JPS5844171B2 - high temperature heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-temperature heat exchanger, and particularly to a high-temperature heat exchanger for effectively thermally expanding a working medium gas of a Stirling engine.

Instead of pushing down the pistons through combustion and explosion in an internal combustion engine, the Stirling engine burns oil and passes the working medium gas through the heat exchanger tubes of a high-temperature heat exchanger that is heated by the flame and combustion gas. This is an engine that pushes down the piston by expansion due to temperature, but in order to effectively thermally expand the working medium gas, it is necessary that the volume of the heat transfer tube of the high temperature heat exchanger through which the working medium gas passes is small.

Of course, the volumes of the Stirling engine cylinder, low-temperature heat exchanger, regenerator, etc. in which the working medium gas is present must be similarly small.

The high-temperature heat exchanger has a structure in which the volume of the heat transfer tube is reduced to make the thermal expansion of the working medium gas more effective.
A large number of circular pipes for passing the working medium gas are arranged in the axial direction of the cylindrical combustion chamber with a burner installed on the front side, at regular intervals in the circumferential direction, with the same center as the cylindrical combustion chamber, and on the peripheral wall of the combustion chamber. A conceivable structure is one in which the pipes are covered with a fireproof material and the group of circular tubes is heated not only by flame radiation and contact heat transfer between the flame and combustion gas, but also by radiation from a fireproof wall, but this can actually be used. In order to achieve this, the flame flows from the inner surface of the front wall of the combustion chamber to the inner surface of the peripheral wall, and the space between the circular tube group and the fireproof wall around the periphery of the combustion chamber is placed at the center of the rear wall of the combustion chamber facing the burner. The gas must flow toward the gas outlet, which has a diameter smaller than the inside diameter of the combustion chamber, cross the circular tube group from an appropriate length position, gather at the center of the combustion chamber, complete combustion, and exit from the gas outlet.

However, it is extremely difficult to control the flow of flame and combustion gas in this way.

In other words, in order for the flame to flow from the inner surface of the front wall of the combustion chamber where the burner is installed along the inner surface of the peripheral wall, the front wall of the combustion chamber must be shaped like a trumpet at a portion of the burner, so the shape of the wall near the burner is important. This is a key point, but the swirling force of the flame also affects the process, making it extremely complicated.

If the shape of the wall near the burner is not appropriate, it is necessary to apply a strong swirling force to the flame in order to cause the flame to flow from the inner surface of the front wall of the combustion chamber along the inner surface of the peripheral wall.

Flame swirl is usually achieved by swirling the combustion air and spraying fuel so that the flame swirls, so the power of the blower that swirls the combustion air becomes too large.

Furthermore, if the fuel and combustion air are poorly mixed, the flames generated may gather near the burner axis and become rod-shaped even if the combustion air is swirled.

In this case, even if the swirling of the combustion air is strengthened, the flame will not flow along the inner surface of the peripheral wall of the combustion chamber.

The present invention solves this problem by allowing the flame to flow from the inner surface of the front wall of the combustion chamber to the inner surface of the peripheral wall, and between the circular tube group and the fireproof wall around the combustion chamber, thereby reducing the heat transfer area. It is an object of the present invention to provide a high-temperature heat exchanger in which a large amount of heat is absorbed by a group of circular tubes to effectively thermally expand a working medium gas passing through the group of circular tubes.

An embodiment of the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a cylindrical combustion chamber, the inner surface of the peripheral wall 2 of which is covered with a refractory material 3, and the front wall with a flame inlet 4 bored in the center. A refractory material 3 is also provided on the inner surface of the baffle 5 and on the inner surface of the rear wall 7 in which the combustion gas outlet 6 is bored in the center.

A wind box 8 is provided in front of the baffle 5, which is the front wall of the combustion chamber 1, and the tip of a burner atomizer 10 is provided to penetrate inside the center of the front wall 9 of the wind box 8. A cone-shaped spray fuel guide plate 11 is provided in the wind box 8 from a portion passing through the tip of the sprayer 10 .

Further, a plurality of air inlets 13 (four in this example) are provided in the peripheral wall 12 of the wind box 8 in the tangential direction for introducing and swirling combustion air into the wind box 8 .

A large number of circular tubes 14 are arranged in the axial direction within the combustion chamber 1 at regular intervals in the circumferential direction concentrically with the center of the combustion chamber 1, and each circular tube 14 has its front and rear ends. is a circular pipe 15
, 15', and the combustion chamber 1 is connected to the header 15.15'.
Pipes 16 and 16' communicating with the outside are connected to each other, each circular pipe 14 receives a working medium gas from, for example, the pipe 16.
It is designed to come out from '.

A fin 17 parallel to the tube axis is provided on the outer periphery of each circular tube 14 to increase the heat transfer area.

In the high temperature heat exchanger of the present invention configured as described above, fuel (oil) is injected into the wind box 8 by the atomizer 10 of the burner, and a conical spray is generated.

On the other hand, combustion air is forced by a blower (not shown) and blown into the wind box 8 from the air inlet 13,
It heads toward the combustion chamber 1 side while turning around on the outside of the engine.

When the combustion air reaches the end of the guide plate 11, its forward movement is restricted by the baffle 5, which is the front wall of the combustion chamber 1, and the combustion air changes direction while turning and heads toward the center of the wind box 8.

Since the atomized fuel (oil) is present in the center of the wind box 8, the combustion air enters the combustion chamber 1 from the flame inlet 4 of the baffle 5 while being mixed with the atomized fuel (oil).

The mixture entering the combustion chamber 1 is swirled by the strong swirl of combustion air, so when the mixture is ignited by an igniter (not shown) installed at an appropriate position at the front of the combustion chamber 1, a flame ignites. flows along the surfaces of the refractory material 3 on the inner surface of the baffle 5, which is the front wall of the combustion chamber 1, and the refractory material 30 on the inner surface of the peripheral wall 2.

When the swirling force is appropriate, the flame moves away from the refractory material 3 of the peripheral wall 2 at an intermediate position within the combustion chamber 1, and moves from the outside to the inside of the group of circular tubes 14 in an attempt to gather at the center of the combustion chamber 1. However, since combustion is completed before passing through the group of circular tubes 14, the flame is not cooled by contact with the circular tubes 14 and the atomized fuel does not become unburned.

Therefore, each circular tube 14 is heated by the contact with the combustion gas, and also by the heat radiation from the surfaces of the baffle 5 and the refractory material 30 of the peripheral wall 2 and the flame, which are heated by the contact with the flame and reach a high temperature. The working medium gas passing through each circular tube 14 absorbs a large amount of heat with a small heat transfer area.

The combustion gas that has passed through the group of circular tubes 14 gathers at the center of the combustion chamber 1 and then passes through the saddle burning gas outlet 6 which opens at the center of the rear wall 7.
It is also discharged outside the combustion chamber 1.

As can be seen from the above explanation, according to the high temperature heat exchanger of the present invention, combustion air can be blown in and swirled to mix with the sprayed fuel.
When this swirling mixture is ignited, the flame flows from the inner surface of the front wall of the combustion chamber to the inner surface of the peripheral wall, and flows between the circular tube group in the combustion chamber and the fireproof wall on the inner periphery of the peripheral wall to complete combustion, and the combustion gas The gas passes through the circular tube group, gathers in the center of the combustion chamber, and is discharged from the gas outlet. Therefore, the circular tube group in the combustion chamber can absorb a large amount of heat with a small heat transfer area, and therefore the carbon dioxide of the circular tube group is This has the excellent effect of efficiently thermally expanding the working medium gas that passes through it.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view showing one embodiment of a high temperature heat exchanger according to the present invention, and FIG. 2 is a left side view of FIG. 1. 1... Combustion chamber, 2... Peripheral wall, 3...
...Fireproof material, 4...Flame inlet, 5...
... Baffle, 6... Combustion gas outlet, 7...
...Rear wall, 8...Wind box, 9...
...Front wall of wind box, 10...Sprayer. 11...Spray fuel guide plate, 12...Peripheral wall of wind box, 13...Blow inlet, 14
・・・・・・Circular tube, 15, 15'・・・Kuyose,
16, 16'...tube, 17...fin.

Claims (1)

[Claims] 1. A wind box with a conical guide plate in the center that covers the sprayed fuel from the oil burner atomizer from the outside and a plurality of combustion air inlets in the tangential direction of the outer periphery, and a wind box connected to the wind box. A flame inlet with a smaller diameter than the maximum diameter of the guide plate is provided in the center of the front wall, a gas outlet with approximately the same diameter as the flame inlet is provided in the center of the rear wall, and fireproofing material is provided on the inner surfaces of the front and rear walls and the peripheral wall. A cylindrical combustion chamber whose inner diameter is larger than the flame inlet, and a large number of cylindrical combustion chambers arranged in the axial direction at regular intervals in the concentric circumferential direction within the cylindrical combustion chamber, the front and rear ends of which are the combustion chambers. A high-temperature heat exchanger consisting of a group of circular tubes connected to an annular header with tubes connected to the outside.