JPS63148013A - Pulse combustion device - Google Patents

Abstract

PURPOSE:To improve a mixing characteristic of air and fuel by a method wherein a plurality of pins are installed near a fuel nozzle. CONSTITUTION:A fuel distributor 6 positioned concentrically around within an air neck part 2 is provided with a fuel nozzle 5 on a periphery near its extremity end and at the same time a plurality of pins 9 are arranged near a fuel nozzle 5. The pins 9 are fixed to the fuel nozzle 5 under an equal pitch of a half pitch displaced. Fuel gas 10 flowed from the nozzle 5 into the air neck 2 is passed through an air valve 3, mixed with air 11 flowed into the air neck part 2 and then an explosion combustion is started under an action of an ignition plug 12. During an intake stroke, a high speed air flow in the air neck part 2 is further struck against a pin 9 to cause a turbulence flow to be promoted together with eddy flow. Since the fuel gas is flowed into the excessive turbulence flow, a better mixing of the air and the fuel gas is made and a uniform mixing is further improved to a mixing degree of the mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a pulse combustion device used as a heat source for industrial, commercial, or domestic water heaters, hot air fans, and the like.

BACKGROUND ART FIG. 2 is a diagram showing a conventional example, in which 1 is a combustion chamber, 2 is an air neck, 3 is an air valve, and 4 is a tail pipe. A fuel distributor 6 with fuel nozzles 5 provided on the circumference
are arranged concentrically inside the air neck 2.

A fuel valve 8 is installed in the middle of the pipe line 7 upstream of the distributor 6. 12 is a spark plug for starting combustion.

Next, the operation of this conventional example will be explained. fuel gas 1o
Due to the supply pressure, the gas flows from the pipe 7 through the gas valve 8 and from the nozzle 6 into the air neck portion 2 . Combustion air 11 is forced by a blower or the like (not shown), flows into the air neck portion 2 through the air valve 3, and mixes with the fuel gas. When this air-fuel mixture is ignited by the action of the spark plug 12, explosive combustion begins. As a result of this explosion, the pressure within the combustion chamber 1 rapidly increases, the air valve 3 and the fuel valve 8 are closed, and the supply of air and fuel gas is stopped. The high-temperature gas in the combustion chamber 1 flows out from the tail pipe 4 as a high-speed flow without flowing backward to the upstream side. As the outflow continues, the pressure within the combustion chamber 1 decreases, but the pressure within the combustion chamber 1 becomes negative due to the inertial force of the outflow flow. Due to the action of this negative pressure, the air valve 3 and the fuel valve 8 open again, and new air and fuel gas flow into the air neck portion 2 to form the next air-fuel mixture. Meanwhile, due to the effect of this negative pressure, some of the high-temperature gas that had been flowing out flows backwards and comes into contact with the newly formed air-fuel mixture, causing the next explosion. The same process is repeated one after another, resulting in a stable pulsed combustion state. Once stable pulse combustion is achieved, pulse combustion will continue automatically even if the blower and spark plugs are turned off. In conventional examples, the air-fuel mixture is formed by generating a fuel gas flow in a direction perpendicular to the high-speed air flow generated in the air neck.

Problems to be Solved by the Invention The pulse combustion device uses a combustion method that utilizes self-excited vibration phenomena, and can perform exhaust and intake intermittently using the high pressure generated by the self-blading blades without adding the action of a blower. The main advantage is that it can provide highly efficient heat utilization equipment. However, in the prior art, combustion based on self-excited vibration phenomena sometimes becomes unstable and there is a risk of misfire. Additionally, there was a problem in that the range in which the combustion amount could be varied was narrow.

Means to Solve the Problems One of the reasons why the combustion sometimes becomes unstable and the variable range of the combustion amount is narrow lies in the air-fuel mixture generation structure of the prior art. By installing multiple pins near the fuel nozzle, the mixing performance of air and fuel is improved.

The high-speed air flow inside the air neck 51 collides with the pin provided near the working fuel nozzle, promoting turbulent flow accompanied by vortices. and fuel mix better, improving mixing degree and mixing uniformity, improving ignitability.

Flammability is improved.

Embodiment FIG. 1 is a diagram showing an embodiment of the present invention, in which the air neck portion 2
A fuel distributor 6 located concentrically inside the fuel distributor 6 is provided with a fuel nozzle 5 on the circumference near the tip thereof, and a plurality of pins 9 are provided near the fuel nozzle 5. The pins 9 are attached to the fuel nozzle 5 at equal pitches or shifted by a half pitch. The mounting position may be on the upstream side of the fuel nozzle 6 as shown in FIG. 1, or vice versa, on the downstream side.

The other components are the same as the conventional example shown in FIG. 2, so opposing parts are indicated by the same numbers. Furthermore, the method of starting combustion and the basic operating principle are the same as in the conventional example. However, during the suction stroke, the high-speed airflow that has flowed into the air neck portion 2 further collides with the pin 9, thereby increasing turbulence with eddies. Since the fuel gas flows into this intense turbulence, the air and fuel gas are mixed well, and the degree of mixing of the air-fuel mixture becomes even more uniform.

As mentioned earlier, pulse combustion is a type of self-excited oscillation phenomenon in which combustion continues with its own explosive force, so if the combustion gas is throttled to reduce the amount of combustion, there will be excess air, which in turn will cause combustion to continue. If the amount of gas is increased, there will be a lack of air and combustion cannot continue. Therefore, this is a combustion method that has a narrow turndown ratio, and is also a combustion method that tends to cause combustion to become unstable at times.

By configuring a pulse combustion method that essentially has such characteristics in accordance with the present invention, combustion stability can be improved and the turndown ratio can be increased. Therefore, it is possible to develop equipment that can perform air supply and exhaust combustion with its own blade and has high combustion heat utilization efficiency.

Effects of the Invention As detailed above, the configuration of the present invention provides 7 l-
7. The pulse combustion method, which is suitable for the development of equipment that can carry out supply and exhaust combustion with its own blade and has high efficiency in the use of combustion heat, will not only be applicable to a wider range, but will also be able to achieve a generally reliable combustion state. can do.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a fourth embodiment of the present invention, and FIG. 2 is a vertical sectional view showing a conventional example. 1... Combustion chamber, 2... Air neck part,
3...Air valve, 5...Fuel nozzle, 6...Distributor, 9...
pin.

Claims (3)

[Claims] (1) A combustion chamber, an air supply means having an air valve via an air neck provided at the upstream end of the combustion chamber, a tail pipe provided at the downstream end of the combustion chamber, and an air supply means provided at the air neck at the upstream end of the combustion chamber; a fuel gas distributor provided concentrically with the nozzle visible; a fuel valve provided in the middle of a fuel pipe on the upstream side of the distributor;
The pulse combustion device further includes a fuel supply means provided with a plurality of pins near the fuel nozzle. (2) The pulse combustion device according to claim 1, wherein the pin is provided on the distributor. (3) The pulse combustion device according to claim 1, wherein the pin is provided on the inner surface of the air neck portion.