JP4073760B2 - Flame control method, small pulse combustor, and heater - Google Patents

Description

【００２０】
管の高温領域は、予混合ガスの着火遅れに応じてその長さ（管の軸方向長さ）が定められるのが好ましい。着火遅れ分を含む自発着火に必要な距離は、予混合ガスの組成や、予混合ガスの管内流速などに応じて変化する。管の高温領域が予混合ガスの自発着火に必要な距離以上の長さを有することにより、予混合ガスが確実に自発着火する。
【００２１】
本発明の火炎の制御方法においては、管内で予混合ガスが振動的に燃焼することから、管内での境界層の発達が抑制され、高い熱伝達率で、燃焼による熱が管壁に移動する。つまり、燃焼による熱が少ない損失で効率的に管壁に移動する。そのため、熱効率の高い発熱が可能となる。しかも、火炎が脈動する領域が発熱領域となることから、局所的な熱集中が防止される。これは、発した熱を他の物体に伝達するにあたって有利である。
【００２２】
また、本発明の火炎の制御方法においては、燃焼容器として、消炎距離程度以下の内径の管を使用し、この管内で予混合ガスを振動的に燃焼させる。そのため、小型の燃焼器への適用が可能である。以下の表２に、上記数種類の予混合ガスについて、その消炎距離（消炎径）をそれぞれ示す。なお、ここで示す消炎距離は常温常圧環境下のものである。
【００２３】

【００２４】
また、実施例として、本発明の火炎の制御方法に基づいて、メタンと空気とを含む予混合ガスを、内径２ｍｍの円管（石英管）内で燃焼させ、その様子を高速度高感度カメラで観察したところ、先の図１に示した過程からなり、高温領域と低温領域との間を約４０Ｈｚで振動する火炎が観察された。
【００２５】
次に、本発明のパルス燃焼器について説明する。
図２は、本発明のパルス燃焼器の実施の形態例を模式的に示す図であり、このパルス燃焼器は、上述した本発明の火炎の制御方法に基づいて、予混合ガスを振動的に燃焼させるものである。
【００２６】
図２において、パルス燃焼器１０は、燃焼容器としての燃焼管１１、加熱装置１２、及び燃焼管１１内に予混合ガスを供給するガス供給装置１３等を備えて構成されている。
【００２７】
予混合ガスは、燃料と必要な量の酸化剤（空気や酸素など）とを予め混合したものである。燃料としては、例えば、プロパン、ヘキサン、エチレン、アセチレン、及び水素などの可燃気体が挙げられる。ただし、本発明はこれに限定されない。また、燃料は単独で使用してもよいし、異種燃料を組み合わせて使用してもよい。
【００２８】
燃焼管１１は、本例では円形の一様な流路断面を有する円管からなり、その内径は使用する予混合ガスの消炎距離と同程度以下である。実際には、燃焼管１１は、後述する低温領域の温度条件において予混合ガスが消炎する内径を有していればよい。一例として、燃焼管１１の内径は、常温環境での消炎距離の１０〜１２０％程度の範囲内に定められる。なお、上記数値は一例であって、燃焼管１１の温度条件に応じて変化する。
【００２９】
また、例えば、プロパンと空気とを含む予混合ガスを用いる場合、その予混合ガスの消炎距離（消炎径）は約２．７ｍｍであることから、燃焼管１１の内径は、２．７ｍｍ以下、例えば２．０ｍｍ程度に形成される。
【００３０】
なお、燃焼管１１は円管に限定されず、矩形の流路断面を有する矩形管など、他の形状であってもよい。この場合、消炎距離の値としては、その流路の形状に応じたものを使用するのが好ましい。また、燃焼管１１の材質としては、金属などの熱伝導率が高いものが好ましい。異なる材質の部材を組み合わせて使用してもよい。
【００３１】
加熱装置１２は、燃焼管１１の一部の領域を、使用する予混合ガスの自発着火温度以上、例えば自発着火温度の１００〜２００％程度の範囲内に加熱するものである。なお、上記数値は一例であって、燃焼管１１の熱特性などに応じて変化する。加熱温度は、予混合ガスが確実に燃焼管１１内で自発着火する温度以上であるのが好ましく、構成部材が耐えられかつエネルギー損失が大きくならない温度以下であるのが好ましい。
【００３２】
例えば、プロパンと空気とを含む予混合ガスを用いる場合、その自発着火温度は、４５０℃程度であることから、加熱温度は例えば４５０〜９００℃程度に定められる。
【００３３】
加熱装置１２としては、燃焼管１１の所定の領域を上記温度以上に加熱できればよく、電熱線を備える電熱ヒータなど、公知の様々な加熱装置が適用可能である。
【００３４】
ここで、上記燃焼管１１のうち、加熱装置１２によって自発着火温度程度以上に加熱される領域を高温領域２０、高温領域２０の一方の側に配される未加熱の領域を低温領域２１と呼ぶことにする。高温領域２０と低温領域２１とは燃焼管１１の軸方向に並べて配される。
【００３５】
高温領域２０は、使用する予混合ガスの着火遅れに応じてその長さ（管の軸方向長さ）が定められる。また、低温領域２１は、高温領域２０から伝播する火炎が確実に消炎するようにその長さが定められる。高温領域２０から伝わる熱による低温領域２１の温度上昇を抑えるために、低温領域２１を冷却してもよい。また、燃焼管１１の高温領域２０と低温領域２１とを互いに異なる部材で構成してもよい。あるいは、燃焼管１１の高温領域２０と低温領域２１との間に熱の伝達を防ぐ部材を挟んでもよい。
【００３６】
ガス供給装置１３は、燃焼管１１の低温領域２１の側から高温領域２０の側に向けて予混合ガスを連続的に流すものである。つまり、燃焼管１１の低温領域２１の側の端部から燃焼管１１の内部に予混合ガスを供給する。予混合ガスの管内流速は、燃焼管１１の高温領域２０での予混合ガスの燃焼速度に比べて低く、低温領域２１での予混合ガスの燃焼速度に比べて高く設定される。なお、前述したように、高温環境になると、燃焼速度は大きくなる。また、燃焼管１１に供給された予混合ガス、及び燃焼ガスは燃焼管１１の高温領域２０の側の端部から適宜排出される。
【００３７】
図３は、本例のパルス燃焼器１０における燃焼の様子を示す図である。
上記のパルス燃焼器１０では、加熱装置１２によって燃焼管１１の一部の領域が加熱されることにより、使用する予混合ガスの自発着火温度以上の高温領域２０と、低温の低温領域２１とが形成される。また、ガス供給装置１３によって、燃焼管１１の低温領域２１の側から高温領域２０の側に向けて予混合ガスが連続的に供給される。
【００３８】
燃焼管１１の高温領域２０で予混合ガスが自発着火し、その火炎が低温領域２１に伝播し、低温領域２１で消炎する。低温領域２１で消炎すると、予混合ガスが再び管の高温領域２０で自発着火する。これにより、燃焼管１１の高温領域２０と低温領域２１との間で、予混合ガスが振動的に燃焼する。振動的な燃焼により、小型でありながら、高い熱効率で発熱する。
【００３９】
図４は、本発明のパルス燃焼器の実施の他の形態例を模式的に示す図である。先の図２に示した例と異なり、本例のパルス燃焼器５０は、他の熱源からの熱を用いて燃焼管の加熱を行うのではなく、予混合ガスの燃焼による熱（排熱）を用いて燃焼管１１の加熱を行う。
【００４０】
パルス燃焼器５０は、先の例と同様に、燃焼容器としての燃焼管５１、加熱装置５２、及び燃焼管５１内に予混合ガスを供給するガス供給装置５３等を備えて構成されている。また、先の例と異なり、加熱装置５２は、燃焼ガスの熱を予混合ガスに伝達する板状の部材（以後、中間伝熱板５２と称する）からなる。
【００４１】
燃焼管５１は、予混合ガスの流れの方向に関して、流路がＵ字状に折り曲げられており、予混合ガスの供給側の流路６０と、燃焼ガスの排出側の流路６１とが上述した中間伝熱板５２を挟んで互いに対向して配されている。なお、燃焼管５１の断面積は、円形でも矩形でもよく、他の形状でもよい。中間伝熱板５２は、金属などの熱伝導率が高い板状部材からなる。
【００４２】
また、予混合ガスの流れの方向に関して、ガス供給側の流路６０とガス排出側の流路６１との間には、着火位置となる流路（着火部６２）が設けられている。この着火部６２は、他の流路６０，６１に比べて断面積が広くなっている。
【００４３】
図５は、本例のパルス燃焼器５０における燃焼の様子を示す図である。
本例のパルス燃焼器５０では、まず、ガス供給装置５３によって燃焼管５１の流路６０側から予混合ガスが供給される。予混合ガスは、流路６０を流れた後、着火部６２で反転し、流路６１を逆方向に向けて流れる。燃焼の始動にあたっては、不図示の始動装置によって着火部６２の予混合ガスを着火する。この始動装置は、例えば、燃焼管５１の内部を一時的に予混合ガスの自発着火温度以上に加熱するもの、あるいは一時的に点火するものなどが用いられる。
【００４４】
着火部６２で着火した火炎は、予混合ガスの供給側である上流に向けて流路６０内を伝播するとともに、その燃焼ガス（燃焼排ガス）が下流側の流路６１内を流れる。燃焼ガスの熱（排熱）は、中間伝熱板５２を介して流路６１の側から流路６０の側に伝えられ、その熱によって流路６０を流れる予混合ガスが加熱される。
【００４５】
伝達される熱は、着火部６２に近いほど多く、離れるほど少ない。そのため、流路６０のうち、着火部６２に近い側の領域が予混合ガスの自発着火温度に近い高温領域６５となり、着火部６２に対して遠い側の領域がそれより低温の低温領域６６となる。
【００４６】
流路６０内を上流に向けて伝播する火炎は、低温領域６６において、消炎距離に基づく冷却効果により、燃焼が維持できずに消炎する。消炎の後、予混合ガスは高温領域６５において自発着火温度に近い温度に加熱され、着火部６２において消炎距離の制約から解放されて自発着火する。
【００４７】
ここで、前述したように、着火部６２は流路６０，６１に比べて断面積が広い。そのため、その環境下における予混合ガスの自発着火温度は流路６０，６１に比べて低く、着火部６２の温度は、その環境下における予混合ガスの自発着火温度以上となる。つまり、予混合ガスは、着火部６２において、流路６０に比べて低い温度で自発着火することができる。
【００４８】
そして、その火炎が低温領域６６に向けて再び伝播する。これにより、高温領域６５と低温領域６６との間で火炎伝播が繰り返され、予混合ガスが振動的に燃焼する。
【００４９】
上記のパルス燃焼器５０では、先の実施例と同様に、振動的な燃焼により、小型でありながら、高い熱効率で発熱する。また、先の実施例と異なり、予混合ガスの燃焼ガスの熱、いわゆる排熱を用いて高温領域６５の加熱を行う。そのため、熱利用の効率化が図られるとともに、他の熱源を備える必要がないため、装置の小型化や簡素化が図られる。
【００５０】
なお、本例では、燃焼管の高温領域の加熱を、燃焼ガスの熱のみを用いて行っているが、他の熱源と組み合わせて高温領域の加熱を行ってもよい。
【００５１】
上記本発明の小型パルス燃焼器は、加熱部を備える様々なヒータに適用することができる。本発明の小型パルス燃焼器を加熱部として備えるヒータは、小型化が容易に図られるとともに、熱効率が高く、様々な用途に適用される。用途としては、例えば、半導体デバイスや液晶デバイスなどの電子デバイスの製造装置、成型装置、真空装置などが挙げられるが、本発明はこれに限定されない。また、本発明の小型パルス燃焼器に熱電素子を設置し、小型の発電機としてもよい。
【００５２】
以上、添付図面を参照しながら本発明に係る好適な実施形態について説明したが、本発明は係る例に限定されないことは言うまでもない。上述した例において示した各構成部材の諸形状や組み合わせ等は一例であって、本発明の主旨から逸脱しない範囲において設計要求等に基づき種々変更可能である。
【００５３】
【発明の効果】
以上説明したように、本発明の火炎の制御方法によれば、熱効率の高い発熱が可能であり、また、燃焼器の小型化を図ることができる。
【００５４】
また、本発明の小型パルス燃焼器によれば、小型化が図られ、しかも熱効率が高い。
【００５５】
また、本発明のヒータによれば、小型化が容易に図られるとともに、熱効率が高い。
【図面の簡単な説明】
【図１】 本発明の火炎の制御原理を説明するための図である。
【図２】 本発明のパルス燃焼器の実施の形態例を模式的に示す図である。
【図３】 図２のパルス燃焼器における燃焼の様子を示す図である。
【図４】 本発明のパルス燃焼器の実施の他の形態例を模式的に示す図である。
【図５】 図４のパルス燃焼器における燃焼の様子を示す図である。
【符号の説明】
１０，５０…パルス燃焼器、１１，５１…燃焼管、１２，５２…加熱装置、１３，５３…ガス供給装置、２０，６５…高温領域、２１，６６…低温領域。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flame control method, and particularly to a technique suitable for downsizing a combustor.
[0002]
[Prior art]
As a flame control method with high thermal efficiency, there is a pulse combustion technique in which a flame is burned in an oscillating manner. In the pulse combustion technique, intake and exhaust into the combustor are intermittently performed by using the inertia of the exhausted combustion gas, and combustion is performed in an oscillating manner. The technology has been developed for propulsion devices and is currently used in various devices such as a boiler heating burner and a gasification burner (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 60-238679 [0004]
[Problems to be solved by the invention]
In the conventional pulse combustion technology, when the combustor is downsized, the friction loss on the exhaust duct surface increases and the operation tends to be difficult. For example, when a hydrocarbon fuel such as propane is used, the operating limit size is said to be about 100 cc in terms of the volume of the combustor.
[0005]
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a flame control method capable of generating heat with high thermal efficiency and reducing the size of the combustor.
Another object of the present invention is to provide a compact pulse combustor that can be miniaturized and can generate heat with high thermal efficiency.
Another object of the present invention is to provide a heater that can be easily downsized and has high thermal efficiency.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a flame control method according to the present invention is a flame control method in which a premixed gas is vibrated in a pipe, and the pipe is configured to extinguish the premixed gas under a predetermined temperature condition. A part of the tube is heated to a temperature equal to or higher than the self-ignition temperature of the premixed gas, and the heated region from the low temperature region side of the tube having the predetermined temperature condition. The premixed gas is allowed to flow to the high temperature region side of the tube.
According to this flame control method, the premixed gas spontaneously ignites in the high temperature region of the pipe, the flame propagates to the low temperature region, and extinguishes in the low temperature region. When the flame is extinguished in the low temperature region, the premixed gas is spontaneously ignited again in the high temperature region of the pipe. As a result, the premixed gas burns in an oscillating manner between the high temperature region and the low temperature region. Oscillating combustion enables heat generation with high thermal efficiency.
The predetermined temperature condition may be a temperature lower than the spontaneous ignition temperature.
[0007]
In the above-described flame control method, the pipe may have an inner diameter determined based on a quenching distance of the premixed gas.
Thereby, the above method can be preferably applied to a small combustor.
[0008]
In the flame control method described above, the flow rate of the premixed gas in the pipe may be set lower than the combustion speed of the premixed gas in the high temperature region of the pipe.
Thereby, the flame spontaneously ignited in the high temperature region reliably propagates toward the low temperature region.
[0009]
A small pulse combustor according to the present invention is a small pulse combustor that vibrates premixed gas in a tube, and the tube has a shape in which the premixed gas is extinguished under a predetermined temperature condition. A heating device that heats a partial region of the tube to a temperature equal to or higher than the self-ignition temperature of the premixed gas, and a high temperature region of the tube that is the heated region from the low temperature region side of the tube having the predetermined temperature condition And a gas supply device for flowing the premixed gas.
According to this small pulse combustor, since the flame control method of the present invention described above can be implemented, it is possible to generate heat with high thermal efficiency while being small.
[0010]
In the small pulse combustor, the inner diameter of the tube is determined based on the extinction distance of the premixed gas, so that the size can be reliably reduced.
[0011]
In the small pulse combustor, the heating device may perform the heating using heat from another heat source, or may perform the heating using heat generated by combustion of the premixed gas. Also good.
By heating the high temperature region of the pipe using the heat generated by the combustion of the premixed gas, further miniaturization and improvement in thermal efficiency can be achieved.
[0012]
The heater of this invention is a heater provided with a heating part, Comprising: The said heating part has said small pulse combustor, It is characterized by the above-mentioned.
According to this heater, miniaturization can be easily achieved and the thermal efficiency is high.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
First, the flame control method of the present invention will be described.
In general, a premixed gas in which a fuel and a required amount of oxidant (air, oxygen, etc.) are mixed reaches a predetermined temperature, and thereafter the temperature rapidly rises and starts to burn. This is called self-ignition (also called self-ignition, self-ignition), and the temperature at that time is called self-ignition temperature. When the premixed gas burns in the pipe, the flame propagates to the surrounding unburned mixed gas. The propagation speed is the combustion speed, and the combustion speed varies depending on the type of fuel and the environment. In the pipe, when the heat transfer rate to the pipe wall exceeds the heat generation rate, the flame is not maintained and quenching is performed.
[0014]
The present inventors paid attention to this general fact regarding the combustion and extinction of the premixed gas and the fact that extinction occurs even when the inner diameter of the pipe is reduced, and as a result of intensive studies, a small-diameter pipe where extinction occurs. It was elucidated that the propagation of flame could be controlled inside the pipe by using the as a combustion container and heating a part of the pipe. Here, the limit value of the gap between two parallel flat plates where the flame does not propagate is called quenching distance, and in the case of a circular tube, it is also called quenching diameter.
[0015]
That is, in the flame control method of the present invention, a tube having an inner diameter less than or equal to the extinction distance of the premixed gas is used as a combustion container, and a partial region of the tube is used as the spontaneous ignition temperature of the premixed gas. The premixed gas is flowed from the low temperature region side to the high temperature region side of the tube. As a result, the premixed gas can be vibrated in an oscillating manner between the low temperature region and the high temperature region.
[0016]
FIG. 1 is a view for explaining the flame control principle of the present invention.
In FIG. 1, a tube as a combustion container has an inner diameter that is less than or equal to the extinction distance (extinguishing diameter) of the premixed gas. Further, a part of the pipe (high temperature region) is heated to a temperature equal to or higher than the spontaneous ignition temperature of the premixed gas, and the premixed gas flows from the unheated low temperature region side to the heated high temperature region side. Note that the spontaneous ignition temperature varies depending on the composition of the premixed gas.
[0017]
In the high temperature region, the premixed gas is spontaneously ignited by being heated to the self-ignition temperature or higher. The flame propagates toward the upstream side (low temperature region) which is the supply side of the premixed gas without standing in the portion. At this time, a part of the heat due to combustion moves to the tube wall as the flame propagates. When the flame reaches a low temperature region, the amount of heat transfer to the tube wall increases and finally extinguishes. That is, in the low temperature region, combustion cannot be maintained due to the cooling effect based on the extinction distance. When the flame is extinguished, the premixed gas is spontaneously ignited again in the high temperature region, and the flame propagates toward the upstream low temperature region. Thereby, flame propagation is repeated between the high temperature region and the low temperature region, and the flame vibrates at a period of several tens Hz to several hundreds Hz, for example.
[0018]
The premixed gas flow rate in the pipe is preferably lower than the combustion speed (propagation speed) of the premixed gas in the high temperature region. As a result, the flame spontaneously ignited in the high temperature region reliably propagates upstream. Table 1 below shows the results of measuring the burning rate under normal temperature and pressure conditions for several types of premixed gases. Note that the combustion rate varies depending on the composition ratio of the premixed gas, and environmental factors such as pressure and temperature. In a high temperature environment, the burning rate increases.
[0019]

[0020]
The length of the high temperature region of the tube (the axial length of the tube) is preferably determined according to the ignition delay of the premixed gas. The distance necessary for the spontaneous ignition including the ignition delay varies depending on the composition of the premixed gas, the pipe flow velocity of the premixed gas, and the like. Since the high temperature region of the pipe has a length longer than the distance necessary for the spontaneous ignition of the premixed gas, the premixed gas is surely spontaneously ignited.
[0021]
In the flame control method of the present invention, since the premixed gas is vibrated in the pipe in an oscillating manner, the development of the boundary layer in the pipe is suppressed, and the heat generated by the combustion moves to the pipe wall with a high heat transfer coefficient. . That is, the heat from combustion is efficiently transferred to the tube wall with a small loss. Therefore, heat generation with high thermal efficiency is possible. In addition, since the region where the flame pulsates becomes the heat generation region, local heat concentration is prevented. This is advantageous in transferring the generated heat to other objects.
[0022]
In the flame control method of the present invention, a pipe having an inner diameter not more than about the extinguishing distance is used as the combustion container, and the premixed gas is vibrated in vibration in the pipe. Therefore, application to a small combustor is possible. Table 2 below shows the extinguishing distance (extinguishing diameter) for the above-mentioned several types of premixed gases. In addition, the flame extinguishing distance shown here is a room temperature and normal pressure environment.
[0023]

[0024]
Further, as an embodiment, based on the flame control method of the present invention, a premixed gas containing methane and air is burned in a circular tube (quartz tube) having an inner diameter of 2 mm, and the state is shown as a high-speed high-sensitivity camera. As a result of the observation, a flame oscillating at about 40 Hz was observed between the high temperature region and the low temperature region, which consisted of the process shown in FIG.
[0025]
Next, the pulse combustor of the present invention will be described.
FIG. 2 is a diagram schematically showing an embodiment of the pulse combustor of the present invention. This pulse combustor oscillates the premixed gas based on the flame control method of the present invention described above. It is to burn.
[0026]
In FIG. 2, the pulse combustor 10 includes a combustion tube 11 as a combustion container, a heating device 12, a gas supply device 13 that supplies a premixed gas into the combustion tube 11, and the like.
[0027]
The premixed gas is a mixture of fuel and a required amount of oxidant (air, oxygen, etc.) in advance. Examples of the fuel include flammable gases such as propane, hexane, ethylene, acetylene, and hydrogen. However, the present invention is not limited to this. In addition, the fuel may be used alone or in combination with different types of fuel.
[0028]
In this example, the combustion tube 11 is a circular tube having a circular uniform channel cross section, and the inner diameter thereof is equal to or less than the extinction distance of the premixed gas used. Actually, the combustion tube 11 only needs to have an inner diameter at which the premixed gas is extinguished under a temperature condition in a low temperature region to be described later. As an example, the inner diameter of the combustion tube 11 is determined within a range of about 10 to 120% of the extinguishing distance in a normal temperature environment. The above numerical value is an example, and changes according to the temperature condition of the combustion tube 11.
[0029]
Further, for example, when a premixed gas containing propane and air is used, the flame extinguishing distance (extinguishing diameter) of the premixed gas is about 2.7 mm. Therefore, the inner diameter of the combustion tube 11 is 2.7 mm or less, For example, it is formed to about 2.0 mm.
[0030]
Note that the combustion tube 11 is not limited to a circular tube, and may have other shapes such as a rectangular tube having a rectangular channel cross section. In this case, it is preferable to use a flame extinguishing distance corresponding to the shape of the flow path. Moreover, as a material of the combustion pipe | tube 11, a thing with high heat conductivity, such as a metal, is preferable. You may use it combining the member of a different material.
[0031]
The heating device 12 heats a partial region of the combustion pipe 11 to a temperature equal to or higher than the self-ignition temperature of the premixed gas to be used, for example, within a range of about 100 to 200% of the self-ignition temperature. The above numerical values are merely examples, and change according to the thermal characteristics of the combustion tube 11 and the like. The heating temperature is preferably equal to or higher than the temperature at which the premixed gas is surely spontaneously ignited in the combustion pipe 11, and is preferably equal to or lower than the temperature at which the constituent members can withstand and energy loss does not increase.
[0032]
For example, when a premixed gas containing propane and air is used, the spontaneous ignition temperature is about 450 ° C., so the heating temperature is set to about 450 to 900 ° C., for example.
[0033]
As the heating device 12, it is only necessary to heat a predetermined region of the combustion tube 11 to the above temperature or more, and various known heating devices such as an electric heater provided with a heating wire can be applied.
[0034]
Here, in the combustion pipe 11, a region heated to about the spontaneous ignition temperature by the heating device 12 is referred to as a high temperature region 20, and an unheated region disposed on one side of the high temperature region 20 is referred to as a low temperature region 21. I will decide. The high temperature region 20 and the low temperature region 21 are arranged side by side in the axial direction of the combustion tube 11.
[0035]
The length of the high-temperature region 20 (the length in the axial direction of the pipe) is determined according to the ignition delay of the premixed gas to be used. The length of the low temperature region 21 is determined so that the flame propagating from the high temperature region 20 is surely extinguished. In order to suppress the temperature rise of the low temperature region 21 due to heat transmitted from the high temperature region 20, the low temperature region 21 may be cooled. Moreover, you may comprise the high temperature area | region 20 and the low temperature area | region 21 of a combustion pipe 11 by a mutually different member. Alternatively, a member that prevents heat transfer may be sandwiched between the high temperature region 20 and the low temperature region 21 of the combustion tube 11.
[0036]
The gas supply device 13 continuously flows the premixed gas from the low temperature region 21 side of the combustion pipe 11 toward the high temperature region 20 side. That is, the premixed gas is supplied into the combustion tube 11 from the end of the combustion tube 11 on the low temperature region 21 side. The in-pipe flow velocity of the premixed gas is set lower than the premixed gas combustion rate in the high temperature region 20 of the combustion tube 11 and higher than the premixed gas combustion rate in the low temperature region 21. As described above, the combustion rate increases when the environment is high. Further, the premixed gas and the combustion gas supplied to the combustion tube 11 are appropriately discharged from the end of the combustion tube 11 on the high temperature region 20 side.
[0037]
FIG. 3 is a view showing a state of combustion in the pulse combustor 10 of this example.
In the above pulse combustor 10, a part of the combustion tube 11 is heated by the heating device 12, so that a high temperature region 20 that is higher than the spontaneous ignition temperature of the premixed gas to be used and a low temperature low temperature region 21. It is formed. Further, the premixed gas is continuously supplied from the low temperature region 21 side of the combustion pipe 11 toward the high temperature region 20 by the gas supply device 13.
[0038]
The premixed gas spontaneously ignites in the high temperature region 20 of the combustion pipe 11, the flame propagates to the low temperature region 21, and extinguishes in the low temperature region 21. When the flame is extinguished in the low temperature region 21, the premixed gas is spontaneously ignited again in the high temperature region 20 of the pipe. As a result, the premixed gas is oscillated between the high temperature region 20 and the low temperature region 21 of the combustion tube 11 in an oscillating manner. Oscillating combustion generates heat with high thermal efficiency despite its small size.
[0039]
FIG. 4 is a diagram schematically showing another embodiment of the pulse combustor according to the present invention. Unlike the example shown in FIG. 2, the pulse combustor 50 of this example does not heat the combustion tube using heat from another heat source, but heats from the combustion of the premixed gas (exhaust heat). Is used to heat the combustion tube 11.
[0040]
As in the previous example, the pulse combustor 50 includes a combustion tube 51 as a combustion container, a heating device 52, a gas supply device 53 that supplies a premixed gas into the combustion tube 51, and the like. Unlike the previous example, the heating device 52 includes a plate-like member (hereinafter referred to as an intermediate heat transfer plate 52) that transmits the heat of the combustion gas to the premixed gas.
[0041]
The combustion pipe 51 has a flow path bent in a U shape with respect to the flow direction of the premixed gas, and the flow path 60 on the premixed gas supply side and the flow path 61 on the exhaust side of the combustion gas are described above. The intermediate heat transfer plates 52 are arranged opposite to each other. The cross-sectional area of the combustion tube 51 may be circular or rectangular, or may be another shape. The intermediate heat transfer plate 52 is made of a plate member having a high thermal conductivity such as metal.
[0042]
Further, with respect to the flow direction of the premixed gas, a flow path (ignition unit 62) serving as an ignition position is provided between the flow path 60 on the gas supply side and the flow path 61 on the gas discharge side. The ignition part 62 has a larger cross-sectional area than the other flow paths 60 and 61.
[0043]
FIG. 5 is a view showing a state of combustion in the pulse combustor 50 of this example.
In the pulse combustor 50 of this example, first, the premixed gas is supplied from the flow path 60 side of the combustion pipe 51 by the gas supply device 53. The premixed gas flows through the flow path 60, then reverses at the ignition unit 62, and flows in the reverse direction in the flow path 61. In starting combustion, the premixed gas in the ignition unit 62 is ignited by a starter (not shown). As this starting device, for example, a device that temporarily heats the inside of the combustion pipe 51 to a temperature equal to or higher than the spontaneous ignition temperature of the premixed gas, or a device that ignites temporarily is used.
[0044]
The flame ignited by the ignition unit 62 propagates in the flow path 60 toward the upstream which is the supply side of the premixed gas, and the combustion gas (combustion exhaust gas) flows in the flow path 61 on the downstream side. The heat (exhaust heat) of the combustion gas is transmitted from the flow path 61 side to the flow path 60 side via the intermediate heat transfer plate 52, and the premixed gas flowing through the flow path 60 is heated by the heat.
[0045]
The more heat that is transmitted, the closer to the igniting part 62, and the less it is away. Therefore, in the flow path 60, the region closer to the ignition unit 62 becomes a high temperature region 65 near the self-ignition temperature of the premixed gas, and the region farther from the ignition unit 62 is a lower temperature region 66 having a lower temperature. Become.
[0046]
The flame propagating upstream in the flow path 60 extinguishes in the low temperature region 66 without being able to maintain combustion due to the cooling effect based on the extinction distance. After the extinction, the premixed gas is heated to a temperature close to the spontaneous ignition temperature in the high temperature region 65, and is released from the restriction of the extinction distance in the ignition unit 62 and spontaneously ignites.
[0047]
Here, as described above, the ignition part 62 has a larger cross-sectional area than the flow paths 60 and 61. Therefore, the self-ignition temperature of the premixed gas in the environment is lower than that of the flow paths 60 and 61, and the temperature of the ignition unit 62 is equal to or higher than the self-ignition temperature of the premixed gas in the environment. That is, the premixed gas can spontaneously ignite at a temperature lower than that of the flow path 60 in the ignition unit 62.
[0048]
Then, the flame propagates again toward the low temperature region 66. Thereby, flame propagation is repeated between the high temperature area | region 65 and the low temperature area | region 66, and premixed gas combusts oscillatingly.
[0049]
In the above-described pulse combustor 50, as in the previous embodiment, heat is generated with high thermal efficiency by virtue of oscillating combustion while being small. Unlike the previous embodiment, the high temperature region 65 is heated using the heat of the combustion gas of the premixed gas, so-called exhaust heat. As a result, the efficiency of heat utilization is improved, and it is not necessary to provide another heat source, so that the apparatus can be reduced in size and simplified.
[0050]
In this example, heating of the high temperature region of the combustion pipe is performed using only the heat of the combustion gas, but heating of the high temperature region may be performed in combination with other heat sources.
[0051]
The small pulse combustor of the present invention can be applied to various heaters including a heating unit. A heater provided with the small pulse combustor of the present invention as a heating unit can be easily downsized and has high thermal efficiency, and is applied to various applications. Applications include, for example, a manufacturing apparatus, a molding apparatus, and a vacuum apparatus for electronic devices such as semiconductor devices and liquid crystal devices, but the present invention is not limited thereto. Moreover, it is good also as a small generator by installing a thermoelectric element in the small pulse combustor of this invention.
[0052]
As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.
[0053]
【The invention's effect】
As described above, according to the flame control method of the present invention, heat generation with high thermal efficiency is possible, and the combustor can be downsized.
[0054]
Further, according to the small pulse combustor of the present invention, the size can be reduced and the thermal efficiency is high.
[0055]
Moreover, according to the heater of this invention, size reduction is achieved easily and thermal efficiency is high.
[Brief description of the drawings]
FIG. 1 is a view for explaining the flame control principle of the present invention.
FIG. 2 is a diagram schematically showing an embodiment of a pulse combustor according to the present invention.
FIG. 3 is a view showing a state of combustion in the pulse combustor of FIG. 2;
FIG. 4 is a diagram schematically showing another embodiment of the pulse combustor according to the present invention.
FIG. 5 is a view showing a state of combustion in the pulse combustor of FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10,50 ... Pulse combustor, 11, 51 ... Combustion tube, 12, 52 ... Heating device, 13, 53 ... Gas supply device, 20, 65 ... High temperature region, 21, 66 ... Low temperature region.

Claims (6)

A method of controlling a flame in which premixed gas is vibrated in a pipe,
The tube has an inner diameter at which the premixed gas is extinguished at a predetermined temperature condition throughout .
Heating a portion of the tube above the auto-ignition temperature of the premixed gas as a high temperature region ,
The low temperature region disposed on one side of the high temperature region maintains the predetermined temperature condition,
And flow pre Ki予mixed gas to the side of the side or found before Symbol hot region before Symbol low temperature region,
The flame control method according to claim 1, wherein a flow rate of the premixed gas in the pipe is set lower than a combustion speed of the premixed gas in a high temperature region of the pipe . A small pulse combustor that vibrates premixed gas in a tube,
The tube has an inner diameter at which the premixed gas is extinguished at a predetermined temperature condition throughout .
The tube has a high temperature region in which a part of the region is heated , and
A low temperature region arranged on one side of the high temperature region and capable of maintaining the predetermined temperature condition,
A heating device for heating the high temperature region to a temperature equal to or higher than a spontaneous ignition temperature of the premixed gas;
Before Ki予mixed gas to the side of the side or found before Symbol hot region before Symbol low temperature region and sets lower than the pipe flow velocity of the premixed gas to the combustion rate of the premixed gas in a high temperature region of the tube a gas supply device for supplying a,
A compact pulse combustor comprising: The small pulse combustor according to claim 2 , wherein the heating device performs the heating using heat from another heat source. 4. The small pulse combustor according to claim 2 , wherein the heating device performs the heating using heat generated by combustion of the premixed gas. 5. In the heating device and its surroundings,
An intermediate heat transfer plate comprising a plate-like member having a high thermal conductivity and transferring the heat of the combustion gas to the premixed gas;
A combustion pipe in which a flow path on the supply side of the premixed gas and a flow path on the discharge side of the combustion gas are arranged opposite to each other with the intermediate heat transfer plate interposed therebetween, and the flow path is bent in a U-shape;
An ignition part having a wider cross-sectional area than the other flow path between the gas supply side flow path and the gas discharge side flow path,
Small pulse combustor according to claim 4, characterized in that with a. A heater comprising a heating unit,
The said heating part has the small pulse combustor in any one of Claims 2-5, The heater characterized by the above-mentioned.

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