Oscillating impact device for spray generation and modulation

Abstract

A system comprises an airflow pathway; a nozzle configured to inject the liquid into the airflow pathway; and a pintle disposed within the nozzle such that an end of the pintle contacts the liquid injected into the airflow pathway, wherein the pintle is configured to impart vibratory energy unto the liquid injected into the airflow pathway.

Description

OSCILLATING IMPACT DEVICE FOR SPRAY GENERATION AND MODULATIONSTATEMENT OF GOVERNMENT SPONSORED SUPPORT

[0002] This invention was made with government support under grant 13423461 and contract N000142212469, both of which were awarded by the Office of Naval Research. The government has certain rights in the invention.CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Patent Application No. 63 / 555,626 titled “Oscillating Impact Device for Spray Generation and Modulation” and filed February 20, 2024, the contents of which are hereby incorporated by reference in their entirety.BACKGROUND

[0002] Rapidly adjustable and reliable fuel injection in harsh conditions is key in modern military aircraft engines. Such military aircraft engines must have the necessary fuel efficiency, stealth, and noise reduction to complete missions. Engine components for fuel injection must be high temperature tolerant and must facilitate droplet formation in fuel ejected from crossflow nozzles into high-speed combusting flows.SUMMARY

[0003] In an embodiment, there is a system comprising an airflow pathway, a nozzle configured to inject the liquid into the airflow pathway, a pintle disposed within the nozzle such that an end of the pintle contacts the liquid injected into the airflow pathway, wherein the pintle is configured to impart vibratory energy unto the liquid injected into the airflow pathway. In some implementations, the nozzle is configured to inject the liquid into the airflow pathway at an angle perpendicular to a central axis of the airflow pathway. In certain implementations, the pintle is disposed at an angle relative to a bottom surface of the nozzle. In further implementations, the pintle comprises a metal and a piezoelectric material. In some implementations, the piezoelectric material is configured to contact the liquid injected into the airflow pathway.

[0004] In some implementations, the nozzle comprises circuitry configured to send electrical signals to the pintle. In further implementations, the pintle comprises a transducer configured to transform the electrical signals into the vibratory energy. In certain implementations, the pintle comprises a surface having a surface wettability configured to facilitate a formation of a thin layer of the liquid on the surface of the pintle.

[0005] In some implementations, the pintle comprises a first layer of metal, a second layer of metal, and a piezoelectric material, the piezoelectric material being disposed between the first layer of metal and the second layer of metal. In certain implementations, the pintle comprises a proximal end and a distal end, the proximal end of the pintle is disposed within the nozzle, and the piezoelectric material is exposed at the distal end of the pintle.

[0006] In some implementations, the liquid comprises fuel. In certain implementations, the liquid comprises medication. In further implementations, the second layer of metal comprises at least one of copper, zirconium, platinum, vanadium, niobium, molybdenum, tungsten, rhenium, or alloys thereof.

[0007] The details of one or more variations of the subject matter described herein are set forth in the accompanying drawings and the description below. Other features and advantages of the subject matter described herein will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which are incorporated in and constitute a part of this specification, show certain aspects of the subject matter disclosed herein and, together with the description, help explain some of the principles associated with the disclosed implementations. In the drawings,

[0009] FIG. 1 illustrates a system comprising an oscillating impact device for spray generation and modulation in accordance with some embodiments described herein;

[0010] FIG. 2A illustrates a cross-section of a nozzle and a pintle device for use in a system for spray generation and modulation in accordance with some embodiments described herein;

[0011] FIG. 2B illustrates a first component of a body of a nozzle for use in a system for spray generation and modulation in accordance with some embodiments described herein;

[0012] FIG. 2C illustrates a second component of a body of a nozzle for use in a system for spray generation and modulation in accordance with some embodiments described herein;

[0013] FIG. 2D illustrates a spray generation and modulation system having a pintle device in accordance with some embodiments described herein;

[0014] FIG. 2E illustrates a spray generation and modulation system having a pintle device in accordance with some embodiments described herein;

[0015] FIG. 3 illustrates a top perspective view of a nozzle for use in a system for spray generation and modulation in accordance with some embodiments described herein; and

[0016] FIG. 4 illustrates a bottom perspective view of a nozzle and a pintle device for use in a system for spray generation and modulation in accordance with some embodiments described herein.DETAILED DESCRIPTION

[0006] Disclosed are materials that pertain to a vibrating pintle device that acts to deflect liquid exiting a nozzle. The deflection of the liquid by the pintle causes the fuel to break up into droplets more quickly, when compared to devices that do not use a vibrating pintle device. The shorter time by which the liquid breaks into droplets produces greater droplet surface area. This greater droplet surface area (which is provided by the pintle based device) may be used for example to provide enhanced fuel-air reaction in support of combustion or the inhalation of liquid droplets in medical settings. The greater this area, the more rapidly the reaction occurs. In implementations in which the pintle device acts to deflect fuel injected into an engine, less space is required to complete the reaction as the air-fuel mixture is carried down the interior of the engine.

[0007] FIG. 1 depicts an example of system 100 configured for increased combustion efficiency using a pintle device 102. The system 100 comprises the pintle device 102, a nozzle 104, and an airflow pathway 106 defined by walls 108a and 108b. Liquid 110 is injected into the airflowpathway 106 through the nozzle 104 via crossflow injection (e.g., liquid 110 is injected into the airflow pathway 106 from a side along one of the walls 108 A of the airflow pathway 106). In some implementations, the liquid 110 is injected into the airflow pathway 106 through the nozzle 104 at an angle that is perpendicular to a central axis of the airflow pathway 106.

[0008] The pintle device 102 comprises a first metal layer 102a and a piezoelectric material 102b. In some implementations, the pintle device 102 further comprises a second metal layer 102c. In some implementations, the piezoelectric material 102b comprises the above noted transducer of the pintle device 102. For example, the piezoelectric material 102b may comprise lithium niobate.

[0009] In certain implementations, the first metal layer 102a and the second metal layer 102c are clamped or affixed to the layer of the piezoelectric material 102b. In further implementations, the piezoelectric material 102b is disposed between the first metal layer 102a and a second metal layer 102c. In certain implementations, at least one of the first metal layer 102a and the second metal layer comprise at least one of copper, zirconium, platinum, vanadium, niobium, molybdenum, tungsten, rhenium, or alloys thereof. The pintle device 102 may comprise a thickness of between about 0.2 millimeters millimeter and about three millimeters. In certain implementations, the pintle device 102 comprises a thickness of about 1 millimeter.

[0010] In some implementations, the liquid 110 comprises fuel, such as fuel for combustion with a jet engine. In such implementations, crossflow air 112 entrains the liquid 110 and facilitates combustion of the liquid 110. In further implementations, the liquid 110 comprises a medication. For example, the systems and methods described herein can be used for the pulmonary delivery of medications, as they can produce droplets of a suitable diameter for deep lung and / or nasal inhalation.

[0011] The pintle device 102 acts to deflect the liquid 110 exiting the nozzle 104. The pintle device 102 may be configured to generate droplets of the liquid 110. In particular, the pintle device 102 may facilitate the breaking up of the liquid 110 into droplets by imparting vibratory energy unto the liquid 110. Liquid 110 entering the airflow pathway 106 and entrained by the crossflow air 112 may, due to natural instability, break up into droplets as it travels through the airflow pathway 106. However, the pintle device 102 may be configured to cause the liquid 110 to breakup into droplets earlier (e.g., closer to the nozzle 104) than it would due to natural instability alone. In implementations in which the liquid 110 is a fuel, the produced droplets provide a greater surface area for the fuel-air reaction in support of combustion. The greater this area, the more rapidly the combustion reaction occurs, and the less space is required to complete the reaction as the air-fuel mixture is carried down the interior of the engine.

[0012] For example, the pintle device 102 may be configured to impart vibratory energy unto the liquid 110. The vibration imparted unto the liquid 110 by the pintle device 102 may facilitate the expeditious breaking up of the liquid 110 into droplets. In some implementations, the pintle device 102 is configured to transmit ultrasound energy unto the liquid 110 by vibrating at ultrasonic frequencies. For example, the pintle device 102 may be configured to vibrate at frequencies between about 1 megahertz and about 2.5 gigahertz. The nozzle 104 may comprise circuitry (e.g., electronic components) that are configured to send or transmit electric signals to a transducer of the pintle device 102. For example, the nozzle 104 may comprise a driver circuit that generates electric signals to drive the transducer of the pintle device 102. These electric signals may be transformed or converted by the transducer into mechanical (e.g., vibratory) energy by the transducer of the pintle device 102. For example, the transducer may may vibrate or induce agitation at ultrasonic frequencies, although other frequencies may be implemented as well. In certain implementations, the driver circuit may be configured to detect a resonance state of the pintle device 102. In some implementations, the driver circuit may be further configured to detect changes in the resonance state of the pintle device 102. In further implementations, the driver circuit may be further configured to detect operating conditions (e.g., conditions in changing engine environments) relevant to the safe and effective operation of the pintle device 102. The driver circuit may be configured to use a closed feedback control loop to detect the resonance state of the pintle device 102, changes in the resonance state of the pintle device 102, and operating conditions relevant to the safe and effective operation of the pintle device 102.

[0013] FIG. 2A illustrates a cross-section of a nozzle 104 that may be used in a system for spray generation and modulation in accordance with some embodiments described herein. For example, the nozzle 104 of FIG. 2A may comprise the nozzle 104 of FIG. 1. In certain implementations, the nozzle 104 comprises a hollow cylinder including a proximal inlet, a distal outlet, and a lumenthrough which a fluid can travel. The nozzle 104 may also have a body having three components as described further with respect to FIG. 2B.

[0014] As shown in FIG. 2A, a proximal end 105 of a pintle device 102 may be disposed in the nozzle 104. Abottom surface 116 of the nozzle 104 forms an angle 114 with the distal end 103 of the pintle device 102. The nozzle 104 may comprise a lumen 202 configured to allow the injection of a fluid into an airflow pathway. For example, the liquid 110 of FIG. 1 may travel through the lumen 202 to be injected into the airflow pathway 106 of FIG. 1. The lumen 202 may connect a proximal inlet 204 to a distal outlet 206. Liquid may be configured to enter an airflow pathway via the distal outlet 206. For example, the liquid 110 of FIG. 1 may be injected into the airflow pathway 106 of FIG. 1 by entering the nozzle 104 at the proximal inlet 204, traveling through the lumen 202, and exiting the nozzle 104 via the distal outlet 206. As shown in FIGs. 2B and 2C, the body of the nozzle 104 may comprise component 104a, 104b, and 104c. Component 104c may be “hot” wired and configured to direct electrical signals to the transducer of the pintle device 102. In some implementations, the component 104c comprises a metal. In certain implementations, the metal layer 102a of the pintle device 102 is formed integrally with the component 104c. Electrical signals may be communicated to the pintle device 102 by wire 113. Component 104a may be configured to electrically insulate the pintle device 102 and the component 104c from the other components of the nozzle 104 and from the surroundings in which the nozzle 104 is disposed, as shown in FIG. 1 . As shown in FIG. 2C, the body of the nozzle 104 may further comprise component 104b that is configured as an electrical ground.

[0015] As shown in FIGs. 2D and 2E, the first component 104a and the second component 104b may be held together by at least a first screw 109. FIGs. 2D and 2E further illustrate different embodiments of the pintle device 102. The pintle device 102 of FIG. 2D comprises a first metal layer 102a, a piezoelectric material 102b, and a second metal layer 102c. The pintle device 102 of FIG. 2E comprises a first metal layer 102a and a piezoelectric material 102b. The connector 111 of FIG. 2D and of FIG. 2E may comprise a SubMiniature version A (SMA) connector. The connector 111 may be connected to a power source and may thus be used to deliver electrical energy to the pintle device 102.

[0016] In some implementations, the pintle device 102 is made conformal with a portion of the nozzle 104 that the pintle abuts. By making the pintle device 102 conformal with the portion of the nozzle 104 that the pintle device 102 abuts, corners that could produce shocks or local hot spots in the passing flow of the liquid 110 are avoided. By avoiding such shocks and hot spots, damage of the system 100 is prevented.

[0017] In certain implementations, the pintle device 102 comprises a distal end 103 and a proximal end 105. The proximal end 105 of the pintle device 102 may be secured to or disposed in the nozzle 104. The distal end 103 of the pintle device 102 may be configured to impart vibratory energy to liquid 110. The piezoelectric material may be disposed between a first metal layer and a second metal layer at the proximal end 105 of the pintle device 102. The piezoelectric material may be exposed at the distal end 103 of the pintle device 102 such that the piezoelectric material may be configured to directly contact the liquid 110 and impart vibratory energy thereunto.

[0018] In certain implementations the pintle device 102 comprises a thickness of between about ten millimeters and about thirty millimeters. The thickness of the pintle device 102 may be selected so that the pintle device 102 can withstand the hot, violent conditions in the environment of an engine in which the pintle may be disposed. The thickness of the pintle device 102 may be further selected so that the pintle device 102 is able to impart sufficient vibratory energy unto the liquid 110 so that the liquid 110 expeditiously breaks up into droplets.

[0019] The pintle device 102 may be disposed at an angle 114 with respect to a bottom surface 116 of the nozzle 104. In other words, the pintle device 102 and the bottom surface 116 of the nozzle 104 may have an angle 114 therebetween. In some implementations, the angle 114 between the pintle device 102 and the bottom surface 116 of the nozzle 104 is between about ten degrees to about eighty degrees. In certain implementations, the angle 114 between the pintle device 102 and the bottom surface 116 of the nozzle 104 is about forty-five degrees.

[0020] In certain implementations, the airflow pathway 106 comprises a length L. The pintle device 102 and the nozzle 104 may be disposed at any point along the length L of the airflow pathway 106.

[0021] The pintle device 102 may comprise a surface wettability (e.g., an oleophilicity). The surface wettability of the pintle device 102 may be selected so that a thin layer of the liquid 110 may form on a surface of the pintle device 102. The surface wettability of the pintle device 102 may be selected so that the thin film of the liquid 110 lays as flat as possible on the surface of the pintle device 102. By increasing the amount of the liquid 110 that is in contact with the surface of the pintle device 102 (e.g., by forming a thin film of liquid 110 on a surface of the pintle device 102) the transfer of vibratory energy from the pintle device 102 unto the liquid 110 is made more efficient. As such, the pintle device 102 facilitates the formation of droplets of liquid 110 via inertial atomization. The droplets formed via inertial atomization may have a consistent diameter.

[0022] In implementations in which the liquid 110 comprises fuel, the pintle device 102 may help improve engine responsiveness by providing a method to rapidly control combustion within. This may help in off-cycle operation, to avoid unstart, and to expand the operating envelope to reduce fuel consumption. Further, the consistent diameter of the droplets formed via inertial atomization increases efficiency of combustion and further supports combustion of fuel at supersonic speeds of cross-flow air 112.

[0023] Moreover, by using the pintle device 102, it is possible to achieve greater Weber numbers for a jet, for example. The Weber number is a measure of the jet's kinetic energy versus its surface energy (from surface tension). The larger the number, the greater the jet flow velocity (generally). We can only drive breakup of jets using vibration from the orifice for Wen 10" to 1015. For the pintle vibration system, the effect of vibration is apparent for Weber numbers up to at least 100. This is closer to the values commonly encountered in jet engines.

[0024] The vibration of the pintle device 102 can be modulated in time and amplitude.. In some implementations, the vibration of the pintle device 102 is at MHz-order (> 1MHz), and so can be activated and deactivated at frequencies well above the audible range. This may enable the reduction or elimination of engine noise at narrow frequency bands, and perhaps broadband noise. In certain implementations, the modulation of the vibration of the pintle device 102 is performed by modulating the amplitude of the input signal passed from the nozzle 104 to the transducer of the pintle device 102. In some implementations, the input signal passed from the nozzle 104 to the transducer of the pintle device 102 is modulated via pulse-width modulation. In furtherimplementations, the input signal passed from the nozzle 104 to the transducer of the pintle device 102 is modulated via frequency modulation.

[0025] In certain implementations, the modulation of the vibration of the pintle device 102 comprises a single frequency modulation. In some implementations, the modulation of the vibration of the pintle device 102 comprises a narrow band modulation. In further implementations, the modulation of the vibration of the pintle device 102 comprises a broadband modulation. The manner in which the input signal to the transducer of the pintle device 102 is modified can be selected based on the desired noise suppression. In some implementations, audible noise is reduced by modulating the input signal provided to the transducer of the pintle device 102 at harmonics of the targeted frequencies of the noise. For example, 40 kHz and 80 kHz modulation may be used to help suppress 20 kHz noise.

[0026] FIG. 3 illustrates a top perspective view of a nozzle 104 that may be used in a system for spray generation and modulation in accordance with some embodiments described herein. For example, the nozzle 104 of FIG. 3 may comprise the nozzle 104 of FIG. 1. As shown in FIG. 3, the nozzle 104 comprises the proximal inlet 204 through which a liquid can travel to be injected into an airflow pathway.

[0027] FIG. 4 illustrates a bottom perspective view of a nozzle 104 that may be used in a system for spray generation and modulation in accordance with some embodiments described herein. For example, the nozzle 104 of FIG. 4 may comprise the nozzle 104 of FIG. 1. As shown in FIG. 4, the nozzle 104 may be configured to receive or otherwise contain a proximal end 105 of a pintle device 102. The nozzle 104 may further comprise a distal outlet 206 through which liquid 110 can exit the nozzle so as to be injected into an airflow pathway. For example, the liquid 110 of FIG. 1 can exit the nozzle 104 via the distal outlet 206 to be injected into an airflow pathway. After exiting the nozzle 104 via the distal outlet 206, the liquid 110 may contact the distal end 103 of the pintle device 102. The distal end 103 of the pintle device 102 may comprise an exposed piezoelectric material. The piezoelectric material may be configured to impart mechanical energy unto the liquid 110 that has exited the nozzle 104 via the distal outlet 206. The liquid 110 may thus be configured to break into droplets of similar diameters, facilitating, e g., the combustion of fuel or the inhalation of medication.

[0028] In the descriptions above and in the claims, phrases such as “at least one of’ or “one or more of’ may occur followed by a conjunctive list of elements or features. The term “and / or” may also occur in a list of two or more elements or features. Unless otherwise implicitly or explicitly contradicted by the context in which it used, such a phrase is intended to mean any of the listed elements or features individually or any of the recited elements or features in combination with any of the other recited elements or features. For example, the phrases “at least one of A and B;” “one or more of A and B;” and “A and / or B” are each intended to mean “A alone, B alone, or A and B together.” A similar interpretation is also intended for lists including three or more items. For example, the phrases “at least one of A, B, and C;” “one or more of A, B, and C;” and “A, B, and / or C” are each intended to mean “A alone, B alone, C alone, A and B together, A and C together, B and C together, or A and B and C together.” Use of the term “based on,” above and in the claims is intended to mean, “based at least in part on,” such that an unrecited feature or element is also permissible.

[0029] The subject matter described herein can be embodied in systems, apparatus, methods, and / or articles depending on the desired configuration. The implementations set forth in the foregoing description do not represent all implementations consistent with the subject matter described herein. Instead, they are merely some examples consistent with aspects related to the described subject matter. Although a few variations have been described in detail above, other modifications or additions are possible. In particular, further features and / or variations can be provided in addition to those set forth herein. For example, the implementations described above can be directed to various combinations and subcombinations of the disclosed features and / or combinations and subcombinations of several further features disclosed above. In addition, the logic flows depicted in the accompanying figures and / or described herein do not necessarily require the particular order shown, or sequential order, to achieve desirable results. Other implementations may be within the scope of the following claims.

Claims

What is claimed:

1. A system comprising: an airflow pathway; a nozzle configured to inject the liquid into the airflow pathway; and a pintle disposed within the nozzle such that an end of the pintle contacts the liquid injected into the airflow pathway, wherein the pintle is configured to impart vibratory energy unto the liquid injected into the airflow pathway.

2. The system of claim 1, wherein the nozzle is configured to inject the liquid into the airflow pathway at an angle perpendicular to a central axis of the airflow pathway.

3. The system of claim 1 , wherein the pintle is disposed at an angle relative to a bottom surface of the nozzle.

4. The system of claim 1, wherein the pintle comprises a metal and a piezoelectric material.

5. The system of claim 4, wherein the piezoelectric material is configured to contact the liquid injected into the airflow pathway.

6. The system of claim 1, wherein the nozzle comprises circuitry configured to send electrical signals to the pintle.

7. The system of claim 6, wherein the pintle comprises a transducer configured to transform the electrical signals into the vibratory energy.

8. The system of claim 1, wherein the pintle comprises a surface having a surface wettability configured to facilitate a formation of a thin layer of the liquid on the surface of the pintle.

9. The system of claim 4, wherein:the pintle comprises a first layer of metal, a second layer of metal, and a piezoelectric material, the piezoelectric material being disposed between the first layer of metal and the second layer of metal.

10. The system of claim 9, wherein: the pintle comprises a proximal end and a distal end, the proximal end of the pintle is disposed within the nozzle, and the piezoelectric material is exposed at the distal end of the pintle.

11. The system of claim 1, wherein the liquid comprises fuel.

12. The system of claim 1, wherein the liquid comprises medication.

13. The system of claim 9, wherein the second layer of metal comprises at least one of copper, zirconium, platinum, vanadium, niobium, molybdenum, tungsten, rhenium, or alloys thereof.

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