Squirrel-cage evaporation pipe oil supply device and combustion chamber

Abstract

The invention relates to the technical field of engine design, in particular to a squirrel-cage evaporation pipe oil supply device and a combustion chamber. Comprising a nozzle with an oil inlet and an oil outlet; an evaporation pipe inlet is formed in one end of the evaporation pipe, the oil outlet of the nozzle is inserted into the evaporation pipe inlet, an end wall surface is arranged at the other end of the evaporation pipe, and a plurality of outlet grooves are formed in the circumferential surface of the evaporation pipe; and the plurality of turbulent flow pieces are arranged on the inner side wall of the evaporation pipe and are positioned between the oil outlet and the outlet groove. In the application, the compressor in the engine can feed high-temperature and high-pressure air into the inlet of the evaporating pipe, and the oil outlet is provided with a plurality of openings, so that fuel jet flow is not a single concentrated stream in the prior art, but is dispersed into a plurality of streams in advance, and the contact circumferential length of fuel and the pipe wall and the contact surface area of the fuel and the air are increased; a part of fuel oil is atomized and evaporated to form a mixture of oil mist.

Description

Technical Field

[0001] This invention relates to the field of engine design technology, specifically to a squirrel-cage type evaporator fuel supply device and a combustion chamber. Background Technology

[0002] As a thermo-mechanical conversion device, an aero-engine primarily converts the chemical energy of fuel into the internal energy of the gas within the combustion chamber. Fuel is supplied through an evaporator tube fuel supply system to the flame tube within the combustion chamber for combustion. Existing evaporator tube fuel supply systems use hollow tubes with smooth inner walls. The nozzles directly inject fuel axially at the inlet of the evaporator tube, and the fuel exits from the outlet, impacting the flame tube wall and mixing with the air inside for combustion. However, this method results in a relatively simple and incomplete mixing process, easily leading to localized overheating and potential damage to the combustion chamber. Summary of the Invention

[0003] In view of this, the present invention provides a squirrel-cage type evaporator fuel supply device and a combustion chamber to solve the problem of insufficient fuel and air mixing caused by existing evaporator fuel supply devices.

[0004] In a first aspect, the present invention provides a squirrel-cage type evaporator oil supply device, comprising: The nozzle has an oil inlet and an oil outlet; An evaporator tube has an evaporator tube inlet at one end, with the oil outlet of the nozzle inserted into the evaporator tube inlet. The other end has an end wall surface, and multiple outlet grooves are provided on the circumferential surface of the evaporator tube. Several baffles are installed on the inner wall of the evaporator tube and located between the oil outlet and the outlet groove. The nozzle has multiple openings at its oil outlet, which face the inner wall of the evaporator tube.

[0005] In this application, the compressor in the engine delivers high-temperature, high-pressure air into the evaporator inlet. The fuel outlet has multiple openings, preventing the fuel jet from becoming a single, concentrated stream as in existing technologies. Instead, it is pre-dispersed into multiple streams, increasing the circumferential contact length between the fuel and the pipe wall, as well as the contact surface area with the air. This atomizes and evaporates part of the fuel, forming an oil-air mixture. Multiple flow-deflecting elements placed between the nozzle and the outlet slot disrupt the continuous liquid film formed by the fuel on the inner wall of the evaporator, forcing the fuel flowing along the wall to detach from the inner wall multiple times. This results in secondary shearing and fragmentation by the high-speed airflow, improving the atomization fineness and evaporation rate of the fuel. The fully premixed oil-air mixture is no longer concentratedly injected from the axial outlet of the traditional evaporator, but rather dispersed and flows out laterally from multiple outlet slots on the circumferential surface. This increases the distribution area of ​​the oil-air mixture in the combustion chamber and the uniformity of mixing with the main combustion air, solving the problems of concentrated fuel distribution and localized overheating and hot spots in the flame tube caused by localized rich combustion at the outlet of the traditional evaporator. The fuel and air are thus thoroughly mixed.

[0006] In one alternative embodiment, the evaporator tube has at least one bend located between the oil outlet and the outlet groove.

[0007] In this application, the bend in the evaporator tube can form abrupt structural changes. When the oil and gas two-phase flow passes through this bend, the flow direction changes drastically, resulting in strong flow separation and vortex structures. This pre-stirring within the evaporator tube improves oil-gas mixing. Furthermore, it can further break up the oil droplets that have already been partially atomized by the turbulent components, forcing the droplets to collide more frequently and violently with the relatively high-temperature tube wall. This enhances the heat transfer process, promotes fuel evaporation, and achieves the goal of improving atomization evaporation efficiency and oil-gas mixing uniformity.

[0008] In one alternative embodiment, the outlet grooves are arranged axially spaced in a coaxial position.

[0009] In this application, the coaxial position allows multiple outlet slots to have the same flow conditions on the same cross-section of the evaporator tube, and the axial spacing ensures that the oil-gas mixture flowing out from different axial positions of the evaporator tube will not be concentrated on a single outlet plane, which can increase the axial coverage of the oil-gas mixture in the combustion chamber and avoid the local high concentration zone that may be formed due to all mixtures being sprayed out from one place at the same time.

[0010] In one alternative embodiment, the outlet groove is a straight groove, and in the circumferential direction, the sidewall of the outlet groove is perpendicular to the tangent of the evaporator tube.

[0011] In this application, the outlet groove is a straight groove, which is relatively simple to manufacture and has relatively low flow resistance. The oil-gas mixture can be ejected with high kinetic energy, enhancing its mixing ability in the combustion chamber. Its sidewall is perpendicular to the tangent of the evaporator tube, and the mixture is ejected from the groove opening along the radial direction of the evaporator tube, allowing the mixture to directly enter the main combustion zone of the flame tube head ring.

[0012] In one alternative embodiment, the outlet groove is a warped groove, and in the circumferential direction, the sidewall of the outlet groove forms an acute angle with the tangent of the evaporator tube.

[0013] In this application, the outlet groove is a warped groove, which means that the oil-gas mixture at the outlet of the evaporator pipe has a tangential velocity component. When the mixture is ejected from the groove, it is no longer a purely radial motion, but forms a rotational motion around the axis of the evaporator pipe. This allows a single evaporator pipe outlet to generate a swirling flow, promoting the entrainment and mixing of the ejected material with the surrounding air. This causes the mixture to be ejected in a centrifugal state, forming a hollow cone-shaped mist torch, which further improves the spatial distribution uniformity of the fuel. Moreover, due to the shearing effect, larger oil droplets that have not been completely evaporated and broken are finely processed.

[0014] In one optional embodiment, the end wall of the evaporator tube has a concave structure; Alternatively, the end wall of the evaporator tube may have an outward convex structure.

[0015] In this application, the end wall surface adopts a concave or convex structure, which can change the flow path of the oil-gas mixture at the outlet end, forcing the mixture to change direction after impacting the surface of the structure, and then flow out from the outlet groove on its periphery. After the mixture impacts the inner surface of the concave structure, it diffuses in all directions, forming an approximately hollow cone-shaped spray with a large angle. By using different curvatures, the size of the spray cone angle can be controlled, thereby adapting to the flow field requirements of different combustion chamber heads. After the mixture impacts the inner surface of the convex structure, the flow pattern is a "jellyfish" spray pattern. Both structures can actively shape the shape of the outlet flow field by using the end wall surface of the evaporator tube with different curvatures, thereby adjusting the distribution of the outlet mixture in the flame tube according to the requirements of the combustion chamber.

[0016] Secondly, the present invention also provides a combustion chamber, comprising: The casing has an annular structure, forming a casing cavity, and has a combustion chamber inlet; The flame tube is disposed inside the casing cavity, has an annular structure, and is connected to the casing; The aforementioned squirrel-cage type evaporator oil supply device consists of several units; The flame tube has a gas combustion hole on its side wall, which connects the inside of the flame tube and the casing cavity. The end of the flame tube away from the combustion chamber inlet has a combustion chamber outlet. The nozzle in the squirrel-cage evaporator oil supply device penetrates the casing. The evaporator tube penetrates the flame tube, and the end with the outlet groove is located inside the flame tube.

[0017] In this application, the evaporator tubes penetrate the flame tube, with one end having an outlet groove located inside the flame tube. Each evaporator tube can independently generate a highly atomized, fully evaporated, and radially dispersed fuel-air mixture, forming a premixed region with uniform fuel concentration distribution within the annular flame tube. Gas orifices on the sidewall of the flame tube provide air for combustion and mixing, ensuring rapid and uniform fuel-air mixing within the three-dimensional space of the annular combustion chamber. This avoids localized high temperatures caused by uneven mixing and reduces the risk of overheating in the inner combustion chamber and downstream turbine components. Simultaneously, uniform mixing creates conditions for achieving efficient lean combustion.

[0018] In one alternative implementation, the housing includes: The inner and outer rings of the casing form the combustion chamber inlet and the casing cavity that communicates with it.

[0019] In this application, the casing is specifically composed of an inner casing ring and an outer casing ring, forming an annular combustion chamber inlet and a casing cavity communicating with it, and aerodynamically connecting the flow channels of the compressor and turbine. The annular cavity formed by the inner and outer casing rings has the function of collecting and guiding air, and can deliver high-pressure, high-temperature air from the compressor to the circumference of the combustion chamber. Part of the air participates in fuel atomization and premixing through the evaporator pipe, while the other part enters the annular cavity between the casing and the flame tube, providing an air source for the cooling of the flame tube and combustion. This not only ensures a reasonable and efficient airflow organization, but its symmetrical annular force-bearing form also has good load-bearing characteristics, and can withstand the high-temperature and high-pressure loads during the operation of the combustion chamber.

[0020] In one alternative embodiment, the flame tube includes: The flame tube inner ring, the flame tube outer ring, and the flame tube head ring are connected to the inner and outer rings of the flame tube at one end near the inlet of the combustion chamber. The inner and outer rings of the flame tube form the combustion chamber outlet at the ends of the flame tubes that are furthest from the combustion chamber inlet. The inner ring of the flame tube is connected to the inner ring of the casing, and the outer ring of the flame tube is connected to the outer ring of the casing; The evaporation tube passes through the head ring of the flame tube, and one end with the outlet groove extends circumferentially along the head ring of the flame tube.

[0021] In this application, the flame tube head ring provides a mounting base for the evaporator tubes. The outlet end of the evaporator tube extends circumferentially along the flame tube head ring, and the injection direction of its lateral outlet groove is coordinated with the geometry of the annular flame tube. Tangentially or at a certain angle to the tangential, a swirling flow field can be formed within the annular combustion space, promoting the mixing of fuels injected from different evaporator tubes and facilitating combustion. The inner ring of the flame tube is connected to the inner ring of the casing, and the outer ring of the flame tube is connected to the outer ring of the casing, ensuring the relative position and pneumatic seal of the structure, allowing gas to enter from the combustion chamber inlet and combustion gas to exit from the combustion chamber outlet of the flame tube.

[0022] In one optional embodiment, the inner ring, outer ring, and head ring of the flame tube are provided with a plurality of cooling holes, and the cooling holes are oriented in the same direction as the end of the evaporator tube with the outlet groove.

[0023] In this application, the cooling holes provided on each ring of the flame tube have the same outflow direction as the outlet groove of the evaporator tube, which can form a coordinated and unified flow field in the combustion chamber. When the injection direction of the airflow from the cooling holes is consistent with the dominant injection direction (usually tangential) of the fuel mixture in the outlet groove of the evaporator tube, the momentum of the high-temperature gas ejected from the evaporator tube and the low-temperature air ejected from the cooling holes is superimposed, thereby strengthening the circulation or swirling flow inside the combustion chamber. In addition, the cooling air injected tangentially from the inner and outer rings of the flame tube also participates in the flow and reaction inside the combustion chamber. When it enters at an angle in the same direction as the main swirling flow, it can smoothly merge into the mainstream and use its kinetic energy to further shear and disperse the fuel spray ejected from the evaporator tube, promoting the final atomization of the fuel and the fuel-air mixture, and ensuring optimal uniformity before combustion. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 2 This is a cross-sectional schematic diagram of Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the inlet cross-section of the evaporator tube in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the evaporator tube outlet cross-section in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the end wall cross-section of Embodiment 1 of the present invention; Figure 6 This is a schematic diagram of the outlet channel structure in Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of the combustion chamber structure in Embodiment 2 of the present invention; Figure 8 This is a schematic diagram of the engine structure in Embodiment 2 of the present invention; Figure 9 This is a schematic diagram of the evaporator tube distribution in Embodiment 2 of the present invention; Figure 10 This is a schematic diagram of the cooling hole distribution in Embodiment 2 of the present invention.

[0026] Explanation of reference numerals in the attached figures: 1. Air intake; 12. Fan; 2. Air compressor; 3. Combustion chamber; 30. Casing; 301. Casing outer ring; 302. Casing inner ring; 31. Inlet diffuser; 32. Squirrel-cage evaporator oil supply device; 321. Evaporator tube; 3211. Evaporator tube inlet; 3212. Evaporator tube outlet; 32121. End wall; 32122. Outlet groove; 32123. Mixture spray direction; 3213. Baffle; 3214. Bend section; 322. Nozzle; 3221. Oil inlet; 3222. Oil outlet; 33. Flame tube; 331. Flame tube head ring; 3311. Head cooling hole; 3312. Head main combustion hole; 3313. Mixing hole; 332. Flame tube outer ring; 333. Flame tube inner ring; 3331. Inner ring cooling hole; 3332. Inner ring main combustion hole; 3a. Combustion chamber inlet; 4. Turbine; 4a. Combustion chamber outlet; 5. Tail nozzle; 6. Exhaust section. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] As a thermo-mechanical conversion device, aero-engines primarily convert the chemical energy of fuel into the internal energy of gas within the combustion chamber. To achieve ultra-high combustion efficiency, traditional combustion technologies typically employ centrifugal nozzles or swirling air atomizing nozzles as fuel injection devices. Centrifugal atomization ensures uniform fuel distribution and combustion within the combustion chamber, resulting in uniform airflow temperature and preventing localized overheating and turbine failure. With the development of low-emission technologies, evaporator nozzles or their derivatives, characterized by lean fuel low-temperature combustion, have gained increasing attention. These have evolved into premixed evaporator nozzles based on lean premixed and pre-evaporated fuel injection, grouped evaporator nozzles based on lean multi-point injection, and small-sized nozzles based on lean direct injection. In these technological approaches, fuel is premixed with inlet air within the evaporator tube and then injected into the combustion chamber as a mixture and a two-phase mixture for combustion. Because premixed fuel in the evaporator is more dispersed than directly injected fuel, the liquid fuel can quickly mix with the air after evaporation, achieving low stoichiometric combustion and thus reducing emissions. As the combustion chamber temperature rises, the demand for fuel flow also increases. A large amount of fuel injected into the evaporator is mainly ejected as a cylindrical two-phase mixture, making it difficult to achieve uniform distribution over a large area within the combustion chamber. This results in localized high fuel-air concentrations and low concentrations elsewhere, leading to locally high combustion temperatures, hot spots, and in severe cases, erosion of the combustion chamber itself and turbine components. To achieve a longer combustion chamber lifespan and better engine performance, it is necessary to improve the evaporator and combustion chamber to achieve uniform fuel mist distribution within the combustion chamber.

[0029] Existing implementation plan: Patent US20180128490 proposes a method of arranging multiple evaporator tubes in groups to reduce the fuel flow rate of a single evaporator tube, achieving a micro-flow mixing and injection effect. This reduces the difficulty of fuel-air mixing and the local equivalence ratio by expanding the injection range through multi-point injection within the combustion chamber. Patents CN114484501 and CN107178793 propose adding a swirl device at the evaporator tube outlet, both aimed at improving fuel atomization and evaporation within the evaporator tube. Simultaneously, they utilize the centrifugal force of the swirl to improve the mixing effect of the fuel-air mixture after entering the combustion chamber. Patent CN116136307 uses an evaporator tube outlet with an expanding profile, changing the original cylindrical outlet to an expanding multi-hole outlet, and adding internal fins to improve fuel atomization and evaporation. The expanded outlet profile increases the injection angle of the fuel-air mixture at the evaporator tube outlet, thereby improving the injection area of ​​the fuel-air mixture from the evaporator tube outlet into the combustion chamber and optimizing the distribution of the fuel-air mixture. Patent CN115468187 adds baffles inside the combustion chamber of the evaporator tube, which work in conjunction with the evaporator tube to promote the formation of vortices inside the combustion chamber. This utilizes the mixing effect of the vortices to actively mix the air-fuel mixture at the evaporator tube outlet, improving the air-fuel mixing effect and low stoichiometric combustion performance in the combustion chamber. Patent US20170356657 allows the evaporator tube outlet to directly impact the flame tube head ring, and designs the head ring with multiple corresponding recessed structures. Swirling devices are designed around these recesses to promote the swirling mixing and combustion effects of the air-fuel mixture at the evaporator tube outlet.

[0030] Existing technologies utilize grouped evaporator tube arrangements, swirl-inducing evaporator tube designs, and modifications such as changing the cylindrical cross-section of the evaporator tube outlet to an expanded cross-section to improve fuel atomization and evaporation within the evaporator tubes, and to some extent, improve the uniformity of fuel distribution in the combustion chamber. While combustion chamber structures with baffles can enhance air-fuel mixing, they also present some challenges, as follows: Patent US20180128490 uses a grouped evaporator tube, which is complex in structure and expensive, making it difficult to apply to the combustion chambers of small and medium-sized aero engines. Patents CN114484501 and CN107178793 significantly increase the complexity of the evaporator tube structure, and the fuel-air mixture is still ejected as a single jet, which may have limited effect on improving the uniformity of fuel-air distribution in the combustion chamber. Patent CN116136307 uses an expanding, multi-hole evaporator tube outlet structure, which is difficult to manufacture and prone to the problem of the multi-hole plate detaching from the evaporator tube expansion section body under hot conditions. Patent CN115468187 arranges a turbulence structure inside the combustion chamber, which has the problem of baffle erosion. Patent US20170356657 simultaneously arranges a swirler and a recess at the head of the flame tube, resulting in a complex structure and high cost.

[0031] It is known that during the use of existing evaporator pipe fuel supply devices and combustion chambers, fuel inside the pipes tends to adhere to the wall and form a film under high-speed airflow, resulting in poor fuel atomization, poor evaporation, and uneven fuel-air mixing. As the fuel is sprayed out from the evaporator pipe, the fuel distribution is concentrated and some fuel cannot be fully burned, leading to local overheating in the combustion chamber and causing failure of the combustion chamber and turbine.

[0032] This invention provides a squirrel-cage type evaporator tube fuel supply device and combustion chamber, which aims to prevent fuel from flowing along the wall of the tube over a large area, resulting in poor atomization and evaporation. It also enables secondary splashing, wall-detachment, and mixing of fuel with air within the evaporator tube, and improves the dispersion angle of the fuel at the outlet of the evaporator tube, so that the fuel at the outlet of the evaporator tube has a hollow cone-like dispersion effect, thereby improving the fuel-air mixing effect in the combustion chamber and ensuring efficient combustion and uniform temperature in the combustion chamber.

[0033] The following is combined Figures 1 to 10 The following describes embodiments of the present invention.

[0034] Example 1 like Figures 1 to 6 As shown, the present invention provides a squirrel-cage type evaporator tube fuel supply device, suitable for installation on the flame tube 33 of the combustion chamber 3, to supply fuel to the flame tube 33, comprising: The nozzle 322 has an oil inlet 3221 and an oil outlet 3222; the nozzle 322 can be a direct-fire nozzle 322.

[0035] The evaporator tube 321 is a cage-type tube with an evaporator tube inlet 3211 at one end. The oil outlet 3222 of the nozzle 322 is inserted into the evaporator tube inlet 3211. The other end is the evaporator tube outlet 3212 and is provided with an end wall surface 32121. Multiple outlet grooves 32122 are provided on the circumferential surface at the evaporator tube outlet 3212. The outlet grooves 32122 connect the inside of the evaporator tube 321 and the flame tube 33. The main function is to provide uniform, grouped, and well-atomized fuel into the flame tube 33, and to make part of the fuel evaporate into fuel vapor before entering the flame tube 33 in order to improve combustion efficiency.

[0036] In this application, the evaporator tube outlet 3212 adopts a "squirrel cage" structure. This structure employs a "closed end, side outflow" design, abandoning the traditional single-inlet / single-outlet or single-inlet / multiple-outlet design of evaporator tubes. By changing the outflow direction of the evaporator tube 321 and simultaneously altering the outlet's structural form, the oil-gas mixture is redirected by impacting the end wall 32121 at the evaporator tube outlet 3212, thereby enhancing airflow turbulence, improving fuel atomization, and promoting oil-gas mixing. Due to the side outlet design of the evaporator tube 321, the oil-gas mixture can enter the flame tube 33 from different directions within the tubular structure, avoiding the complex situation where a single jet of mixture from the traditional evaporator tube 321 needs to impact the end wall 32121 for remixing. It is important to note that during the interaction between the evaporator tube 321 and the flame tube 33, to prevent fuel combustion within the evaporator tube 321, the fuel ejected from the evaporator tube outlet 3212 is often relatively fuel-rich. If the fuel-rich mixture does not mix well with the air inside the flame tube 33, it will also affect the working efficiency of the combustion chamber 3. Traditionally, the combustion chamber 3 achieves further combustion by having the outlet mixture impact the inner wall of the flame tube 33 head and then disperse with the airflow inside the flame tube 33. However, because the evaporator tube 321 ejects fuel film, fuel mist, and fuel-air mixture simultaneously in the same direction, the initial fuel mist concentration is uneven, making it difficult for the fuel to truly disperse. This results in localized high temperatures during combustion, causing erosion and carbon buildup, which affects the long-term use of the combustion chamber 3. This application uses a squirrel-cage evaporator tube 321, and the oil mist mixture flows out from the side of the evaporator tube outlet 3212. The injection direction changes from a single normal direction to a surface injection, which greatly improves the degree of freedom of the secondary mixing of the outlet mixture and the airflow in the flame tube 33. The mixing effect is improved, and the working efficiency of the combustion chamber 3 and the uniformity of temperature distribution in the flame tube 33 are also improved, thereby improving the overall utilization efficiency of the squirrel-cage evaporator tube 321 and the combustion chamber 3.

[0037] A plurality of baffles 3213 are disposed on the inner wall of the evaporator tube 321, and located between the oil outlet 3222 and the outlet groove 32122. The baffles 3213 can be arranged in multiple ways along the axial direction of the evaporator tube 321 according to the fuel flow pattern. The baffles 3213 can be baffle rings, such as… Figure 2 , Figure 4 as well as Figure 5As shown, the turbulence ring is arranged against the inner wall of the evaporator tube 321. After passing through the turbulence ring, the fuel and airflow create a stepped turbulence effect, increasing the turbulence of the air flowing through the turbulence ring and causing the fuel film flowing through the turbulence ring to detach from the inner wall of the evaporator tube 321 and further contact the air for atomization and mixing. It should be added that due to the viscosity and surface tension of the fuel, after the fuel is injected through the outlet 3222, the fuel column contacts the inner wall of the evaporator tube 321, undergoing various processes such as wall-attached flow, splashing, merging, breaking up, and evaporation. Under high engine operating conditions, the fuel flow rate is large, and the fuel injected from the direct-injection nozzle 322 mainly flows against the wall. To fully recover heat, the evaporator tube 321 is generally arranged inside the flame tube 33 of the combustion chamber 3 and is heated by the flame. When the evaporator tube 321 is heated, the Reidenfrew phenomenon occurs during the fuel's wall-attached flow, making it difficult for the fuel to absorb heat from the side wall of the evaporator tube 321 for atomization and evaporation. By adding multiple turbulence rings, the fuel will "lift up" as the structure of the inner wall of the evaporator tube 321 changes when it flows along the wall, changing its original state of low heat absorption and difficulty in atomization and evaporation, thereby improving the atomization, evaporation and mixing effect of the fuel during the flow process in the evaporator tube 321.

[0038] In addition to the annular structure, the evaporator tube 321 also employs other structures that can achieve turbulence and fuel film separation, such as turbulence vanes, turbulence columns, or turbulence bands.

[0039] The nozzle 322 has multiple openings at its oil outlet 3222, which face the inner wall of the evaporator tube 321. Specifically, it may have two openings, angled towards the inner wall of the evaporator tube 321. The dispersion of oil mist at the oil outlet 3222 of the direct-fired nozzle 322 can improve the initial dispersion effect of fuel at different positions within the evaporator tube 321.

[0040] In this application, the compressor 2 in the engine delivers high-temperature, high-pressure air into the evaporator inlet 3211. The fuel outlet 3222 has multiple openings, allowing the fuel jet to be pre-dispersed into multiple streams instead of a single, concentrated stream as in the prior art. This increases the circumferential length of the contact between the fuel and the pipe wall, as well as the contact surface area with the air, atomizing and evaporating part of the fuel to form an oil-mist mixture. Multiple baffles 3213 positioned between the nozzle 322 and the outlet groove 32122 disrupt the continuous liquid film formed by the fuel on the inner wall of the evaporator 321, forcing the fuel flowing along the wall to repeatedly detach from the inner wall and be sheared and broken up by the high-speed airflow, thus improving the atomization fineness and evaporation rate of the fuel. The fully premixed fuel-air mixture is no longer concentratedly injected from the axial outlet of the traditional evaporator tube, but instead flows out laterally from multiple outlet slots 32122 on the circumferential surface. This increases the distribution area of ​​the fuel-air mixture in the combustion chamber 3 and the uniformity of mixing with the main combustion air, solving the problems of local overheating and hot spots in the flame tube 33 caused by concentrated fuel distribution and localized rich fuel combustion at the outlet 3212 of the traditional evaporator tube. The fuel and air are mixed thoroughly.

[0041] In one optional embodiment, the evaporator tube 321 has at least one bend 3214 located between the oil outlet 3222 and the outlet groove 32122. Specifically, there can be one bend 3214, with a bend angle ranging from 45° to 135°, specifically 90°. The evaporator tube 321 not only guides the airflow but also utilizes the bend structure to further enhance the turbulence and atomization effect of the airflow. The bend 3214 of the evaporator tube 321 adopts a sudden structural design, which, unlike traditional streamlined bends, maximizes the use of the abrupt change in the flow channel to increase the degree of flow turbulence within the tube, thereby creating a "pre-stirring" effect and improving oil-gas mixing.

[0042] In this application, the bend 3214 of the evaporator tube 321 can form abrupt structure. When the oil and gas two-phase flow passes through this bend 3214, the flow direction changes drastically, generating strong flow separation and vortex structure, which pre-stirs within the evaporator tube 321, improving oil-gas mixing. It can further break up the oil droplets that have been initially atomized under the action of the turbulence element 3213, forcing the droplets to collide more frequently and violently with the relatively high-temperature tube wall, thereby enhancing the heat transfer process, promoting fuel evaporation, and achieving the goal of improving atomization evaporation efficiency and oil-gas mixing uniformity.

[0043] In one optional embodiment, the outlet grooves 32122 are coaxially spaced. After the mixture impacts the end wall 32121, it turns to the side of the evaporator pipe 321 and is ejected from the outlet grooves 32122 on the side. Because the outlet grooves 32122 have abrupt changes in shape relative to the evaporator pipe 321 itself, they also produce a certain atomization and evaporation aid effect, thereby improving the fuel atomization, evaporation and mixing effect of the entire evaporator pipe 321.

[0044] In this application, the coaxial position allows multiple outlet slots 32122 to have the same flow conditions on the same cross section of the evaporator tube 321, and the axial spacing allows the oil-gas mixture flowing out from different axial positions of the evaporator tube 321 to not concentrate on a single outlet plane, which can increase the coverage of the oil-gas mixture in the combustion chamber 3 axially and avoid the local high concentration area that may be formed due to all mixtures being sprayed out from one place at the same time.

[0045] In one alternative implementation, such as Figure 6 As shown in the left figure, the outlet groove 32122 is a straight groove, and in the circumferential direction, the side wall of the outlet groove 32122 is perpendicular to the tangent of the evaporator tube 321.

[0046] In this application, the outlet groove 32122 is a straight groove, which is relatively simple to manufacture and has relatively low flow resistance. The oil-gas mixture can be ejected with higher kinetic energy, enhancing its mixing ability in the combustion chamber 3. Its sidewall is perpendicular to the tangent of the evaporator pipe 321, and the mixture is ejected from the groove opening along the radial direction of the evaporator pipe 321, allowing the mixture to directly enter the main combustion zone of the flame tube head ring 331.

[0047] In one alternative implementation, such as Figure 6 As shown in the right figure, the outlet groove 32122 is a warped groove, and in the circumferential direction, the angle between the side wall of the outlet groove 32122 and the tangent of the evaporation tube 321 is an acute angle. The cross-section of the outlet groove 32122 can gradually increase along the direction of mixture ejection, making the mixing of the ejected material with the air inside the flame tube 33 more uniform.

[0048] In addition to being designed as a traditional straight-through channel, the outlet channel 32122 can also be designed with other structures. Through specific design, a portion of the mixture can be sprayed directly from the outlet channel 32122, while another portion first adheres to the wall and then enters the channel tangentially before being sprayed outwards, achieving secondary turning and enhanced atomization and evaporation effects. The difference between a traditional grid straight-through channel and a warped channel lies in whether the mixture can be sprayed directly, or whether a certain proportion can be sprayed directly. By controlling this proportion, for example, by setting the angle between the sidewall of the outlet channel 32122 and the tangent of the evaporation tube 321 to a certain angle, the probability of the mixture turning and hitting the wall can be controlled, thereby maximizing the utilization of the inherent function of the evaporation tube 321 and achieving optimal atomization and evaporation effects while integrating structural complexity and cost. When the outlet channel 32122 adopts a warped structure, the outlet mixture also has a certain tangential rotation effect, causing the mixture to be sprayed out in a centrifugal state. Matching this with a suitable concave structure of the evaporation tube outlet 3212 achieves a spraying effect close to that of a swirling centrifugal nozzle 322.

[0049] In addition to straight or warped channels, outlet channels 32122 also employ other deformable and adjustable channel structures to distribute the concentration of oil mist mixture at different axial positions of the evaporator tube 321.

[0050] In this application, the outlet groove 32122 is a warped groove, which is the tangential velocity component of the oil-gas mixture at the evaporator tube outlet 3212. When the mixture is ejected from the groove, it is no longer a purely radial motion, but a rotational motion around the axis of the evaporator tube 321. This allows a single evaporator tube outlet 3212 to generate a swirling flow, promoting the entrainment and mixing of the ejected material with the surrounding air. This causes the mixture to be ejected in a centrifugal state, forming a hollow cone-shaped mist torch, which further improves the spatial distribution uniformity of the fuel. Moreover, due to the shearing action, larger oil droplets that have not been completely evaporated and broken are finely processed.

[0051] In one optional embodiment, the end wall 32121 of the evaporator tube 321 has a concave structure; Alternatively, the end wall 32121 of the evaporator tube 321 has an outward convex structure.

[0052] The evaporator tube outlet 3212 includes an end wall surface 32121 and an outlet groove 32122. The end wall surface 32121 has a concave or convex structure. Concave means that the end wall surface 32121 protrudes into the evaporator tube 321, while convex means that the end wall surface 32121 covers the outlet in a bowl shape. For example, when the end wall surface 32121 at the evaporator tube outlet 3212 has a concave structure, the mixture can be redirected when it hits the end face of the evaporator tube outlet 3212, and the concave design can also change the shape of the mixture when it is ejected from the outlet groove 32122. When the curvature of the concave structure at the evaporator outlet 3212 is small, the mixture tends to be ejected radially perpendicular to the axis of the evaporator outlet 3212, resulting in a large dispersion area and long distance. When the curvature of the concave structure at the evaporator outlet 3212 is large, or when it extends into the evaporator 321 in the form of multiple arcs, the mixture tends to be ejected tangentially from the outlet groove 32122 along the concave end wall 32121. Figure 5 As shown, the mixture is ejected in directions 32123, where, Figure 5 The left image shows the image with smaller curvature. Figure 5 The diagram shows a concave structure with a large curvature. With the evaporator outlet 3212 designed as a concave structure, the mixture ejected from the evaporator pipe 321 exhibits an intermittent conical injection pattern, similar to the fuel mist cone effect of the centrifugal nozzle 322. Furthermore, by designing different concave structures for the evaporator outlet 3212, the cone angle of the near-injection cone of the outlet mixture can be adjusted, thereby allowing for regulation of the distribution of the outlet mixture within the flame tube 33 according to the requirements of the combustion chamber 3. When the evaporator outlet 3212 has a convex structure, such as... Figure 4 As shown, the flow pattern of the outlet mixture resembles a "jellyfish," and the design can be adjusted similarly according to the requirements of the combustion chamber 3. Generally, the radius of curvature of the end wall 32121 of the evaporator tube 321 is 0.5 to 1.5 times the radius of the evaporator tube 321.

[0053] In this application, the end wall 32121 adopts a concave or convex structure, which can change the flow path of the oil-gas mixture at the outlet end, forcing the mixture to change direction after impacting the surface of the structure, and then flow out from the outlet groove 32122 on its periphery. After the mixture impacts the inner surface of the concave structure, it will spread outwards, forming an approximately hollow cone-shaped spray with a large angle. By using different curvatures, the size of the spray cone angle can be controlled, thereby adapting to the flow field requirements of different combustion chamber 3 head. After the mixture impacts the inner surface of the convex structure, the flow pattern is a "jellyfish" spray pattern. Both structures can actively shape the shape of the outlet flow field by using the end wall 32121 of the evaporator tube 321 with different curvatures, thereby adjusting the distribution state of the outlet mixture in the flame tube 33 according to the requirements of the combustion chamber 3.

[0054] In addition to using a spherical surface, the concave or convex structure of the end wall 32121 can also use a corrugated surface, a rough surface, etc.

[0055] Example 2 like Figures 7 to 10 As shown, the present invention also provides a combustion chamber, comprising: The casing 30 has an annular structure, forming a casing cavity, and has a combustion chamber inlet 3a; strictly speaking, the casing cavity is a cavity formed by the inner casing ring 302, the outer casing ring 301, the inner ring 333 of the flame tube, and the outer ring 332 of the flame tube.

[0056] The flame tube 33 is disposed inside the casing cavity, has an annular structure, and is connected to the casing 30; There are several of the above-mentioned squirrel-cage type evaporator oil supply devices 32; The flame tube 33 has a gas combustion hole on its side wall, which connects the inside of the flame tube 33 and the casing cavity. The end of the flame tube 33 away from the combustion chamber inlet 3a has a combustion chamber outlet 4a. The nozzle 322 in the squirrel cage evaporator oil supply device 32 penetrates the casing 30. The evaporator tube 321 penetrates the flame tube 33, and one end with the outlet groove 32122 is located inside the flame tube 33.

[0057] It should be noted that the combustion chamber 3 with the squirrel-cage type evaporator fuel supply device 32 can be used in common gas turbine engines, such as... Figure 8 The diagram illustrates the application of a combustion chamber 3 with a squirrel-cage evaporator fuel supply device 32 in a typical gas turbofan engine. This gas turbofan engine mainly consists of an intake duct 1, a fan 12, a compressor 2, a combustion chamber 3, a turbine 4, a tailpipe 5, and an exhaust section 6. The combustion chamber 3 is often annular in structure to fully utilize the engine space. In addition to the aforementioned evaporator 321, the combustion chamber 3 includes a combustion chamber inlet 3a, a combustion chamber outlet 4a, an inlet diffuser 31, a casing 30, and a flame tube 33. The combustion chamber inlet 3a is formed by an inner casing ring 302 and an outer casing ring 301.

[0058] In this application, the evaporator tube 321 penetrates the flame tube 33, and one end with the outlet groove 32122 (i.e., the end of the evaporator tube 321) is located inside the flame tube 33. Each evaporator tube 321 can independently generate a highly atomized, fully evaporated, and radially dispersed oil-gas mixture, forming a premixed region with uniform fuel concentration distribution within the annular flame tube 33. The combustion gas orifices on the sidewall of the flame tube 33 provide air for combustion and mixing, ensuring rapid and uniform oil-gas mixing within the three-dimensional space of the annular combustion chamber 3. This avoids localized high temperatures caused by uneven mixing and reduces the risk of overheating inside the combustion chamber 3 and downstream turbine components 4. Simultaneously, uniform mixing creates conditions for achieving efficient lean combustion.

[0059] In one alternative embodiment, the housing 30 includes: The inner ring 302 and the outer ring 301 of the casing form the combustion chamber inlet 3a and the casing cavity connected thereto.

[0060] In this application, the casing 30 is specifically composed of an inner casing ring 302 and an outer casing ring 301, forming an annular combustion chamber inlet 3a and a casing cavity communicating with it, and aerodynamically connecting the flow channels of the compressor 2 and the turbine 4. The annular cavity formed by the inner and outer rings of the casing 30 has the function of collecting and guiding air, and can deliver high-pressure, high-temperature air from the compressor 2 to the circumference of the combustion chamber 3. Part of the air participates in fuel atomization and premixing through the evaporator pipe 321, while the other part enters the annular cavity between the casing 30 and the flame tube 33, providing an air source for the cooling of the flame tube 33 and combustion. This not only ensures the rational and efficient airflow organization, but its symmetrical annular force-bearing form also has good load-bearing characteristics, and can withstand the high-temperature and high-pressure loads during the operation of the combustion chamber 3.

[0061] In one alternative embodiment, the flame tube 33 includes: The inner ring 333 of the flame tube, the outer ring 332 of the flame tube, and the head ring 331 of the flame tube are connected to the inner ring 333 and the outer ring 332 of the flame tube at one end near the combustion chamber inlet 3a. The inner ring 333 and the outer ring 332 of the flame tube form a combustion chamber outlet 4a at the ends away from the combustion chamber inlet 3a; The inner ring 333 of the flame tube is connected to the inner ring 302 of the casing, and the outer ring 332 of the flame tube is connected to the outer ring 301 of the casing. The evaporator tube 321 penetrates the flame tube head ring 331, and one end with the outlet groove 32122 extends circumferentially along the flame tube head ring 331. Multiple evaporator tubes 321 can be evenly distributed. In the combustion chamber 3, the combustion process is mainly completed within the annular flame tube 33. Multiple evaporator tubes 321 are discretely arranged on the flame tube head ring 331, inserted internally and fixed to the flame tube head ring 331 in a tangential injection manner. The oil-gas mixture generated within the cage-type evaporator tube 321 is ejected at high speed under the pressure difference between the inside and outside of the flame tube 33, dispersing the oil-gas mixture tangentially and radially along the annular flame tube 33, and is ignited by an igniter or an already burning flame, achieving uniform combustion. The flame tube head ring 331 can have a hemispherical cross-section (this embodiment is not limited to this), and the end of the evaporator tube 321 can be oriented radially along the flame tube head ring 331, with its axis perpendicular to the hemispherical bottom surface of the flame tube head ring 331.

[0062] The characteristics of the oil-gas mixture at the evaporator outlet 3212 include: fuel atomization particle size, liquid fuel concentration distribution, oil-gas mixing uniformity, and evaporation rate. Smaller atomization particle size, more uniform liquid fuel concentration distribution, better oil-gas mixing uniformity, and higher evaporation rate result in lower difficulty in secondary mixing, atomization, and combustion of fuel within the flame tube 33, which is more conducive to improving the working efficiency of the combustion chamber 3. The evaporator tube 321 is fixedly installed on the flame tube head ring 331, and the direct-injection nozzle 322 supplies fuel to the squirrel-cage evaporator tube 321 through the outer ring 301 of the casing. To effectively organize combustion and regulate the internal temperature distribution of the combustion chamber 3, multiple rows of large holes are designed on the outer ring 332 and inner ring 333 of the flame tube as combustion gas ports, including the head main combustion port 3312, the inner ring main combustion port 3332, and the mixing port 3313. The main combustion port 3312 is located closer to the combustion chamber inlet 3a than the mixing port 3313.

[0063] In this application, the flame tube head ring 331 provides a mounting base for the evaporator tube 321. The evaporator tube outlet 3212 extends circumferentially along the flame tube head ring 331, and the injection direction of its lateral outlet groove 32122 is coordinated with the geometry of the annular flame tube 33. Tangentially or at a certain angle to the tangent, a swirling flow field can be formed in the annular combustion space, which can promote the mixing of fuels injected from different evaporator tubes 321 and reduce combustion resistance. The inner ring 333 of the flame tube is connected to the inner ring 302 of the casing, and the outer ring 332 of the flame tube is connected to the outer ring 301 of the casing, which can ensure the relative position of the structure and pneumatic sealing, so that gas enters from the combustion chamber inlet 3a and combustion gas exits from the combustion chamber outlet 4a of the flame tube 33.

[0064] In one optional embodiment, the inner ring 333, outer ring 332, and head ring 331 of the flame tube are provided with a plurality of cooling holes, and the cooling holes are oriented in the same direction as the end of the evaporator tube 321 with the outlet groove 32122. Specifically, multiple rows of cooling holes, such as head cooling holes 3311 and inner ring cooling holes 3331, are designed on the head ring 331, outer ring 332, and inner ring 333 of the flame tube to reduce the wall temperature of the flame tube 33 and extend its service life.

[0065] Cooling holes arranged on the flame tube head ring 331, the inner ring 333, and the outer ring 332 are oriented in the same direction as the squirrel-cage evaporator tube 321, promoting internal circulation within the flame tube 33 and thus improving the uneven distribution of oil mist concentration in different squirrel-cage evaporator tubes 321. With the powerful atomization, evaporation, and mixing effects of the squirrel-cage evaporator tube 321, uniform combustion and lower emissions can be achieved in the combustion chamber 3.

[0066] In this application, the cooling holes provided on each ring of the flame tube 33 have the same outflow direction as the outlet groove 32122, which can form a coordinated and unified flow field in the combustion chamber 3. When the injection direction of the airflow from the cooling holes is consistent with the dominant injection direction (usually tangential) of the fuel mixture in the outlet groove 32122, the momentum of the high-temperature gas ejected from the evaporator pipe 321 and the low-temperature air ejected from the cooling holes is superimposed, thereby strengthening the circulation or swirling flow inside the combustion chamber 3. In addition, the cooling air injected tangentially from the inner ring 333 and the outer ring 332 of the flame tube also participates in the flow and reaction in the combustion chamber 3. When it enters at an angle in the same direction as the main swirling flow, it can smoothly merge into the mainstream and use its kinetic energy to further shear and disperse the fuel spray ejected from the evaporator pipe 321, promoting the final atomization of fuel and fuel-air mixing, and ensuring optimal uniformity before combustion.

[0067] This application employs multiple turbulence rings inside the evaporator tube 321 to improve its atomization and evaporation performance. The turbulence rings enhance the flow turbulence within the tube, promoting fuel atomization, evaporation, and fuel-air mixing.

[0068] The closed, side-flow structure of the evaporator tube outlet 3212 in this application can improve the uniformity of the oil mist mixture distribution within the flame tube 33. The side-flow of the evaporator tube 321 can effectively disperse the spray pattern of the mixture inside the tube into the flame tube 33.

[0069] The evaporator outlet 3212 of this application adopts a concave or convex structure, which can adjust its outlet flow state. The concave structure can make the oil mist mixture at the evaporator outlet 3212 spray out as a mist cone, while the convex structure can adjust the outlet mixture within a wider range of spray directions.

[0070] The outlet tank 32122 of this application adopts a grid or warped design. The grid design can achieve rapid mixing of the mixture through the nozzle 322 while maintaining good atomization and evaporation effect in the evaporation tube 321. It has a simple structure and low cost. The warped design can further improve the atomization, evaporation and mixing effect.

[0071] This application employs a tangentially injected evaporator pipe 321 and combustion chamber 3 design. The evaporator pipe 321 injects tangentially at the head of the flame tube 33, and the cooling airflow on the flame tube 33 also flows out in the same direction, which can promote circulation within the combustion chamber 3 and improve the fuel-air mixing and combustion effect.

[0072] The direct-injection nozzle 322 of the evaporator inlet 3211 of this application is designed to inject fuel in multiple streams. The multi-stream direct-injection nozzle 322 can effectively improve the initial dispersion of fuel in the evaporator 321, laying the foundation for further atomization, evaporation and mixing of fuel in the evaporator 321.

[0073] The evaporator tube 321 of this application adopts a multi-section bending design. The multi-section bending of the evaporator tube 321 utilizes the abrupt change in the profile of the evaporator tube 321 to cause the flow state of the mixture to change, thereby improving the atomization and evaporation effect.

[0074] Simulation results have demonstrated that the fuel is evenly distributed and well atomized after passing through the evaporator pipe 321 of this application. It also shows good mixing effect with the air in the pipe, other intake air in the combustion chamber 3, and the existing air in the combustion chamber 3, indicating high application prospects.

[0075] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A squirrel-cage type evaporator oil supply device, characterized in that, include: The nozzle (322) has an oil inlet (3221) and an oil outlet (3222). Evaporator tube (321), one end is evaporator tube inlet (3211), the oil outlet (3222) of the nozzle (322) is inserted into the evaporator tube inlet (3211), the other end is provided with end wall (32121), and multiple outlet grooves (32122) are provided on the circumferential surface of evaporator tube (321). Several baffles (3213) are provided on the inner wall of the evaporator tube (321) and located between the oil outlet (3222) and the outlet groove (32122); The nozzle (322) has multiple openings at its oil outlet (3222) and faces the inner wall of the evaporator tube (321).

2. The squirrel-cage type evaporator oil supply device according to claim 1, characterized in that, The evaporator tube (321) has at least one bent section (3214) located between the oil outlet (3222) and the outlet groove (32122).

3. The squirrel-cage type evaporator oil supply device according to claim 2, characterized in that, The outlet grooves (32122) are arranged axially at intervals on the same axis.

4. The squirrel-cage type evaporator oil supply device according to claim 2, characterized in that, The outlet groove (32122) is a straight groove, and in the circumferential direction, the side wall of the outlet groove (32122) is perpendicular to the tangent of the evaporator tube (321).

5. The squirrel-cage type evaporator oil supply device according to claim 2, characterized in that, The outlet groove (32122) is a warped groove, and in the circumferential direction, the side wall of the outlet groove (32122) forms an acute angle with the tangent of the evaporator tube (321).

6. The squirrel-cage type evaporator oil supply device according to claim 1, characterized in that, The end wall (32121) of the evaporator tube (321) has a concave structure; Alternatively, the end wall (32121) of the evaporator tube (321) has an outward convex structure.

7. A combustion chamber, characterized in that, include: The casing (30) has an annular structure, forming a casing cavity, and has a combustion chamber inlet (3a). The flame tube (33) is disposed inside the housing cavity, has an annular structure, and is connected to the housing (30); The squirrel-cage type evaporator oil supply device (32) as described in any one of claims 1 to 6 is a plurality of such devices; The flame tube (33) has a gas combustion hole on its side wall, which connects the inside of the flame tube (33) and the casing cavity. The end of the flame tube (33) away from the combustion chamber inlet (3a) has a combustion chamber outlet (4a). The nozzle (322) in the squirrel cage evaporator oil supply device (32) penetrates the casing (30). The evaporator (321) penetrates the flame tube (33) and has an outlet groove (32122) at one end located inside the flame tube (33).

8. The combustion chamber according to claim 7, characterized in that, The casing (30) includes: The inner ring (302) and outer ring (301) of the casing form the combustion chamber inlet (3a) and the casing cavity connected thereto.

9. The combustion chamber according to claim 8, characterized in that, The flame tube (33) includes: The inner ring (333), outer ring (332), and head ring (331) of the flame tube are connected to the inner ring (333) and outer ring (332) of the flame tube near the end of the combustion chamber inlet (3a). The inner ring (333) and outer ring (332) of the flame tube form a combustion chamber outlet (4a) at the ends away from the combustion chamber inlet (3a); The inner ring (333) of the flame tube is connected to the inner ring (302) of the casing, and the outer ring (332) of the flame tube is connected to the outer ring (301) of the casing; The evaporation tube (321) passes through the flame tube head ring (331) and has an outlet groove (32122) at one end extending circumferentially along the flame tube head ring (331).

10. The combustion chamber according to claim 9, characterized in that, The inner ring (333), outer ring (332), and head ring (331) of the flame tube are provided with a number of cooling holes, and the cooling holes are oriented in the same direction as the end of the evaporator tube (321) with the outlet groove (32122).

Images