JPS6152507A - Pulsating burner - Google Patents

Abstract

PURPOSE:To make a variable range of thermal output wider, by forming two rows at least of fuel injection ports on the circumference of a fuel feed pipe, and by positioning one of the fuel injection rows in a combustion chamber, while the other row is located in an air passage. CONSTITUTION:A combustion chamber 1 is composed of a primary combustion chamber 1a and the secondary combustion chamber 1b of which internal diameter is larger that of the primary combustion chamber 1a. Two rows of fuel injection ports 9 and 10 are provided on the circumference of a fuel feed pipe 8, and one row 9 of fuel injection ports is provided in an air passage 3, while the other row 10 of fuel injection ports is provided in the combustion chamber 1. When the combustion rate is large, main flames are mostly formed in the secondary combustion chamber 1b which is away from the air passage 3, so that the temperature in the air passage 3 will not rise much, and combustion air will not be prevented from coming into the combustion chamber 1, so that the upper limit of combustion range is not narrowed. When the combustion rate is small, the main flames are formed in the primary combustion chamber 1a, and in addition, the main flames are stabilized as the flames in the air passage 3 near the fuel injection ports 9 heat the roots of flames in the primary combustion chamber 1a. The lower limit of combustion range can be widened, because flames can be burned stably even if the combustion rate is small.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a pulse combustor that serves as a heat source for household or industrial water heaters, space heaters, and the like.

Conventional configuration and problems A pulse combustor uses fuel and a blower fan to supply combustion air to the combustion chamber at startup, and forces combustion by operating a spark plug, and once the system stabilizes. When a combustion cycle is formed, even if the spark plug and blower fan are stopped, combustion air is automatically sucked in and self-ignition continues pulse combustion at a constant frequency of several tens to hundreds of hertz.

Such a pulse combustor has very good heat transfer characteristics because the flow rate of combustion gas is high and pulsates, and can be used as a combustor with high heat exchange efficiency. Furthermore, the pulse combustor burns under high load, does not require a power source except during startup, and has the advantage of being simple in structure.

However, the pulse combustor produces a loud sudden noise during combustion.
There was a problem that the variable range of heat output was narrow. Therefore, as a noise countermeasure, a method is generally used to install a silencer on the supply and exhaust pipes, but installing a silencer increases the ventilation resistance of the supply and exhaust system and reduces the supply and exhaust capacity of the pulse combustor.
Furthermore, a problem arises in that the variable range of heat output becomes narrower.

OBJECTS OF THE INVENTION The present invention has been made in view of these problems, and an object of the present invention is to provide a pulse combustor whose heat output can be varied over a wide range.

Structure of the Invention In order to achieve the above object, the pulse combustor of the present invention has a combustion chamber composed of a plurality of chambers each having a larger inner diameter toward the downstream side, and an air passage connected to the upstream side 11111 of the combustion chamber. , the fuel cylinder projects into the combustion chamber, and at least two rows of fuel injection ports are formed on the circumference of the fuel cylinder, one row of fuel injection ports is located inside the combustion chamber, and the other row of fuel injection ports is located within the combustion chamber. It is located within the air passage.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. As shown in FIG. 1, the pulse combustor of this embodiment has a combustion chamber 1
, first combustion chamber 1a, second combustion chamber 1b, tail pipe 2,
Air passage 3, air chamber 4, air pipe 5, air pulp chamber 6
, air pulp 7, fuel tube 8, fuel jet port 9, 10. It is composed of a fuel pulp 11 and a spark plug 12.

Generally, in a pulse combustor, at the upper limit of the combustion range, there is a shortage of combustion air and CO is generated, and at the lower limit of the combustion range, there is an excess of combustion air, which causes the flame to lift and cause a misfire. When there are many combustors, the pressure inside the combustion chamber is high and the flame is in a suppressed shape, and the flame is present in the air path near the fuel nozzle of the fuel tube, and this flame is the main cause of formation within the combustion chamber. By heating the base of the flame, the main flame burns stably. When the amount of combustion is small, the pressure inside the combustion chamber is low and the flame becomes thin and elongated, and there is no flame in the air path mentioned above, so the root of the main flame fluctuates unstablely and the main flame lifts and combustion becomes unstable. The flame existing in the air passage near the fuel nozzle of the fuel tube contributes to flame stability.

Therefore, even if the amount of combustion is small, by allowing the flame to exist in the air passage near the fuel injection port, the lower limit of the combustion range can be expanded. In addition, the amount of combustion is reduced,
Even if the pressure inside the combustion chamber decreases, the main flame does not grow thin and
By creating a coherent flame, the combustion range can be further expanded.

Therefore, in this implementation, the combustion chamber 1 is composed of a first combustion chamber 1a and a second combustion chamber 1b having a larger inner diameter, and the fuel cylinder 8
Two rows of fuel nozzles 9 and 10 are provided on the circumference of the combustion chamber, with one row of 9 fuel nozzles located within the air passage 3 and the other row of 10 fuel nozzles located within the combustion chamber 1. . For this reason, the fuel gas ejected from the fuel nozzle 9 collides with the wall surface of the air passage 3, and as a result, the flow velocity of the fuel gas becomes slow, and an area where the mixture flow velocity is low is created in the air passage 3 near the fuel nozzle 9. can. Therefore, the flame remains in the air passage 3 near the fuel injection port 9 without being blown out, and this flame heats the base of the main flame, thereby increasing the stability of the main flame.

When the amount of combustion is large, the main flame is mostly formed in the second combustion chamber 1b, which is far from the air passage 3, and only a part of the fuel gas is combusted in the air passage 3, so the temperature inside the air passage 3 decreases. Since the rise is small, the flow of combustion air into the combustion chamber 1 is not inhibited. Therefore, the upper limit of the flammability range is not narrowed.

When the amount of combustion is small, the main flame is mostly in the first combustion chamber 1.
The main flame is formed in the first combustion chamber 1a, and the main flame burns together in the first combustion chamber 1a due to the influence of the circulating flow within the first combustion chamber 1a. In addition, since a flame exists in the air passage 3 near the fuel injection port 9, this flame heats the base of the main flame, thereby stabilizing the main flame. Therefore, even if the combustion amount is reduced, the flame burns stably and the lower limit of the combustion range is widened.

Effects of the Invention As described above, according to the pulse combustor of the present invention, the flame is divided into the main flame that burns in the combustion chamber and the flame that burns in the air passage. In the combustion chamber
Furthermore, when the amount of combustion is small, the main flame is formed in the upstream combustion chamber, which has a smaller diameter, so the combustion range of the pulse combustor can be expanded.

BRIEF DESCRIPTION OF THE DRAWINGS The figure is a sectional view of a pulse combustor according to an embodiment of the present invention. 1... Combustion chamber, 2... Tail pipe,
3...Air passage, 9,10...Fuel spout.

Claims (1)

[Claims] A combustion chamber having an inner diameter larger on the upstream side than on the downstream side, an air passage connected to the upstream side of this combustion chamber, and a fuel cylinder penetrating this air passage and facing into the combustion chamber, the fuel cylinder having a circular shape. A pulse combustor having at least two rows of fuel nozzles disposed on the circumference, one row of fuel nozzles located within the combustion chamber, and the other row of fuel nozzles located within the air passage.