JP3873119B2 - In-cylinder swirl combustor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a combustor for a continuous combustion apparatus used for various applications, and more particularly to an in-cylinder swirl combustor. The combustor according to the present invention can be used as a combustor for a gas turbine or various heating devices.
[0002]
[Prior art]
  2. Description of the Related Art Conventionally, as a combustor for gaseous fuel, one that causes a mixture of fuel and air to flow out in an axial direction from an outlet having a round shape or a slit shape has been widely used. In this case, the flame is stabilized without increasing the flow rate of the air-fuel mixture so that the flame base is surely positioned at the outlet of the outlet. Since the flame and the outlet are almost in contact with each other, the outlet tends to receive heat from the flame and easily deteriorate or deform due to overheating. If the outflow rate of the air-fuel mixture decreases due to deformation of the outlet portion or the like, a problem called backfire is likely to occur, in which the flame returns from the outflow port to the upstream side, combined with an increase in the combustion speed due to warming of the air-fuel mixture. On the other hand, if the outflow speed of the air-fuel mixture is sufficiently increased, the above problem can be avoided. However, the flame rises to a height where the speed of the air-fuel mixture attenuates and matches the combustion speed. Such a flame holding method cannot be used except for special purposes because there are problems such as a change in the spatial position of the flame and a long flame.
[0003]
  In the cylindrical combustion chamber, when the air-fuel mixture flows in the circumferential direction along the wall surface from a slot-like opening that is long in the axial direction of the combustion chamber provided on the side wall, a swirl flow field around the central axis is formed. In the swirling flow field, a continuous cylindrical flame surface is formed which is substantially symmetrical with respect to the combustion chamber central axis and increases in diameter toward the combustion chamber outlet. Inside this cylindrical flame surface, there is a region where burnt gas with low density at high temperature exists, and there is an unburned mixture in the annular space between the cylindrical combustion chamber side wall surface outside it. A region to be formed is formed.
[0004]
  The flame of the air-fuel mixture by swirling in the cylindrical combustion chamber mentioned above is in contact with the burned gas having a high temperature in the center and the air-fuel mixture over a large area, and the mixture is perpendicular to the contact surface, that is, the flame surface. It is known that the combustion flame can be maintained up to a fuel / air ratio close to the combustion limit in the case of a static mixture because of the extremely low velocity of the gas. The above-described flame structure in which a burned gas having a low density exists inside the swirl flow field and a gas mixture having a high density exists outside the swirl flow field is extremely stable in terms of hydrodynamics. In addition, the fact that the flame and the inlet of the air-fuel mixture are separated due to this structure is extremely effective in suppressing backfire, which is one of the problems inherent to premixed combustion.
[0005]
  Since NOx discharged from the combustion apparatus has an adverse effect on health and the global environment, various regulations have been implemented, but in large cities, further reduction of NOx generation is required. Since the production rate of NOx increases rapidly at high temperatures, lean premixed combustion, in which fuel and air are mixed and burned with a reduced fuel / air ratio, makes the most reasonable suppression. The characteristics of the swirl combustion in a cylinder, which provides excellent flame stability under lean conditions and is difficult to cause backfire even when supplying premixed gas, suppresses the disadvantages due to the essential characteristics of lean premixed combustion and maximizes the advantages. It is thought that it is very effective in exhibiting to the limit.
[0006]
  Japanese Patent Laid-Open No. 2001-280605 “Premixed swirl combustor” shows a combustor of a mixture of air and fuel gas using swirl combustion in a cylinder. This combustor will be described with reference to FIG. 6 which is a conceptual diagram of the embodiment. In this combustor, when the flow rate of the air-fuel mixture is excessive with respect to the size of the combustor, the problem that has occurred in the swirling field combustion using the straight cylinder until then, the cylindrical flame surface 21 and the cylindrical side wall In order to solve the problem that the air-fuel mixture 17 escapes from the gap between the combustion chamber 16 and unburned, a step 61 is provided in the vicinity of the outlet of the combustion chamber 11. The cylindrical flame 21 spreads in the radial direction due to the sudden expansion of the cross-sectional flow area by the step 61, and a recirculation flow is formed downstream of the step 61. Incomplete combustion components such as unburned air-fuel mixture and carbon monoxide are burned in the region of such recirculation flow. In addition, a heat retaining member 62 made of ceramic or the like is provided in the combustion chamber so that the flame can be retained even under lean conditions. With the above configuration, flame stability near the lean limit and high inflow rate is improved, and leakage of unburned mixture along the wall surface, which has been a problem with swirl combustion in the cylinder, is almost eliminated, and complete combustion is achieved. The load range can be expanded.
[0007]
  In a combustion apparatus and an engine equipped with the combustion apparatus, the heat generation rate and output are controlled by increasing or decreasing the fuel flow rate per unit time. In order to maintain the combustion efficiency sufficiently high and keep the generation of NOx at a minimum regardless of the amount of heat generation and output, the amount of air mixed with the fuel can be adjusted to the temperature and pressure of the air to the combustor. It should be as close as possible to the optimum value determined by.
[0008]
  As an example of controlling the air flow rate according to the output, hot water supply equipped with a premixing burner that causes the air flow rate to the combustor to follow the increase and decrease of the fuel flow rate by variably controlling the rotation speed of the blower with an inverter motor There is a combustor. This combustor is equipped with three burners. By increasing or decreasing the number of operating burners and increasing or decreasing the air flow rate, the burner fuel / air ratio is kept in the range of about 1: 1.3, and a 1:10 turndown (minimum heat generation). The ratio of the maximum calorific value to the quantity) is realized. In the prototype combustor based on the above-mentioned Japanese Patent Laid-Open No. 2001-280605 “Premixed swirl combustor”, if the air flow rate is precisely controlled in accordance with the fuel flow rate, the result is that even one burner can achieve the same level of turndown. However, when it is put to practical use, there is a problem that the cost becomes very high due to the high accuracy of the control device and the addition of the safety device. Further, in order to further reduce NOx, it is required that combustion is possible even at a smaller fuel / air ratio, but it is extremely difficult only because it is related to the essential characteristics of premixed combustion.
[0009]
  On the other hand, in the case of gas turbines, the air flow rate cannot be adjusted except for special exceptions, but the flow rate used for combustion out of the total air flow rate should be controlled by a mechanism such as a valve according to the fuel flow rate. Various forms have been proposed so far. The lack of reliability of the air flow control mechanism in high-temperature and high-pressure atmospheres and the need for larger driving force and valves compared to fuel flow control are obstacles to the widespread use of combustion air flow control systems. Yes.
[0010]
  Without air flow control, even with the “premixed swirl combustor” disclosed in the above publication, it is difficult to achieve low NOx under complete combustion over most of the operating range normally required for gas turbines. At present, an overwhelming majority of combustors are equipped with a plurality of burners and are adapted to output by increasing or decreasing the number of burners to be operated and controlling the flow rate. Obviously, the range of change in the fuel / air ratio in the operating range of the burner per burner becomes smaller in inverse proportion to the number of burners, but cannot be kept constant.
[0011]
[Problems to be solved by the invention]
  As described above, in a combustor that utilizes swirling of an air-fuel mixture in a cylinder, a fuel that can hold a flame even under a condition where the fuel / air ratio is extremely small and can perform low NOx combustion without controlling the air flow rate There is a problem to be solved in terms of expanding the range of the air ratio. If this problem is solved and the flame can be maintained and the high combustion efficiency can be obtained even under a condition where the fuel / air ratio is much smaller than before without controlling the air flow rate, NOx emission over a wide operating range is achieved. In addition to being significantly reduced, the operating range is greatly expanded, application to practical devices is facilitated, and popularization can be promoted.
[0012]
  The object of the present invention is to solve these problems of the in-cylinder swirl combustor so that the flame can be maintained even when the fuel / air ratio is smaller than the lean flammability limit of the premixed homogeneous mixture, and the air flow rate is reduced. It is to provide a new in-cylinder swirl combustion type combustor that enables both complete combustion and low NOx combustion without control.
[0013]
[Means for Solving the Problems]
  In order to solve the above-described problem, this swirl combustor in a cylinder has a swirl flow around the central axis of the cylindrical combustion chamber formed inside the cylindrical combustion chamber having one end as a bottom surface, and is approximately the center axis. In a cylindrical swirl combustor in which an axisymmetric cylindrical flame surface is held,A bottom surface fuel supplier for supplying fuel into the cylindrical combustion chamber is provided at the periphery of the bottom surface of the cylindrical combustion chamber, and a side wall fuel supplier is disposed on the side wall of the cylindrical combustion chamber. With an elongated slot-like opening to supply air withIt is characterized by.
[0014]
  Here, the definition of “peripheral part” will be described with reference to FIG. A slot-like opening 18 through which an air-fuel mixture (air when fuel is supplied from the side wall inside the combustion chamber) to form a swirling flow 22 around the central axis 20 in the combustor When translated along the central axis of the path 19, a virtual cylinder 57 coaxial with the combustion chamber circumscribing the virtual extension 56 in the cylindrical combustion chamber is determined. The annular portion 58 formed outside the projection portion of the virtual cylinder 57 is the definition of the peripheral portion in the present invention. In addition, the position of the bottom fuel supplier on the bottom surface is defined as the center of gravity of the opening 59.
[0015]
  Above formAs described above, the air-fuel mixture prepared upstream of the slot-shaped opening 18 of the cylindrical combustion chamber is introduced into the cylindrical combustion chamber in the circumferential direction along the cylindrical side wall surface from the slot-shaped opening 18. Generally, a side wall fuel supplier is arranged on the side wall, and fuel injected from the side wall and air flowing from the slot-like opening of the cylindrical side wall are swirled to form a mixture. LikeByIt is completely free from the problem of flashback.
[0016]
  A cylindrical extension flame surface having a diameter different from that of the cylindrical combustion chamber and a swirling flow around the central axis and a substantially axisymmetric shape is formed downstream of the cylindrical combustion chamber via a connecting portion. One or more extended cylindrical combustion chambers can be connected. If one or more extended cylindrical combustion chambers that perform swirl combustion in a cylinder having a diameter different from that of the cylindrical combustion chamber are connected in series downstream of the cylindrical combustion chamber, a plurality of cylindrical combustion chambers are connected. In addition to being able to finely control the fuel / air ratio of the air-fuel mixture in accordance with the calorific value and output of the combustion device and engine, it is possible to achieve low NOx over a wide operating range by simply controlling the fuel flow without air flow control. Extremely high combustion efficiency can be realized at the same time.
[0017]
  A side wall fuel supplier is also arranged on the side wall of the extended cylindrical combustion chamber so that the fuel injected therefrom and the air flowing in from the slot-like opening on the cylindrical side wall are mixed while swirling to form an air-fuel mixture. May be.
[0018]
  Further, if the connection portion fuel supply device is provided on the wall surface of the connection portion in the circumferential direction, and the fuel is injected into the upstream or downstream cylindrical combustion chamber according to the structure of the wall surface, the overall As a result, combustion is possible up to a small amount of fuel / air, and low NOx and high combustion efficiency can be obtained by appropriately distributing the fuel.
[0019]
  Furthermore, an extension duct having a diameter of an inscribed circle larger than the inner diameter of the cylindrical combustion chamber is connected to the outlet of the cylindrical combustion chamber of the most downstream cylindrical swirl type, and an air duct is connected to the side wall of the extension duct. An inflow port is formed through which either fuel or a mixture of air and fuel flows substantially toward the center, and these are mixed with the combustion gas from the upstream, thereby weakening the swirling of the combustion gas and the combustion gas. It is possible to optimize the temperature distribution of the combustion gas and the temperature distribution of the combustion gas at the outlet.
[0020]
Furthermore, an extension duct having a diameter of an inscribed circle larger than the inner diameter of the cylindrical combustion chamber is connected to the outlet of the cylindrical combustion chamber of the most downstream cylindrical swirl type, and the side wall of the extension duct has An inlet is formed for flowing either air, fuel, or a mixture of air and fuel into the cylindrical combustion chamber in a direction that produces a swirling direction opposite to that of the upstream cylindrical combustion chamber, from which air, The effect of weakening the swirl becomes stronger when fuel or air-fuel mixture is injected.
[0021]
  The fuel that can be burned by the above-mentioned in-cylinder swirl combustor is not only gas fuel but also air and CO.₂A gas fuel mixed with a non-combustion gas such as mist or liquid fuel is also included. Moreover, the fuel of each flame of the said cylindrical combustion chamber and the pilot combustion chamber arrange | positioned in the upstream does not necessarily need to be the same. Also, the air-fuel mixture need not be completely homogeneous. Even when it is supplied as an air-fuel mixture for in-cylinder swirling combustion, it need not be homogeneous.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
  An embodiment of an in-cylinder swirl combustor according to the present invention will be described with reference to the drawings. Figure 1Cylindrical swirl combustor according to reference example1A shows a cross section including the central axis of the cylindrical combustion chamber, and FIG. 1B shows an AA cross section (arrow AA) perpendicular to the axis. Yes. In this in-cylinder swirl combustor, a small cylindrical combustion chamber (pilot combustion chamber) 11a having a bottom surface 12a completely closed is connected to an opening 13 of a bottom surface 12 of a cylindrical combustion chamber 11 having a large diameter. . Two elongated slot-shaped openings 18 through which the air-fuel mixture 17 flows into the combustion chamber 11 are provided in the circumferential direction on the side wall surface 16 of the cylindrical combustion chamber 11, and the side wall surface 16 a is also provided on the pilot combustion chamber 11 a. Two openings 18a having the same shape are provided. The flow paths 19, 19a connected to the openings 18, 18a and the combustion chamber side wall surfaces 16, 16a are in a positional relationship where the air-fuel mixture 17, 17a flows out along the inner wall surfaces of the respective combustion chambers 11, 11a with a circumferential velocity component. Thus, swirl flows 22 and 22a of the air-fuel mixture are formed in the combustion chambers 11 and 11a. An extension duct 24 having a diameter of an inscribed circle larger than its inner diameter is connected downstream of the cylindrical combustion chamber 11.
[0023]
  The more slot-shaped openings 18 and 18a are in the circumferential direction, the more stable the cylindrical flame can be made. A plurality of the slot-shaped openings 18 and 18a may be arranged in the axial direction, and if they are arranged shifted in the circumferential direction, the combustion chamber 11 becomes a problem when the wall surface of the combustion chamber is a thin plate. , 11a and the slot-shaped openings 18, 18a can be reduced. As shown in FIG.ExampleThen, since the cylinder forming the combustion chamber 11 is thin, a flow path 19 made of a thin plate is connected to the upstream portion of the slot-shaped opening 18, but if the wall surface is sufficiently thick to be molded with a refractory material, A slot-like opening can be formed on the wall surface. In this specification, the slot-like openings 18 and 18a mean that the gas flowing into the cylindrical combustion chambers 11 and 11a swirls around the central axis 20 in the cylindrical combustion chambers 11 and 11a. It is a term that represents all of the inlets that can be configured, and includes, for example, a plurality of circular openings arranged in a straight line.
[0024]
  As shown in the figure, the flame 21a of the pilot combustion chamber 11a suddenly spreads in the radial direction at a sudden expansion portion located immediately downstream of the connection portion with the cylindrical combustion chamber 11, and high-temperature burned gas also spreads with it. They act as a reliable ignition source of the air-fuel mixture flowing from the slot-like opening 18 of the cylindrical combustion chamber 11 and further enhance the stability of the flame 21. This makes it possible to burn a leaner air-fuel mixture that could not be burned by an in-cylinder swirl combustor comprising only a single cylindrical combustion chamber. The rapid expansion of the flow passage area formed by the connection between the cylindrical combustion chamber 11 and the extension duct 24 forms a circulation flow downstream of the connection portion, and thereby the uncirculated flow between the flame 21 and the cylindrical side wall 16 is not formed. The fuel mixture can be burned almost completely.
[0025]
  If the temperature after mixing the burned gas from the pilot combustion chamber 11a and the air-fuel mixture from the slot-shaped opening 18 of the cylindrical combustion chamber 11 is sufficiently high, for example, 1200 ° C. Even if the air-fuel mixture flowing into the cylindrical combustion chamber 11 is thin, it can be completely reacted. Adjustment of the heat generation rate of the device and the output of the engine can be performed only by controlling the flow rate of the fuel. As long as the air-fuel mixture from the slot-shaped opening 18 of the cylindrical combustion chamber 11 is sufficiently lean, there is almost no generation of NOx due to the reaction. Therefore, if the combustion in the pilot combustion chamber 11a is made lean, NOx is generated as a whole. Are very few. In a simulation experiment in which application to a gas turbine combustor was examined, it was confirmed that the NOx concentration was as low as 10 ppm or less.
[0026]
  The inflow direction of the air-fuel mixture 17, 17a in the pilot combustion chamber 11a and the cylindrical combustion chamber 11 is more advantageous for improving the stability of the flame 21 in the cylindrical combustion chamber 11, and the leaner combustion, therefore NOx. Discharge can be maintained at a lower level. On the other hand, when it is desired to shorten the length of the cylindrical combustion chamber 11 or to weaken the turning at the outlet, the reverse turning is suitable.
[0027]
  Fig. 2 shows the in-cylinder swirl combustorOther reference examples2A is a cross-sectional view in a plane including the central axis of the cylindrical combustion chamber, and FIG. 2B is a cross-sectional view taken along the line BB along a plane perpendicular to the central axis. It is an arrow BB). In addition, the code | symbol in a figure is common to all the figures except for a new thing. The mechanism for generating the swirling flow of the air-fuel mixture inside the cylindrical combustion chamber 11 is shown in FIG.things andAre the same. The bottom surface 12 is provided with a fuel injector made of a circular pipe as a bottom surface fuel supply device 26 at the periphery. When the fuel is a gas, such a simple one is sufficient, but when it is a liquid, it is necessary to use the atomizing nozzle as a fuel supply device, and in some cases atomizing air is required. In addition to pure fuel, CO2 such as fuel droplets transported mixed with air and its vapor, and gas generated from coal gasifiers₂A combustible gas containing air, oxygen, etc. can also be used as fuel.
[0028]
  Here, what is important is that the fuel supply position into the combustion chamber 11 must be a peripheral portion. If fuel is supplied at the center or a position close thereto, the jet of fuel is stabilized due to the swirling flow in the combustion chamber 11, and mixing with the air or air-fuel mixture flowing in from the slot-like opening 18 is greatly suppressed. . As a result, the flame of the fuel jet supplied from the bottom fuel supplier 26 becomes an elongated diffusion flame and burns in a state of air shortage, soot is likely to occur. Of course, it is suitable for a superheated furnace using radiant heat transfer, but it is counterproductive to reducing NOx. On the other hand, when fuel is supplied from the peripheral portion, interference with the air or air-fuel mixture from the slot-shaped opening 18 occurs, and mixing proceeds in the peripheral portion, but the fuel concentration is high on the central axis near the bottom surface. A region is formed. This is extremely effective in expanding the limit on the lean side where the flame can be held.
[0029]
  In the form shown in FIGS. 1 and 2, the air-fuel mixture 17 supplied from the slot-shaped opening 18 is a mixture of fuel and air upstream thereof.Of the present inventionAs shown in FIG. 3, which is a conceptual diagram of the embodiment, only air flows from the slot-shaped opening 18, and the fuel is injected from a side wall fuel supplier 25 provided on the side wall 16 of the cylindrical combustion chamber 11, Even in a method in which mixing of fuel and air is advanced while swirling in the combustion chamber 11, a substantially axisymmetric cylindrical flame 21 can be formed as in the case of supplying the air-fuel mixture. FIG. 3A is a cross-sectional view in a plane including the central axis of a cylindrical combustion chamber according to another embodiment of the present invention, and FIG. 3B is a cross-sectional view taken along the line CC along the plane perpendicular to the central axis. (Arrow CC). In this embodiment, the fuel is supplied only from the bottom fuel supply device 26 at the time of low output, and combustion is performed by injecting only air from the slot-shaped opening 18. The fuel is injected from the sidewall fuel supply device 25 at the time of high output. The fuel and the air flowing in from the slot-shaped opening 18 are mixed while being swirled in the cylindrical combustion chamber 11 and burned. The output control at the time of high output is performed only by controlling the fuel flow rate from the side wall fuel supplier 25. In this way, it is possible to operate under conditions in which the fuel / air ratio is significantly smaller than in a conventional in-cylinder swirl combustor. In order to minimize NOx emission, it is effective to narrow the fuel flow rate from the bottom fuel supply device 26 within a range in which the firing efficiency does not decrease.
[0030]
  FIG.Other examplesIt is a conceptual diagram which shows as a longitudinal cross-sectional view. The form of the upstream part is shown in FIG.thingIs basically the same. A cylindrical swirl combustion chamber 11b having a different inner diameter is connected to the downstream via a connecting portion 41. In this way, even when the air flow rate cannot be controlled, the heat generation rate of the combustion device and the engine output can be controlled by controlling the fuel flow rate of each stage. By increasing the number of stages, the degree of freedom in setting the fuel / air ratio at each stage is increased, enabling more appropriate settings.As shown in FIG. 1 or FIG.Furthermore, NOx reduction and complete combustion can be realized simultaneously over a wider range.
[0031]
  thisExampleThen, the connecting portion 41 is further provided with a connecting portion fuel supply device 27 for supplying fuel into the combustion chamber 11b on the wall surface of the connecting portion 41. The fuel supplied from the connecting portion fuel supply device 27 is already the bottom surface in the second embodiment. The same effect as that of the fuel supply device 26 can be brought about, and the degree of freedom in setting the fuel / air ratio is increased, so that more appropriate setting is possible. Thus, NOx reduction and complete combustion can be realized simultaneously over a wider range than in the first embodiment employing two stages.
[0032]
  An extension duct 24b having an inflow port 23 into which dilution air flows is connected to the downstream side of the most downstream cylinder swirl combustion chamber. It is more effective to provide an extension guide 44 at the inlet 23 so that the diluted air flows out toward the center of the cross section of the combustor. The introduction of this diluted air is effective in weakening the swirl component generated in the upstream swirl type combustion chamber in the cylinder. In particular, in gas turbines, it is necessary to avoid such swirling components because the strong swirling component of the hot gas from the combustor adversely affects the efficiency of the downstream turbine. If an air-fuel mixture is used instead of air, the temperature of the combustion gas can be further increased.
[0033]
【The invention's effect】
  As described above, in the in-cylinder swirl combustor according to the first aspect, the bottom surface fuel supply device is provided at the periphery of the bottom surface of the in-cylinder swirl combustion chamber so that fuel can be supplied into the combustion chamber. Therefore, the fuel and the air and air-fuel mixture from the slot-shaped opening are mixed moderately, and a region with a high fuel concentration is formed near the center near the bottom surface. The air that flows in from the slot and the fuel from the side wall fuel supply unit provided on the side wall of the combustion chamber are mixed in the combustion chamber, which brings about an effect in holding the flame of the air-fuel mixture, particularly on the lean side, The combustible range on the lean side can be greatly expanded. As a result, it is possible to operate the combustion apparatus and engine while suppressing NOx emission over a wide range of fuel / air ratios without troublesome control of the air flow rate.
[0034]
  And in the in-cylinder swirl combustor of claim 1 and claim 3,Since the mixture is formed in the combustion chamber, the problem of flashback can be completely eliminated, and a highly safe apparatus can be realized. Further, there is an effect that it is possible to safely burn a substance that easily ignites when it comes into contact with air.
[0035]
  In the cylindrical swirl combustor according to claim 2,A cylindrical swirl type combustion chamber with different internal diameters is connected, so it is possible to achieve both low NOx and complete combustion over a very wide range of fuel / air ratios simply by controlling the fuel / air ratio of the air-fuel mixture to each stage. it can. Even from the point of not requiring complicated air flow control, a clean combustor and engine with excellent cost and durability can be realized.
[0036]
  And claims4In the in-cylinder swirl combustor described above, a connection portion fuel supply device is provided in the circumferential direction on the wall surface of the connection portion, and fuel is injected into the combustion chamber on the upstream side or the downstream side depending on the structure of the wall surface. As a result, combustion can be achieved up to a smaller fuel / air ratio as a whole, and there is an effect that low NOx and high combustion efficiency can be obtained by appropriately distributing the fuel.
[0037]
  AlsoClaim 5In the in-cylinder swirl combustor described above, an extension duct having an inscribed circle diameter larger than the inner diameter is connected to the outlet of the in-cylinder swirl combustion chamber located on the most downstream side. And a circulating flow is formed downstream thereof, so that when unburned components and air-fuel mixture flow out along the wall surface, they can be burned and have an important practical effect.Also, an inlet is provided on the side wall of the extension duct so that either air, fuel, or a mixture of air and fuel flows almost toward the center in the radial direction so that they mix with the combustion gas from the upstream. As a result, the swirling of the combustion gas can be weakened, the temperature of the combustion gas can be adjusted, and the temperature distribution of the combustion gas at the outlet can be optimized.
[0038]
  Further, in the in-cylinder swirl combustor according to claim 6, an extension duct having a diameter of an inscribed circle larger than the inner diameter is connected to the outlet of the swirl combustion chamber in the cylinder located on the most downstream side. A step is formed in the connecting part, and a circulation flow is formed downstream of it, so that when unburned components and air-fuel mixture flow out along the wall surface, they can be burned, which is a practically important effect. There is. In addition, the inlet is provided at an angle that causes a swirl in a direction opposite to the swirl upstream, and when air, fuel, or air-fuel mixture is injected therefrom, the effect of weakening the swirl is stronger. When it is harmful that the combustion gas from the combustor has a strong swirl, it is an effective means for suppressing swirl, for example, in application to a gas turbine.
[Brief description of the drawings]
FIG. 1 shows the present invention.Reference exampleIt is a conceptual diagram of the in-cylinder swirl combustor.
FIG. 2 of the present inventionOther reference examplesIt is a conceptual diagram of the in-cylinder swirl combustor.
FIG. 3 is a conceptual diagram of an in-cylinder swirl combustor according to an embodiment of the present invention.
FIG. 4 of the present inventionOther reference examplesIt is a conceptual diagram of the in-cylinder swirl combustor.
FIG. 5 is an explanatory diagram of the definition of the peripheral portion on the bottom surface of the cylindrical combustion chamber in the present specification.
FIG. 6 is a conceptual diagram of a prior art combustor employing a premixed cylinder swirl combustion method.
[Explanation of symbols]
11 Cylindrical combustion chamber 11a Pilot combustion chamber
12, 12a Bottom surface 13, 13a Opening
14 Air 15 Fuel
16, 16a Side wall surface of cylindrical combustion chamber 17, 17a Air-fuel mixture
18, 18a Slot-shaped opening 19 Flow path connected to the slot-shaped opening
20 Central axis of cylindrical combustion chamber 21 Cylindrical flame
22, 22a Swirling flow 23 Inlet
24 Extension duct 25 Side wall fuel supplier
26 Bottom fuel supply device 27 Fuel supply injector
44 Guide 56 Virtual extension
57 Virtual cylinder 58 Bottom annular part
59 Bottom fuel supply opening 61 Step
62 Thermal insulation member

Claims (6)

  In an in-cylinder swirl combustor in which a swirl flow around a central axis of the cylindrical combustion chamber is formed inside a cylindrical combustion chamber having one end as a bottom surface, and a cylindrical flame surface substantially axisymmetric about the central axis is held A bottom fuel supply device for supplying fuel into the cylindrical combustion chamber is provided at a peripheral portion of a bottom surface of the cylindrical combustion chamber, and a side wall fuel supply device is disposed on a side wall of the cylindrical combustion chamber. And an elongated slot-like opening for supplying air is provided. One piece having a diameter different from that of the cylindrical combustion chamber and a swirling flow around the central axis and a substantially axisymmetric cylindrical flame surface are formed downstream of the cylindrical combustion chamber via a connecting portion. The in-cylinder swirl combustor according to claim 1 , wherein the extended cylindrical combustion chamber is connected. The in-cylinder swirl combustor according to claim 2 , wherein a side wall fuel injector is disposed on a side wall of the extended cylindrical combustion chamber, and an elongated slot-like opening for supplying air is provided. The in-cylinder swirl combustor according to claim 2 or 3 , wherein a connection portion fuel injector is disposed in a circumferential direction on a wall surface of the connection portion. An extension duct having a diameter of an inscribed circle larger than the inner diameter of the cylindrical combustion chamber is connected to the outlet of the cylindrical combustion chamber of the most downstream cylindrical swirling method. Or an inflow port through which either the air-fuel mixture or the air-fuel mixture flows substantially toward the center is formed so as to weaken the swirl component generated in the upstream cylindrical swirl type cylindrical combustion chamber. cylindrical inner swirl combustor according to any one claims 1 to 4. An extension duct having a diameter of an inscribed circle larger than the inner diameter of the cylindrical combustion chamber is connected to the outlet of the cylindrical combustion chamber of the most downstream cylindrical swirling method. Or an inlet for flowing either the air / fuel mixture into the cylindrical combustion chamber in a direction opposite to that of the upstream cylindrical combustion chamber. The in-cylinder swirl combustor according to any one of claims 1 to 4 , wherein swirl components generated in the combustion chamber are weakened.

Images