Partitioned cooling combustion chamber flame tube structure

Abstract

The invention discloses a partition cooling combustion chamber flame tube structure, and belongs to the field of gas turbine flame tubes, the partition cooling combustion chamber flame tube structure comprises a flame tube body, a flame tube inlet section and a flame tube outlet section are arranged on the two sides of the flame tube body respectively, and a seam groove and a seam groove gas film cooling hole are formed in the joint of the flame tube body and the flame tube inlet section; a plurality of mixing holes and a plurality of inclined holes are formed in the flame tube body, the flame tube body comprises an expansion section, a horizontal section and a contraction section which are sequentially arranged in the direction from the flame tube inlet section to the flame tube outlet section, and the flame tube body is provided with a hexagonal central section. According to the combustion chamber flame tube structure with the partition cooling function, the hexagonal central section is designed to be matched with the expansion section flow channel, the horizontal section flow channel and the contraction section flow channel, the fuel residence time is prolonged through geometric optimization, turbulent mixing is enhanced, and the problems that low-heat-value fuel is low in combustion speed and prone to flameout are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas turbine flame tube, in particular to a partition cooling combustion chamber flame tube structure. BACKGROUND

[0002] The gas turbine is an internal combustion engine that converts the chemical energy of fuel into mechanical energy by rotating a turbine. The flame tube is one of the core components of the gas turbine, which is made of thin alloy sheet and needs to withstand high temperature of 1600-1800℃ and high-speed airflow impact. The flame tube realizes combustion organization, airflow stabilization and heat transfer through vortex finder, cylinder and flame transfer pipe. The vortex finder maintains flame stability by forming a backflow zone, and the cylinder main combustion zone ensures complete combustion of fuel. To cope with extreme working conditions, the flame tube adopts air film cooling and composite cooling technology to isolate high-temperature gas and reduce wall temperature. In the field of aviation, the design layout directly affects the combustion efficiency and emission control. Single-tube and annular combustion chambers adopt different flame tube configurations due to different needs.

[0003] The existing flame tube for low heat value fuel combustion has the following problems:

[0004] 1) Poor combustion stability: traditional single-stage swirl or cylindrical flame tube is difficult to adapt to the slow combustion characteristics of low heat value fuel, and is prone to flameout or incomplete combustion.

[0005] 2) Insufficient cooling efficiency: multi-inclined hole cooling has insufficient film coverage in low flow rate area, and is easily blown away in high flow rate area (contraction section), resulting in wall overheating or cooling gas waste.

[0006] 3) Limited fuel adaptability: most combustion chambers are designed for normal heat value gas such as natural gas, and the mixing and combustion dynamics of low heat value gas (such as biomass gas and synthetic gas) are not optimized.

[0007] 4) Large pressure loss: multi-stage swirl or sudden expansion structure increases flow resistance and reduces overall system efficiency.

[0008] 5) Complex manufacturing and maintenance: porous media combustor is prone to carbon deposition, and lean premixed combustion (DLN) system is sensitive to fuel fluctuations, resulting in high maintenance cost. SUMMARY

[0009] The purpose of the present application is to provide a partition cooling combustion chamber flame tube structure, which designs a hexagonal center section with expansion, horizontal and contraction section flow channels, prolongs the fuel residence time through geometric optimization, enhances turbulent mixing, and solves the problems raised in the background art.

[0010] To achieve the above object, the application provides a combustion chamber flame tube structure with partition cooling, which comprises a flame tube body, a flame tube inlet section and a flame tube outlet section arranged on two sides of the flame tube body respectively, a slot and a slot film cooling hole arranged at a connecting position of the flame tube body and the flame tube inlet section, a plurality of mixing holes and a plurality of inclined holes arranged on the flame tube body, and the flame tube body comprising an expansion section, a horizontal section and a contraction section arranged in sequence along a direction from the flame tube inlet section to the flame tube outlet section, and the flame tube body being provided with a hexagonal section.

[0011] Preferably, one end of the expansion section expanded outward is connected with one end of the horizontal section, one end of the expansion section away from the horizontal section is connected with the flame tube inlet section, one end of the contraction section contracted inward is connected with one end of the flame tube outlet section, and one end of the contraction section away from the flame tube outlet section is connected with one end of the horizontal section away from the expansion section.

[0012] Preferably, the flame tube inlet section comprises a connecting disc connected with one end of a connecting ring, the other end of the connecting ring is connected with an expansion ring, and the expansion section of the flame tube body is connected with the connecting ring.

[0013] Preferably, the expansion ring and the expansion section form a slot, the slot film cooling hole is arranged on one end of the expansion section close to the connecting ring, and the slot film cooling hole is located inside the slot.

[0014] Preferably, the plurality of inclined holes comprises a plurality of inclined holes one, a plurality of inclined holes two and a plurality of inclined holes three, the plurality of inclined holes one are arranged uniformly on the expansion section, the plurality of inclined holes one are arranged on one end of the expansion section close to the horizontal section, the plurality of inclined holes two are arranged uniformly on the horizontal section, and the plurality of inclined holes three are arranged uniformly on the contraction section.

[0015] Preferably, the flame tube outlet section is uniformly arranged with a plurality of the plurality of inclined holes three.

[0016] Preferably, the plurality of inclined holes one, the plurality of inclined holes two and the plurality of inclined holes three are all inclined to the direction of the flame tube outlet section, and the inclination angle is 20°-30°.

[0017] Preferably, the mixing hole is arranged at a middle position of the horizontal section, and a plurality of the mixing holes are arranged uniformly along a circumferential surface of the horizontal section.

[0018] Therefore, the application has the following beneficial effects by adopting the above-mentioned combustion chamber flame tube structure with partition cooling.

[0019] 1. The geometric design of the flame tube, by designing the hexagonal section to cooperate with the expansion section, the horizontal section and the contraction section, the geometric optimization prolongs the fuel residence time, enhances the turbulent mixing, and solves the problems of slow combustion speed and easy flameout of low calorific value fuel.

[0020] 2. Partition cooling strategy: the expansion section is a high heat load area, and a thick gas film is provided by slot cooling to reduce wall overheating; the horizontal section is a stable combustion area, and is cooled by small aperture, low angle and multi-inclined hole cooling to reduce interference to the main flow; the contraction section is a low temperature area, and is cooled by large aperture multi-inclined hole cooling to reduce flow resistance; the combination of slot and multi-inclined hole can adapt to different heat load areas, and maintenance is more convenient;

[0021] 3. Structural reliability and adaptability: the flame tube adopts a hexagonal center section to withstand the fluctuating load of low calorific value fuel combustion, improving the anti-deformation ability of the flame tube; the hexagonal center section corner area vortex enhances the near-wall airflow disturbance, improving the adhesion of the cooling gas film.

[0022] The technical solutions of the present application will be further described in detail below with the aid of drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the flame tube of the embodiment of the present application.

[0024] Figure 2 It is a cross-sectional view of the flame tube of the embodiment of the present application.

[0025] Figure 3 It is a hexagonal cross-sectional view of the flame tube of the embodiment of the present application.

[0026] Figure 4 It is a center section velocity nephogram of the combustion chamber of the embodiment of the present application.

[0027] Figure 5 It is a 0 velocity line diagram of the combustion chamber of the embodiment of the present application.

[0028] Figure 6 It is a center section temperature diagram of the combustion chamber of the embodiment of the present application.

[0029] Figure 7 It is an outlet temperature nephogram of the combustion chamber of the embodiment of the present application.

[0030] Figure 8 It is a wall surface temperature nephogram of the combustion chamber of the embodiment of the present application.

[0031] REFERENCE NUMERALS

[0032] 1. Flame tube inlet section; 2. Flame tube outlet section; 3. Expansion section; 4. Horizontal section; 5. Contraction section; 6. Multi-inclined hole 1; 7. Multi-inclined hole 2; 8. Multi-inclined hole 3; 9. Slot; 10. Slot film cooling hole; 11. Mixing hole; 12. Connection disc; 13. Connection ring; 14. Expansion ring. DETAILED DESCRIPTION

[0033] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application are further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present application and should not be used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application. The examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout.

[0034] It should be noted that the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or server comprising a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0035] Similar reference signs and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0036] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present application.

[0037] In the description of the present application, it should also be noted that unless otherwise explicitly specified and limited, the terms "arranged", "mounted", "connected" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrally connected; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0038] Embodiments

[0039] As Figure 1 , Figure 2As shown, the partitioned cooling combustion chamber flame tube structure of the present application comprises a flame tube body, and a flame tube inlet section 1 and a flame tube outlet section 2 are arranged on both sides of the flame tube body. The flame tube body comprises an expansion section 3, a horizontal section 4 and a contraction section 5 arranged in sequence from the flame tube inlet section 1 to the flame tube outlet section 2. The flame tube body is provided with a hexagonal central section, as shown. Figure 3 As shown, the top three edges and the bottom three edges (excluding the inlet and outlet at both ends) of the flame tube body form the hexagonal central section of the flame tube body. The hexagonal central section of the flame tube geometry design induces secondary vortex flow, strengthens mixing and flame stabilization.

[0040] One end of the outwardly expanding expansion section 3 is connected to one end of the horizontal section 4, and the other end of the expansion section 3 is connected to the flame tube inlet section 1. One end of the inwardly contracting contraction section 5 is connected to one end of the flame tube outlet section 2, and the other end of the contraction section 5 is connected to the other end of the horizontal section 4 away from the expansion section 3. The flame tube inlet section 1 comprises a connecting disc 12 connected to one end of a connecting ring 13, the other end of the connecting ring 13 is connected to an expansion ring 14, and the expansion section 3 of the flame tube body is connected to the connecting ring 13.

[0041] The connecting part of the flame tube body and the flame tube inlet section 1 is provided with a slot 9 and a slot 9 film cooling hole 10. The slot 9 is formed between the expansion ring 14 and the expansion section 3, the slot 9 film cooling hole 10 is arranged on one end of the expansion section 3 close to the connecting ring 13, and the slot 9 film cooling hole 10 is located inside the slot 9.

[0042] A plurality of mixing holes 11 and multi-inclined holes are arranged on the flame tube body. The multi-inclined holes comprise multi-inclined hole one 6, multi-inclined hole two 7 and multi-inclined hole three 8. The multi-inclined hole one 6 is uniformly arranged on the expansion section 3, and the multi-inclined hole one 6 is arranged on one end of the expansion section 3 close to the horizontal section 4. The multi-inclined hole two 7 is uniformly arranged on the horizontal section 4, and the multi-inclined hole three 8 is uniformly arranged on the contraction section 5. The inclination angle of the multi-inclined hole one 6, the multi-inclined hole two 7 and the multi-inclined hole three 8 is 20°-30°. The hole diameter of the multi-inclined hole two 7 is 0.5-0.6mm, and the hole diameter of the multi-inclined hole three 8 is 0.8-1mm. The mixing hole 11 is arranged at the middle position of the horizontal section 4, and a plurality of mixing holes 11 are uniformly arranged on the circumference of the horizontal section 4. The hole diameter of the mixing hole 11 is 3-7mm. The flame tube outlet section 2 is also uniformly arranged with a plurality of multi-inclined hole three 8.

[0043] The flame tube body employs an expansion section 3 to reduce flow velocity and extend reaction time; a horizontal section 4 to stabilize combustion; and mixing holes 11 to regulate the temperature field; while a contraction section 5 accelerates combustion and reduces flow separation. Cooling optimization design includes slotted cooling (expansion section 3) with a high-flow-rate gas film covering high-heat-load areas; and multi-slanted-hole cooling (horizontal / contraction section 5): the horizontal section 4 features small-diameter, low-angle holes for precise cooling, while the contraction section 5 has large-diameter holes for low flow resistance. A strong swirling mixing hole 11 layout is adopted for low-calorific-value fuels: the small-diameter air jet in the horizontal section 4 counteracts the high-temperature zone on the wall.

[0044] Air and low-calorific-value gaseous fuel enter the inlet section 1 of the flame tube via a strong swirling flame stabilization device at the head, undergoing diffusion combustion. In the expansion section 3 of the flame tube body, the flow velocity decreases, extending the fuel's residence time in the combustion chamber and compensating for the slow combustion rate of low-calorific-value fuels. The increased cross-section further enhances turbulent mixing (similar to the principle of a "sudden expansion combustion chamber"). The flame temperature is high in the expansion section 3 region, and it is close to the wall; the expansion section 3 has a large surface area, reduced flow velocity, and relatively high heat load. Using slotted cooling (9) provides a thicker gas film, effectively isolating the high-temperature combustion gas and preventing wall overheating. Simultaneously, the low flow velocity in the expansion section 3 means that slotted cooling (9) does not significantly increase pressure loss, making it suitable for high-flow-rate cooling requirements. Multiple oblique holes (6) are used for auxiliary cooling in the area near the horizontal section 4, where the gas film is difficult to cover. Figure 3 As shown, the corner region of the hexagonal central section induces secondary eddies, breaking the laminar boundary layer and promoting microscopic mixing of fuel and air, which is crucial for the complete combustion of low-calorific-value fuels. Stabilizing the flame by anchoring it to the corner region of the hexagonal central section can create a local low-velocity zone, helping the flame to remain stationary and preventing it from being blown out.

[0045] In the horizontal section 4, the flame burns stably. This region has a high temperature, and the densely packed, small-diameter, multi-angled orifice 7 is more conducive to cooling. The angle of the angled orifice is low (20°–30°), minimizing interference with the main flow. The diameter of the horizontal section 4 of the flame tube is 100-140 mm. Under the influence of the strong swirling flow and the preceding expansion section 3, the flame burns against the wall, and the high-temperature zone is generated near the flame tube wall. Therefore, to optimize the outlet temperature distribution, multiple small-diameter mixing holes 11 with a diameter of 3-7 mm are opened in the middle of the horizontal section 4. The low-momentum air penetration counteracts the high-temperature zone near the flame tube wall.

[0046] A separate contraction section 5 downstream of the flame tube accelerates combustion products and avoids an excessively large recirculation zone that could reduce combustion efficiency. The convergent structure with a hexagonal central cross-section reduces flow separation and maintains a stable flow field. Due to the entry of the mixed gas in the front section, this part has a lower temperature and smaller heat load, so opening multiple oblique holes of 0.8-1mm is sufficient.

[0047] In the numerical simulation of the combustion chamber, the standard k-ε turbulence model and the flame surface generated manifold (FGM) model are selected for coupled calculation considering the calculation accuracy and efficiency. The standard k-ε model can well predict high Reynolds number turbulent flow and has low calculation cost, which is suitable for the main flow simulation of the combustion chamber. The FGM model can significantly reduce the calculation amount of complex combustion reaction by generating a low-dimensional manifold containing chemical and thermodynamic information in advance, and can accurately predict the temperature field and key component distribution. The commonly used grid division method in CFD calculation is structured grid and unstructured grid. The calculation model using structured grid often has higher grid quality, faster calculation speed and less memory. However, the grid drawing process is slow, and it is difficult to apply to complex and variable geometry. In this embodiment, unstructured grid is selected to adapt to the complex combustion chamber, and the main combustion area is grid-encrypted, with a total of 24.801 million grids.

[0048] ①Velocity

[0049] The velocity cloud chart of the center section of the combustion chamber and the 0 velocity line are shown in Figure 4 、 Figure 5 After checking, the high-temperature gas pressure loss is 3.4%, the air inlet pressure loss is 3.90%, and the pressure loss through the flame tube is 3.11%.

[0050] ②Temperature

[0051] The temperature cloud chart of the center section of the combustion chamber and the outlet temperature distribution are shown in Figure 6 、 Figure 7 The average outlet temperature is 1224K, the maximum outlet temperature is 1321K, and the OTDF is calculated as follows. The OTDF of the combustion chamber is 0.15.

[0052]

[0053] T 4max : maximum outlet temperature, K; T 4ave : average outlet temperature, K; T 3ave : average inlet temperature, K;

[0054] The assembled test piece is simplified, and the fluid-solid coupling calculation wall temperature is carried out, in which the wall material parameters are referenced to high-temperature alloy. The wall temperature calculation result is shown in Figure 8 The maximum wall temperature does not exceed 1200K, which meets the requirements of the flame tube.

[0055] It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A zoned-cooled combustor flame tube structure characterized by: The flame tube comprises a flame tube body, a flame tube inlet section and a flame tube outlet section arranged on two sides of the flame tube body respectively, a slot and a slot film cooling hole arranged at a connection position of the flame tube body and the flame tube inlet section, a plurality of mixing holes and multi-inclined holes arranged on the flame tube body, and the flame tube body comprises an expansion section, a horizontal section and a contraction section arranged in sequence along a direction from the flame tube inlet section to the flame tube outlet section, and the flame tube body is provided with a hexagonal central section.

2. The zoned-cooled combustor flame tube structure according to claim 1, characterized by: An outwardly expanding end of the expansion section is connected with an end of the horizontal section, an end of the expansion section away from the horizontal section is connected with the flame tube inlet section, an inwardly contracting end of the contraction section is connected with an end of the flame tube outlet section, and an end of the contraction section away from the flame tube outlet section is connected with an end of the horizontal section away from the expansion section.

3. The zoned-cooled combustor flame tube structure according to claim 2, characterized by: The flame tube inlet section comprises a connecting disc connected with one end of a connecting ring, the connecting ring is provided with an expansion ring at the other end, and the expansion section of the flame tube body is connected with the connecting ring.

4. The zoned-cooled combustor flame tube structure according to claim 3, characterized by: The slot is formed between the expansion ring and the expansion section, the slot film cooling hole is arranged on the expansion section close to the connecting ring, and the slot film cooling hole is located in the slot.

5. The zoned-cooled combustor flame tube structure according to claim 2, wherein: The multi-inclined holes comprise multi-inclined hole one, multi-inclined hole two and multi-inclined hole three, the multi-inclined hole one is uniformly arranged on the expansion section, the multi-inclined hole one is arranged on the expansion section close to the horizontal section, the multi-inclined hole two is uniformly arranged on the horizontal section, and the multi-inclined hole three is uniformly arranged on the contraction section.

6. The zoned-cooled combustor flame tube structure according to claim 5, wherein: The flame tube outlet section is uniformly provided with a plurality of multi-inclined hole three.

7. The zoned-cooled combustor flame tube structure according to claim 5, wherein: The multi-inclined hole one, the multi-inclined hole two and the multi-inclined hole three are all inclined to the direction of the flame tube outlet section, and the inclination angle is 20°-30°.

8. The zoned-cooled combustor flame tube structure according to claim 1, wherein: The mixing hole is arranged at a middle position of the horizontal section, and a circle of the mixing holes is uniformly arranged along the circumferential surface of the horizontal section.

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