JPH03122408A - Combustion device with ultrasonic atomization device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention generally relates to a combustion device equipped with an ultrasonic atomizer for atomizing supplied liquid fuel using ultrasonic vibration, and The present invention relates to a combustion device with an ultrasonic atomizer that is suitably used in commercial and domestic boilers, heating furnaces, water heaters, dryers, gas turbines, heating burners, and the like.

[Conventional technology]

Until now, in combustion devices such as boilers and fan heaters, when burning the supplied liquid fuel, from the viewpoint of combustion performance, this liquid fuel has been reduced to an extremely small size.
In addition, it is desirable to atomize and supply the droplets with a uniform particle size.

BACKGROUND ART Conventionally, an ultrasonic atomization device that atomizes supplied liquid fuel using ultrasonic vibration is known as such a device that atomizes liquid fuel into extremely small droplet size. In this type of ultrasonic atomizer, in order to ensure good atomization efficiency over a wide fuel supply range, it is necessary to stabilize combustion by promoting the mixing of atomized droplets with air. Required. Various efforts have been made for this purpose.

For example, in Utility Model Application Publication No. 83-167022,
Using a solid vibrator horn whose diameter increases toward the tip, the atomized fuel droplets are sent to the combustion chamber where they are ignited by the spark plug, and the swirling flow of air moves the fuel droplets into the combustion chamber. A method has been proposed to send the data to

[Problems to be Solved by the Invention] However, in the above-mentioned conventional ultrasonic atomization device,
After the fuel is atomized, the atomized droplets are conveyed by a swirling air flow, resulting in non-uniform mixing of the atomized droplets and air.
The problem is that combustion becomes unstable.

Furthermore, since the ignition plug is always placed in the fuel droplets, there is a problem in that the medium adheres to the ignition plug, resulting in poor ignition performance.

Furthermore, it is difficult to effectively and efficiently atomize the required fuel in a large amount in a short period of time with a fine atomized particle size suitable for combustion. That is, it is difficult to obtain sufficient amplitude needed to atomize a large amount of liquid. This is because the above-mentioned vibrator horn is a solid type and has a large mass, and if a high amplitude is to be ensured, high stress is generated and the material is not durable.

Another drawback is that the power consumption required to atomize the fuel supplied using this device is high. This is because the ultrasonic energy generated from the ultrasonic vibration generating means vibrates the ultrasonic vibrator horn, and the vibration of the ultrasonic vibrator horn causes the supplied fuel to be atomized at the atomization part of the ultrasonic vibrator horn. When atomizing fuel with a solid ultrasonic transducer horn with a large mass, a large amount of ultrasonic energy is required to obtain a large amplitude, and therefore a large amount of fuel cannot be atomized. To do that,
A large amount of energy is required, resulting in stress on the horn that is too high to atomize large amounts of fuel efficiently.

The present invention solves the above problems, and provides a combustion device with an ultrasonic atomizer that can stabilize combustion and improve ignitability by homogenizing the mixing of atomized droplets and air. The purpose is to

Another object of the invention is to provide a combustion device with an ultrasonic atomizer that uses less power when atomizing liquid substances.

Another object of the present invention is to provide an ultrasonic atomizer capable of atomizing a liquid substance even if the liquid substance is supplied to the atomizing section of an ultrasonic atomizer in excess of a set and proper atomization amount. An object of the present invention is to provide a combustion device with a oxidation device.

[Means to solve the problem]

To this end, the ultrasonic atomizer of the present invention includes an ultrasonic vibration generating means 2, a vibrator horn 3 connected to the ultrasonic generating means, and an atomizing section 4 formed at the tip of the vibrator horn. ,
a fuel supply means 5a16a that supplies fuel to the atomization section;
It has an ignition means 10a and a swirl flow generating means 12 disposed between the fuel supply means and the atomization section, and the atomization section 4
has an enlarged diameter part 4a whose diameter becomes larger toward the tip, and a hollow part 4b is formed in the enlarged diameter part, and further,
The distance between the swirling flow generating means 12 and the tip of the atomizing section 4 is set in the range of 1/4 to 3/4 of the diameter of the atomizing section 4, and the distance between the ignition means 10a and the axis of the vibrator horn 3 is set. The distance therebetween is set at a position that is at least 1/2 of the diameter of the atomizing section 4 and at a position that does not cause electrical leakage with the swirling flow generating means 12.

Note that the numbers added to the above configurations are for comparison with the drawings to facilitate understanding, and the configurations of the present invention are not limited thereby.

[Effect]

In the present invention, for example, as shown in FIG. 1, fuel is atomized toward the atomization section 4 of the vibrator horn 3 through the liquid supply path 5avf3a, and the liquid that has reached the atomization section 4 is It is atomized by ultrasonic vibrations from the ultrasonic vibration generator 2. At this time, the atomized droplets are ignited by the ignition means 10a and are immediately transported by the swirling flow generated by the swirling flow generation means 12, so that the medium does not adhere to the ignition means 10a and combustion is prevented. Stability can be improved.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1st
The figure is a sectional view showing an embodiment of the combustion apparatus with an ultrasonic π-increasing device of the present invention, and FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1.
FIG. 3 is a sectional view taken along the m-m gland in FIG. 1, FIG. 4 is a sectional view showing the detailed structure of the atomizing section, and FIG. 5 is a diagram for explaining its operation.

In FIG. 1, an ultrasonic atomizer 1 includes an ultrasonic vibration generator 2 at its base for generating ultrasonic vibrations, and a vibrator horn 3 is connected to the ultrasonic vibration generator 2. At the tip of this vibrator horn 3, an atomizing section 4 having a hollow tip is formed. On the outer periphery of the vibrator horn 3,
A liquid supply member 5 is provided, and a liquid supply nozzle member 6 is screwed onto the inner periphery of the liquid supply member 5. The liquid supply member 5 and the liquid supply nozzle member 6 each have a liquid supply path 5ax8.
As shown in FIG. The connecting portion of the liquid supply nozzle member 6 communicates with the fuel supply path 5a.

The ultrasonic atomization device 1 is fixed by a support portion 8 provided on the housing 7, and an ignition device 10 is disposed on the outer periphery of the liquid supply member 5 with a mounting band 9. Also,
An outer cylinder 11 that covers the ultrasonic atomizer 1 is provided at the tip of the housing 7 .

On the outer periphery of the vibrator horn 3, a turning plate 12 is provided, in which a spark plug 10a of an ignition device 0 and a turning blade 12a are cut and raised. As shown in FIG. 2, a notch 12b is formed in the upper part of the rotating plate 12, and a spark plug 10a is disposed between the notch 12a and the vibrator horn 3.

This is to ensure electrical insulation between the spark plug 10a and the rotating plate 12. The housing 7 is connected to an air blower (not shown), and the air is supplied to the ultrasonic atomizer 1.
It flows toward the rotating plate 12 through the outer periphery of the rotating plate 12 .

As a result of various experiments, the rotating plate 12 and the vibrator horn 3
The distance between the tip of the atomizing part 4 and the diameter of the atomizing part 4 is D.
Then, the range is D/4 to 3D/4, preferably D/2
It has been found that combustion stability is good if the position is set to . This is because if L is made too small, the atomized droplets will collide with the rotating plate 12, and if L is made too large, the droplets will scatter.

Further, the distance H between the spark plug 10a and the vibrator horn 3 on the axis is D/2 or more, and the position where there is no electric leakage with the swivel plate is preferable, preferably, the tip of the spark plug 10a is located in the atomizing part 4 as shown in the figure. A position (D/2) matching the outer diameter is preferred. This is because this position is a position where no flame is formed, so the ignitability is good and the medium does not adhere to the spark plug 10a.

The operation of the present invention having the above configuration will be explained. The fuel is atomized toward the atomization section 4 of the vibrator horn 3 through the liquid supply channels 5a and 6a, and the liquid that has reached the atomization section 4 is
It is atomized by ultrasonic vibrations from the ultrasonic vibration generator 2. At this time, the atomized droplets are ignited by the spark plug 10a and are immediately transported by the swirling flow generated by the swirling plate 12, so that the medium does not adhere to the spark plug 10a and the combustion is stabilized. It is something that can be improved.

Next, as shown in FIGS. 4 and 5, the vibrator horn 3 is
The atomizing section 4 will be explained.

In FIG. 4, the vibrator horn 3 is connected to the ultrasonic generating potato stage 2.
A small diameter part is formed on a cylinder along the axial direction of the vibrator horn 3 from the end connected to the oscillator horn 3, and the opposite end is formed to have a large diameter and is connected to the small diameter part. In the section reaching the diameter part, an enlarged diameter part 4a is formed so as to have a conical shape. The shape formed in this enlarged diameter part is
In some cases, it is formed to have a curved shape that widens towards the end (in this case, it becomes a trumpet shape).

Furthermore, in the present invention, a hollow part 4b is formed which extends from the enlarged diameter part 4a of the atomizing part 4 to a part of the small diameter part of the vibrator horn 4 and is open to the large diameter part.

That is, in order to make the vibration at the end 4c of the atomizing part 4 have the maximum amplitude, the hollow part 4b is formed so that the end 4c is the antinode of the vibration. At this time, the inner peripheral surface of the hollow part 4b is cut by a plane S that crosses the hollow part 4b perpendicularly to the axis of the vibrator horn 3.
The cross-sectional area of the donut cane formed between d and the outer peripheral surface 4f either decreases slightly from the terminal end 4g to the end 4c, or remains almost constant from the terminal end 4g to the end 4c. A hollow portion 4b is formed as shown in FIG. This cross-sectional area is allowed up to ±40%.

A simple method for forming the hollow portion 4b to have the above-mentioned cross-sectional area is to adjust the apex angle of the enlarged diameter horn formed toward the axis of the vibrator horn 3 along the inclination of the outer circumferential surface 4f, i.e. The apex angle of the outer peripheral surface 4f is 01, and the inner peripheral surface 4
When the apex angle of the hollow portion 4b formed toward the axis of the vibrator horn 4 along the inclination of O''
The hollow portion 4b may be formed in a conical shape or a conical curved surface shape (trumpet shape) with an angle of ~30°, preferably 5° to 10°. Note that there is virtually no difference in the performance of the ultrasonic transducer horn of the present invention whether the enlarged diameter part is conical or trumpet-shaped. The angle formed by the tangent at the center of the enlarged diameter section (the midpoint of the outer peripheral surface from the start of the enlarged diameter section to its tip) toward the axis of the vibrator horn is substituted for the apex angle. This angle is preferably 30 to 60'' as in the case of a conical horn.

Further, the wall thickness between the inner circumferential surface 4d and the outer circumferential surface 4f of the hollow portion 4b, that is, the wall thickness of the enlarged diameter portion 4a is the same as that of the end 4 of the enlarged diameter portion 4a.
At c, the radius is 20% or less of the radius d. That is, the reason why the wall thickness of the enlarged diameter portion 4a formed by forming the hollow portion 4b is set to 20% or less of the radius d is from the viewpoint of making it easier to generate vibrations in the radial direction.

Regarding the above, by forming the hollow part 4b, the mass of the ultrasonic transducer horn 3 is reduced, and therefore, the atomization surface 4f of the ultrasonic transducer horn 4 atomizes the supplied fuel. The vibration energy required for atomization is reduced because the mass of the hollow part of the ultrasonic vibrator horn 3 is smaller, and the atomization surface 4f is thinner due to the thinner wall thickness of the atomization surface 4f. Has flexibility,
In addition, the end portion 4c of the atomization surface 4f is set to be the antinode of vibration so that the maximum amplitude can be obtained, and the vibration energy from the ultrasonic generating means is transmitted to the ultrasonic vibrator horn 3. The vibration is transmitted to the axial direction of the atomizing surface (radial direction) and the atomizing surface direction (radial direction) which has an inclination angle with respect to this axial direction, and as a result, compound vibration occurs on the atomizing surface 4f (hereinafter referred to as flexural vibration). This flexural vibration easily generates a large amplitude on the atomization surface 4f, and therefore, the large amplitude of this flexural vibration effectively acts as an effective amplitude necessary to atomize the fuel, which is supplied to the atomization surface 4f. The present invention is extremely effective in atomizing fuel with a fine particle size, and is also effective in easily atomizing a large amount of fuel, resulting in low power consumption.

To further describe this flexural vibration with reference to FIG. 5, when the vibrator horn 3 is at rest before vibration is applied, the tip of the vibrator horn 3 is at position a, and when the vibrator horn 3 is contracted, The tip of the vibrator horn 3 is at position a', and when the vibrator horn 3 is extended, the tip of the vibrator horn 3 is at position a#. Therefore, the tip radius d of the vibrator horn 3 increases when the vibrator horn 3 is contracted, and decreases when the vibrator horn 3 is expanded. As a result, the atomization surface 4f of the ultrasonic transducer horn 3 receives not only the normal vertical vibration of absolute amplitude applied from the ultrasonic generating means but also the radial vibration with respect to the axial direction of the transducer horn 3. Vibration is induced and added, and as a result, the atomizing surface 4f performs a composite vibration that is a combination of these vibrations, that is, a flexural vibration.

〔Effect of the invention〕

As described above, according to the combustion apparatus with an ultrasonic atomizer of the present invention, since the swirling flow generating means is disposed upstream of the atomizing section of the vibrator horn, the combustion gas is immediately transferred to the swirling flow generating means. The fuel is transported by the swirling flow generated by this process, which makes it possible to homogenize the mixture with air and stabilize combustion.

Furthermore, since the tip of the ignition means is at a position where no flame is formed, the ignition performance is good and the adhesion of the medium to the ignition means can be prevented, thereby improving the ignition performance.

Furthermore, according to the ultrasonic vibrator horn of the present invention, compared to conventional ultrasonic vibrator horns that do not form a hollow part, in order to obtain the same atomization m, less power is consumed, and For the same power supply, the ultrasonic transducer horn of the present invention has a higher power consumption than the conventional ultrasonic transducer horn.
It is possible to atomize a large amount of liquid substance.

Further, with the ultrasonic vibrator horn of the present invention, it is possible to obtain the large amplitude necessary to effectively atomize fuel into fine particle sizes. Therefore, on the atomization surface, a large amplitude can be easily obtained compared to conventional ones, so it is easy to atomize the fuel with smaller particle size and also to easily atomize a large amount. .

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the combustion apparatus with an ultrasonic atomizer of the present invention, FIG. 2 is a cross-sectional view taken along the line n-■ in FIG. 1, and FIG. A cross-sectional view along the l1l-III line,
FIG. 4 is a sectional view showing the detailed structure of the atomizing section, and FIG. 5 is a diagram for explaining its function. 1... Ultrasonic atomization device, 2... Ultrasonic vibration generator,
3... Vibrator horn, 4... Atomization part, 4a... Expanded diameter part, 4b... Hollow part N 5 aN 6 a...
・Fuel supply means, 10a... Spark plug (ignition means)
, 12... swirling plate (swirling flow generating means). Applicant: Tonen Corporation

Claims (4)

[Claims] (1) Ultrasonic vibration generating means, a vibrator horn connected to the ultrasonic generating means, an atomizing section formed at the tip of the vibrating horn, and a fuel supply supplying fuel to the atomizing section and an ignition means and a swirling flow generating means disposed between the fuel supply means and the atomizing section, and the atomizing section has an expanding diameter section whose diameter increases toward the tip. and a hollow part is formed in the enlarged diameter part, and further, the distance between the swirling flow generating means and the tip of the atomizing part is set to 1/4 to 3 of the diameter of the atomizing part.
/4 range, and the distance between the ignition means and the axis of the vibrator horn is set at a position that is 1/2 or more of the diameter of the atomizing section and at a position that does not cause electrical leakage to the swirling flow generating means. Combustion device with ultrasonic atomization device. (2) The combustion apparatus with an ultrasonic atomizer according to claim 1, wherein a notch is formed in the swirling flow generating means, and an ignition means is disposed between the notch and the vibrator horn. (3) The combustion apparatus with an ultrasonic atomizer according to claim 1 or 2, wherein the atomizer has a substantially constant cross-sectional area perpendicular to the axis of the vibrator horn. (4) The fuel supply means is characterized by comprising a liquid supply member and a liquid supply nozzle member disposed on the outer periphery of the vibrator horn, and a plurality of fuel supply passages formed in the liquid supply nozzle member. A combustion apparatus with an ultrasonic atomizer according to any one of claims 1 to 3.