Reflux combustion chamber and gas turbine engine

Abstract

The invention relates to the technical field of aero-engines, and discloses a backflow combustion chamber and a gas turbine engine. The backflow combustion chamber comprises a combustion chamber main body and a sand dust collecting device; the sand and dust collecting device is arranged in the end cavity of the combustion chamber body, a separation structure of the airflow channel and the sand and dust collecting cavity is formed, cooling airflow is divided in the end cavity, and due to the fact that the inertia of cooling gas carrying sand and dust is large, the cooling gas entering from the airflow channel can enter the sand and dust collecting cavity through the first through hole along an original path; the cooling gas which does not carry the sand dust flows along the airflow channel under the guiding effect of the sand dust collecting device, and after the cooling gas entering the sand dust collecting cavity collides with the outer casing, the probability that the sand dust directly enters the flame tube and a subsequent turbine along with the cooling air is effectively reduced under the condition that the air inlet pressure loss is not obviously increased; and the deposition and abrasion risks of sand dust in a combustion chamber and a turbine are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engines, in particular to a backflow combustion chamber and a gas turbine engine. BACKGROUND

[0002] During take-off, landing, hovering or low-altitude flight, the rotor downwash airflow and the wake backflow of a helicopter will blow a large amount of sand, dust and fine particles on the ground into the air, causing the gas turbine engine to be in a high-dust intake environment. The sand and dust entering the engine air path will easily cause erosion and deposition in the internal flow passage, leading to a decrease in engine performance and a reduction in service life, and even affecting flight safety in severe cases. To reduce the harm of sand and dust to the engine, the existing helicopter usually installs a particle separation device in the engine intake duct to separate sand and dust by using the inertia difference between gas and solid phases, thereby reducing the particles entering the engine; a dust screen is installed in front of the intake duct to block the impact of large particles on the compressor blades; and the cumulative damage risk is reduced by limiting the use time in the sand and dust environment. In the combustion chamber part, the risk of cooling hole blockage is reduced by increasing the cooling hole diameter of the flame tube.

[0003] However, the existing technology still has deficiencies. The particle separation device is difficult to effectively separate fine particles, and increasing the separation efficiency often causes an increase in intake pressure drop, thereby affecting the overall performance of the engine; the dust screen can block large particles, but has limited effect on fine dust and is prone to blockage and additional pressure loss; limiting the use time can only reduce the risk at the management level and cannot fundamentally reduce the damage of sand and dust to the hot end components. After the sand and dust enters the combustion chamber through the compressor, on the one hand, it will block the cooling holes of the flame tube, causing abnormal distribution of cooling air, damage to the cooling film, local overheating, ablation and cracks, and on the other hand, it will continue to enter the high-temperature turbine components, causing blockage of the cooling holes of the turbine blades and guide vanes, a decrease in cooling effect, and abrasion and deposition damage to the coating, resulting in an increase in metal temperature and an increase in thermal fatigue. Even if the cooling hole diameter is increased to reduce the risk of blockage, the cooling efficiency and combustion stability will be affected due to the increase in cooling air flow. In addition, the deposition or remelting of sand and dust on the surface of the combustion chamber and turbine components will also change the surface roughness and thermal boundary conditions, increase the flow loss and cause distortion of the temperature field, further shortening the service life and maintenance cycle of the hot end components.

[0004] Therefore, how to effectively reduce the probability of sand and dust entering the flame tube of the combustion chamber and the turbine, and reduce the comprehensive impact of sand and dust on the combustion chamber and the turbine without significantly increasing the intake pressure loss and weakening the cooling effect, has become a technical problem to be solved. SUMMARY

[0005] Therefore, the application provides a backflow combustion chamber and a gas turbine engine to solve the problem that the prior art is prone to causing serious air inlet pressure loss and poor cooling effect while reducing the comprehensive influence of sand dust on the combustion chamber and turbine.

[0006] To solve the above technical problems, the technical scheme of the application is as follows: In a first aspect, the application provides a backflow combustion chamber, comprising: a combustion chamber body and a sand dust collecting device; the combustion chamber body comprises an outer casing and a flame tube, and an end chamber is formed by the outer casing and a head end of the flame tube; the sand dust collecting device is arranged in the end chamber and is adapted to separate the end chamber into an airflow passage and a sand dust collecting chamber, the airflow passage is arranged on one side close to the flame tube, and the sand dust collecting chamber is arranged on one side close to the outer casing; the sand dust collecting device is provided with a first through hole and a second through hole, the first through hole and the second through hole communicate the airflow passage and the sand dust collecting chamber, and the first through hole and the second through hole are symmetrically distributed above and below the nozzle center axis; cooling air flows from the airflow passage, enters the sand dust collecting chamber through the first through hole, and then flows back to the airflow passage from the second through hole.

[0007] The application has the following advantages: By arranging the sand dust collecting device in the end chamber of the combustion chamber body to form a separation structure of the airflow passage and the sand dust collecting chamber, the cooling air flows back to the airflow passage from the second through hole after flowing into the sand dust collecting chamber through the first through hole, and the cooling airflow is divided in the end chamber; because the inertia of the cooling gas carrying sand dust is large, the cooling gas entering from the airflow passage will enter the sand dust collecting chamber along the original path through the first through hole, and the cooling gas not carrying sand dust will flow along the airflow passage under the guidance of the sand dust collecting device; the cooling gas in the sand dust collecting chamber collides with the outer casing, thereby effectively reducing the probability of sand dust entering the flame tube and the subsequent turbine directly with the cooling air without significantly increasing the air inlet pressure loss, and reducing the deposition and abrasion risk of sand dust in the combustion chamber and turbine; at the same time, because the sand dust is mainly collected in the sand dust collecting chamber of the end chamber, the accumulation of sand dust in the high-temperature area is avoided, which helps to prolong the service life of the combustion chamber and turbine and improve the overall working reliability and stability.

[0008] According to the first aspect of the application, the first through hole is inclined from top to bottom to make the axial direction of the first through hole have a first included angle with the nozzle center axis; and the second through hole is inclined from bottom to top to make the axial direction of the second through hole have a second included angle with the nozzle center axis, and the first included angle is equal to the second included angle.

[0009] According to the first aspect of the present application, the first through holes and the second through holes are arranged in an array.

[0010] According to the first aspect of the present application, the first through holes are arranged in multiple rows, and the first distance between two adjacent rows of the first through holes in the vertical direction is 4-5 mm, and the second distance between two adjacent first through holes in the same row in the horizontal direction is 8-10 mm, and the two adjacent rows of the first through holes are arranged in a staggered manner in the vertical direction.

[0011] According to the first aspect of the present application, the first through holes and the second through holes symmetrically arranged on both sides of the nozzle central axis have a third distance in the vertical direction, and the first distance is 10-15 mm.

[0012] According to the first aspect of the present application, the outer casing and the outer ring of the flame tube form an outer ring flow channel, and the outer casing and the inner ring of the flame tube form an inner ring flow channel, and the outer ring flow channel, the airflow channel and the inner ring flow channel are sequentially communicated, and the outer ring flow channel is communicated with the combustion chamber inlet; the sand dust collecting device is in an arc plate structure, so that the airflow channel is arranged in an arc structure, and the airflow channel has a first tangent direction at the communication position with the outer ring flow channel, and the airflow channel has a second tangent direction at the communication position with the inner ring flow channel. The horizontal direction of the outer ring flow channel and the first tangent direction have a third included angle, and the horizontal direction of the inner ring flow channel and the second tangent direction have a fourth included angle, and the third included angle, the fourth included angle and the first included angle / second included angle have the same angle value range, which is 20°-30°.

[0013] According to the first aspect of the present application, the distance width of each part in the outer ring flow channel is consistent, which is a first width gap; the airflow channel and the outer ring flow channel have a second width gap at the joint; the airflow channel has a third width gap at the nozzle central axis, and the airflow channel and the inner ring flow channel have a fourth width gap at the joint. The width value range of the first width gap, the second width gap, the third width gap and the fourth width gap is consistent, and the width value range is 15-25 mm.

[0014] According to the first aspect of the present application, the difference between two adjacent width gaps in the flow direction of the cooling gas is ±5 mm.

[0015] According to the first aspect of the present application, the outer casing is provided with a sand discharge hole, which is communicated with the sand dust collecting cavity and is adapted to discharge the sand dust in the sand dust collecting cavity.

[0016] In a second aspect, the present application also provides a gas turbine engine comprising the recirculation combustion chamber. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0018] Figure 1 Structure diagram of the recirculation combustion chamber provided in some embodiments of the present application; Figure 2 Structure diagram of the sand dust collecting device provided in some embodiments of the present application; Figure 3 Structure diagram of the recirculation combustion chamber provided in some embodiments of the present application; Figure 2 Cross-sectional view of A-A in FIG. 1; Figure 4 Principle diagram of the cooling gas flow of the recirculation combustion chamber provided in some embodiments of the present application; Figure 5 Structure diagram of the lower half of the central axis of the recirculation combustion chamber provided in some embodiments of the present application.

[0019] Explanation of reference signs: 1, combustion chamber main body; 11, outer casing; 12, outer ring of flame tube; 13, inner ring of flame tube; 14, head end of flame tube; 15, outer ring flow channel; 16, gas flow channel; 17, sand dust collecting cavity; 18, inner ring flow channel; 19, sand discharge hole; 2, sand dust collecting device; 21, first through hole; 22, second through hole. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0021] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0022] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0023] In addition, the technical features involved in the different embodiments of the application described below can be combined with each other as long as there is no conflict.

[0024] Reference Figures 1 to 4 As shown in the first aspect of the present application, the present application provides a backflow combustion chamber, comprising: a combustion chamber body 1 and a sand dust collecting device 2; the combustion chamber body 1 comprises an outer casing 11 and a flame tube, and the outer casing 11 and the head end 14 of the flame tube form an end chamber; the sand dust collecting device 2 is arranged in the end chamber and is adapted to divide the end chamber into an airflow passage 16 and a sand dust collecting cavity 17, the airflow passage 16 is arranged near one side of the flame tube, and the sand dust collecting cavity 17 is arranged near one side of the outer casing 11; the sand dust collecting device 2 is provided with a first through hole 21 and a second through hole 22, the first through hole 21 and the second through hole 22 communicate the airflow passage 16 and the sand dust collecting cavity 17, and the first through hole 21 and the second through hole 22 are symmetrically distributed on the nozzle center axis; cooling air flows from the airflow passage 16, enters the sand dust collecting cavity 17 through the first through hole 21, and then flows back to the airflow passage 16 from the second through hole 22.

[0025] The combustion chamber body 1 further comprises an inner casing, wherein the inner casing and the outer casing 11 form a combustion chamber outer contour, and are connected with the front and rear compressors and the turbine. The outer casing 11 and the outer ring of the flame tube form an outer ring flow channel 15, and the outer casing 11 and the inner ring of the flame tube form an inner ring flow channel 18; the combustion chamber inlet is formed between the inner casing and the outer casing 11, and the outer ring flow channel 15 is communicated with the inlet; the end of the flame tube is communicated with the fuel nozzle through or six seven, and one end of the fuel nozzle extends to the fuel source through the sand dust collecting device 2 and the outer casing 11.

[0026] Specifically, by arranging the sand dust collecting device 2 in the end chamber of the combustion chamber body 1, a separation structure of the airflow channel 16 and the sand dust collecting cavity 17 is formed, so that the cooling air flows into the sand dust collecting cavity 17 through the first through hole 21 and then flows back to the airflow channel 16 through the second through hole 22, and the cooling airflow is divided in the end chamber. Since the inertia of the cooling gas carrying sand dust is large, the cooling gas entering from the airflow channel 16 will enter the sand dust collecting cavity 17 along the original path through the first through hole 21, and the cooling gas not carrying sand dust will flow along the airflow channel 16 under the guidance of the sand dust collecting device 2. The cooling gas in the sand dust collecting cavity 17 collides with the outer casing 11, thereby effectively reducing the probability of sand dust entering the flame tube and the subsequent turbine directly with the cooling air without significantly increasing the inlet pressure loss, and reducing the deposition and abrasion risk of sand dust in the combustion chamber and the turbine. At the same time, since the sand dust is mainly collected in the sand dust collecting cavity 17 of the end chamber, the accumulation of sand dust in the high temperature area is avoided, which helps to prolong the service life of the combustion chamber and the turbine, and improves the overall working reliability and stability.

[0027] In the first aspect of the present application, the first through hole 21 is inclined from top to bottom, so that the axis direction has a first included angle with the nozzle center axis; the second through hole 22 is inclined from bottom to top, so that the axis direction has a second included angle with the nozzle center axis, and the first included angle and the second included angle are equal. As shown in the figure, the first included angle is Figure 3 , , , ; wherein the first included angle and the second included angle have equal hole diameters, and the hole diameter is in the range of 2mm-3mm.

[0028] Specifically, by inclining the first through hole 21 from top to bottom, the second through hole 22 from bottom to top, and making the axial directions of the two form equal angles with the center axis of the nozzle, on the one hand, the symmetrical and inclined arrangement of the first through hole 21 and the second through hole 22 helps to form a balanced and stable circulation path for the cooling air in the process of entering the sand dust collection cavity 17 and flowing back to the airflow channel 16, thereby avoiding turbulence and increased pressure loss caused by sudden changes in airflow direction; on the other hand, the inclined through hole enables the cooling airflow to produce a guiding effect during the exchange process, enhancing the deviation and settlement of sand dust particles to the wall surface of the sand dust collection cavity 17, and improving the sand dust separation efficiency.

[0029] In the first aspect of the present application, the first through hole 21 and the second through hole 22 are arranged in an array.

[0030] Specifically, by arranging the first through hole 21 and the second through hole 22 in multiple and arrayed distribution, the multiple-point array distribution of the first through hole 21 and the second through hole 22 can make the cooling air present uniform distribution characteristics when entering the sand dust collection cavity 17 and flowing back to the airflow channel 16, thereby avoiding the phenomenon of excessive or insufficient local flow rate caused by a single through hole, ensuring more stable airflow organization; in addition, the array arrangement significantly increases the exchange area between the cooling airflow and the sand dust collection cavity 17, which helps to improve the efficiency of sand dust capture and settlement, and enhances the overall separation effect; the dispersed distribution of multiple through holes in space can also share the airflow impact to a certain extent, reducing the risk of single-point wear and blockage, and prolonging the service life of the device.

[0031] In the first aspect of the present application, the multiple first through holes 21 are arranged in multiple rows, along the vertical direction, the first spacing between the adjacent two rows of first through holes 21 is 4-5mm; along the horizontal direction, the second spacing between the adjacent two first through holes 21 in the same row is 8-10mm, and the adjacent two rows of first through holes 21 are arranged in vertical staggered manner.

[0032] Specifically, by arranging multiple first through holes 21 in multiple rows, and limiting the range of first spacing and second spacing in vertical and horizontal directions respectively, and using the arrangement mode of vertical staggered arrangement of adjacent two rows, the first spacing of 4-5mm in vertical direction and the second spacing of 8-10mm in horizontal direction are matched and arranged, so that the through hole maintains sufficient opening density when arranged in array to ensure that the cooling air enters the sand dust collection cavity 17 uniformly, and avoids excessive density causing structural strength weakening or airflow turbulence, thereby achieving a balance between structural reliability and flow stability. On the other hand, the two adjacent rows of first through holes 21 are arranged in a staggered manner in the vertical direction, which can form staggered distribution of airflow at different height positions in the sand dust collection cavity 17, thereby establishing a multi-level disturbance and guiding effect in the sand dust collection cavity 17, and enhancing the sedimentation and separation efficiency of sand dust particles. At the same time, the staggered arrangement can effectively weaken the flow channeling phenomenon caused by the alignment of local airflow, and avoid the short-circuiting of sand dust backflow to the airflow passage 16 along with the airflow.

[0033] In the first aspect of the present application, the first through hole 21 and the second through hole 22 arranged symmetrically on both sides of the nozzle center axis have a third spacing in the vertical direction, and the first spacing ranges from 10mm to 15mm.

[0034] Similarly, since the first through hole 21 and the second through hole 22 are symmetrically distributed about the nozzle center axis, the arrangement of the second through hole 22 is consistent with that of the first through hole 21. Specifically, as shown in FIG. 2, the first spacing P1 between the two adjacent rows of second through holes 22 is 10mm-15mm. Figure 2 Similarly, since the first through hole 21 and the second through hole 22 are symmetrically distributed about the nozzle center axis, the arrangement of the second through hole 22 is consistent with that of the first through hole 21. Specifically, as shown in FIG. 2, the first spacing P1 between the two adjacent rows of second through holes 22 is 10mm-15mm.

[0035] Specifically, by limiting the third spacing between the first through hole 21 and the second through hole 22 arranged symmetrically on both sides of the nozzle center axis to be 10mm-15mm, the reasonable setting of the third spacing makes the exchange path of the cooling airflow between the upper and lower through holes maintain a moderate flow length, which helps to form sufficient deviation and sedimentation space in the sand dust collection cavity 17, thereby improving the capture efficiency of sand dust. In addition, the spacing range of 10mm-15mm avoids the short-circuiting of airflow caused by too close through holes, and also prevents the problems of uneven distribution of cooling air or local cooling deficiency caused by too far through holes, thereby balancing the sand dust separation effect and cooling performance.

[0036] In addition, the first through hole 21 and the second through hole 22 are arranged symmetrically about the nozzle center axis and maintain a third spacing in the vertical direction, which can also ensure that the airflow forms a symmetrical circulation channel on both sides of the nozzle, further inhibits the generation of asymmetric vortex and turbulence, and improves the stability of the airflow field and the overall operation reliability of the combustion chamber.

[0037] ​In the first aspect of the present application, the outer casing 11 and the outer ring 12 of the flame tube form an outer ring flow channel 15, the outer casing 11 and the inner ring 13 of the flame tube form an inner ring flow channel 18, the outer ring flow channel 15, the airflow channel 16 and the inner ring flow channel 18 are sequentially communicated, and the outer ring flow channel 15 is communicated with the combustion chamber inlet; the sand dust collecting device 2 is in an arc plate structure, so that the airflow channel 16 is arranged in an arc shape, the airflow channel 16 has a first tangent direction at the communication position with the outer ring flow channel 15, and the airflow channel 16 has a second tangent direction at the communication position with the inner ring flow channel 18. The horizontal direction of the outer ring flow channel 15 and the first tangent direction have a third included angle, the horizontal direction of the inner ring flow channel 18 and the second tangent direction have a fourth included angle, the third included angle, the fourth included angle and the first included angle / second included angle have the same angle value range, and the angle value range is 20°-30°.

[0038] Specifically, the outer ring flow channel 15 is formed between the outer casing 11 and the outer ring 12 of the flame tube, the inner ring flow channel 18 is formed between the inner ring 13 of the flame tube, the outer ring flow channel 15, the airflow channel 16 and the inner ring flow channel 18 are sequentially communicated, the sand dust collecting device 2 is in an arc plate structure, the airflow channel 16 is arranged in an arc shape, and the sand dust particles can be guided to deviate to the sand dust collecting cavity 17 due to inertia during airflow turning, so that the separation and sedimentation effect of sand dust is significantly enhanced.

[0039] The airflow channel 16 is communicated with the outer ring flow channel 15 and the inner ring flow channel 18, and the first tangent direction and the second tangent direction are set respectively, the first tangent direction and the horizontal direction of the outer ring flow channel 15 have a third included angle, the second tangent direction and the horizontal direction of the inner ring flow channel 18 have a fourth included angle, the first included angle, the second included angle, the third included angle and the fourth included angle have the same angle value range, and the angle value range is 20°-30°; specifically, the first included angle and the third included angle can have the same angle value, and the second included angle and the fourth included angle can have the same angle value, so that when the cooling airflow enters the airflow channel 16 from the outer ring flow channel 15, the cooling gas carrying sand dust can directly enter the sand dust collecting cavity 17 through the first through hole 21, the sand dust collecting device 2 is avoided to block the cooling gas, and the collection efficiency of sand dust is improved; Similarly, the cooling gas flowing out of the sand dust collecting cavity 17 through the second through hole 22 can directly enter the inner ring flow channel 18, and the cooling of the flame tube is realized; The structure ensures that the guiding characteristics of the entire cooling airflow during the conversion process of different channels are coordinated, which can effectively avoid airflow turbulence and increase in pressure loss, and can maintain the stability and uniformity of the cooling airflow.

[0040] In the first aspect of the present application, the width of the gap at each position in the outer ring flow channel 15 is consistent, which is the first width gap; the gap between the airflow channel 16 and the outer ring flow channel 15 has a second width gap; the gap at the center axis of the nozzle of the airflow channel 16 has a third width gap; and the gap between the airflow channel 16 and the inner ring flow channel 18 has a fourth width gap. The width of the first width gap, the second width gap, the third width gap and the fourth width gap is consistent, and the width range is 15mm-25mm.

[0041] Specifically, by setting the width gap of the outer ring flow channel 15, the airflow channel 16 and the inner ring flow channel 18 at each key connection position to be 15mm-25mm, the first width gap ensures the stability of the overall airflow distribution of the outer ring flow channel 15, preventing excessive flow rate caused by local narrowness or flow stagnation caused by local wide.

[0042] The width range is controlled to be 15mm-25mm, which not only ensures sufficient airflow throughput, but also avoids weakening the sand dust separation effect due to excessive gap, thereby achieving the best balance between cooling performance and protection performance.

[0043] In the first aspect of the present application, the difference between adjacent two width gaps in the flow direction of the cooling gas is ±5mm.

[0044] Specifically, by limiting the difference between adjacent two width gaps to be ±5mm, the ±5mm difference range avoids the sudden change of adjacent flow channel gaps, thereby effectively inhibiting the turbulence and pressure loss increase caused by local airflow contraction or expansion, and ensuring the stability and uniformity of the overall flow field of the airflow. In addition, the gradual change of the width gap allows the cooling air to gradually adjust the flow rate and flow direction during the flow process, which is beneficial to maintaining the inertial separation and settling effect of the sand dust particles in the flow field, and improving the stability and efficiency of sand dust collection. At the same time, this limitation can also reduce the impact and wear on the combustion chamber wall and the sand dust collecting device 2 caused by local cross-section mutation, prolonging the service life of the components.

[0045] Referring to Figure 5 In the first aspect of the present application, the outer casing 11 is provided with a sand discharge hole 19, and the sand discharge hole 19 is communicated with the sand dust collecting cavity 17, so as to discharge the sand dust in the sand dust collecting cavity 17.

[0046] It can be understood that the sand leakage hole 19 is arranged directly below the combustion chamber body 1.

[0047] Specifically, by opening the sand leakage hole 19 on the outer casing 11 and making it communicate with the sand dust collection cavity 17, the sand leakage hole 19 provides a sand discharge channel for the sand dust collection cavity 17, so that the sand dust gradually deposited in the long-term operation of the cooling airflow can be discharged regularly, avoiding the situation that the sand dust continuously accumulates in the collection cavity, resulting in insufficient containing space or secondary entry into the airflow channel 16. In addition, the arrangement of the sand leakage hole 19 helps to reduce the accumulation pressure and abrasion risk of sand dust on the collection device and the inner wall of the outer casing 11, thereby prolonging the service life of the combustion chamber structural components.

[0048] The sand leakage hole 19 is in a closed state when the combustion chamber is in a hot operation, and is opened when the engine is in a cold operation and cleaning to discharge the sand dust. The sand discharge mode of the sand leakage hole 19 can maintain the cleanliness of the collection cavity and improve the stability and maintainability of the system operation without significantly increasing energy consumption or complex devices.

[0049] In a second aspect, the application further provides a gas turbine engine comprising a backflow combustion chamber.

[0050] Specifically, by using the backflow combustion chamber in the gas turbine engine, the probability of sand dust entering the flame tube and turbine with the cooling airflow during engine operation can be significantly reduced, thereby reducing the abrasion, deposition and blockage risk of sand dust on the combustion chamber and turbine components.

[0051] On the one hand, the backflow combustion chamber of the present application realizes reasonable organization of the cooling airflow and efficient collection of sand dust without significantly increasing the inlet air pressure loss, so that the engine can maintain stable combustion and efficient cooling in a sand-containing environment, ensuring the combustion efficiency and output performance. On the other hand, the long-term accumulation of sand dust can be discharged in time through the sand leakage hole 19, avoiding the damage of secondary backflow of sand dust to the core components, thereby prolonging the service life of the key components of the engine and reducing the maintenance frequency and operating cost.

[0052] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A recirculation combustion chamber, characterized in that, include: The combustion chamber body (1) includes an outer casing (11) and a flame tube, wherein the outer casing (11) and the flame tube head end (14) enclose each other to form an end chamber; A sand and dust collection device (2) is provided in the end chamber and is adapted to divide the end chamber into an airflow channel (16) and a sand and dust collection chamber (17). The airflow channel (16) is provided on the side close to the flame tube, and the sand and dust collection chamber (17) is provided on the side close to the outer casing (11). The sand and dust collection device (2) is provided with a first through hole (21) and a second through hole (22). The first through hole (21) and the second through hole (22) connect the airflow channel (16) and the sand and dust collection chamber (17). The first through hole (21) and the second through hole (22) are symmetrically distributed up and down about the nozzle central axis. Cooling air enters the sand and dust collection chamber (17) through the airflow channel (16), the first through hole (21), and then flows back to the airflow channel (16) through the second through hole (22).

2. The recirculation combustion chamber according to claim 1, characterized in that, From the direction of the cooling air flow, the first through hole (21) is opened at an angle from top to bottom so that its axial direction has a first angle with the central axis of the nozzle; the second through hole (22) is opened at an angle from bottom to top so that its axial direction has a second angle with the central axis of the nozzle, and the first angle and the second angle are equal.

3. The recirculation combustion chamber according to claim 2, characterized in that, Both the first through hole (21) and the second through hole (22) are provided in multiples and are arranged in an array.

4. The recirculation combustion chamber according to claim 3, characterized in that, Multiple first through holes (21) are arranged in multiple rows. In the vertical direction, there is a first spacing between two adjacent rows of first through holes (21), and the first spacing ranges from 4mm to 5mm. In the horizontal direction, there is a second spacing between two adjacent first through holes (21) in the same row, and the second spacing ranges from 8mm to 10mm. The first through holes (21) in two adjacent rows are staggered and spaced apart in the vertical direction.

5. The recirculation combustion chamber according to any one of claims 1 to 4, characterized in that, The first through hole (21) and the second through hole (22) located symmetrically on both sides of the central axis of the nozzle have a third spacing in the vertical direction, and the first spacing ranges from 10mm to 15mm.

6. The recirculation combustion chamber according to claim 2, characterized in that, The outer casing (11) and the outer ring (12) of the flame tube enclose to form an outer ring flow channel (15), and the outer casing (11) and the inner ring (13) of the flame tube enclose to form an inner ring flow channel (18). The outer ring flow channel (15), the airflow channel (16) and the inner ring flow channel (18) are connected in sequence. The outer ring flow channel (15) is connected to the combustion chamber inlet. The sand and dust collection device (2) has an arc-shaped plate structure so that the airflow channel (16) is set in an arc-shaped structure. The airflow channel (16) has a first tangential direction at the connection between it and the outer ring flow channel (15), and the airflow channel (16) has a second tangential direction at the connection between it and the inner ring flow channel (18). The horizontal direction of the outer ring channel (15) has a third angle with the first tangential direction, and the horizontal direction of the inner ring channel (18) has a fourth angle with the second tangential direction. The third angle, the fourth angle, and the angle between the first angle and the second angle have the same range, and the angle range is 20° to 30°.

7. The recirculation combustion chamber according to claim 6, characterized in that, The spacing width of each part in the outer ring channel (15) is the same, which is the first width gap; the airflow channel (16) has a second width gap at the junction with the outer ring channel (15); the airflow channel (16) has a third width gap at the central axis of the nozzle; and the airflow channel (16) has a fourth width gap at the junction with the inner ring channel (18). The width values ​​of the first width gap, the second width gap, the third width gap, and the fourth width gap are all within the same range, which is 15mm-25mm.

8. The recirculation combustion chamber according to claim 7, characterized in that, Along the flow direction of the cooling gas, the difference between two adjacent width gaps is ±5mm.

9. The recirculation combustion chamber according to claim 1, characterized in that, The outer casing (11) is provided with a sand discharge hole (19), which is connected to the sand and dust collection chamber (17) to discharge the sand and dust from the sand and dust collection chamber (17).

10. A gas turbine engine, characterized in that, Includes the recirculation combustion chamber as described in any one of claims 1-9.

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