阅读说明：本技术 一种带燃烧稳定装置的无焰燃烧器 (Flameless combustor with combustion stabilizing device ) 是由 李鹏飞 吕元 许军 吕复 于 2021-09-14 设计创作，主要内容包括：本发明属于燃烧器领域,并具体公开了一种带燃烧稳定装置的无焰燃烧器,其中燃烧稳定腔体包括燃料喷管、腔体底部氧化剂开口、腔体内开缝钝体、腔体预混反应物出口、腔体顶部环形凹槽结构,燃烧稳定腔体内部及顶部出口处均可提供燃烧稳定机制,促使点火及功率调节时燃烧不熄灭；氧化剂无焰燃烧喷嘴包括带渐缩管与直管的氧化剂喷管、带烟气卷吸口的环形喷管,环形喷管的烟气卷吸口用于卷吸炉内循环烟气,且环形射流对环形内中心主射流起保护作用,以减缓氧化剂中心射流的动量消耗,使氧化剂主射流可提供强烈的炉内大尺度卷吸作用。本发明能够在燃烧稳定腔体内部与出口形成燃烧稳定机制,在点火、预热、燃烧状态切换、及功率灵活性调节阶段保证燃烧不熄灭,提高无焰燃烧在各个燃烧阶段的燃烧稳定性及炉膛安全性。(The invention belongs to the field of burners, and particularly discloses a flameless burner with a combustion stabilizing device, wherein a combustion stabilizing cavity comprises a fuel spray pipe, an oxidant opening at the bottom of the cavity, a slotted bluff body in the cavity, a premixed reactant outlet in the cavity and an annular groove structure at the top of the cavity, and a combustion stabilizing mechanism can be provided in the combustion stabilizing cavity and at the outlet at the top so as to promote the combustion not to be extinguished during ignition and power regulation; the oxidant flameless combustion nozzle comprises an oxidant spray pipe with a reducing pipe and a straight pipe, and an annular spray pipe with a smoke volume suction port, wherein the smoke volume suction port of the annular spray pipe is used for sucking the circulating smoke in the furnace, and the annular jet flow plays a role in protecting the annular inner center main jet flow so as to slow down the momentum consumption of the oxidant center jet flow and enable the oxidant main jet flow to provide a strong large-scale entrainment effect in the furnace. The invention can form a combustion stabilizing mechanism in the combustion stabilizing cavity and at the outlet, ensures that the combustion is not extinguished in the stages of ignition, preheating, combustion state switching and power flexibility adjustment, and improves the combustion stability and the hearth safety of flameless combustion in each combustion stage.)

1. A flameless burner with combustion stabilization means, characterized in that it comprises a combustion stabilization chamber (7) and an oxidant flameless combustion nozzle (12), wherein:

the combustion stabilizing cavity (7) comprises a fuel spray pipe (1), a cavity bottom oxidant opening (2), a slotted bluff body (3) in the cavity, a cavity premixed reactant outlet (4) and a cavity top annular groove structure (6), wherein the fuel spray pipe (1) is arranged along the central line of the combustion stabilizing cavity (7) and is connected with the bottom of the combustion stabilizing cavity (7) and used for spraying fuel to the combustion stabilizing cavity (7), the cavity bottom oxidant opening (2) is provided with a plurality of rectangular openings and is distributed annularly relative to the central line of the combustion stabilizing cavity (7) and used for providing a part of oxidant in the combustion stabilizing cavity (7), the oxidant comes from an oxidant upstream pipeline (13), the slotted bluff body (3) in the cavity is used for forming a low-speed mixing zone in the cavity and ensuring stable combustion in the cavity, and the cavity premixed reactant outlet (4), the combustion chamber consists of a circular opening (5) arranged along the central line of the chamber and a plurality of rectangular openings (14) arranged at the top of the chamber in an annular manner, and is used for injecting flue gas and unburned reactants into a combustion chamber, and an annular groove structure (6) at the top of the chamber is used for further promoting the combustion stability at the top of the chamber;

the oxidant flameless combustion nozzle (12) comprises a reducing pipe (8), a straight pipe (9) arranged along the central line of the oxidant flameless combustion nozzle and an annular spray pipe (10) with a smoke roll suction port (11), wherein an oxidant is provided by an oxidant upstream pipeline (13), except for a part of the oxidant entering a combustion stabilizing cavity (7) from an oxidant opening (2) at the bottom of the cavity, most of the rest oxidant passes through the reducing pipe (8) and is sprayed into a hearth by the straight pipe (9) arranged along the central line of the oxidant flameless combustion nozzle and the annular spray pipe (10) with the smoke roll suction port (11), the reducing pipe (8) is used for realizing jet flow speed raising, the smoke roll suction port (11) of the annular spray pipe (10) is used for rolling and sucking the smoke in the furnace, so as to realize dilution of the annular jet flow oxidant, and the annular spray nozzle (10) forms annular jet flow and is used for reducing momentum consumption of the straight pipe (9) oxidant main jet flow in the annular jet flow, and a strong jet entrainment effect is obtained.

2. The flameless combustor with a combustion stabilizing device according to claim 1, wherein the combustion stabilizing cavity (7) is preferably a cylinder, the height of the combustion stabilizing cavity (7) is preferably 1.5 to 3.5 times the diameter of the combustion stabilizing cavity (7), and the diameter of the combustion stabilizing cavity (7) is 2 to 5 times the diameter of the fuel nozzle (1).

3. The flameless combustor with a combustion stabilization device according to claim 1 or 2, wherein the inside diameter of the slit bluff body (3) inside the combustion stabilization cavity (7) is 0.3 to 0.8 times the diameter of the fuel nozzle (1), the top diameter of the slit bluff body (3) is 1.5 to 3 times the slit inside diameter of the slit bluff body (3), the height of the slit bluff body (3) is 1 to 2 times the top diameter of the slit bluff body (3), and the height of the bottom of the slit bluff body (3) from the combustion stabilization cavity (7) is 1 to 6 times the diameter of the fuel nozzle (1).

4. The flameless combustor with a combustion stabilization device according to claim 1, wherein the number of the oxidant openings (2) at the bottom of the chamber is preferably 3 to 5, the length to width ratio is 1 to 5, the premixed reactant outlet (4) of the chamber has a central circular opening (5) with a diameter of 0.4 to 0.8 times the inner diameter of the slots of the slotted blunt body (3), the number of the rectangular openings (14) at the top of the chamber is 3 to 5, and the length to width ratio is 1 to 5.

5. The flameless combustor with a combustion stabilization device according to claim 1, wherein the inner diameter of the annular structure surrounded by the cavity top annular groove structure (6) is 0.5 to 0.8 times the diameter of the combustion stabilization cavity (7), the cavity top annular groove structure (6) is rectangular, the groove depth is 1.5 to 4 times the diameter of the fuel nozzle (1), and the groove height of the cavity top annular groove structure (6) is 1 to 3 times the groove depth.

6. The flameless burner with combustion stabilization means according to claim 1, wherein the inlet area of the reducer (8) is 3 to 30 times larger than the oxidant opening (2) at the bottom of the chamber. The diameter of the straight pipe (9) arranged along the center line of the oxidant flameless combustion nozzle is 1-8 times that of the fuel spray pipe (1).

7. The flameless burner with a combustion stabilizing device according to claim 1, wherein the smoke entrainment inlet (11) of the annular nozzle (10) is provided in 2 to 4 layers, and the opening of the smoke entrainment inlet (11) forms an angle of 10 to 45 degrees with the jet axis. The equivalent diameter of the annular spraying pipe (10) is 0.2-0.5 times of that of the straight pipe (9), and the heights of the annular spraying pipe (10) and the straight pipe (9) are 5-20 times of that of the straight pipe (9).

Technical Field

The invention belongs to the field of burners, and particularly relates to a flameless burner with a combustion stabilizing device.

Background

NO produced by combustion process_xIs an important pollution source for atmospheric environmental problems such as haze and the like, and currently, the NO of a newly built boiler is required in Jingjin Ji area of China_xThe discharge is not more than 30mg/m³NO of boiler in other areas of the country_xEmissions set new standards requirements, and therefore NO control of the combustion process_xAnd (4) generating. Conventional low NO_xThe combustion technology mainly comprises a staged combustion technology, a lean-burn premixed combustion technology, a flue gas recirculation technology, a concentration deviation combustion technology and the like. These techniques all can reduce NO to some extent_xThe original production amount of (1). But these conventional low NO_xThe combustion technology still has flame front and local high temperature area, and can not meet the requirement of NO_xUltra low emission requirements.

Compared with the conventional low NO_xThe combustion technology and flameless combustion have very outstanding advantages, a combustion area does not have a local high-temperature area and a flame peak surface, the temperature distribution of the combustion area is more uniform, and NO including thermal type and fuel type can be greatly reduced_xIn the presence of NO_xAnd (5) discharging. The flameless combustion is characterized in that: the temperature of the combustion chamber is uniformly distributed, the overall temperature is lower, and the temperature pulsation is small; combustion is uniformly carried out in the whole combustion chamber, no obvious flame frontal surface exists, and the thermal performance is good; ③ NO_xAnd the soot emission is remarkably reduced; high combustion stability and low combustion noise. Low NO compared to others_xThe combustion mode, the biggest characteristic of flameless combustion is that NO can be inhibited on the basis of not reducing combustion efficiency_xCan generate extremely high thermal performance of the combustion chamber and low NO simultaneously_xAnd (5) discharging.

For example, CN104990078B proposes "a burner capable of achieving flameless combustion quickly", which adopts a flame stabilizing bluff body and a nozzle structure with different pipelines to achieve switching between flameless combustion and flameless combustion quickly. However, the flameless combustion still has a pipeline switching process, and a flameout hidden danger may be generated in the switching process. CN104132344B proposes "a gas flameless combustion device with very low nox emission", which can switch the flameless combustion mode between the non-premixed and premixed states by adjusting the position relationship between the gas nozzle and the air nozzle, but due to the lack of a combustion stabilizing device, the switching process also has a risk of flameout.

Disclosure of Invention

Aiming at the defects or the improvement requirements of the prior art, the invention provides a flameless combustor with a combustion stabilizing device, which is based on the characteristics of flameless combustion high-momentum oxidant jet flow, correspondingly designs an oxidant flameless combustion nozzle, researches and designs the central jet flow and the annular jet flow of the oxidant and the matching thereof caused by key components such as a straight pipe and an annular nozzle which are arranged along the central line of the oxidant flameless combustion nozzle, correspondingly can effectively relieve the consumption of the entrainment of flue gas in a hearth to the momentum of the central jet flow of the oxidant, improves the penetration distance of the central jet flow of the oxidant, also designs a combustion stabilizing cavity based on the combustion stabilizing principle, researches and designs the structure of the key components such as the combustion stabilizing cavity and the arrangement of an internal slotted bluff body thereof, correspondingly can realize the combustion stability in the processes of ignition, preheating, combustion mode switching and power flexibility adjustment, avoiding the problem of flameout, thereby being particularly suitable for the application occasions of flameless combustion.

In order to achieve the above object, the present invention provides a flameless burner with a combustion stabilization device, the burner comprising a combustion stabilization chamber and an oxidant flameless combustion nozzle, wherein:

the combustion stabilizing cavity comprises a fuel spray pipe, a cavity bottom oxidant opening, a cavity internal slotting bluff body, a cavity premixed reactant outlet and a cavity top annular groove structure, wherein the fuel spray pipe is arranged along the central line of the combustion stabilizing cavity and connected with the bottom of the combustion stabilizing cavity and used for spraying fuel to the combustion stabilizing cavity, the cavity bottom oxidant opening is provided with a plurality of rectangular openings which are annularly distributed relative to the central line of the combustion stabilizing cavity and used for providing a part of oxidant to the combustion stabilizing cavity, the oxidant comes from an oxidant upstream pipeline, the cavity internal slotting bluff body is used for forming a low-speed mixing zone in the cavity and ensuring stable combustion in the cavity, the cavity premixed reactant outlet consists of a circular opening arranged along the central line of the cavity and a plurality of cavity top rectangular openings annularly arranged and used for spraying flue gas and unburned reactants into a hearth, the cavity top annular groove structure is used for further promoting combustion stability at the top of the cavity;

the oxidant flameless combustion nozzle comprises a reducing pipe, a straight pipe and an annular spray pipe, wherein the straight pipe is arranged along the central line of the oxidant flameless combustion nozzle, the annular spray pipe is provided with a smoke roll suction port, an oxidant is provided by an upstream pipeline of the oxidant, except for a part of the oxidant which enters a combustion stabilizing cavity from an oxidant opening at the bottom of the cavity, most of the rest of the oxidant passes through the reducing pipe, the straight pipe is arranged along the central line of the oxidant flameless combustion nozzle, and the annular spray pipe is provided with the smoke roll suction port and is sprayed into a hearth, the reducing pipe is used for realizing jet flow speed increase, the smoke roll suction port of the annular spray pipe is used for rolling up smoke in the furnace, so that the annular jet flow oxidant is diluted, and meanwhile, the annular spray nozzle forms annular jet flow, so that the momentum consumption of main jet flow of the straight pipe oxidant in the annular jet flow is reduced, and the strong jet flow rolling and suction effect is obtained.

Preferably, the combustion stabilizing cavity is a cylinder, the height of the combustion stabilizing cavity is preferably 1.5-3.5 times of the diameter of the combustion stabilizing cavity, and the diameter of the combustion stabilizing cavity is 2-5 times of the diameter of the fuel nozzle.

Preferably, the internal diameter of a slit of the slit bluff body in the combustion stabilizing cavity is 0.3-0.8 times of the diameter of the fuel spray pipe, the diameter of the top of the slit bluff body is 1.5-3 times of the slit internal diameter of the slit bluff body, the height of the slit bluff body is 1-2 times of the diameter of the top of the slit bluff body, and the height from the bottom of the slit bluff body to the combustion stabilizing cavity is 1-6 times of the diameter of the fuel spray pipe.

Preferably, the number of the oxidant openings at the bottom of the cavity is 3-5, the length-width ratio is 1-5, the diameter of the central circular opening of the premixed reactant outlet of the cavity is 0.4-0.8 times of the inner diameter of the slit bluff body, the number of the rectangular openings at the top of the cavity is 3-5, and the length-width ratio is 1-5.

Preferably, the inner diameter of an annular structure formed by the annular groove structures at the top of the cavity is 0.5-0.8 times of the diameter of the combustion stabilizing cavity, the annular groove structures at the top of the cavity are rectangular, the depth of the groove is 1.5-4 times of the diameter of the fuel spray pipe, and the height of the groove of the annular groove structures at the top of the cavity is 1-3 times of the depth of the groove.

Preferably, the area of the inlet of the reducer is 3-30 times of the oxidant opening at the bottom of the cavity. The diameter of the straight pipe arranged along the center line of the oxidant flameless combustion nozzle is 1-8 times of that of the fuel spray pipe.

Preferably, the smoke winding suction port of the annular spraying pipe is arranged in 2-4 layers, and the angle between the opening of the smoke winding suction port and the jet flow axis is 10-45 degrees. The equivalent diameter of the annular spray pipe is 0.2-0.5 times of that of the straight pipe, and the heights of the annular spray pipe and the straight pipe are 5-20 times of that of the straight pipe.

Generally, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:

1. according to the invention, by arranging the combustion stabilizing cavity and correspondingly arranging the oxidant opening at the bottom of the cavity, the slit bluff body in the cavity, the premixed reactant outlet of the cavity and the annular groove structure at the top of the cavity, part of the oxidant can enter the cavity and be mixed with the fuel, and then a low-speed entrainment region is formed in the cavity, so that stable combustion in the cavity can be realized no matter the flow of the reactant in the cavity is small or the load is changed, and meanwhile, a combustion stabilizing mechanism is formed in the annular groove structure at the outlet at the top of the cavity, the combustion is stable and is not influenced by changes of working conditions such as ignition, preheating, combustion mode switching, fuel power flexibility adjustment and the like, the flameout problem in the combustion working condition change process is avoided, and the combustion stabilizing cavity has higher combustion stability and operation safety;

2. meanwhile, the invention has no flame in the oxidantSet up the reducing pipe among the combustion nozzle, the straight tube that arranges along oxidant flameless combustion nozzle central line, and take the annular spray tube of flue gas book suction inlet, the reducing pipe not only can make most oxidant by upstream pipeline supply get into this pipe, can also realize the effect of accelerating oxidant efflux, oxidant annular efflux relies on flue gas book suction inlet to draw up flue gas in the furnace, dilute the oxidant, and annular efflux can play the guard action to the central main efflux of arranging along the oxidant central line, slow down the consumption of oxidant central main efflux's momentum, promote the penetration distance of oxidant central main efflux, promote the large-scale stirring effect of oxidant efflux to the stove, promote the realization and the maintenance of flameless burning, realize positive displacement flameless burning according to this, restrain NO and roll up the realization and the maintenance of flameless burning, the annular spray tube of taking the flue gas book suction inlet, the reducing pipe can not only make the most of the oxidant central main efflux, the annular jet can be used for the long-term combustion_xAnd the NO reburning reduction effect is enhanced, and the further reduction of the generated NO is promoted.

3. In addition, the height of the slotted bluff body can be adjusted by the slotted bluff body arranged in the combustion stable cavity, the height of the slotted bluff body is adjusted according to the supply amount of an oxidant and the oxygen concentration, and the combustion stability in the cavity can be ensured no matter air, pure oxygen or different oxygen concentrations are adopted by optimizing matching parameters of the slotted bluff body and the combustion stable cavity, so that even if the cavity is flameout instantaneously, the heat source in the cavity can ignite the space outside the cavity again, and the combustion stability of the integral flameless combustion can be ensured.

Drawings

FIG. 1 is a cross-sectional view of a flameless combustor with combustion stabilization apparatus constructed in accordance with a preferred embodiment of the present invention;

FIG. 2 is a bottom view of a flameless combustor with combustion stabilization apparatus constructed in accordance with a preferred embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of a planar oxidant flameless combustion nozzle and chamber premixed reactant outlet constructed in accordance with a preferred embodiment of the present invention;

the same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein:

1-fuel nozzle, 2-cavity bottom oxidant opening, 3-cavity internal slotted bluff body, 4-cavity premixed reactant outlet, 5-central circular opening arranged on the central line of cavity, 6-cavity top annular groove structure, 7-combustion stabilizing cavity, 8-reducing pipe, 9-straight pipe arranged along the central line of oxidant flameless combustion nozzle, 10-annular nozzle, 11-smoke volume suction port, 12-oxidant flameless combustion nozzle and 13-oxidant upstream pipeline.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

As shown in fig. 1 to 3, the embodiment of the present invention provides a flameless combustor with a combustion stabilizing device, the combustor includes a combustion stabilizing cavity 7 and an oxidant flameless combustion nozzle 12, wherein:

the combustion stabilizing cavity 7 comprises a fuel spray pipe 1, a cavity bottom oxidant opening 2, a cavity internal slotted bluff body 3, a cavity premixed reactant outlet 4 and a cavity top annular groove structure 6, wherein the fuel spray pipe 1 is arranged along the central line of the combustion stabilizing cavity 7 and is connected with the bottom of the combustion stabilizing cavity 7 and used for spraying all fuel to the combustion stabilizing cavity 7, the cavity bottom oxidant opening 2 is provided with a plurality of rectangular openings which are annularly distributed relative to the central line of the combustion stabilizing cavity 7 and used for providing a part of oxidant to the combustion stabilizing cavity 7, the oxidant comes from an oxidant upstream pipeline 13, the slotted bluff body 3 in the cavity is used for forming a low-speed mixing area in the cavity to ensure stable combustion in the cavity, the slotted structure of the slotted bluff body 3 allows part of the fuel to pass through, and the low-speed mixing area at the top of the bluff body can promote mixing and stable combustion of the fuel and the oxidant, the cavity premixing reactant outlet 4 consists of a circular opening 5 arranged along the center line of the cavity and a plurality of cavity top rectangular openings 14 arranged in an annular manner and used for spraying flue gas and unburned reactants into a hearth, the plurality of rectangular openings 14 are used for leading to multi-strand jet flow, the problem of thermoacoustic oscillation is relieved, and combustion stability is further promoted, and the cavity top annular groove structure 6 is used for forming a low-speed backflow area at the top of the cavity and further promoting mixing and stable combustion of the reactants;

the main reasons why the combustion stabilization chamber 7 causes stable combustion are: the fuel and the oxidant entering the combustion stable cavity 7 through the fuel nozzle 1 and the oxidant opening 2 at the bottom of the cavity can form a low-speed backflow area at the top of the slotted cavity 3, the low-speed backflow area can promote the mixing of the fuel and the oxidant, and can also enhance the preheating of hot flue gas to low-temperature reactants after combustion, so that the combustion is stably maintained at the top of the slotted bluff body 3; (II) the cavity premixed reactant outlet 4 consists of a circular opening 5 arranged along the central line of the cavity and a plurality of cavity top rectangular openings 14 arranged in an annular manner, so that a central main jet and a plurality of annularly distributed rectangular jets are formed, the distribution of the plurality of jets can reduce the combustion thermoacoustic oscillation problem caused by single jet, promote the combustion stability and maintain, and ensure the safety of the combustor; (III) cavity top annular groove structure 6 can further cause low-speed backward flow district at the cavity top, not only can promote the reactant mixing effect in the stranded efflux, still can further strengthen the mixture of hot flue gas and reactant, promotes the combustion stability at cavity top to this matches with the combustion stabilization mechanism of cavity inside, and in time a certain department takes place to flame out, and the stable burning high temperature in the cavity or outside the cavity also can ignite flame-out region once more, has guaranteed combustion stability.

The oxidant flameless combustion nozzle 12 comprises a reducer 8, a straight tube 9 arranged along the centerline of the oxidant flameless combustion nozzle, a circular nozzle 10 with a fume entrainment port 11, an oxidant upstream line 13 supplying oxidant, except for a portion of the oxidant entering the combustion stabilization chamber 7 through the chamber bottom oxidant opening 2, most of the rest oxidant is sprayed into the hearth through a reducing pipe 8, a straight pipe 9 arranged along the center line of the oxidant flameless combustion nozzle and an annular spray pipe 10 with a smoke winding suction port 11, the reducing pipe 8 is used for realizing jet flow acceleration, the smoke winding suction port 11 of the annular spray pipe 10 is used for winding and sucking smoke in the furnace, the annular jet flow oxidant is diluted, meanwhile, the annular spray nozzle 10 forms annular jet flow, the jet flow entrainment device is used for reducing the momentum consumption of the main jet flow of the oxidant of the annular jet flow inner straight pipe 9, obtaining the strong jet flow entrainment effect and promoting the establishment and stable maintenance of the volume type flameless combustion in the hearth.

The reasons for achieving high penetration distances for the oxidant flameless combustion nozzle 12 are: the inlet diameter of the reducer 8 is larger, and through the reducing structure, most of the oxidant can be sucked to flow through the reducer 8, the speed-up effect on jet flow can be realized, and the jet flow momentum is improved; (II) the high momentum jet flow is divided into two jet flows at the outlet of the reducing pipe 8, one jet flow is oxidant central jet flow caused by the straight pipe 9, the other jet flow is annular jet flow caused by the annular spray pipe 12, the annular jet flow has the protective effect on the oxidant central jet flow, and the momentum of the oxidant central jet flow is less consumed in entrainment with surrounding smoke, so that the oxidant central jet flow can obtain longer penetration distance compared with single jet flow, the large-scale entrainment and mixing effect in the furnace can be enhanced, and establishment and maintenance of flameless combustion are promoted; and (III) the smoke rolling suction port 11 of the annular spray pipe 12 can roll and suck the smoke in the furnace and can promote the integral circulation effect of a large-scale flow field in the furnace, so that the hot smoke in the furnace forms the integral large-scale effect, most of the smoke in the furnace is contacted and mixed with the annular jet flow, and the contact between the smoke in the furnace and the central jet flow is reduced.

Further, the combustion stabilization cavity 7 is preferably a cylinder, a low-speed mixing area at the top of the slotted blunt body 3 in the cavity needs a certain space, fuel and oxidant are mixed with hot flue gas in the low-speed space, combustion stabilization is realized, due to the requirements of the transverse space and the longitudinal space of the low-speed mixing area, the height of the combustion stabilization cavity 7 is 1.5-3.5 times of the diameter of the combustion stabilization cavity 7, and the diameter of the combustion stabilization cavity 7 is 2-5 times of the diameter of the fuel spray pipe 1. The internal diameter of a slit blunt body 3 inside the combustion stabilizing cavity 7 is 0.3-0.8 times of the diameter of the fuel spray pipe 1, the diameter of the top of the slit blunt body 3 is 1.5-3 times of the internal diameter of the slit blunt body 3, the height of the slit blunt body 3 is 1-2 times of the diameter of the top of the slit blunt body 3, and the height of the bottom of the slit blunt body 3 from the combustion stabilizing cavity 7 is 1-6 times of the diameter of the fuel spray pipe 1.

Furthermore, the oxidant opening 2 at the bottom of the combustion stabilization cavity 7 only allows a small part of the oxidant from the oxidant upstream pipeline 13 to enter the cavity, the oxidant entering the combustion stabilization cavity 7 only maintains the combustion stability inside and outside the cavity, and the inlet area of the reducing pipe 8 is 3-30 times of the oxidant opening 2 at the bottom of the cavity.

Furthermore, the oxidant enters the cavity in a plurality of strands, combustion thermoacoustic oscillation can be reduced while mixing is enhanced, the number of oxidant openings 2 at the bottom of the cavity is preferably 3-5, the length-width ratio is 1-5, premixed reactants of the cavity are sprayed out in a plurality of strands, the thermoacoustic oscillation is relieved, combustion noise is reduced, a premixed reactant outlet 4 of the cavity is provided, the diameter of a central circular opening 5 of the premixed reactant outlet 4 is 0.4-0.8 times of the inner diameter of a slot of the slotted bluff body 3, the number of rectangular openings 14 at the top of the cavity is 3-5, and the length-width ratio is 1-5.

Further, cavity top annular groove structure 6 also can form the low-speed mixed area, promote the burning at cavity top stable, with the stable mechanism phase-match of the inside burning of cavity, even a certain department is flame-out, also can be lighted immediately, the annular structure internal diameter that cavity top annular groove structure 6 encloses is 0.5 ~ 0.8 times of the stable cavity 7 diameter of burning, the groove depth of cavity top annular groove structure 6 is 1.5 ~ 4 times of 1 diameter of fuel spray tube, the groove height of cavity top annular groove structure 6 is 1 ~ 3 times of groove depth.

Further, the diameter of a straight pipe 9 arranged along the center line of the oxidant flameless combustion nozzle is 1-8 times of that of the fuel spray pipe 1.

Further, the annular efflux that annular spray tube 10 leads to can play the guard action to the central efflux that oxidant straight tube 9 leads to, through annular efflux entrainment surrounding flue gas, makes central fluidic momentum and energy cause longer penetration distance and the stove is stirred, and the suction inlet 11 is rolled up to the flue gas of annular spray tube 10 and sets up to 2 ~ 4 layers, and the angle that 11 openings of suction inlet and efflux axis are rolled up to the flue gas is 10 ~ 45 degrees. The equivalent diameter of the annular spray pipe 10 is 0.2-0.5 times of that of the straight pipe 9, and the heights of the annular spray pipe 10 and the straight pipe 9 are 5-20 times of that of the straight pipe 9.

The operation of the flameless burner with the combustion stabilizing device provided by the present invention will be described in detail.

The combustion stable cavity 7 and the oxidant flameless combustion nozzle 12 provided by the invention are integrally arranged on the wall surface of a hearth as a combustor, during ignition, fuel enters the combustion stable cavity 7 through the fuel nozzle 1, a part of oxidant enters the cavity through the oxidant opening 2 at the bottom of the cavity, stable combustion is formed in the combustion stable cavity 7, combustion smoke and unburnt reactants in the combustion stable cavity 7 are discharged out of the cavity through the cavity premixed reactant outlet 4, stable combustion outside the cavity is further formed in the annular groove structure 6 at the top of the cavity, so that the stable preheating process of the hearth is realized, after the preheating process is finished, the supply amount of the fuel and the oxidant is increased, the stable combustion inside and outside the combustion stable cavity 7 is continuously carried out, and most of the oxidant reaches the straight pipe 9 arranged along the center line of the oxidant flameless combustion nozzle and the annular nozzle 12 with the smoke winding suction port 11 through the reducing pipe 8, the annular jet flow caused by the annular spray pipe 12 is used for entrainment of flue gas in the furnace and promotion of large-scale entrainment in the furnace, and the straight pipe jet flow caused by the central straight pipe 9 of the oxidant is not in large-area contact with the flue gas in the furnace due to blocking of the annular jet flow, so that the momentum and energy of the straight pipe jet flow caused by the central straight pipe 9 are less consumed in entrainment of the flue gas around, a longer jet flow penetration distance and a large-scale stirring effect in the furnace can be caused, and realization and stable maintenance of flameless combustion are promoted.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.