Fuel mixer

Abstract

A mixer for providing a fuel-air mixture for a combustor of an engine. The mixer can include a fuel stream and an air stream into an internal passage of the mixer. The air stream can be composed of three independent air streams. A first air stream can be parallel to a central axis of the mixer for pulling fuel into the internal passage. A second air stream can be angled relative to the central axis of the mixer and a third air stream can be tangential to the mixer body. The second and third air streams can push the fuel stream toward the internal passage and away from a boundary layer flow.

Description

Technical Field

[0001] This disclosure relates to a fuel mixer for a gas turbine engine. In particular, this disclosure relates to a fuel mixer configured to mix hydrogen fuel. Background Technology

[0002] Current mixers used in natural gas-powered turbine engines mix fuel with air to produce a fuel-air mixture for the engine's combustor. Conventional mixers combine inlet air and inlet fuel to create a fuel-air mixture. The inlet air can be introduced into the combustor without creating swirl. Summary of the Invention

[0003] According to one embodiment, a mixer is configured to provide a fuel-air mixture to a combustor of an engine. The mixer includes: a mixer body having an internal channel having a central axis; a fuel flow parallel to the central axis; a first air flow parallel to the central axis and the fuel flow; a second air flow inclined relative to the first air flow and the fuel flow; and a third air flow tangential to the mixer body. The first air flow is configured to pull the fuel flow along the central axis through the internal channel. The second air flow is configured as a forward swirling jet to prevent low-speed flow on a conical surface within the mixer body. The third air flow is configured to prevent the fuel flow from approaching the inner wall of the mixer body.

[0004] According to one embodiment, a mixer is configured to provide a fuel-air mixture to a combustor of an engine. The mixer includes: a mixer body having an outer surface, an internal passage, and a central axis; a fuel inlet positioned parallel to the central axis and configured to introduce a fuel flow into the internal passage of the mixer body; a central air jet positioned parallel to the central axis; a first set of openings inclined relative to the central axis; and a second set of openings having an inlet surface tangential to the mixer body. The central air jet, the first set of openings, and the second set of openings are each configured to introduce an air flow into the internal passage of the mixer body. The first set of openings and the second set of openings are configured to prevent the fuel flow from approaching a boundary layer flow near the inner surface of the mixer body. The fuel flow comprises H2 fuel in the range of 0% to 100%.

[0005] According to one embodiment, a mixer array includes one or more mixers according to any embodiment disclosed herein.

[0006] Additional features, advantages, and embodiments of this disclosure will be set forth or apparent from consideration of the following detailed description, drawings, and claims. Furthermore, it should be understood that the foregoing summary and the following detailed description of this disclosure are exemplary and intended to provide further explanation, without limiting the scope of the claimed disclosure. Attached Figure Description

[0007] The foregoing and other features and advantages will become apparent from the following more specific description of various exemplary embodiments, as illustrated in the accompanying drawings, wherein similar reference numerals generally denote the same, functionally similar and / or structurally similar elements.

[0008] Figure 1 A schematic cross-sectional view of a conventional mixer according to an embodiment of the present disclosure is shown.

[0009] Figure 2 A schematic perspective view of a mixer array according to an embodiment of the present disclosure is shown.

[0010] Figure 3A A schematic perspective view of a mixer according to an embodiment of the present disclosure is shown.

[0011] Figure 3B An embodiment according to this disclosure is shown. Figure 3A The mixer along Figure 3A A schematic diagram of the section line AA in the diagram.

[0012] Figure 3C An embodiment according to this disclosure is shown. Figure 3A The mixer along Figure 3A A schematic diagram showing the section line BB in the diagram.

[0013] Figure 3D An embodiment according to this disclosure is shown. Figure 3A The mixer along Figure 3A A schematic diagram of the section line CC in the diagram.

[0014] Figure 4 A schematic perspective view of a mixer according to an embodiment of the present disclosure is shown.

[0015] Figure 5 The embodiments of the present disclosure are shown along a path similar to... Figure 3A A schematic cross-sectional view of the mixer taken from the section line of BB.

[0016] Figure 6 The embodiments of the present disclosure are shown along similar lines. Figure 3A A schematic cross-sectional view of the mixer taken by the CC section line. Detailed Implementation

[0017] Various embodiments of the mixer are discussed in detail below. Although specific embodiments are discussed, this is for illustrative purposes only. Those skilled in the art will recognize that other components and constructions can be used without departing from the spirit and scope of this disclosure.

[0018] Current mixers have low-speed pockets on the walls of the mixer components, and the fuel-air mixture in these pockets can cause backfire / flame retention within the mixer, potentially leading to high temperatures that could damage the mixer and / or combustor structure. Therefore, conventional mixers are not well-suited for hydrogen and hydrogen fuel mixtures due to the increased risk of flame retention and high temperatures on the mixer components. A mixer is needed that can safely deliver hydrogen fuel and air to the engine's combustor at any percentage.

[0019] The mixer disclosed herein can allow fuel to be injected from a central point (e.g., along a central axis extending longitudinally through the center point of the mixer) or at a radial offset distance relative to the centerline of the mixer tube. The mixer may include three air streams injectable into the mixer tube. A central air stream can be injected along a channel parallel to the fuel stream. A first air stream can be injected through a rearward D-shaped forward swirling injection orifice. A second air stream can be introduced through a tangentially circular or shaped air nozzle closer to the outer diameter of the mixer. The first air stream can generate high speeds on a conical surface within the mixer tube. The second air stream can generate high near-wall velocities and can prevent fuel from approaching the walls and boundary layer flow. The mixer tube can produce a desired fuel / air distribution that can reduce flame hold-up, reduce NOx and CO emissions, and allow combustion of different mixtures of hydrogen (H2) fuel.

[0020] The mixer disclosed herein avoids low-speed cavitation and provides a uniform mixture of fuel and air. Compared to prior art mixers, the mixer can be arranged such that the premixing length and residence time of the mixture within the mixer are shorter. The mixer disclosed herein can provide enhanced mixing while keeping the fuel, and therefore the fuel-air mixture, away from the walls and boundary layer. The mixer disclosed herein allows combustion of any percentage of H2 fuel, including high percentage or 100% H2 fuel.

[0021] refer to Figure 1The figure shows a cross-sectional view of a conventional mixer 10. The mixer 10 may include an outer impeller 12 and an inner impeller 14. The outer impeller 12 may include one or more openings 16. Fuel can be injected or introduced through one or more openings 16. The inner impeller 14 may include an opening 18. A swirling airflow can be injected or introduced through the opening 18. The swirling airflow from the inner impeller 14 may be separated on the outer surface of the central body 20. As shown, the cross-section of the passage of the mixer 10 may be annular. This arrangement of the mixer 10 is not suitable for hydrogen (H2) fuel because it results in a recirculation region on the outer surface of the central body 20, which may increase the flame retention risk associated with H2 fuel. The length of the mixer 10 may result in a residence time of the fuel-air mixture within the mixer 10 that could lead to a high flame retention risk. The mixer 10 may result in a low-speed zone near the impellers. Arrangements such as the mixer 10 may allow for the mixing of a smaller volume of H2 fuel in the fuel mixture.

[0022] refer to Figure 2 The diagram shows a schematic perspective view of a mixer array 100. The mixer array 100 may include one or more mixers 102. The mixer array 100 may be divided into one or more zones. For example, in... Figure 2 In this configuration, the mixer array 100 can be divided into multiple zones, namely zone A, zone B, and zone C. One or more mixers 102 disposed in zones A, B, and C can all have the same structure, or they can all have different structures, or they can include some mixers with the same structure and some mixers with different structures. The mixer array 100 can be located on a support member 104 connected to the burner liner 106.

[0023] refer to Figures 3A-3D A schematic diagram of mixer 200 is shown. (Reference) Figure 3A The diagram shows a partial perspective view of mixer 200. Mixer 200 may include a first set of openings 202. Each opening 202 may be D-shaped. That is, opening 202 may have a generally curved surface 202a and a generally flat surface 202b, such that opening 202 is represented as "D" in a plan view. The flat surface 202b may be upstream of opening 202 to allow flow to be trapped or guided along the outer surface of mixer 200 and into opening 202. The entire cross-section of opening 202 may present a D-shape. D-shaped openings 202 can introduce air into a forward swirling jet, which can prevent the conical surface 216 ( Figure 3D The low-speed flow on the conical surface. Other shapes of openings 202 can be envisioned, as long as the shape allows air to be introduced into the forward swirling jet to prevent low-speed flow on the conical surface. The first set of openings 202 can allow the first airflow A (such as...) Figure 3D (As shown) is introduced into mixer 200.

[0024] Continue to refer to Figure 3A The mixer 200 may include a second set of openings 204. The openings 204 may extend through the body 210 of the mixer 200. Each opening 204 may be a tangential opening. That is, the opening 204 may have a surface 205 tangential to the mixer body. Figure 3D The cross-section of opening 204 can be circular or it can be an air nozzle of other shapes. (Brief reference) Figure 3D Compared to opening 202 (which allows air to be introduced closer to the center of the internal passage 220), opening 204 allows air to be introduced closer to the wall 214 of the internal passage 220 of the mixer 200. The second set of openings 204 allows air to be introduced to generate a high near-wall velocity that prevents fuel flow from approaching the inner wall 214. That is, the airflow through opening 204 can form an air boundary layer along the inner wall 214. The airflow through opening 202 can be a high-speed airflow. The first set of openings 202 allows a first airflow A and the second set of openings 204 allows a second airflow B to be introduced into the mixer 200.

[0025] refer to Figure 3B and 3C , showed Figure 3A A cross-sectional view of the mixer 200. Specifically, Figure 3B It shows along Figure 3A The view of the first set of openings 202, taken by section line AA, and Figure 3C It shows along Figure 3A The figure shows a view of the second set of openings 204, taken by section line BB. As shown, six openings 202 and six openings 204 are arranged around the circumference of the mixer 200. The number of openings 202 and 204 can be increased or decreased based on desired flow characteristics and fuel-air mixing. Figure 3B and 3C One or more fuel inlets 206 are also visible. The fuel inlets 206 may be circumferentially positioned around the central air nozzle 208. Depending on the location and application of the mixer 200, the fuel inlets 206 may be offset from the central axis 201. Figure 3D As mentioned, the first airflow A can flow through opening 202 and the second airflow B can flow through opening 204.

[0026] refer to Figure 3DThe diagram shows a cross-sectional view of mixer 200. Mixer 200 may include a mixer body 210 having an outer surface 212 and an inner wall 214. A first set of openings 202 and a second set of openings 204 may extend from the outer surface 212 through the body 210 to the inner wall 214. Body 210 may include a tapered surface 216. As mentioned, body 210 may include one or more fuel inlets 206 having fuel passages 218 for delivering fuel flow C to the internal passage 220 of mixer 200. Body 210 may include a central air nozzle 208 having a passage 222 for delivering a central air flow D to the internal passage 220. Air flow D may draw fuel through passage 222 of mixer 200. Air flow A may impinge on tapered surface 216 to push fuel toward the core (e.g., toward central axis 201). Due to the inclination of the air flows relative to passage 222, air flows A and B may introduce swirl. The tilting of airflows A and B is intended to introduce swirls into the mixer.

[0027] Continue to refer to Figure 3D Flows A and B can be introduced at an angle, causing them to push fuel flow C into channel 220 and away from inner wall 214. This allows the fuel-air mixture to move away from the boundary layer. Flow A achieves this by impacting conical surface 216 to push fuel toward the core. Flow B achieves this by remaining near and / or adhering to inner wall 214 to generate high speed in the boundary layer, preventing fuel flow from migrating to inner wall 214. The location, size, and angle of openings 202, 204, 206, and 208 can be selected based on the desired fuel / air distribution and desired flow at outlet 224 of mixer 200.

[0028] refer to Figure 4 The image shows a partial perspective view of mixer 300. Mixer 300 can be... Figure 1 The mixer 102 is provided in the mixer array 100. The mixer 300 may include a first set of openings 302. The first set of openings 302 may be the same as openings 202 and may introduce flow into the interior of the mixer 300 in the same manner. The mixer 300 may include a second set of openings 304. Openings 304 may be the same as openings 204 and may introduce flow into the interior of the mixer 300 in the same manner.

[0029] Continue to refer to Figure 4The mixer 300 may include one or more openings 326. The openings 326 may extend through the body of the mixer 300 in the same manner as the openings 302. The diameter of each opening 326 may be larger than the diameter of a single opening 304. By presenting openings 304 with diameters smaller than those of the openings 326, circumferential staging of the air can occur. That is, flows with higher and lower velocities and other different flow characteristics can be patterned around the circumference of the mixer 300. This can allow for the formation of air at the mixer outlet (e.g., Figure 3D Different fuel distribution at (224) can lead to variations in heat release and contribute to desired flow dynamics. Although shown as a single opening 326, multiple openings 326 can be presented in an alternating pattern with opening 304. In some examples, openings 326 and 304 can be presented in any pattern around the circumference of mixer 300 (e.g., two openings 326, one opening 304, repeating, or vice versa, etc.). Any pattern of openings 304 and 326 can be presented based on the desired flow at the outlet of mixer 300.

[0030] refer to Figure 5 The diagram shows a cross-sectional view of mixer 400. Mixer 400 can be... Figure 1 The mixer 102 is provided in the mixer array 100. The mixer 400 may be the same as or similar to the mixer 200. For example, the mixer 400 may include a first set of openings 402. The first set of openings 402 may be the same as openings 202 and may introduce flow into the interior of the mixer 400 in the same manner. The mixer 400 may include a second set of openings 404. Openings 404 may be the same as openings 204 and may introduce flow into the interior of the mixer 400 in the same manner. The mixer 400 may include one or more fuel inlets 406. Fuel inlets 406 may be the same as fuel inlets 206 and may introduce fuel flow into the interior of the mixer 400 in the same manner. The mixer 400 may include a central air opening 408 that may be the same as the central air nozzle 208.

[0031] Continue to refer to Figure 5 The central air opening 408 may include a stationary impeller 428. The stationary impeller 428 may include one or more impeller components 430. The stationary impeller 428 can operate as a central axial vortex. The stationary impeller 428 can therefore introduce airflow D in a swirling manner. Figure 3D (As air flows over the blade assembly 430 of the stationary blade 428). The stationary blade 428 can introduce low swirl into the airflow D to improve the radial diffusion of the fuel / air mixture.

[0032] refer to Figure 6The diagram shows a cross-sectional view of mixer 500. Mixer 500 can be... Figure 1 The mixer 102 is provided in the mixer array 100. The mixer 500 may include a first set of openings 502. The first set of openings 502 may be the same as opening 202 and may introduce flow A into the interior of the mixer 500 in the same manner. The mixer 500 may include a second set of openings 504. Openings 504 may be the same as opening 204 and may introduce flow B into the interior of the mixer 500 in the same manner.

[0033] Continue to refer to Figure 6 Fuel inlet 506 can be a central fuel inlet 506 (compared to a radially positioned fuel inlet 206). Fuel inlet 506 can introduce fuel flow C along the central axis 501 of mixer 500. Central air nozzle 508 can be positioned radially around and parallel to central fuel inlet 506. Therefore, air flow can be introduced parallel to fuel flow C. Figure 6 Fuel is injected from the center or at a radial offset distance relative to the mixer's central axis 501. Different pipes (e.g., different mixers in array 100) may have different offset directions to create variations in heat release at the outlet of the mixer array. Fuel inlet 506 may be a single orifice or multiple orifices.

[0034] The mixers described herein (e.g., mixers 200, 300, 400, and 500) can be Figure 1 The mixer 102 is provided in the mixer array 100. As mentioned, Figure 1Some or all of the mixers 102 in the mixer array 100 can be any mixer described herein. For example, region A may include a first mixer type (e.g., any of mixers 200, 300, 400, and 500), region B may include a second mixer type, and region C may include a third mixer type. Each of the first, second, and third mixer types can be the same or different. In some examples, region A may be the same as region B but different from region C. In some examples, region A may be different from both regions B and C. In some examples, the mixers within a single region may be different. In some examples, region A may have different mixer types within the mixer region itself. That is, for example, region A may include mixer 200 and mixer 300. Any combination of mixers can appear in the array. It should be understood that the specific mixer type of a particular mixer 102 in array 100 can be selected based on the desired operation and flow characteristics expected at that location. Therefore, each individual mixer 102 can be selected individually. This could result in all mixers 102 being different, all mixers 102 being the same, or any combination of mixers being presented in array 100. The mixers presented in each zone can be selected and controlled independently and separately.

[0035] The mixer described herein may include a third set of openings for introducing air into a central channel. Three or more sets of openings are conceivable. The third set of openings may be positioned axially further away from the fuel inlet. The third set of openings may include separate channels and openings. The third set of openings may include channels branching from the channels of the second set of openings and extending to a third outlet.

[0036] In a mixer, the number of openings can be based on the desired amount of airflow to be mixed into the fuel. The number of openings, the number of openings within each opening, the size of the openings, the location of the openings, the angle of the openings, or any combination thereof can depend on the amount of air available to the system and the desired fuel-air mixture at the mixer output.

[0037] As described herein, the mixer of this disclosure can reduce the risk of backfire / flame sustaining. In conventional mixers, a recirculation zone exists on the central body, where high-H2 fuel may be trapped due to the low-velocity zone, leading to flame sustaining. Compared to the mixer described in Figures 3-6, Figure 2 Conventional mixers also have a longer mixer length, which can result in longer fuel residence times within the mixer, leading to a higher risk of flame persistence. Such conventional mixers may result in lower H2 fuel mixing capacity. Conventional mixers may include low-velocity fuel cavities that can promote flame persistence.

[0038] A high-speed central jet of air generates low pressure that drives fuel toward the center. Due to the swirling and flow dynamics exhibited by the mixer of this disclosure, the flame is stabilized. Little or no fuel approaches the mixer wall. The mixer of this disclosure produces a compact flame structure and low, uniform downstream temperature. The mixer of this disclosure therefore allows for the absence of low-velocity regions within the mixer, instead providing higher velocities near the outer mixer wall to prevent fuel from approaching the boundary layer. Fuel can be distributed centrally, away from the outer diameter of the mixer. The mixer of this disclosure can have a shorter mixing length (compared to prior art mixers), resulting in a shorter residence time.

[0039] The percentage of hydrogen fuel can vary by volume from 0% to 100% of the fuel mixture. The percentage of hydrogen fuel can vary by volume from 10% to 100% of the fuel mixture. The percentage of hydrogen fuel can vary by volume from 20% to 100% of the fuel mixture. The percentage of hydrogen fuel can vary by volume from 30% to 100% of the fuel mixture. The percentage of hydrogen fuel can vary by volume from 40% to 100% of the fuel mixture. The percentage of hydrogen fuel can vary by volume from 50% to 100% of the fuel mixture. The percentage of hydrogen fuel can vary by volume from 60% to 100% of the fuel mixture. The percentage of hydrogen fuel can vary by volume from 70% to 100% of the fuel mixture. The percentage of hydrogen fuel can vary by volume from 80% to 100% of the fuel mixture. The percentage of hydrogen fuel can vary by volume from 90% to 100% of the fuel mixture. The percentage of hydrogen fuel can vary by volume from 55% to 95% of the fuel mixture. The hydrogen fuel percentage can vary from 60% to 90% by volume in the fuel mixture. The hydrogen fuel percentage can vary from 65% to 85% by volume in the fuel mixture. The hydrogen fuel percentage can vary from 70% to 80% by volume in the fuel mixture. The hydrogen fuel percentage can vary from 85% to 100% by volume in the fuel mixture. The hydrogen fuel percentage can vary from 95% to 100% by volume in the fuel mixture. The hydrogen fuel percentage can vary from approximately 55%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100% by volume in the fuel mixture. The mixer disclosed herein allows for the combustion of 100% hydrogen fuel in an engine.

[0040] Enhanced mixing (compared to existing mixing techniques), such as that provided by the mixer disclosed herein, can reduce NOx emissions. The mixer of this disclosure directs the fuel flow away from the inner wall of the mixer, i.e., away from the boundary layer air flow. By keeping the fuel flow away from the inner wall, the risk of backfire / flame retention is reduced, and the different stages of air contribute to achieving uniform fuel-air mixing within the mixer channels, helping to maintain low NOx emissions.

[0041] Of particular note regarding the mixer of this disclosure are the following capabilities: 1) injecting fuel near the center of the mixer and having little or no fuel near the inner wall of the mixer; 2) introducing air with high velocity and momentum to keep the fuel toward the center of the mixer; and 3) providing a swirling air jet near the inner wall to prevent fuel from approaching the inner wall of the mixer. A mixer with the above principles can achieve lower emissions and a lower risk of backfire / flame retention, thus enabling the combustion of higher hydrogen fuel concentrations.

[0042] The mixer disclosed herein can reduce or eliminate carbon emissions by achieving the combustion of different mixtures of H2 fuel. The percentage of H2 in the fuel can vary from 0% to 100% H2 and any incremental values ​​in between. The percentage of H2 fuel can be mixed to achieve lower NOx and CO emissions. The percentage of H2 fuel can be selected or predetermined based on jurisdictional or system emission requirements and / or based on the desired engine performance. The combustion of H2 fuel ensures reduced NOx emissions. The mixer disclosed herein can provide the distribution of the air and fuel mixture that eliminates the risks of autoignition, backfire, and flame persistence associated with pure premixed combustor / mixer designs with high H2 fuel mixtures.

[0043] The mixer disclosed herein may include a central high-speed axial air jet. This central jet can generate a low pressure at the center of the mixer tube. This central low pressure allows the H2 fuel mixture to remain at the center of the mixer tube and away from the outer wall of the premixer. This avoids the risk of flame persistence within the mixer tube. The central air jet may have low swirl to improve radial diffusion of the fuel-air mixture.

[0044] H2 fuel or a mixture thereof can be injected from the conical surface at an angle (e.g., any increment from 0 to 90 degrees relative to the axis of the central mixer). Due to the arrangement of the tubes, the mixer of this disclosure can achieve a smaller, more compact flame. The system of this disclosure can be used with fuel mixtures, i.e., multiple fuels can be injected through different mixers. For example, zones A and C ( Figure 2One or more mixer tubes in section B can be fueled with H2, while section B can be fueled with natural gas. This allows for lower NOx and CO emissions. Fuel can be injected from the center or at a radial offset distance relative to the mixer centerline. Different tubes in the array can have different offset directions to alter the heat release at the mixer array outlet. One or more fuel orifices can be provided.

[0045] A swirling or non-swirling main airflow can be introduced onto the conical surface, creating a high-speed flow at the cone's tip. Air introduced at this angle can keep the fuel on the mixer's centerline. The main airflow can include a rear swirl orifice that can be angled relative to the central mixer axis. This allows the flow to be closer to the mixer's outer wall, thus streamlining it.

[0046] The mixer disclosed herein may include a second set of blades that can introduce secondary, low-swirl air in the same direction (e.g., co-swirling) or opposite direction to the aforementioned air. This may create a high-speed air mass closer to the outer wall of the mixture, which may prevent fuel from approaching the outer wall boundary layer. The combination of the central non-swirling jet and the co-swirling flow from the conical surface and the outer mixer wall can produce a unique flow structure that maintains high speed and higher fuel concentration in the core of the mixer, which may reduce flame persistence and produce less emissions.

[0047] Therefore, this disclosure proposes a mixer that allows for circumferential gradation of air (by making some air inlet orifices smaller than the remaining air inlet orifices). This allows for specific fuel distribution patterns at the mixer outlet, which may result in variations in heat release and contribute to kinetics. The shear between the mixed, impinging swirling air (e.g., primary and secondary airflows) and the strong core jet (e.g., fuel flow) can produce the desired fuel:air ratio at the mixer outlet. Further mixing of the fuel-air mixture can occur after the mixer outlet and before the flame front surface due to swirling caused by the flow structure. The mixer of this disclosure provides a series of compact swirling flames.

[0048] The mixer disclosed herein has applications in aero-derivative engines, other gas turbine engines, and applications beyond gas turbines. The mixer disclosed herein can allow the combustion of 100% hydrogen fuel in an engine (e.g., a DLE engine). The ability to burn up to 100% hydrogen fuel enables a zero carbon footprint, which can be combined with renewable energy sources while requiring little or no water to achieve lower NOx emissions.

[0049] Further aspects of this disclosure are provided by the subject matter of the following clauses.

[0050] 1. A mixer configured to provide a fuel-air mixture to a combustor of an engine, the mixer comprising: a mixer body having an internal channel having a central axis; a fuel flow parallel to the central axis; a first air flow parallel to the central axis and the fuel flow; a second air flow inclined relative to the first air flow and the fuel flow; and a third air flow tangential to the mixer body, wherein the first air flow is configured to pull the fuel flow along the central axis through the internal channel, wherein the second air flow is configured as a forward swirling jet to prevent low-speed flow on a conical surface within the mixer body, and wherein the third air flow is configured to prevent the fuel flow from approaching an inner wall of the mixer body.

[0051] 2. The mixer according to any of the preceding clauses, wherein the fuel flow, the first air flow, the second air flow, and the third air flow are independent flows before entering the internal passage of the mixer body.

[0052] 3. The mixer according to any of the preceding clauses, wherein the fuel flow or the first air flow coincides with the central axis of the mixer.

[0053] 4. The mixer according to any of the preceding clauses, wherein the first airflow is configured to draw the fuel flow into the internal channel of the mixer.

[0054] 5. The mixer according to any of the preceding clauses, wherein the second air flow and the third air flow are configured to move the fuel flow toward the central axis.

[0055] 6. The mixer according to any of the preceding clauses, wherein the third airflow prevents the fuel flow from reaching the boundary layer airflow.

[0056] 7. The mixer according to any of the preceding clauses, wherein the fuel stream comprises H2 in the range of 0% to 100%.

[0057] 8. The mixer according to any of the preceding clauses, wherein the fuel stream comprises H2 in the range of 10% to 100%.

[0058] 9. A mixer configured to provide a fuel-air mixture to a combustor of an engine, the mixer comprising: a mixer body having an outer surface, an internal passage, and a central axis; a fuel inlet positioned parallel to the central axis and configured to introduce a fuel flow into the internal passage of the mixer body; a central air nozzle positioned parallel to the central axis; a first set of openings inclined relative to the central axis; and a second set of openings having an inlet surface tangential to the mixer body, wherein the central air nozzle, the first set of openings, and the second set of openings are each configured to introduce an air flow into the internal passage of the mixer body, wherein the first set of openings and the second set of openings are configured to prevent the fuel flow from approaching a boundary layer flow near the inner surface of the mixer body, and wherein the fuel flow comprises H2 fuel in the range of 0% to 100%.

[0059] 10. The mixer according to any of the preceding clauses, wherein the fuel inlet or the central air nozzle has a central axis that coincides with the central axis of the mixer body.

[0060] 11. The mixer according to any of the preceding clauses, wherein the central air nozzle, the first set of openings, and the second set of openings are independent entry points into the internal passage.

[0061] 12. The mixer according to any of the preceding clauses, wherein the first set of openings and the second set of openings are circumferentially positioned around the outer surface of the mixer body.

[0062] 13. The mixer according to any of the preceding clauses, wherein the second set of openings comprises one or more first openings and one or more second openings, the one or more second openings being larger than the one or more first openings, and wherein the second set of openings is circumferentially positioned around the outer surface of the mixer body.

[0063] 14. The mixer according to any of the preceding clauses further includes stationary blades within the central air nozzle, the stationary blades being configured to cause the airflow to swirl through the central air nozzle.

[0064] 15. The mixer according to any of the preceding clauses, wherein the fuel stream comprises H2 in the range of 10% to 100%.

[0065] 16. The mixer according to any of the preceding clauses, wherein the fuel stream comprises 50% to 100% H2.

[0066] 17. A mixer array comprising one or more mixers according to any of the preceding clauses.

[0067] While the foregoing description is directed to preferred embodiments, it should be noted that other variations and modifications will be apparent to those skilled in the art and can be made without departing from the spirit or scope of this disclosure. Furthermore, features described in connection with one embodiment may be used in conjunction with other embodiments, even if not explicitly stated above.

Claims

1. A mixer configured to provide a fuel-air mixture to a combustor of an engine, characterized in that, The mixer comprises: a mixer body having an interior passage with a central axis; a fuel stream parallel to the central axis; a first air stream parallel to the central axis and the fuel stream; a second air stream oblique to the first air stream and the fuel stream; and a third air stream tangential to the mixer body, wherein the first air stream is configured to pull the fuel stream through the interior passage along the central axis, wherein the second air stream is configured as a forward spinning jet to prevent low speed flow over a conical surface within the mixer body, wherein the third air stream is configured to prevent the fuel stream from approaching an inner wall of the mixer body, and wherein the fuel stream, the first air stream, the second air stream, and the third air stream are independent streams prior to entering the interior passage of the mixer body.

2. The mixer of claim 1, wherein wherein, the fuel stream or the first air stream coincides with the central axis of the mixer.

3. The mixer of claim 1, wherein wherein, the first air stream is configured to pull the fuel stream into the interior passage of the mixer.

4. The mixer of claim 1, wherein wherein, the second air stream and the third air stream are configured to move the fuel stream towards the central axis.

5. The mixer of claim 1, wherein wherein, the third air stream prevents the fuel stream from reaching a boundary layer air stream.

6. The mixer of claim 1, wherein wherein, the fuel stream includes H2 in a range of 0% to 100%.

7. The mixer of claim 6, wherein wherein, the fuel stream includes H2 in a range of 10% to 100%.

8. A mixer configured to provide a fuel-air mixture to a combustor of an engine, characterized in that, The mixer comprises: a mixer body having an exterior surface, an interior passage, and a central axis; a fuel inlet positioned parallel to the central axis, the fuel inlet configured to introduce a fuel stream into the interior passage of the mixer body; a central air jet positioned parallel to the central axis; a first set of openings oblique to the central axis; and a second set of openings having an entry surface tangential to the mixer body, wherein the central air jet, the first set of openings, and the second set of openings are each configured to introduce an air stream into the interior passage of the mixer body, wherein the first set of openings and the second set of openings are configured to prevent the fuel stream from approaching a boundary layer flow near an inner surface of the mixer body, wherein the fuel stream includes H2 fuel in a range of 0% to 100%, and wherein the central air jet, the first set of openings, and the second set of openings are independent entry points into the interior passage.

9. The mixer of claim 8, wherein wherein, the fuel inlet or the central air jet has a central axis that coincides with the central axis of the mixer body.

10. The mixer of claim 8, wherein wherein, the first set of openings and the second set of openings are positioned circumferentially around the exterior surface of the mixer body.

11. The mixer of claim 8, wherein, wherein the second set of openings includes one or more first openings and one or more second openings, the one or more second openings being larger than the one or more first openings, and wherein the second set of openings is positioned circumferentially around the outer surface of the mixer body.

12. The mixer of claim 8, wherein, further comprising a stationary vane within the central air jet, the stationary vane configured to spin the air stream through the central air jet.

13. The mixer of claim 8, wherein, wherein, the fuel stream includes H2 in a range of 10% to 100%.

14. The mixer of claim 8, wherein wherein, the fuel stream includes H2 in a range of 50% to 100%.

15. A mixer array comprising: the mixer array includes one or more mixers according to claim 8.

Images