JPS62178756A - Air preheater and combustor for external combustion engine - Google Patents

Abstract

PURPOSE:To perform flame holding action, by forming an air preheater of a Stirling engine in a spiral-type air preheater and supplying preheated air in a spiral state into a combustion chamber. CONSTITUTION:Two sheets of discs are spirally wound in the periphery of a combustion chamber 6 in the upper part of a Stirling engine, forming spiral- shaped passages of two systems in the inside. One of the passages serves as a combustion gas passage from a hole 12, and the other passage serves as a combustion air passage from a hole 13. Combustion air, which passes through the spiral-shaped passage being heated, is allowed to flow into a combustion chamber 6 from a hole 9. Since an inflow of the combustion air rotates in a spiral state, the inflow air in the combustion chamber acts so as to hold a flame of a burner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an air preheater and combustor for an external combustion engine.

[Prior art]

Fig. 4 is a sectional view showing a conventional air preheater and combustor for a Stirling engine. 5 is a fuel nozzle, 6 is a combustion chamber, 7 is a heat exchanger for exchanging heat between working gas and combustion gas, and 8 is a heat insulating material.

Next, the operation will be explained.

When the combustion air at room temperature introduced into the air preheater 1 passes through the tube 2, it exchanges heat with the combustion gas existing around the tube 2, and receives heat energy from the combustion gas. Exhaust heat is recovered by becoming high-temperature preheated air. Thereafter, the preheated air is swirled by the guide vanes 4, mixed with fuel injected from the fuel nozzle 5, and ignited.

be burned. Here, the guide vanes 4 are provided to form a backflow region in the combustion chamber 6 by swirling the air and to perform flame stabilization. The combustion gas leaving the combustion chamber 6 imparts thermal energy to the working gas in the heat exchanger 7, and then is introduced into the air preheater I, where it imparts thermal energy to the combustion air in the tube 2. It is discharged outside the system. At this time, a heat insulating material 8 is disposed outside the air preheater 1 in order to reduce heat loss to the surrounding atmosphere.

[Problem that the invention seeks to solve]

The conventional air preheater and combustor are constructed as described above, and the high-temperature combustion gas comes into direct contact with the shell 3, so that the heat insulating material 8 is required to reduce heat loss to the outside. Furthermore, the preheated air that has passed through the air preheater 1 needs to be swirled again by the guide vanes 4 in order to stabilize the flame, which makes it difficult to miniaturize the device.

In view of the above-mentioned points, it is an object of the present invention to provide an air preheater and a combustor for an external combustion engine that do not require heat insulating materials or guide vanes and are structurally simplified and downsized.

[Means for solving problems]

The air preheater and combustor for an external combustion engine according to the present invention include a spiral air preheater disposed around the combustor, whereby a swirling air flow having a predetermined angular momentum is introduced into the combustor and combusted. The vessel is shaped like a cyclone.

[Effect]

In this invention, since the spiral air preheater is disposed around the combustion chamber, heat loss from the combustion chamber to the surrounding atmosphere is reduced, and since the high temperature part is insulated from the combustion air chamber, especially the heat insulating material is used. does not require. Furthermore, the combustion air has angular momentum when passing through the spiral air preheater, and a swirling air flow is obtained by introducing this into the combustor, so that no guide vanes are particularly required.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 14 denotes a spiral air preheater disposed around the combustion chamber 6, inside which air and combustion gas passages are formed in a spiral shape by partition walls 15 (second (see figure). Further, 16 is a packing that constitutes the air preheater 14 together with the partition wall 15, and 17 is a packing holder. 5 is a fuel nozzle; 18 is a fuel injection hole provided at the tip of the fuel nozzle 5; 7 is a heat exchanger for exchanging heat between the working gas of the engine and combustion gas; 9 and 13 are spiral air preheaters 1; 10 is an air swirling chamber, 11 is an air throttle, and 12.19 is a combustion gas inlet and outlet of the spiral air preheater 1. In the figure, the part indicated by the opening in the air preheater 1 represents combustion gas, and the other parts represent air. In addition, in FIG. 1, the spacer inserted between and supporting the partition wall 15 is Not shown.

FIG. 2 shows a schematic cross-sectional view of a spiral heat exchanger. In the figure, -111 represents the flow of combustion gas, and - represents the flow of air.

Next, the effects will be explained.

The combustion air introduced from the air port 13 of the spiral heat exchanger 14 comes into contact with the combustion gas through the partition wall 15 when passing through the spiral air preheater having a spiral flow path. It receives thermal energy from the combustion gas and becomes high-temperature air as it flows along the flow path. Therefore, the combustion air has angular momentum. The preheated air with this angular momentum enters the swirling chamber 10 through the air outlet 9 of the spiral air preheater 14. After the preheated air is once throttled by the air throttle 11, it is mixed with fuel injected from the fuel injection hole 18 of the fuel nozzle 5 and combusted. At this time, the preheated air becomes a swirling flow and is introduced into the combustion chamber 6, so there is no need for a special flame stabilizer as in the conventional case.

After the combustion gas exchanges heat with the working gas in the heat exchanger 7, the combustion gas enters the air preheater 14 through the combustion gas port 12 of the spiral air preheater 14, and the air newly introduced into the air preheater 14 enters the air preheater 14. After imparting thermal energy to it, it is discharged from the system through the outlet 19. At this time, the spiral air preheater 14 is connected to the combustion chamber 6. Since the high-temperature part of the heat exchanger 7 is surrounded by air in a spiral shape, no special heat insulating material is required as in conventional devices.

Although the above embodiment does not use any means to strengthen the swirl, as shown in FIG. 3, a conversion plate 20 for converting the air flow from static pressure to dynamic pressure is provided near the outlet of the air passage of the air preheater 14. That is, by providing the partition plate 20 to narrow the air flow path and increase the air flow velocity, a stronger swirling flow can be obtained.

Note that FIG. 3 shows the spiral air preheater 14 partially expanded.

〔Effect of the invention〕

As described above, according to the present invention, a high-temperature part such as a combustion chamber is surrounded by a spiral air preheater and is insulated with combustion air, so there is no need for special insulation material, and the combustion air is spiral-shaped. Since angular momentum is obtained when passing through the shaped air preheater, a swirling flow can be obtained without a special flame stabilizer, and as a result, the structure can be simplified and the device can be manufactured at low cost.

[Brief explanation of drawings]

FIG. 1 is a sectional side view showing an air preheater and combustor for an external combustion engine according to one embodiment of the present invention, FIG. 2 is a sectional plan view thereof, and FIG. 3 is an air preheater and combustor according to another embodiment of the present invention. FIG. 4 is a partially exploded view of the preheater, and is a cross-sectional side view of a conventional air preheater and combustor for an external combustion engine. 5... Fuel nozzle, 6... Combustion chamber, 7... Heat exchanger, 10... Air swirling chamber, 11... Air throttle, 14
...Spiral type air preheater, 20...Air static pressure dynamic pressure conversion plate. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A spiral air preheater having a spiral air passage and an exhaust gas passage of the combustor around the combustor of an external combustion engine and recovering the thermal energy possessed by the exhaust gas into combustion air. An air preheater and combustion for an external combustion engine, characterized in that the preheated air having angular momentum obtained by the spiral air preheater is introduced into the combustor to perform flame stabilization. vessel.