Mixer suitable for high-temperature fuel gas and air in staged combustion chamber

Abstract

The invention discloses a high-temperature gas and air mixer suitable for a staged combustion chamber, and relates to the technical field of gas turbines. The mixer comprises a barrel and mixing pipes, a mixing pipe inlet is formed in the side wall of the barrel, the mixing pipes are all located in the barrel, one end of each mixing pipe is communicated with the mixing pipe inlet, and the other end of each mixing pipe is a mixing pipe outlet. The mixing pipes are arranged in multiple rows in the flowing direction of the mixer, the radial section of the mixer is divided into multiple core areas and near-wall areas through sections, when outlets of the mixing pipes are located in the core areas, the mixing pipes are arranged in a radial centering mode, and the axes of the mixing pipes are perpendicular to the tangent line of the barrel; when the outlet of the mixing pipe is located in the near wall area, the mixing pipe is tangentially arranged in the circumferential direction of the barrel, and an acute angle is formed between the axis of the mixing pipe and the tangent line of the barrel. According to the combustor, high-temperature fuel gas generated in the first-stage combustion chamber and second-stage cold air needed during combustion in the second-stage combustion chamber can be rapidly and evenly mixed, and meanwhile the mixing performance at the position close to the wall and control over unnecessary turbulent flow or rotational flow in a convection field are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of gas turbines, and particularly relates to a mixer for high-temperature gas and air suitable for a staged combustor. Background Art

[0002] With the continuous development of heavy-duty gas turbines towards high parameters, high performance, and low pollution, as one of the core components of gas turbines, the combustor must be able to effectively suppress the generation of NOx while continuously increasing the initial gas temperature to meet the emission requirements.

[0003] Currently, the most widely used lean-premixed combustion technology has the core idea of pre-mixing excess air and fuel and then burning it to control the peak flame temperature outside the temperature window range where a large amount of NOx is generated, thereby effectively controlling NOx emissions. However, with the continuous increase in the design temperature at the combustor outlet, the design space for combustion organization has become increasingly narrow and has approached the design space limit. Simply relying on lean-premixed combustion technology is difficult to meet the performance requirements of higher-level gas turbines.

[0004] Among the new generation of combustion technologies, micro-mixing combustion and axial staging combustion are two combustion organization methods with relatively high technology readiness levels and both have successful application cases. Among them, the micro-mixing combustion technology has some inherent defects that need to be overcome. For example, the operation window is narrow and the operation regulation performance of the combustor is poor; the heat load of the flame tube cross-section is small, and the combustor changes from the traditional "slender type" to the "short and thick type", which will cause chain effects on the combustor layout, cylinder design, etc. The axial staging combustion technology divides the combustor into two stages. The first stage can adopt the traditional lean-premixed combustion method or the micro-mixing combustion method. The generated hot gas is mixed with another part of the air to cool down and then enters the secondary combustor as an oxidant, where it is mixed with the secondary fuel for the second combustion. By using this method, the peak temperature in the primary combustor and the residence time in the secondary combustor can be controlled to effectively suppress the large-scale generation of NOx. At the same time, adopting the axial staging combustion technology can also largely follow the traditional combustor structure design and reduce the R & D cost.

[0005] The mixer is one of the key components newly added to the axial staging combustor compared with the traditional lean-premixed combustor. Its function is to achieve the uniform mixing of the primary high-temperature gas and the secondary air within a short time. On the premise of minimizing the pressure loss, the component field, velocity field, and temperature field at the outlet of the mixer should be uniform. At the same time, it is necessary to avoid generating unnecessary strong turbulence or recirculation in the flow field. In the axial staging combustor with secondary combustion, the secondary combustion relies on the auto-ignition of the combustible mixture to maintain stable combustion. Therefore, the auto-ignition delay time is a key factor affecting the performance of the secondary combustor. At a certain pressure, the auto-ignition delay time will decrease with the increase of the mixture temperature and fuel mixing fraction, and increase with the decrease of the oxygen concentration in the mixture. Therefore, the uniformity of the component field and temperature field distribution at the outlet of the mixer will directly affect the local auto-ignition delay time characteristics of the mixture downstream of the fuel nozzle in the secondary combustor. The flame anchoring position depends on the matching relationship between the turbulent flame propagation speed and the axial macroscopic flow velocity. Therefore, the uniformity of the velocity field distribution at the outlet of the mixer will also have a very important impact on the stable combustion performance and thermoacoustic characteristics of the secondary combustor.

[0006] The existing mixer has a relatively complex structure. The mixing tube has a large shielding area in the flow field. When the working medium flows around the mixing tube, more wake vortices will be generated downstream, resulting in unnecessary turbulence or swirl, which increases the overall pressure loss of the mixer. Although two rows of mixing tubes are arranged downstream of the mixer in the existing design to strengthen the mixing near the wall, due to the existence of the boundary layer, both the heat transfer and mass transfer processes will be adversely affected. The high temperature and low velocity near the wall will cause the downstream combustible mixture to ignite prematurely and the flame anchoring position to shift upstream, seriously threatening the stable and reliable operation of the secondary combustor.

[0007] The existing patent CN114688560A discloses a mixing device for a staged combustor. The mixing device for the staged combustor includes a cylinder body, a first mixing tube, and a second mixing tube. The eccentric directions of the mixing tube and the second mixing tube are opposite, and two swirls with opposite rotation directions can cancel each other out the velocity non-uniformity caused by the swirl, ensuring the temperature when the mixed gas flows out of the cylinder body. This patent also discloses two rows of mixing tubes arranged to strengthen the mixing near the wall, and there are the above-mentioned defects.

[0008] The existing patent CN118129184A discloses a mixing hole arrangement structure suitable for a gas turbine combustor, including two rows of front and rear mixing holes arranged on the inner and outer side walls of the flame tube body. While ensuring the jet penetration of this patent's mixing hole arrangement structure, the uniform distribution of the mixing gas is achieved, and it can be changed independently of other components of the engine such as the swirler and atomization device. The technical solution of this patent is to set mixing holes on the side wall of the combustor, and it does not solve the problem of the stable operation of the above-mentioned secondary combustor.

[0009] In summary, the above-mentioned existing patents are all to solve the problem that the heat transfer and mass transfer processes of the mixer in the secondary combustion chamber are affected, seriously threatening the stable operation of the secondary combustion chamber. Summary of the Invention

[0010] The present invention provides a mixer for high-temperature gas and air in a staged combustion chamber, which solves the problem that the heat transfer and mass transfer processes of the mixer in the secondary combustion chamber in the prior art are affected, seriously threatening the stable operation of the secondary combustion chamber.

[0011] To achieve the above object, the present invention provides a mixer for high-temperature gas and air in a staged combustion chamber. The specific technical solution is as follows:

[0012] A mixer for high-temperature gas and air in a staged combustion chamber includes a cylinder body and a plurality of mixing pipes. An inlet of the mixing pipe is provided on the side wall of the cylinder body. All the mixing pipes are located inside the cylinder body. One end of each mixing pipe is communicated with the inlet of the mixing pipe. The radial cross-section of the cylinder body is divided into a core area and a near-wall area along the radial direction. The core area is close to the axis of the cylinder body, and the near-wall area is close to the wall of the cylinder body. The radius of the core area is 3 / 4 - 5 / 6 of the radius of the cylinder body. The mixing pipes include a first mixing pipe and a second mixing pipe. The outlet of the first mixing pipe is located in the core area, and the outlet of the second mixing pipe is located in the near-wall area.

[0013] Further, both the first mixing pipe and the second mixing pipe are arranged at one end of the cylinder body close to the cylinder body inlet. The distance between the first mixing pipe and the cylinder body inlet is less than the distance between the second mixing pipe and the cylinder body inlet.

[0014] Further, the first mixing pipes are arranged at intervals along the circumferential direction of the cylinder body and multiple rows of the first mixing pipes are arranged at intervals along the axial direction of the cylinder body;

[0015] The second mixing pipes are arranged at intervals along the circumferential direction of the cylinder body and multiple rows of the second mixing pipes are arranged at intervals along the axial direction of the cylinder body.

[0016] Further, the first mixing pipes are arranged concentrically along the radial direction of the cylinder body. The axis of the first mixing pipe is perpendicular to the tangent of the cylinder body. The second mixing pipes are arranged tangentially along the cylinder body. The included angle between the axis of the second mixing pipe and the tangent of the cylinder body is 10° ≤ θ < 90°.

[0017] Further, the inner diameters of the first mixing pipe and the second mixing pipe are determined according to the ratio of the total flow area of the mixing pipes in the core area and the total flow area of the mixing pipes in the near-wall area, and the number of the first mixing pipes and the number of the second mixing pipes.

[0018] Further, the number of rows of both the first mixing pipe and the second mixing pipe is not less than 2. The number of pipes in each row of the first mixing pipe is an even number, and its value range is 2 - 8. The number of pipes in each row of the second mixing pipe is 4 - 20.

[0019] Further, the ratio of the total flow - through area of the mixing pipes in the core region to the total flow - through area of the mixing pipes in the near - wall region is

[0020]

[0021] where A2 is the total flow - through area of the mixing pipes in the core region, and A3 is the total flow - through area of the mixing pipes in the near - wall region. is the air mass flow rate in the core region, is the air mass flow rate in the near - wall region.

[0022] Further, the air mass flow rate in the core region is

[0023]

[0024] The air mass flow rate in the near - wall region is

[0025]

[0026] where H2 is the total amount of energy change during the mixing process in the core region, H3 is the total amount of energy change during the mixing process in the near - wall region, C pair is the specific heat capacity of air at constant pressure, T air is the initial temperature of the mixed air, T ex is the temperature of the mixture at the outlet of the mixer.

[0027] Further, the total amount of energy change during the mixing process in the core region is

[0028]

[0029] The total amount of energy change during the mixing process in the near - wall region is

[0030]

[0031] where T2 and T3 are the average temperatures of the working fluids in the core region and the near - wall region respectively, C p2 、C p3 are the specific heat capacities of the working fluids at constant pressure in the core region and the near - wall region respectively, are the mass flow rates of the working fluids in the core region and the near - wall region respectively.

[0032] Further, the radius of the first mixing pipe has a value range of 0 < R < 0.25D, and the radius of the second mixing pipe has a value range of 0 < r ≤ 0.125D, where D is the cross - sectional diameter of the cylinder.

[0033] Further, the radius of the first mixing pipe is the same for each row, and the radius of the second mixing pipe is the same for each row.

[0034] Further, the radius of the first mixing pipe decreases row by row, and the radius of the second mixing pipe is the same for each row.

[0035] Further, the pipe length of the first mixing pipe decreases row by row, and the pipe length of the second mixing pipe is the same for each row.

[0036] Further, the pipe length of the first mixing pipe is 1 / 5 - 1 / 4 of the cylinder radius, and the pipe length of the second mixing pipe is 1 / 10 of the cylinder radius.

[0037] Further, the mixing pipe outlet directions of two adjacent rows of the second mixing pipes are opposite.

[0038] Based on the above technical solutions, the present invention has at least the following beneficial effects:

[0039] 1. A mixer for mixing high-temperature gas and air in a staged combustion chamber proposed by the present invention divides the fluid domain in the mixer into a core region and a near-wall region, and adopts different mixing methods according to the regional characteristics. The mixing pipes in the core region are arranged near the mixer inlet, which can quickly and evenly mix the high-temperature gas generated in the primary combustion chamber with the secondary cold air required for combustion in the secondary combustion chamber, enabling the secondary combustion chamber to operate stably and reliably.

[0040] 2. A mixer for mixing high-temperature gas and air in a staged combustion chamber proposed by the present invention adopts a cross-jet mode of centripetal injection for mixing in the core region, minimizing the pressure loss, and at the same time achieving a balance between the mixing effect and the pressure loss by reasonably controlling the number of mixing pipes in the core region.

[0041] 3. A mixer for mixing high-temperature gas and air in a staged combustion chamber proposed by the present invention adopts a wall-attached swirling flow mode of tangential injection for mixing in the near-wall region, strengthening the heat and mass transfer processes near the boundary layer as much as possible, enhancing the mixing performance near the wall, and controlling the unnecessary turbulence or swirling flow in the flow field.

[0042] 4. A mixer for mixing high-temperature gas and air in a staged combustion chamber proposed by the present invention can refine the control of the mixing process through more detailed regional division, and further improve the mixing uniformity on the premise of sacrificing a certain amount of pressure loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The schematic diagrams in the specification, which form a part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0044] Figure 1 Schematic diagram of a mixer for high-temperature gas and air in a staged combustor proposed by the present invention;

[0045] Figure 2 Axial sectional view of a mixer for high-temperature gas and air in a staged combustor proposed by the present invention;

[0046] Figure 3 Arrangement diagram of the mixing pipe of a mixer for high-temperature gas and air in a staged combustor in an embodiment of the present invention:

[0047] Figure 4 Temperature contour map at the outlet of the mixer under operating condition 1 in an embodiment of the present invention;

[0048] Figure 5 Temperature contour map at the outlet of the mixer under operating condition 2 in an embodiment of the present invention. Specific implementation manner

[0049] The present invention will be further described in detail below in conjunction with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present invention.

[0050] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0051] Embodiment

[0052] To solve the problem that the heat transfer and mass transfer processes of the mixer in the secondary combustor in the prior art are affected, seriously threatening the stable operation of the secondary combustor, the present invention proposes a mixer for high-temperature gas and air in a staged combustor.

[0053] To achieve the above object, a mixer for high-temperature gas and air in a staged combustor proposed by the present invention is used in an axial staged combustor adopting a two-stage combustion mode, which can quickly and evenly mix the high-temperature gas generated in the primary combustor with the secondary cold air required for combustion in the secondary combustor, and strengthen the mixing performance near the wall and the control of unnecessary turbulence or swirl in the flow field.

[0054] Refer to Figure 1As shown, it is a specific implementation of a mixer for high-temperature gas and air in a staged combustor proposed by the present invention. The mixer includes a cylinder body and a mixing pipe. The first end of the cylinder body is the mixer inlet, and the second end of the cylinder body is the mixer outlet. A mixing pipe inlet is provided on the side wall of the cylinder body. The mixing pipes are all located inside the cylinder body. One end of the mixing pipe is communicated with the mixing pipe inlet, and the other end is the mixing pipe outlet. The mixing pipes are arranged at one end close to the mixer inlet, are arranged at intervals along the circumferential direction, and are arranged in multiple rows along the flow direction of the mixer. In this implementation, the number of rows of the mixing pipes is 4 for illustration.

[0055] Referring to Figure 2 As shown, the cross-sectional circle where the mixing pipe outlet is located can divide the radial cross-section of the mixer into at least two regions: a core region and a near-wall region. In this embodiment, taking the cross-sectional circle of the second row of mixing pipe outlets as the boundary, the axial cross-section of the mixer is divided into a core region and a near-wall region. Referring to Figure 3 As shown, the outlets of the first row of mixing pipes and the second row of mixing pipes are located in the core region and are called core region mixing pipes. The outlets of the third row of mixing pipes and the fourth row of mixing pipes are located in the near-wall region and are called near-wall region mixing pipes. The core region mixing pipes are arranged concentrically along the radial direction of the cylinder body, and their axes are perpendicular to the tangent of the cylinder body; the near-wall region mixing pipes are arranged tangentially along the circumferential direction of the cylinder body, and an acute angle is formed between their axes and the tangent of the cylinder body. The value range of the acute angle is 10° ≤ θ < 90°.

[0056] Optionally, the number of each row of core region mixing pipes is 2 - 8, and they are all even numbers.

[0057] Optionally, the number of each row of near-wall region mixing pipes is 4 - 20.

[0058] In some other embodiments, the axial cross-section partition inside the mixer can be further refined by increasing the number of rows of mixing pipes. For example: three rows of core region mixing pipes are set, and the pipe lengths of the mixing pipes decrease row by row. The axial cross-sectional circle where the outlet of each row of mixing pipes is located can divide the core region into a first core region, a second core region, and a third core region. The number and inner diameter of the mixing pipes in each region can be designed according to needs to achieve stepped mixing. Multiple rows of near-wall region mixing pipes can also be set, and the pipe lengths of the mixing pipes in each row are the same.

[0059] Optionally, the number of rows N of the core region mixing pipes ≥ 2, the pipe length of the mixing pipes is 1 / 5 - 1 / 4 of the radius of the cylinder body, and the pipe lengths of the mixing pipes in each row are the same or decrease row by row.

[0060] Optionally, the number of rows N of the near-wall region mixing pipes ≥ 2, the pipe length of the mixing pipes is 1 / 10 of the radius of the cylinder body, and the pipe lengths of the mixing pipes in each row are the same.

[0061] Specifically, the inner diameter of the mixing pipe is determined according to the working fluid characteristics in each virtual partition on the inlet side of the mixer. The cross-sectional area of the mixer is S, the area of the core region is S2, and the area of the near-wall region S3≈S - S2. According to the characteristics of the component, temperature, and flow rate distribution of the working fluid in the two regions on the inlet side, the enthalpy value per unit mass of the working fluid in S2 is h2, and the enthalpy value per unit mass of the working fluid in S3 is h3. Assume that the temperature of the mixture at the outlet of the mixer is T ex , then the total energy change during the mixing process in S2 and S3 is:

[0062]

[0063] In the formula, T2 and T3 are the average temperatures of the working fluid in the core region and the near-wall region, respectively, in °C p2 , C p3 are the specific heat capacities at constant pressure of the working fluid in the core region and the near-wall region, respectively, are the mass flow rates of the working fluid in the core region and the near-wall region, respectively. The temperature and mass flow rate can be determined according to the CFD calculation results, and the specific heat capacity at constant pressure is calculated according to the physical properties of the working fluid, specifically estimated according to the temperature and the proportion of the substance components as an ideal gas.

[0064] According to the energy change, the air mass flow rates input into the two regions can be obtained as follows:

[0065]

[0066] In the formula, C pair is the specific heat capacity at constant pressure of air, and T air is the initial temperature of the mixing air.

[0067] According to the above proportion of the air mass flow rate, the approximate proportion of the total flow-through area A2 of the mixing pipes in the core region and the total flow-through area A3 of the mixing pipes in the near-wall region can be determined, that is:

[0068]

[0069] Combining the proportion of the total flow-through area A2 of the mixing pipes in the core region and the total flow-through area A3 of the mixing pipes in the near-wall region calculated by the above method, as well as the number of mixing pipes in the core region and the number of mixing pipes in the near-wall region, the inner diameters of the mixing pipes in the core region and the near-wall region can be specifically determined.

[0070] When determining the inner diameter of the mixing pipes in the core region, it should also be ensured that the air jets ejected from the mixing pipes in the same row develop radially to the center of the mixer as much as possible, but there should be no head-on collision or obvious interference, avoiding unnecessary complex flow situations in the flow field. At the same time, it should also be ensured that the jet momentum of the air jets ejected from the downstream mixing pipes does not exceed the jet momentum of the air jets ejected from the mixing pipes in the row above. That is, in this embodiment, it is necessary to satisfy

[0071]

[0072] In the formula, a1 and a2 respectively represent the total effective flow area of the first row of mixing pipes and the total effective flow area of the second row of mixing pipes, a1 + a2 = A2, and represents the mass flow rate of the air ejected from the first row of mixing pipes and the second row of mixing pipes,

[0073] Specifically, determine the number of mixing pipes in the core area and the near-wall area. When determining the number of mixing pipes in the core area, when the length and total flow area of the mixing pipes are certain, the more the number of mixing pipes, the larger the area blocked on the axial section of the mixer, and the greater the impact on the flow of the working fluid. Therefore, on the premise of ensuring the mixing effect, the number of mixing pipes penetrating into the core area should be reduced as much as possible. Since the mixing pipes in the near-wall area are arranged tangentially, when the number of rows of mixing pipes in the near-wall area exceeds 1, it is necessary to ensure that the outlet side directions of two adjacent rows of mixing pipes are opposite to play a role in eliminating swirl and avoid too obvious tangential flow in the near-wall area. It is also possible to consider directly machining inclined cut holes in the near-wall area to replace the tangentially arranged mixing pipes, and the mixing pipes in the same row are evenly arranged on the circumference.

[0074] Specifically, determine the value range of the relevant dimensions of the mixing pipes. The length of the mixer cylinder is L, the diameter of the axial section of the mixer is D, the distance from the first row of mixing pipes in the core area to the mixer inlet is L1, the length of the mixing pipe is 0.5*(D - D1), the radius is R1, and the number of mixing pipes is N1; the distance from the second row of mixing pipes in the core area to the mixer inlet is L2, the length of the mixing pipe is 0.5*(D - D2), the radius is R2, and the number of mixing pipes is N2. The distance from the first row of mixing pipes in the near-wall area to the mixer inlet is l1, the radius is r1, and the number of mixing pipes is n1; the distance from the second row of mixing pipes in the near-wall area to the mixer inlet is l2, the radius is r2, and the number of mixing pipes is n2.

[0075] Among them, the dimensional relationship of the mixing pipes is as follows:

[0076] L > D; 0 < 0.5*(D - D1) < 0.125*D; 0 < 0.5*(D - D2) ≤ 0.5*(D - D1) < 0.125*D;

[0077] 0 < R1 < 0.25*D; 0 < R2 ≤ R1 < 0.25*D; 0 < r1 = r2 < 0.125*D.

[0078] The positions of the mixing pipes are as follows:

[0079] R1 < L1 < (L - R1 - 2*R2 - 2*r1 - 2*r2);

[0080] L1 ≤ L2 < (L - R2 - 2*r1 - 2*r2);

[0081] (L2 + R2) < l1 < (L - r1 - 2*r2);

[0082] l1 ≤ l2 < (L - r2).

[0083] The working process of the above-mentioned mixer for high-temperature gas and air in a staged combustor proposed by the present invention: The high-temperature gas generated by the combustion in the upstream first-stage combustor enters the mixer through the inlet side of the mixer, and the secondary air from the combustion pressure cylinder enters the mixer through the inlet of the mixing pipe. After the two are uniformly mixed in the mixer, they flow out from the outlet side of the mixer. In the core region, the air jet and the mainstream are mixed in the way of cross jet, but it is necessary to avoid obvious counterflow or interference between the air jets ejected from the same row of mixing pipes. The balance between the mixing effect and the pressure loss is achieved by reasonably controlling the number of mixing pipes in the core region. In the near-wall region, the air jet enters tangentially and forms a swirling flow close to the wall at the near-wall to strengthen the heat and mass transfer processes at the near-wall. At the same time, since the flow rate of the mixing air in this part is small, it will not cause obvious influence on the overall pressure loss and velocity field distribution of the mixer due to the tangential intake of air at the near-wall.

[0084] Using the above-mentioned mixer for high-temperature gas and air in a staged combustor, the uniformity of the temperature distribution at the outlet of the mixer was simulated and compared under two working conditions. On the premise that the structure of the first-stage combustor and the mixer remains unchanged, by adjusting the air and fuel flow rates fed into the first-stage combustor, the flow rate and temperature of the combustion products of the first-stage combustor will change, and the amount of secondary air that the mixer needs to mix in will also be different. Under the condition of working condition 1, the volume ratio of the hot gas generated by the first-stage combustor to the secondary air under standard conditions is about 0.57; under the condition of working condition 2, the volume ratio of the hot gas generated by the first-stage combustor to the secondary air under standard conditions is about 0.88.

[0085] Refer to Figure 4 As shown, under the condition of working condition 1, the maximum temperature difference on the outlet section of the mixer is about 180K; refer to Figure 5 As shown, under the condition of working condition 2, the maximum temperature difference on the outlet section of the mixer is about 110K. The temperature distribution non-uniformity within the outlet section of the mixer can be calculated according to the following formula:

[0086]

[0087] In the formula, T ex,i is the temperature at a certain point on the outlet section of the mixer, and T ex is the average temperature of the outlet interface of the mixer. The results of the temperature distribution non-uniformity calculated according to the above formula are U n1 = 4.38% and U n2= 2.54%. The smaller the Un value, the more uniform the temperature distribution. Generally, it is considered that Un ≤ 5% can meet the design requirements. Thus, it can be seen that the existing structural design has a relatively wide flow adaptation range. If detailed optimization is carried out according to the characteristics of the working conditions, better mixing effects can be achieved.

[0088] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0089] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0090] It should be noted that in the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

Claims

1. A mixer for high-temperature gas and air in a staged combustion chamber, comprising a cylinder body and a plurality of mixing pipes. An inlet for the mixing pipes is provided on the side wall of the cylinder body. All the mixing pipes are located inside the cylinder body, and one end of each mixing pipe is communicated with the inlet for the mixing pipes. It is characterized in that: The radial cross-section of the cylinder body is divided into a core area and a near-wall area along the radial direction. The core area is close to the axis of the cylinder body, and the near-wall area is close to the wall of the cylinder body. The radius of the core area is 3 / 4 - 5 / 6 of the radius of the cylinder body. The mixing pipe includes a first mixing pipe and a second mixing pipe. The outlet of the first mixing pipe is located in the core area, and the outlet of the second mixing pipe is located in the near-wall area.

2. The mixer for high-temperature gas and air in a staged combustor according to claim 1, wherein: Both the first mixing pipe and the second mixing pipe are arranged at one end of the cylinder body close to the cylinder body inlet. The distance between the first mixing pipe and the cylinder body inlet is less than the distance between the second mixing pipe and the cylinder body inlet.

3. The mixer for high-temperature gas and air in a staged combustor according to claim 2, wherein: The first mixing pipes are arranged at intervals along the circumferential direction of the cylinder body and multiple rows of the first mixing pipes are arranged at intervals along the axial direction of the cylinder body. The second mixing pipes are arranged at intervals along the circumferential direction of the cylinder body and multiple rows of the second mixing pipes are arranged at intervals along the axial direction of the cylinder body.

4. The mixer for high-temperature gas and air in a staged combustor according to claim 3, characterized in that: The first mixing pipe is arranged concentrically along the radial direction of the cylinder body. The axis of the first mixing pipe is perpendicular to the tangent line of the cylinder body. The second mixing pipe is arranged tangentially along the cylinder body. The included angle between the axis of the second mixing pipe and the tangent line of the cylinder body is 10° ≤ θ < 90°.

5. The mixer for high-temperature gas and air in a staged combustor according to any one of claims 1-4, characterized in that: The inner diameters of the first mixing pipe and the second mixing pipe are determined according to the ratio of the total flow area of the mixing pipes in the core area and the total flow area of the mixing pipes in the near-wall area, as well as the number of the first mixing pipes and the number of the second mixing pipes.

6. The mixer for high-temperature gas and air in a staged combustor according to claim 5, wherein: The number of rows of both the first mixing pipe and the second mixing pipe is not less than 2. The number of each row of the first mixing pipe is an even number, and the value range is 2 - 8. The number of each row of the second mixing pipe is 4 - 20.

7. The mixer for high-temperature gas and air in a staged combustor according to claim 5, wherein: The ratio of the total flow area of the mixing pipes in the core area and the total flow area of the mixing pipes in the near-wall area is wherein, A2 is the total flow area of the mixing pipes in the core region, and A3 is the total flow area of the mixing pipes in the near-wall region. is the air mass flow rate in the core region, is the air mass flow rate in the near-wall region.

8. The mixer for high-temperature gas and air in a staged combustor according to claim 7, characterized in that: The air mass flow rate in the core area is The air mass flow rate in the near-wall area is Among them, H2 is the total amount of energy change during the mixing process in the core region, H3 is the total amount of energy change during the mixing process in the near-wall region, C pair is the specific heat capacity of air at constant pressure, T air is the initial temperature of the entrained air, T ex is the temperature of the mixture at the outlet of the mixer.

9. The mixer for high-temperature gas and air in a staged combustor according to claim 8, characterized in that: The total amount of energy change during the mixing process in the core area is The total amount of energy change during the mixing process in the near-wall area is where T2 and T3 are the average temperatures of the working fluid in the core region and the near-wall region, respectively, C p2 and C p3 are the specific heat capacities at constant pressure of the working fluid in the core region and the near-wall region, respectively, are the mass flow rates of the working fluid in the core region and the near-wall region, respectively.

10. The mixer for high-temperature gas and air in a staged combustor according to claim 7, characterized in that: The value range of the radius of the first mixing pipe is 0 < R < 0.25D, and the value range of the radius of the second mixing pipe is 0 < r ≤ 0.125D, where D is the cross-sectional diameter of the cylinder body.

11. The mixer for high-temperature gas and air in a staged combustor according to claim 10, characterized in that: The radius of each row of the first mixing pipe is the same, and the radius of each row of the second mixing pipe is the same.

12. The mixer for high-temperature gas and air in a staged combustor according to claim 10, wherein: The radius of the first mixing pipe decreases row by row, and the radius of each row of the second mixing pipe is the same.

13. The mixer for high-temperature gas and air in a staged combustor according to claim 2, wherein: The pipe length of the first mixing pipe decreases row by row, and the pipe length of each row of the second mixing pipe is the same.

14. The mixer for high-temperature gas and air in a staged combustor according to claim 13, wherein: The pipe length of the first mixing pipe is 1 / 5 - 1 / 4 of the radius of the cylinder body, and the pipe length of the second mixing pipe is 1 / 10 of the radius of the cylinder body.

15. The mixer for high-temperature gas and air in a staged combustor according to claim 2, wherein: The outlet directions of the mixing pipes of two adjacent rows of the second mixing pipe are opposite.

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