JPS6079144A - Stirling engine - Google Patents

Abstract

PURPOSE:To improve safety, thermal output and thermal efficiency by arranging an radiation member having specific heat resistance while surrounding heater tube group for heating the operating gas through combustion heat from a combuster thereby uniforming the temperature distribution of heater tube group. CONSTITUTION:Upon start of Stirling engine 3 under such state where combustion is performed continuously in combustion chamber 1 while cooling is performed continuously by a cooler 7, the operating gas will form Stirling cycle to produce power. A gas feed piston 8 will feed operating gas to a heater tube 4 and cooling tube 7 in order to heat/cool alternatively. Here, a radiation body 11 made of metal mesh having heat resistance higher than the heater tube temperature is arranged while surrounding the heater tube 4 and supported by a supporting ring 12. Consequently, the metal mesh 11 is heated by combustion gas flowing out between the heater tubes 4 to radiate heat. Consequently, the rear face of heater tube 4 is heated to uniform the temperature distribution of heater tube 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a Stirling engine that uses combustion heat as a heat source and has a patented Stirling engine that uniformly heats a heater tube.

[Prior art]

Conventionally, there is a Stirling engine that is driven by combustion heat, as shown in FIG. In the figure, 1 is a combustion chamber, 2 is an air preheater for preheating combustion air using combustion exhaust, 3 is a single cylinder Stirling engine, and 4 is for heating the engine's working gas, such as helium, with combustion gas. a heater tube 5, fins 6 fixed to the heater tube 4 on the side exposed to low-temperature combustion gas;
7 is a regenerator, 7 is a cooler for cooling the working gas with a medium such as water, 8 is an air supply piston, 9 is a power piston, 10 is a role for extracting the output of the Stirling engine 3, and the air supply piston 8 This is a crank mechanism that has the function of moving the power piston 9 ahead of the power piston 9 by a phase of several tens of degrees.

The operation of the Stirling engine configured as described above will be explained next. The Stirling engine 3 is started with continuous combustion in the combustion chamber 1 and continuous cooling in the cooler 7.The working gas in the Stirling engine 3 undergoes isothermal expansion, isovolumic cooling, isothermal compression, and A Stirling cycle is constructed that combines each process of isovolumic heating to generate power. In operation of the Stirling engine, the air supply piston 8 serves to feed the working gas to the heater pipe 4 and cooler 7 for alternate heating and cooling. The heater tube 4 in such a Stirling engine has an important role of absorbing the energy of combustion gas.

For this reason, it is necessary to make the heater tube 4 have a uniform temperature distribution, and also to be able to use this material up to a high temperature range close to its heat resistance limit. From this point of view, the Stirling engine is constructed as shown in FIG. 1, and the 4 sections of the rotor tube are approximately the same in structure as shown in FIG. 2 (&).

There is also a heater tube with the structure shown in FIG. 2 (6) for all four parts of the heater tube. The heater tube 4 shown in FIG. 2(b) is
It has the advantage of requiring a smaller installation space than the one shown in Figure (al).

However, the heater tube 4 shown in FIG. 2(a) has the problem of the installation space mentioned above, and also has a problem in that it is difficult to avoid complicating the assembly when attaching the fins 5 to the heater tube 4. On the other hand, the heater tube 4 shown in FIG. 2(b) is heated by radiant heat from the combustion gas and convection, which heats only substantially the front surface of the heater tube 4. Therefore, the amount of heat transfer differs significantly between the front side where the combustion gas flows in and the rear side where the combustion gas flows out. Therefore, a large temperature difference occurs between the front and rear surfaces of the heater tube 4, generating a large thermal stress, resulting in a disadvantage that the heat resistance strength of the heater tube 4 is reduced.

[Summary of the invention]

This invention was made in order to completely eliminate the above-mentioned drawbacks, and a radiator having a heat resistance strength higher than the temperature of the heater tubes is placed between the heater tube group and the air preheater to surround the heater tubes. By arranging it in such a way, heat transfer from the front and rear surfaces of this heater tube! ? Similarly, it is an object of the present invention to provide a Stirling engine that can reduce the temperature difference between the front and rear surfaces and increase the overall amount of heat exchange.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings.

In one embodiment of the present invention shown in FIG. 3, 11 is a metal mesh which is a radiator and is arranged to surround the heater tube 4, and 12 is a support ring that supports this metal mesh 11. Although not shown in the figure, an air preheater is attached to the outside of the metal mesh 3-11 so as to surround it.

In the 4 groups of heater tubes of the Stirling engine configured as described above, the metal mesh 11 is heated to a high temperature by the combustion gas passing between the heater tubes 4 and flowing out, thereby radiating heat. As is well known, the amount of heat radiation from the surface of the metal mesh 11 is much larger than the amount of radiation from gas, so the heater tube 4 is heated from the rear surface. In this way, by applying this radiant heat transfer from the rear surface of the heater tube 4, the combustion gas is transferred to the heater tube 4.
The total amount of heat transferred to can be increased.

Therefore, if we compare the temperature distribution of the heater tube of the conventional Stirling engine and that of the present invention, in the graph of FIG. While the temperature difference is 100°C, the temperature difference according to the present invention is approximately 20° or less as shown by the solid line. Therefore, not only can the thermal stress on the tube wall of the heater tube 4 be reduced, but also the amount of transmission from the inner surface of the heater tube 4 to the working gas can be significantly increased, improving the overall efficiency of the Stirling engine and increasing the output. can achieve an increase. In addition, since the air preheater provided outside the metal mesh 11 receives heat radiation from the metal mesh 1, the wall temperature of the heater tube 4 increases, which also has the advantage of improving the efficiency of the air preheater. have.

It should be noted that using a heat-resistant metal rod such as ceramics instead of the metal mesh 11 used in this invention also prevents these radiators from receiving the heat of the combustion gas and reaching a temperature higher than that of the heater tube. If so, the same effects as the embodiments of the present invention can be obtained. In particular, in this invention, this metal mesh 1
It is preferable to use a cylindrical ceramic having a plurality of pores instead of 1, since a high effect can be obtained.

〔Effect of the invention〕

As explained above, this invention improves the safety of the Stirling engine by arranging a radiator that radiates heat so as to surround the group of heater tubes, thereby making the temperature distribution of the heater tubes uniform. , has the effect of improving thermal output and thermal efficiency.

[Brief explanation of drawings]

Fig. 1 is a sectional view for explaining the Stirling engine, Fig. 2 is an enlarged view of a conventional heater tube, Fig. 3 is an enlarged view of an embodiment of the present invention, and Fig. 4 is the surface temperature of the heater tube of the Stirling engine. This is a graph representing 4... Heater tube, 5... Fin, 11... Metal mesh, 12... Support ring. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Masuo Oiwa Figure 1 Figure 2 (b) (0)'' - Client - Written amendment to the procedure (voluntarily submitted) To the Commissioner of the Japan Patent Office 1, Indication of the case Patent Application No. 186430/1986 2. Name of the invention Stirling engine 3. Person making the amendment Representative Hitoshi Katayama. 5. Drawing subject to the amendment 6. Details of the amendment Figure 2 of the drawing is corrected as shown in the attached sheet. 7.Inventory of attached documents (Figure 2) Corrected drawing 1 copy

Claims (1)

[Claims] +11 In a Stirling engine equipped with a group of heater tubes for heating working gas using combustion heat from a combustor, and an air preheater St- arranged so as to surround the group of heater tubes, the group of heater tubes and the air A Stirling engine, characterized in that a radiant having a heat resistance strength higher than the temperature of the heater tube is disposed between the preheater and the heater tube so as to surround the heater tube.