a nozzle 103a held in the housing 101 for spouting fuel into the combustion chamber 100.・) It was composed of 03 and. Here heater tube 10
Heat-receiving fins 104 were provided on the outer periphery of 2. This heat receiving fin 104 has holes 104a. And hole 1
The heat receiving fan 104 is fixed by brazing the inner circumference of the heater tube 102 and the outer circumference of the heater tube 102.
As shown in Figure 9, it was wrapped around in a ring shape. The heat receiving fins 104 are connected to the heater tube 1 as shown in FIG.
02, a large number of them are stacked at predetermined intervals. In the conventional Stirling engine combustor in which the heat receiving fins 104 are provided on the heater tube 102, the heater tube 1
02, the heat receiving fins 104 can efficiently absorb heat from the combustion gas burning in the combustion chamber 100.

Furthermore, as a conventional technique in which the heater tube has heat receiving fins, as shown in FIGS. 10 and 11, a heat receiving fin 104 is spirally wound around the outer circumference of the heater tube 106 and fixed by welding or the like. has been done.

In the conventional method shown in FIGS. 8 and 9, when the heat receiving fins 104 are thin, the hole 104a and the heater tube 10
There is a problem in that the heat-receiving fins 104 cannot be properly assembled when fitting and assembling the heat-receiving fins 104. Therefore, there is a limit to how thin the heat-receiving fins 104 can be made. .

Furthermore, in the conventional method shown in FIGS. 10 and 11, since the heat receiving fins 104 are erected perpendicularly to the heater tube 106 and wound in a spiral shape, the protrusion height h of the heat receiving fins 104 from the outer periphery of the heater tube 102 is limited. ) is difficult to increase, so the heat receiving area is small.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned problems, and its purpose is to assemble the heat receiving fins into the heater tube even when the heat receiving fins are made thinner. Easy to attach,
Another object of the present invention is to provide a combustor for a Stirling engine in which the height of the heat-receiving fins protruding from the outer periphery of the heater tube can be increased to increase the heat-receiving area.

[Structure of the Invention] (Means for Solving the Problems) A combustor for a Stirling engine according to the present invention includes: a housing having a combustion chamber; It is composed of a large number of heater tubes having heat receiving fins on the outer periphery, and a burner that is held in the housing and injects fuel into the fuel chamber, and the combustion gas of the fuel ejected from the burner is absorbed into the heat receiving fins of the heater tube. In a combustor for a Stirling engine, the heat receiving fins are folded into an accordion shape and are formed of a plate having overlapping through holes at each folded portion, and the heater tube is inserted into the overlapping through holes. The heat receiving fin is held by the heater tube by fixing the inner circumference of the through hole and the outer circumference of the heater tube.

The same housing, combustion chamber, and burner as conventional ones can be used.

The heater tube according to the present invention is a member through which a working gas such as helium gas supplied into the cylinder of a Stirling engine passes. Heat receiving fins are provided on the outer periphery of the heater tube. The heat receiving fin is formed of a plate body folded into a bellows shape. This plate has through holes that match each fold. Preferably, the through holes overlap in a substantially coaxial manner. This is because it is easy to insert the heater tube. It is preferable that the thickness of the plate is uniform. The material of the plate is determined by considering thermal conductivity, heat resistance, etc., and metals such as steel materials are preferable.

Preferably, the inner diameter of the through hole is approximately equal to the outer diameter of the heater tube. When the heater tube has an outer periphery with a circular cross section, the through hole is preferably formed with an inner periphery with a circular or elliptical cross section. It is advantageous when the heater tube is curved if the through hole has an inner circumferential portion with an elliptical cross section. Further, when the heater tube is bent, the inner diameter of the d through hole may be made larger than the outer diameter of the heater tube.

In the present invention, the heat receiving fin is held on the heater tube by fitting the heater tube into the overlapping through holes and fixing the inner circumference of the through hole and the outer circumference of the heater tube. It is the composition. As the fixing means, brazing, welding, etc. can be used. Brazing is
Considering heat resistance and the like, nickel brazing is preferable.

Here, it is preferable that the outer periphery of the heater tube and the inner periphery of the through hole are brazed so as to go around the outer periphery of the heater tube once. This is because it is advantageous for improving the bonding strength between the heater tube and the heat receiving fin and for improving the heat transfer effect from the heat receiving fin to the heater tube.

<Example> The present invention will be described below based on a specific first example.

(Configuration of Example) For the combustion chamber, housing, burner, etc., the conventional Stirling engine combustor shown in FIG. 8 is used as is. Therefore, the entire configuration other than the heat receiving fins is almost the same as the conventional device shown in FIG. That is, the difference between the Stirling engine combustor according to this embodiment and the conventional combustor is the heat receiving fins 2 of the heater tube 1.

As shown in FIG. 1, the heat-receiving fin 2 is formed of a plate body folded multiple times into a bellows shape. This heat receiving fin 2
The plate forming the folding portion 20 is made of a heat-resistant alloy plate, and has a through hole 21 that overlaps each folded portion 20 substantially coaxially. FIG. 2(A) shows the state before the plate forming the heat receiving fin 2 is folded. As shown in FIG. 2(A), a large number of through holes 21 are arranged in negative rows at a constant pitch (P2) in the plate. By folding the space between the through holes 21, the heat receiving fins 2 are formed in a state before being fixed, as shown in FIG. Here, the through hole 21 is large enough to allow the heater tube 1 to be inserted through it.
It forms a circular shape. The reason for the circular shape is that the heater tube 1 having an outer peripheral portion having a circular cross section is inserted into the through hole 21 .

In this embodiment, the heater tubes 1 are inserted into the overlapping through holes 21. When both ends of the plate forming the heat-receiving fin 2 are left free in the fitted state, the cough plate extends in its longitudinal direction in a folded state due to the elasticity of the plate. Then, the inner peripheral part of the through hole 21 and the heater tube 1
The folded plate stops when it is in contact with the outer periphery of the plate.

In this state, the heater tube 1 and the plate are placed in a furnace and nickel brazing is performed. Brazing was specifically performed in a high-temperature vacuum furnace. Brazing is performed around the outer circumference of the heater tube 1 once. By performing brazing in this manner, the inner circumferential portion of the through hole 21 and the outer circumferential portion of the heater tube 1 are fixed, thereby holding the heat receiving fin 2 to the heater tube 1. The state in which the heat receiving fins 2 are held on the heater tube 1 is shown in FIGS. 4 and 5.

(Function of Actual Flow Example) In the Stirling engine combustor according to this embodiment, fuel is supplied to the nozzle 1 of the burner 103 as in the conventional case shown in FIG.
03a into the combustion chamber 100 of the housing 101 and is combusted. The combustion generates combustion gas at a high temperature of about 1400°C. The high-temperature combustion gas flows in the direction of the arrow shown in FIG. 7 and heats the portion 10 of the heater tube 1 where the heat receiving fins 2 are not formed. As a result, the temperature of the combustion gas drops to nearly 900°C. Furthermore, the combustion gas flows between the heat receiving fins 2 and heats the heat receiving fins 2 and the heater tube 1. When the combustion gas flows between the heat-receiving fins 2 in this manner, the heat of the high-temperature combustion gas is transmitted to the heat-receiving fins 2 of the heater tube 1 and further to the working gas within the heater tube 1. The working gas thus becomes hot and is conducted into the cylinder of the Stirling engine, thereby driving the piston within the cylinder. Note that the combustion gas that has flowed through the heat receiving fins 2 is normally exhausted from an exhaust hole formed in the combustion chamber 100. The temperature of the discharged combustion gas is generally about 750°C.

(Effects of Example) In this example, the amount of heat of the combustion gas is mainly transmitted to the heat receiving fins 2 of the heater tube 1.

The heat transferred to the heat receiving fins 2 is further transferred to the heater tube 1.
can be conveyed to. Therefore, the working gas flowing inside the heater tube 1 can be efficiently heated.

Furthermore, in this embodiment, the heat receiving fins 2 are held on the heater tube 1 by fitting the heater tube 1 into the overlapping through holes 21 and fixing the inner circumference of the through hole 21 and the outer circumference of the heater tube 1. has been done. Therefore, unlike the conventional ones shown in FIGS. 8 and 9, a large number of heat receiving fins 10 are used.
4 into the heater tube 102 one by one; instead, it is only necessary to insert the entire plate folded into a bellows shape forming the heat receiving fin 2 into the heater tube 1. The second assembly can improve work efficiency.

Furthermore, as described above, the workability of assembling the heat receiving fins 2 can be improved. In this embodiment, even when the thickness of the cough plate is made thin, the thickness of the plate may be reduced to 0°1 to 0. .21111
Even when the thickness is reduced to about 11, the heat receiving fins 2 can be assembled well. Therefore, it is advantageous to reduce the thickness of the heat-receiving fin 2 compared to the conventional techniques shown in FIGS. 8 and 9, and compared to the conventional techniques shown in FIGS. 10 and 11.

Furthermore, in this embodiment, as shown in FIGS. 4 and 5,
Since the heat receiving fins 2 are continuous in the length direction of the heater tube 1, the folds 2 of the heat receiving fins 2 are continuous as shown in FIG.
By arranging the heat receiving fins 5 to face the direction in which the combustion gas is sent (that is, in the direction of the arrow), the heat receiving fins 2 can effectively stop receiving the combustion gas. Therefore, the heat receiving effect of the heat receiving fins 2 can be improved. Similarly, heater tube 1
Since the heat-receiving fins 2 continuous in the length direction also receive axial heat from the flame in the combustion chamber 100, the heat-receiving effect of the heat-receiving fins 2 can be further improved.

Furthermore, in this embodiment, by adjusting the pitch of the bellows of the plate forming the heat receiving fins 2, the length L (see FIG. 4) of the folded portion 20 of the heat receiving fins 2 can be adjusted. can. Therefore, the protrusion height of the heat receiving fins 2 from the outer periphery of the heater tube 1 (corresponding to the conventional dimension shown in FIG. 10) can also be increased. When it is increased in this way, the heat receiving area of the heat receiving fin 2 is increased by 1q
1 to improve the heating efficiency of the working gas in the heater tube 1.

Furthermore, in this embodiment, by reducing the pitch between the through holes 21 (P2 shown in FIG. 2), it is easy to increase the number of folding parts 20. Therefore, the heat receiving area of the heat receiving fins 2 can be increased accordingly, and the heating efficiency of the working gas in the heater tube 1 can be further improved.

In this embodiment, the heat-receiving fins 2 are formed from a plate folded into a bellows shape, and this plate is made of an elastic heat-resistant alloy material, so before the heat-receiving fins 2 are fixed, The elastic force of the bellows acts. Therefore, due to the elastic force, the bellows-shaped plate tends to extend in its length direction. Therefore, it is possible to prevent adjacent folded portions 20 from coming into contact with each other. Therefore, the distance between the - folded part 20 and the adjacent folded part 20 can be narrowed, the number of folded parts 20 can be increased, and the heat receiving area of the heat receiving fins 2 can be increased. The heating efficiency of the working gas in the chamber 1 can be further improved.

Further, in this embodiment, when inserting the through hole 21 and the heater tube 1, the plate forming the heat receiving fin 2 is folded tightly, for example, the folded part 20 of 1 and the folded part adjacent thereto are folded tightly. 20 are tightly folded so that they are in contact with each other, and in this state, the through hole 21 and the heater tube 1 are inserted, and the insertion work is really easy.

(Second Embodiment) A second embodiment of the present invention is shown in FIG. 2(B). In the second embodiment, the through hole 25 formed in the plate forming the heat receiving fin 2 has an elliptical shape, and has a longer diameter portion in the longitudinal direction of the plate. This second embodiment is convenient for joining the inner circumference of the through hole 25 and the outer circumference of the heater tube 1 all around. That is, when the heat-receiving fins 2 are held on the heater tube 1 as shown in FIG. 4, the folded portions 20 of the heat-receiving fins 2 are positioned obliquely with respect to the longitudinal direction of the heater tube 1. Therefore, if the through hole 25 is formed into an elliptical shape as described above, the outer circumference of the heater tube 1 and the through hole 25
It is easy to join the entire circumference to the inner circumference by brazing.

〔Effect of the invention〕

As is clear from the above description, according to the combustor for a Stirling engine according to the present invention, the heat receiving fin is formed of a plate that is folded into a bellows shape and has through holes that overlap each folded portion. Even when the heat receiving fins are made thinner, the heat receiving fins can be easily assembled to the heater tube.

Furthermore, if the through-hole is formed into an elliptical shape with a longer diameter in the longitudinal direction of the plate, it is easier to join the inner circumference of the through-hole and the outer circumference of the heater tube all around, thereby increasing the bonding strength. It can be planned.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the state before the through hole and the heater tube are inserted, Fig. 2 (A) and Fig. 2<8) are plan views of the state before the heat receiving fin is folded, and Fig. 3 is A plan view of the heater tube holding heat receiving fins, FIG. 4 is a side view of the same,
Figure 5 is a side view of a state where many heater duplexes are installed.
FIGS. 6 and 7 are side views viewed from different directions. FIG. 8 and FIG. 9 show a conventional combustor. FIG. 8 is a sectional view of a conventional Stirling a open-use combustor, and FIG. 9 is a plan view of a main part of a conventional combustor for a Stirling engine. Fig. 10 and Fig. 11 show different conventional ones, and Fig. 10 is a side view of a conventional heater tube holding heat receiving fins;
FIG. 11 is a side view showing the assembly in progress. In the figure, 1 is a heater tube, 2 is a heat receiving fin, 20 is a folding part, 21 and 25 are through holes, 1oO is a combustion chamber,
101 represents a housing, and 103 represents a burner. Patent applicant Aisin Seiki Co., Ltd. Agent
Patent Attorney Hirodo Okawa Patent Attorney Akio Maruyama Figure 1 Figure 3 Figure 4 Figure 5 Figure 10 Figure 11

Claims (3)

[Claims] (1) a housing having a combustion chamber; a large number of heater tubes held by the housing and arranged in parallel at intervals within the combustion chamber and having heat receiving fins on their outer peripheries; held by the housing and supplying fuel to the fuel chamber; In the Stirling engine combustor, the combustion gas of the fuel ejected from the burner flows between the heat-receiving fins of the heater tube, the heat-receiving fins are folded into a bellows shape and each folded portion The heater tube is inserted into the overlapping through-holes, and the inner circumference of the through-hole and the outer circumference of the heater tube are fixed to each other to receive the heat. A combustor for a Stirling engine in which a fan is held in the heater tube. (2) The heater tube has an outer circumference with a circular cross section,
The combustor for a Stirling engine according to claim 1, wherein the through holes of the heat receiving fins have an inner peripheral portion having a circular or elliptical cross section. (3) The combustor for a Stirling engine according to claim 1, wherein the outer circumference of the heater tube and the inner circumference of the through hole of the heat receiving fin are fixed by brazing.