Patent Application
20180058483
This disclosure is protected under United States and International Copyright Laws. © 2017 Jetoptera. All rights reserved. A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyrights whatsoever.
It has been demonstrated in tests that conditions in which there is less than optimal primary fluid flow supplied to an ejector/thruster, the operation in the round ends of the thruster or ejector remains very performant. However, the straight portion of the thruster is where the primary fluid injectors suffer a rapid performance degradation. Tests show that the efficiency of the thruster declined significantly with lower flow, yet measurements of the velocity of the mixed entrained/primary fluids efflux from the two ends of the thruster remain high even at low flows. In one test the velocity measured behind the round ends of the thruster at about one length of the ejector downstream of its exit plane remained in excess of 200 mph, whereas in the middle of the thruster corresponding to the straight or linear geometry, the velocity dropped to less than 100 mph. This is due to the specific flow pattern and the configuration of the rounded ends of the thruster in addition to the relative orientation of the emerging primary wall jets at non-parallel angles, facilitating the rapid entrainment and mixing with the ambient air, whereas the wall jets originating from the linear portion are parallel to each other and less efficient at lower flows.
This patent application is intended to describe one or more embodiments of the present invention. It is to be understood that the use of absolute terms, such as “must,” “will,” and the like, as well as specific quantities, is to be construed as being applicable to one or more of such embodiments, but not necessarily to all such embodiments. As such, embodiments of the invention may omit, or include a modification of, one or more features or functionalities described in the context of such absolute terms.
An embodiment includes a Coanda thruster that can change its primary fluid introduction conditions to match the flow conditions, thereby performing more efficiently and generating higher entrainment at conditions different from the ideal conditions described with regard to
Specifically,
Referring now to
Flow controller 240 further includes an actuating apparatus coupled to the shims 440. The actuating apparatus is configured to urge the shims 440 toward their corresponding wall portion 460, thereby reducing the cross-sectional area of each associated passage 450. Additionally, the actuating apparatus may be configured to actively withdraw the shims 440 away from their corresponding wall portion 460, thereby increasing the cross-sectional area of each associated passage 450.
In the embodiment illustrated in
As shown in
As shown in
The local increase in velocity decreases the static pressure per Bernoulli's principle, allowing more air to be entrained from the ambient and resulting in a larger mass flow compared to the fixed-geometry thruster at similar conditions of primary mass flow rate, pressure and temperature.
For instance, a turbine gas generator producing 1 kg/sec of combustion gas at a temperature of 1000 K and 2 bar pressure at 100,000 RPM and supplying a thruster-ejector designed for these conditions with the primary fluid produces 150 lbf of thrust. However, the same gas generator working at 85,000 RPM speed produces only 0.75 kg/s of combustion gas at 950 K and 1.4 bar and the performance of the fixed geometry primary fluid passage determines a drop in thrust to 100 lbf. The main reason for it is the reduction of the emerging velocity of the primary fluid into the entrainment area, determining a higher local static pressure and therefore less entrainment happens. The changing (reduction) of the primary area to determine a higher local primary fluid emerging velocity, and according to Bernoulli principle a lower static pressure, increases significantly the entrainment ratio and the thrust to 120 lbf, mainly due to an increase of 20% in the entrained air.
For those familiar with the subject, the isentropic expansion of the primary fluid jet results in the ideal thrust value of:
Where {dot over (W)} is the mass flow rate of the primary fluid, γ is the specific heat coefficient, Ru is the universal gas constant and T is the temperature, while P are pressures coresponding to the ambient and the total pressure of the flow. By augmentation ratio, we refer to the ratio between the measured thrust and the formula above, calculated for the respective parameters at hand.
The ability of changing the cross-sectional area of passages 450 is thusly beneficial, improving the overall performance of an otherwise fixed geometry thruster designed for optimal operation only at a certain condition of the primary fluid (flow, temperature, pressures).
In one embodiment the shims 440 may be manufactured out of stainless steel or any other material that can withstand high temperatures of up to 1750 F and still retain elasticity and a life of at least 2000 cycles.
The mechanism of moving the pins 430 to reduce the passage 450 area and optimize the flow may be mechanical in character. However, other actuation mechanisms could be employed. In an alternative embodiment, a manifold (not shown) may be employed to provide compressed air from a source, such as a compressor or any other high pressure source, to actuate the pins 430 to urge the shims 440 into the flow. Alternatively, electric or magnetic actuators (not shown) could be used to perform the same function. In yet another embodiment, a mechanism that contains linear and semicircular actuators (not shown) is employed to enable the change in geometry of various segments or slot blocks of the thruster, adapting it to the conditions at hand.
In another embodiment, the deflection of shims 440 may be such that the mechanism completely blocks the flow into all passages, shutting off the flow and cancelling thrust generation at various stages of the flight of a vehicle. In yet another embodiment, the preferential shutting off of portions of the primary slots is employed to generate a vectored thrust to reduce the landing distance of an flying vehicle. In yet another embodiment, the thruster is used to balance a tailsitter in a symmetrical deployment (i.e., two or more thrusters on the plane or aerial vehicle) and the actuation of the shims 440 allows attitude control of the aircraft in hovering or take off or landing. In yet another embodiment, a flying car hover is enhanced by employing the variable geometry feature of the thrusters to control its attitude/speed and can be used for landing or take off or level flight.
Although the foregoing text sets forth a detailed description of numerous different embodiments, it should be understood that the scope of protection is defined by the words of the claims to follow. The detailed description is to be construed as exemplary only and does not describe every possible embodiment because describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims.
Thus, many modifications and variations may be made in the techniques and structures described and illustrated herein without departing from the spirit and scope of the present claims. For example, in one embodiment, thruster 200 can be integrated into the induction track between an air filter and a throttle-body/carburetor, and upstream of a cylinder or combustion chamber, associated with an internal combustion engine. Alternatively, thruster 200 could be placed in an exhaust pipe downstream of the combustion chamber of an internal combustion engine. Accordingly, it should be understood that the methods and apparatus described herein are illustrative only and are not limiting upon the scope of the claims.
This application claims priority to U.S. Provisional Application No. 62/379,711, filed Aug. 25, 2016, and U.S. Provisional Application No. 62/380,108, filed Aug. 26, 2016, the entire disclosures of which are hereby incorporated by reference as if fully set forth herein. U.S. patent application Ser. No. 15/670,943 filed Aug. 7, 2017, U.S. patent application Ser. No. 15/654,621 filed Jul. 19, 2017, U.S. patent application Ser. No. 15/221,389, filed Jul. 27, 2016, U.S. patent application Ser. No. 15/221,439, filed Jul. 27, 2016, and U.S. patent application Ser. No. 15/256,178, filed Sep. 2, 2016 are hereby incorporated by reference in their entireties as if fully set forth herein.
| Number | Date | Country | |
|---|---|---|---|
| 62379711 | Aug 2016 | US | |
| 62380108 | Aug 2016 | US |
