Low pollution center body staged combustion chamber interstage cooling annulus configuration

Abstract

The application discloses a low-pollution center multi-stage combustion chamber inter-stage cooling ring cavity structure, which comprises a cooling ring cavity, the cooling ring cavity is arranged in a swirler, and the swirler is arranged in a low-pollution center multi-stage combustion chamber; an inter-stage cooling air inlet channel is arranged in the cooling ring cavity, an inter-stage ring gap inlet I is arranged at the input end of the inter-stage cooling air inlet channel, an H wall surface, an L wall surface and a P wall surface are arranged on one side of the cooling ring cavity, and the H wall surface, the L wall surface and the P wall surface all refer to a section of wall surface of a sleeve. The structure can make the next step and the main combustion stage swirler gas volume better mixed and combusted, make the main combustion stage combustion area oil-lean combustion more uniform, burn at an equivalence ratio close to an oil-lean extinction boundary, the main combustion area temperature is low, the residence time is short, the NOx emission can be kept at a very low level, and the backfire problem can be avoided as much as possible.

Description

Technical Field

[0001] This invention relates to the field of cooling ring cavity technology, and more specifically, to a low-pollution central staged combustion chamber interstage cooling ring cavity structure. Background Technology

[0002] Due to the dual requirements of low fuel consumption and low emissions, especially the increasingly stringent emission requirements for NOx emissions under the new emission standards, advanced civil aircraft engines need to adopt a more lean combustion mode at the head of the engine, with a large amount of air entering from the head of the combustor, reducing or eliminating the air intake through the large holes on the combustor wall.

[0003] When designing a cyclone separator, the primary pre-combustion stage is generally selected as shown in the appendix to the instruction manual. Figure 3 Instruction manual attached Figure 4 The structure shown is attached to the instruction manual. Figure 3 The circled area indicates the fuel injection point location. This structure is prone to carbon buildup at the fuel injector of the main combustion stage. Literature review shows that the sleeve expansion angle can control the size and shape of the pre-combustion stage recirculation zone, thereby controlling the interaction between the pre-combustion stage and the main combustion stage, and further controlling combustion chamber performance. However, as the sleeve expansion angle gradually increases, the area of ​​the sleeve's internal wall surface in direct contact with the high-temperature combustion gases will increase rapidly, and the corresponding area requiring cooling will also increase. Therefore, the instruction manual includes... Figure 3 Instruction manual attached Figure 4 Traditional structures in the Central Plains can lead to excessively high temperature gradients on the sleeve wall, which in severe cases may even burn out the hydrocyclone.

[0004] Therefore, we proposed a low-pollution central staged combustion chamber interstage cooling annular cavity structure to solve the above problems. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, embodiments of the present invention provide a low-pollution central staged combustion chamber interstage cooling annular cavity structure to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a low-pollution central staged combustion chamber interstage cooling ring cavity structure, including a cooling ring cavity, wherein the cooling ring cavity is disposed in a swirler, and the swirler is disposed in a low-pollution central staged combustion chamber;

[0007] The cooling ring cavity is provided with an interstage cooling air intake channel. The input end of the interstage cooling air intake channel is provided with an interstage annular slot inlet I. The cooling ring cavity is provided with H wall, L wall and P wall on one side, and H wall, L wall and P wall all refer to a section of the sleeve wall.

[0008] The H wall, L wall, and P wall are provided with A rows of holes, B rows of holes, C rows of holes, M rows of holes, and N rows of holes;

[0009] K line is arranged in the inter-stage cooling air inlet channel, D line and E line are arranged on one side of the inter-stage cooling air inlet channel, F line, G line and J line are arranged on one side of the E line, J line and F line are parallel to K line, and X line and G line are parallel to P wall surface;

[0010] The center of the fuel injection port of the main combustion stage is located at the center position of the P wall surface.

[0011] The structure can make the next step better mixed with the swirling air volume of the main combustion stage for combustion, make the lean combustion of the main combustion stage more uniform, burn at the equivalence ratio close to the lean extinction boundary, the main combustion zone temperature is low, the residence time is short, the NOx emission can be kept at a very low level, and the flashback problem can be avoided as much as possible.

[0012] In a preferred embodiment, H 内 refers to the inner wall surface of the H wall surface, H 外 refers to the outer wall surface of the H wall surface, L 内 refers to the inner wall surface of the L wall surface, L 外 refers to the outer wall surface of the L wall surface, P 内 refers to the inner wall surface of the P wall surface, P 外 refers to the outer wall surface of the P wall surface.

[0013] In a preferred embodiment, A row of holes, B row of holes, C row of holes, M row of holes and N row of holes all refer to the air outlet channels of the cooling ring cavity;

[0014] A row of holes, B row of holes and C row of holes are air outlet channels of sleeve expansion cooling air volume;

[0015] M row of holes and N row of holes are air outlet channels of inter-stage premixed gas volume.

[0016] In a preferred embodiment, M row of holes and N row of holes are arranged in cross, 54 holes in each row, and the hole diameter is 0.55mm.

[0017] In a preferred embodiment, A row of holes, B row of holes and C row of holes are arranged in cross, 90 holes in each row, and the hole diameter is 0.55mm.

[0018] In a preferred embodiment, the dashed line K line is the center axis of the inter-stage cooling air inlet channel, the height R of K line from the center axis of the swirler is 18.4624mm, and the height of K line from R line and T line on the upper and lower sides is consistent.

[0019] In a preferred embodiment, if the upper end of D line is connected with E line as X line, K line intersects with the midpoint of X line;

[0020] If the lower end of D line is extended, it will intersect with the left end point of H 外 . 外 ​

[0021] If the right end of F is extended, it will intersect with the lower end point of P 内 If the right end of J is extended, it will intersect with the upper end point of P 内 外 外

[0022] In a preferred embodiment, M rows of holes and N rows of holes are arranged on both sides of the center of the main combustion stage fuel injection port, the hole center axes of the M rows of holes and the N rows of holes are parallel to J line, and are located at 1 / 3 and 2 / 3 of P 内

[0023] In a preferred embodiment, the inter-stage cooling air enters from the inter-stage annular gap entrance I, and the hole center axes of the A rows, B rows and C rows of holes are perpendicular to the wall surface.

[0024] Technical effects and advantages of the present application:

[0025] 1. The center of the main combustion stage fuel injection port is located at the center of P wall surface, M rows of holes and N rows of holes are arranged on both sides of the center, the hole center axes of the M rows of holes and the N rows of holes are parallel to J line, and are located at 1 / 3 and 2 / 3 of P 内 This design solves the problem of carbon deposition at the fuel injection port, and since the main combustion stage fuel distribution accounts for a large proportion, the part of air volume plays a role in premixing and pre-evaporation, so that the oil-gas mixture of the main combustion stage fuel and the inter-stage premixing air volume is in a state of very uniform spatial distribution close to gaseous fuel before meeting the main combustion stage swirling air volume. According to literature, compared with liquid fuel combustion, the NOx emission level of gaseous fuel at the same flame temperature is significantly lower. Therefore, this design can make the next step of mixing and burning with the main combustion stage swirling air volume better, make the lean combustion of the main combustion stage combustion area more uniform, burn at an equivalence ratio close to the lean extinction boundary, the main combustion zone temperature is low, the residence time is short, the NOx emission will remain at a very low level, and the backfire problem is avoided as much as possible.

[0026] 2. The inter-stage cooling air is arranged circumferentially at the sleeve expansion angle position, which solves the high-temperature cooling problem caused by the gradual increase of the sleeve expansion angle, greatly reduces the temperature gradient of the sleeve wall surface, and avoids the ablation of the swirler sleeve by high temperature. For example Figure 1 ​​​​As shown, the inter-stage cooling gas enters from the inter-stage annular gap entrance I, the hole center axes of the holes in the A row, the B row and the C row are perpendicular to the wall surface, the holes in the A row are located at the center of the wall surface H, the holes in the B row and the C row are located at the 1 / 3 and 2 / 3 positions of the wall surface L respectively, so as to ensure sufficient cooling of the sleeve wall surface. The outlet of the inter-stage cooling gas entering from the inter-stage annular gap entrance I is located at the X line center position in the annular cavity, which is radially staggered with each row of holes, so that the introduced cooling gas impacts the H wall surface and the L wall surface, and is introduced from each row of holes to the main combustion zone in the annular cavity to form a wall-attached gas film, which cools each wall surface at the sleeve expansion angle through the divergent cooling mode, improves the cooling efficiency of the cooling gas, and fully excavates and utilizes the potential cooling capacity of the inter-stage cooling gas. Under the condition that the inter-stage cooling gas amount remains unchanged, the wall surface temperature of the central staged swirler is reduced, the service life of the part is prolonged, the reliability is enhanced, and the cost is reduced. Under the condition that the wall surface temperature of the swirler remains unchanged, the cooling gas used for inter-stage cooling can be distributed to other places to optimize the performance of the combustion chamber. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The inter-stage cooling annular cavity structure of the present application;

[0028] Figure 2 The inter-stage cooling annular cavity structure of the present application;

[0029] Figure 3 The central sectional view of the central staged swirler of the present application;

[0030] Figure 4 The side view of the central staged swirler of the present application;

[0031] Figure 5 The structure design drawing of the low-pollution central staged combustion chamber of the present application. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0033] REFERENCE Figures 1-5 The inter-stage cooling annular cavity structure of the low-pollution central staged combustion chamber is taken as an example, the working condition is selected as the cruise working condition, the annular combustion chamber is selected, the number of heads is 20, the research working condition, the structure limiting size, the overall gas amount distribution and the central staged swirler structure parameters of the single-head annular combustion chamber are shown in Tables 1, 2, 3 and 4.

[0034] Table 1 Research conditions of overall performance scheme

[0035]

[0036] Table 2 Structural limiting dimensions of overall performance scheme

[0037]

[0038] Table 3 Combustion chamber overall layout and air distribution

[0039]

[0040]

[0041] Table 4 Structural parameters of central staged swirler

[0042]

[0043] Calculate the combustion chamber inclination angle:

[0044]

[0045] Since 20% of the turbine cooling air does not participate in combustion, then

[0046] Available air quantity q m3.1 = 2.12625 x 80% = 1.701 kg / s,

[0047] Therefore, the proportion of each air quantity of the flame tube to the available air quantity is shown in Table 5:

[0048] Table 5 Proportion of each air quantity of the flame tube to the available air quantity

[0049]

[0050]

[0051] Calculate the effective area of the flame tube:

[0052]

[0053] In the formula, q m3.1 = 1.701 kg / s, ΔP L = pressure drop of the flame tube, which is the total pressure P t3.1 at the inlet of the flame tube minus the static pressure P4 at the outlet of the flame tube;

[0054] ΔP L = 1752990 Pa x 3.5% = 61354.65 Pa;

[0055]

[0056] Under design conditions, from NO x From an emissions perspective, it is generally desirable for the main combustion stage equivalence ratio to be in the lean combustion range of 0.6-0.8, while from a combustion stability perspective, it is desirable for the main combustion stage lean premixed combustion equivalence ratio to be greater than 0.5.

[0057] Therefore, the fuel distribution ratio of the main pre-combustion stage is designed to be 90% and 10%, and the equivalence ratio of the main combustion stage is:

[0058]

[0059] When designing a cyclone separator, the primary pre-combustion stage is generally selected as shown in the appendix to the instruction manual. Figure 3 Instruction manual attached Figure 4 The structure shown is attached to the instruction manual. Figure 3 The circled area indicates the fuel injection point location. This structure is prone to carbon buildup at the fuel injector of the main combustion stage. Literature review shows that the sleeve expansion angle can control the size and shape of the pre-combustion stage recirculation zone, thereby controlling the interaction between the pre-combustion stage and the main combustion stage, and further controlling combustion chamber performance. However, as the sleeve expansion angle gradually increases, the area of ​​the sleeve's internal wall surface in direct contact with the high-temperature combustion gases will increase rapidly, and the corresponding area requiring cooling will also increase. Therefore, the instruction manual includes... Figure 3 Instruction manual attached Figure 4 Traditional structures in the Central Plains can lead to excessively high temperature gradients on the sleeve wall, which in severe cases may even burn out the hydrocyclone.

[0060] Therefore, this patent addresses the shortcomings of the existing traditional central-stage cyclone separator structure by designing, for example... Figure 1 The main pre-combustion stage interstage cooling annular cavity structure is shown, and the interstage cooling gas volume accounts for 3.5% of the available air volume.

[0061] The designed airflow splits into two streams after entering the annular cavity:

[0062] One of the airflows is arranged crosswise around the fuel nozzle of the main combustion stage, accounting for 1% of the air volume, and is called the interstage premixed air volume;

[0063] Another stream of air is arranged at the expansion section on one side of the outer diameter of the second-stage cyclone, i.e. at the expansion angle of the sleeve, accounting for 2.5% of the total air volume, and is called the sleeve expansion cooling air volume.

[0064] When designing the interstage cooling annular cavity structure Figure 1 The initial value of the flow coefficient at the intermediate cooling inlet I is 0.7;

[0065] Therefore, 1786.2183 × 3.5% = 62.5176 mm 2 =0.7 × Ain;

[0066] The interstage cooling inlet area A is calculated.in = 89.3109 mm 2 ;

[0067] The center axis of the inter-stage cooling intake passage (i.e. Figure 2 K line) is measured at a height R = 18.4624 mm from the center axis of the cyclone;

[0068] Then, the inter-stage cooling intake entrance height h = 0.769904 mm is obtained from the inter-stage cooling intake entrance area calculation formula 2πRh = 89.3109 mm 2 .

[0069] After multiple iterations, the inter-stage cooling intake entrance flow coefficient C d = 0.6281, the inter-stage cooling intake entrance area A in = 99.5299 mm 2 , and the inter-stage cooling intake entrance height h = 0.857996 mm are finally determined.

[0070] The inter-stage premixed gas amount part is calculated as follows:

[0071] 1786.2183 x 1% = 17.8622 mm 2 = 0.7 x Ac, Ac = 25.5174 mm 2 ;

[0072] r = 0.275 mm, d = 0.55 mm, πr 2 = 0.2376 mm 2 ;

[0073] 25.5174 mm 2 ÷ 0.2376 mm 2 = 108;

[0074] M rows of holes and N rows of holes are arranged in cross arrangement, each row having 54 holes with a hole diameter of 0.55 mm.

[0075] The sleeve expansion cooling gas amount part is calculated as follows:

[0076] 1786.2183 x 2.5% = 44.6555 mm 2 = 0.70 x Ac, Ac = 63.7936 mm 2 ;

[0077] r = 0.275 mm, d = 0.55 mm, πr 2 = 0.2376 mm 2 ;

[0078] 63.7936 mm 2 ÷ 0.2376 mm 2 = 270;

[0079] A row of holes, B row of holes and C row of holes cross arrangement, each row of 90 holes, hole diameter is 0.55mm.

[0080] The main precombustion interstage cooling ring cavity structure described in the patent is specifically designed as follows, and the description is attached Figure 1 and the description is attached Figure 2 H wall, L wall and P wall all refer to a section of the sleeve wall, the wall thickness is 0.5mm, H 内 refers to the inner wall of H wall, H 外 refers to the outer wall of H wall, L 内 refers to the inner wall of L wall, L 外 refers to the outer wall of L wall, P 内 refers to the inner wall of P wall, P 外 refers to the outer wall of P wall;

[0081] A row of holes, B row of holes, C row of holes, M row of holes and N row of holes all refer to the gas outlet channel of the cooling ring cavity; wherein A row of holes, B row of holes and C row of holes are the gas outlet channels of the sleeve expansion cooling gas; M row of holes and N row of holes are the gas outlet channels of the interstage premixed gas, Figure 2 A row of holes, B row of holes, C row of holes, M row of holes and N row of holes in the drawing are the center axes of the corresponding gas outlet channels on the sketch section.

[0082] Figure 2 The dashed line K line is the center axis of the interstage cooling inlet channel, which is 18.4624mm above the center axis of the swirler, and the distance between K line and R line and T line on the upper and lower sides is consistent, which is 1 / 2 of the interstage cooling inlet gap height h = 0.857996mm calculated above.

[0083] D line and E line are on the same straight line, if the upper end of D line is connected with E line as X line, then K line intersects with the midpoint of X line;

[0084] If the lower end of D line is extended, it will intersect with the left end point of H 外 ; 外 ;

[0085] J line and F line are parallel to K line, and X line and G line are parallel to P;

[0086] If the right end of F line is extended, it will intersect with the lower end point of P 内 ; 内 If the right end of J line is extended, it will intersect with the upper end point of P 外 ; 外

[0087] The main precombustion interstage cooling ring cavity structure designed in the patent has the following advantages:​

[0088] First, the center of the main combustion stage fuel injector is located at the center of the P wall, with M rows and N rows of holes arranged intersecting on both sides. The central axes of the M and N rows of holes are parallel to the J line and are located at P. 内 At the 1 / 3 and 2 / 3 points, this design solves the problem of carbon buildup at the fuel injector. Furthermore, because the main combustion stage fuel accounts for a larger proportion, this portion of the gas acts as a premixing and pre-evaporating agent, ensuring that the fuel-air mixture between the main combustion stage fuel and the interstage premixed gas is in a spatially uniform state, close to that of gaseous fuel, before encountering the main combustion stage swirling gas. Literature review shows that compared to liquid fuel combustion, gaseous fuels have significantly lower NOx emissions at the same flame temperature. Therefore, this design allows for better mixing and combustion with the main combustion stage swirling gas, resulting in more uniform lean combustion in the main combustion stage. Combustion at an equivalence ratio close to the lean quenching boundary, with low temperatures and short residence times in the main combustion zone, keeps NOx emissions at very low levels while minimizing the risk of backfire.

[0089] Secondly, the interstage cooling gas flow is arranged circumferentially at the expansion angle of the sleeve. This design solves the high-temperature cooling problem caused by the gradual increase in the expansion angle of the sleeve, greatly reducing the temperature gradient on the sleeve wall and preventing the hydrocyclone sleeve from being burned by high temperature. Figure 1 As shown, the interstage cooling gas enters through the interstage annular inlet I. The central axes of the holes in rows A, B, and C are all perpendicular to their respective wall surfaces. Row A holes are located at the center of wall surface H, while rows B and C holes are located at 1 / 3 and 2 / 3 of the length of wall surface L, respectively, to ensure sufficient cooling of the sleeve wall. Furthermore, the outlet of the interstage cooling gas entering through the interstage annular inlet I is located at the X-ray center within the annular cavity, radially offset from each row of holes. This allows the introduced cooling gas to impact and cool the walls H and L, and then be drawn out from each row of holes into the main combustion zone within the annular cavity, forming a wall-adhering gas film. This film cools the walls at the sleeve expansion angle through divergent cooling, improving the cooling efficiency of the cooling gas and fully utilizing its potential cooling capacity. While maintaining a constant interstage cooling gas volume, this reduces the wall temperature of the central stage cyclone separator, extends the service life of components, enhances reliability, and reduces costs. While keeping the cyclone wall temperature constant, the amount of cooling gas used for interstage cooling can be reduced and distributed elsewhere to optimize combustion chamber performance.

[0090] The designed interstage cooling annular cavity structure of the central staged cyclone separator was applied to the designed low-emission central staged combustion chamber, such as... Figure 5 As shown.

[0091] Before the design of the low pollution center staged combustion chamber, five kinds of research conditions were given, and the specific parameters are shown in Table 6. The cruise condition was selected for the design of the baseline combustion chamber. Under different conditions, the NOx emission results of the low pollution center staged combustion chamber with inter-stage cooling ring cavity structure and traditional non-inter-stage cooling ring cavity structure are shown in Table 7. Through comparison, it can be seen that, except for the take-off condition, the NOx emissions of the two are similar, and under the remaining four conditions, the NOx emissions of the low pollution center staged combustion chamber with inter-stage cooling ring cavity structure are significantly lower than those of the traditional non-inter-stage cooling ring cavity structure.

[0092] Table 6 Five kinds of research conditions of the low pollution center staged combustion chamber

[0093]

[0094]

[0095] Table 7 Comparison of NOx emission results of low pollution center staged combustion chamber with and without ring cavity structure under different conditions

[0096]

[0097]

[0098] The ppm value calculation formula of NOx emission:

[0099]

[0100] In the formula, molef-NOx is the mole fraction of nitrogen oxides, and molef-H2O is the mole fraction of gaseous water.

[0101] Post-processing of NOx emission:

[0102]

[0103] In the formula, EI-NOx is the emission index of NOx, with the unit of g / kg fuel, W 31c is the available air quantity into the flame tube, a NO is the mass fraction of NO at the outlet of the flame tube, W f is the fuel flow, M NO are the molar mass of NO2 and NO respectively.

Claims

1. A low-pollution, center-habited, staged combustion, annular cavity cooling chamber structure, characterized by; The low pollution center classification combustion chamber comprises a cooling ring cavity, and the cooling ring cavity is arranged in a cyclone, and the cyclone is arranged in the low pollution center classification combustion chamber; An inter-stage cooling air inlet channel is arranged in the cooling ring cavity, an inter-stage ring gap inlet I is arranged at an input end of the inter-stage cooling air inlet channel, H, L and P wall surfaces are arranged on one side of the cooling ring cavity, and the H, L and P wall surfaces all refer to a section of wall surface of a sleeve; A row of holes is arranged on the H wall surface, B and C rows of holes are arranged on the L wall surface, and M and N rows of holes are arranged on the P wall surface; K lines are arranged in the inter-stage cooling air inlet channel, D and E lines are arranged on one side of the inter-stage cooling air inlet channel, F, G and J lines are arranged on one side of the E line, the J and F lines are parallel to the K lines, and the X and G lines are parallel to the P wall surface; A center of a main combustion stage fuel injection port is located at a center position of the P wall surface; The M and N rows of holes are arranged on both sides of the center of the main combustion stage fuel injection port in a cross manner, the hole center axes of the M and N rows of holes are parallel to the J line, and the M and N rows of holes are located at 1 / 3 and 2 / 3 of the inner side of the P wall surface, respectively.

2. The low-pollution, center-fired, staged combustion, inter-stage cooling, annular cavity structure of claim 1, wherein: The A, B, C, M and N rows of holes all refer to air outlet holes of the cooling ring cavity; The A, B and C rows of holes are air outlet holes of sleeve expansion cooling air volume; The M and N rows of holes are air outlet holes of inter-stage premixed air volume.

3. The low contamination, center-stage, staged combustion, inter-stage cooling, annulus cavity structure as described in claim 1, wherein: The M and N rows of holes are arranged in a cross manner, each row has 54 holes, and the hole diameter is 0.55 mm.

4. The low contamination, center-stage, staged combustion, inter-stage cooling, annulus cavity structure as described in claim 1, wherein: The A, B and C rows of holes are arranged in a cross manner, each row has 90 holes, and the hole diameter is 0.55 mm.

5. The low contamination, center-stage, staged combustion, inter-stage cooling, annulus cavity structure as described in claim 1, wherein: The dotted K line is a center axis of the inter-stage cooling air inlet channel, the K line is 18.4624 mm away from a center axis of the cyclone, and the K line has the same height as the R and T lines on the upper and lower sides.

6. The low contamination, center-stage, staged combustion, inter-stage cooling, annulus cavity structure as described in claim 1, wherein: Inter-stage cooling air volume enters from the inter-stage ring gap inlet I, and the hole center axes of the A, B and C rows of holes are perpendicular to the wall surfaces.

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