Patent Grant
9713243
The embodiments described herein relate to corona generation and use, optionally in the fields of electrical power and/or Radio Frequency (RF) generation.
Atmospheric-pressure electric corona is a phenomenon observed when an existing high potential electric field between two electrodes causes ionization of gas media in the vicinity of the electrodes. Atmospheric-pressure electric corona, which usually appears as a Blue-Pink plasma cloud, is considered a precursor to gap discharge and Van De Graaff type sparks if the electrostatic potential is elevated over a certain threshold.
Electric Corona's are usually observed in defective electric circuits or high voltage electric lines as an unstable, elongated and luminescent plasma cloud. Coronal onset under atmospheric pressure requires potential fields on the order of 10 to 100 KV between two well-defined electric nodes. Thus, in the absence of imposed electric field and well-defined nodes atmospheric pressure corona generation is rare.
The phenomena known as Saint Elmo's Fire offers one example of an electric corona. It has been observed at the tip of ship masts under stormy sea conditions. In these conditions, an electric corona can be generated between a ship's mast tip, offering a first well-defined node and highly charged clouds which can function as a second node and which can create an estimated potential electric field in the range of millions of volts.
Under controlled conditions, the underlying matter of corona generation—in the form of a stable plasma state of material—has numerous uses. Plasmas find application in the fields of metallurgy, spraying and coating, cleaning, etching, metal cutting and welding, lighting, and others. The corona producing approaches described herein create plasma which may be used in many of these existing fields. More importantly, the approaches described herein open entirely new field-based opportunities for commercial applications and research.
The devices and methods described herein can employ a high pressure water jet directed at or impacting a dielectric plate to create plasma and associated atmospheric pressure corona. Dielectrics in some applications are commonly known to be electrically insulating material that can be polarized by applying an electric field. Systems and methods employing these principles are described, in which energy is created in addition to corona light. Use of water jets in corona production offers a number of potential advantages.
One set of advantages derives from the ability to have no direct application of electrical energy for the plasma generation. While piezo-electric devices, such as those from TDK, Inc., can be powered with an input or applied electric potential of up to 15 kV and can produce a so-called “cold” atmospheric pressure plasma, these devices are entirely reliant on the applied electrical potential to create the desired effect. Accordingly, plasma generated from such devices is not suitable for energy generation applications which may tap the electrical potential of the plasma. One reason for this is the inherent inefficiency of any such electricity-to-plasma-to-electricity cycle or conversion. While electrical components may be employed in the subject systems, methods, and devices described herein, in other example embodiments, none are required.
Another set of advantages of water-jet produced corona devices and methods concerns the shape or form of the plasma formed. Namely, the subject water jet approach can form a toroid shaped plasma corona. This form-factor can be uniquely applied as described below in addition to other potential applications.
Moreover, plasma corona formed by the systems, methods and devices described herein is boundary-less. In some embodiments it may be generated at atmospheric pressure or in any range of pressure between 800 to 1100 milliard. It can also be produced using a range of gases. These gases may include mixtures (e.g., atmospheric air) or pure gasses (e.g., He, N2, Ar, Ne, O2). Under confinement, the pressure of the generated plasma can be reduced to a small fraction of normal atmospheric pressure and the water jet used may be able to produce a boundary-less corona. Furthermore, it is possible to use heavy water and other non-conductive dielectric liquids (e.g., oil) to generate similar plasma.
When produced without application of an electrical field, the subject plasma is called “cold” plasma. Yet, it contains ample free electrons.
Devices, systems and kits in which they are included (both assembled and unassembled), methods of use and methods of manufacture contemplated herein are all included within the scope of the present disclosure. Some aspects and advantages are described above with a more detailed discussion presented in connection with the figures below. Other systems, devices, methods, features and advantages of the subject matter described herein will be or will become apparent to one with skill in the art upon examination of the following figures and Detailed Description. It is intended that all such additional systems, devices, methods, features and advantages be included within this description, be within the scope of the subject matter described herein, and be protected as described by the accompanying claims. In no way should the features of the example embodiments be construed as limiting the appended claims, absent express recitation of those features in the claims.
The details of the subject matter set forth herein, both as to its structure and operation, may become apparent by study of the accompanying figures, in which like reference numerals refer to like parts. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the subject matter disclosed herein. Moreover, all illustrations are intended to convey concepts, where relative sizes, shapes and other detailed attributes may be illustrated schematically rather than literally or precisely, as understood by those with skill in the art.
Various exemplary embodiments are described below. Reference is made to these examples in a non-limiting sense, as it should be noted that they are provided to illustrate more broadly applicable aspects of the devices, systems and methods. Various changes may be made to these embodiments and equivalents may be substituted without departing from the true spirit and scope of the various embodiments. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process act or step without departing from the objectives, spirit and scope of the present invention. All such modifications are intended to be within the scope of the claims made herein.
Before the present subject matter is described in detail, it is to be understood that this disclosure is not limited to the particular example embodiments described, as such may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular example embodiments only, and is not intended to be limiting, since the scope of the present disclosure will be limited only as described by the limitations of the appended claims.
All features, elements, components, functions, and steps described with respect to the embodiments provided herein are intended to be freely combinable and substitutable with those from any other embodiment as would be understood by one of skill in the art to accomplish the objectives described herein. If a certain feature, element, component, function, or step is described with respect to only one embodiment, it should be understood that such feature, element, component, function, or step can be used with many or all other embodiments described herein unless explicitly stated otherwise or unless such usage would compromise functionality of the particular system or method for its intended purpose. This paragraph therefore serves as antecedent basis and written support for the introduction of claims, at any time, that combine features, elements, components, functions, and steps from different embodiments, or that substitute features, elements, components, functions, and steps from one embodiment with those of another, even if the following description does not explicitly state, in a particular instance, that such combinations or substitutions are possible. Express recitation of every possible combination and substitution is overly burdensome, especially given that the permissibility that such combinations and substitutions will be readily recognized by those of ordinary skill in the art upon reading this description.
Jet-and-Plate System
A self-excited micro-scale toroidal electric corona can be generated by the impinging a water jet of micron-size on many dielectric surfaces. An experiment with a setup 10, as shown in
The setup 10 can include a commercial ruby nozzle 12 of 80 micrometer diameter fed with deionized water in a tank or reservoir 34 with a non-electric pump (powered by compressed air at fitting 38) capable of producing water jet speeds in the range of 1 to 430 meters per second. Ruby nozzle 12 was designed to deliver a disturbance-free laminar water-jet 20 in this speed range. The generated high-speed laminar jet 20 can maintains a disturbance-free character for 30 to 40 millimeters and subsequently break into a spray-type water-jet depending on the jet speed applied. Distance between a nozzle tip and impinging surfaces was maintained at 20 millimeters throughout some experiments, therefore avoiding spray-type formation before the jet impingement.
Water jets were formed with de-ionized or highly distilled and de-bubbled water with an ohmic resistance of about 18 MΩ-cm.
Under white light illumination, impacting jet 20 and a subsequent radial spreading of water from the water jet show the smooth surface and presence of a well-defined hydraulic jump 42 for jet speeds below 200 meters per second (m/s). This result is well expected from previous studies of thin water jet impingements. For some experimental setups, the core region 44 of an impinging jet appears as a black disk of about 80 micrometer similar to that of the impacting water-jet diameter, as shown in
Appearance of the luminescent region 48 can be concurrent with the appearance of surface capillary waves and resultant spray generation emanating from a circumference of circular hydraulic jump 42 as shown. Notably, the luminescence did not appear when normal water (i.e., tap water containing minerals causing low ohmic resistance) or conducting metallic wafers or plates 32 were used as opposed to non-conducting dielectric plates.
Some experimental setups allowed optical access through a circular opening under wafer 32 in the direction of the arrow in
In this image, a rich structure including the presence of a toroid or donut-shaped luminescent region 50 outside the core area disk 52 followed by neighboring dark ring 54 and the presence of a surrounding third cloud-like glowing ring 56 can be observed. (Note that the central faint blue region 58 appears to be the reflection of the light from the first ring on the nozzle housing or tip 14.)
Through experiments, it was further discovered that while the threshold jet speed requirement for the onset of corona luminescence of approximately 200 m/s was required for a smooth quartz target plate, the jet speed could be significantly lower (e.g., about 150 m/s) for rougher surfaces to achieve a similar effect.
Also, a monotonic increase of glow intensity was observed with increasing jet speed as set forth in
The source luminescence was shown to be in the gas phase (rather than residing in solid media) as is evident after review of
In
The striking feature of the emission spectra in a single gas medium is that the lines are from excited molecules, despite being in Argon, Helium, etc. As in the example of
A dramatic change in the overall spatial appearance of the corona is observed when changing a target wafer or plate 32 from a relatively smooth to a relatively rough surface. Example surface roughnesses for selected plate materials are provided in the table below:
Especially notable are the appearance of radial narrow band bridges 96 connecting the first and the second rings 50 and 56. Video images of these intriguing patterns reveal a highly dynamic nature that manifests itself in the form of strong mode switching and locking and a visual perception of rotation. One possible explanation for these observations is that the patterns may be a consequence of excitation of spatial hydrodynamic instability modes of a radially expanding water layer associated with the target plate surface roughness. Regardless of the cause, the apparent additional corona generation (with such results at lower jet speeds and pressures for rough surfaces as commented above) may increase power yield in the power generation Example discussed below.
It is important to appreciate that the toroidal corona is observed in the absence of an externally imposed electric field between usually well-defined nodes (i.e., anode and cathode). However, the observation of strong excited or ionized spectral lines points indicates the presence of a strong ionizing electric field near the free-surface of the impinging water-jet. To map the strength of this electric field, the region surrounding the toroidal corona was surveyed using the Langmuir two-probe technique.
When the potential of a single probe, placed directly in the toroidal corona was compared to a ground value, the average voltage readings indicated a strong negative potential. This observation indicates an accrual of negatively charged particles in the toroidal corona region. The potential difference between this region and ground exhibited a great dynamic range from −300V to −1000V (the corona being at the lower potential). To map the extent and strength of the electric field of the corona, one probe was positioned 75 micrometers from the jet impingement annulus, while the second probe was moved radially away from the center at varying angles. Average 30 second voltages at each x-y coordinate provided enough data to generate a map of the electric field within a 3 mm radius.
It is believed that one explanation for the mechanism responsible for generating the observed electric field should be closely related to the interaction of the impinging jet with the surface of the dielectric target. One candidate for the charge generating-mechanism is a process known as “streaming potential.” Stream potential is due to voltages that can be produced by the triboelectric action of flowing liquid over solid surfaces.
To explore this effect, numerical simulation of a flow field was performed. In
A resulting strain field is shown in
The triboelectric process, also known as charge transfer process, occurs when two non-conducting materials come into contact with one another. The rate of electron transfer can depend on the refreshment rate of contacting surfaces, which can be in the form of periodic or continuous rubbing of these materials against each other. The triboelectric process for non-conducting fluids running over dielectric materials is well-known and has been studied and documented extensively. In some example embodiments herein, deionized water or other fluid can act as a non-conducting dielectric material when rubbing against sapphire, quartz, LiNbO3 or other plate material that is both non-conducting and dielectric, (e.g., with a dielectric constant, Er, in the range from about 4 to about 12 for the plate material).
One possible explanation that positive charges accumulate in expanded hydraulic jump region 42 where the flow rate decelerates rapidly, causing a positive charge concentration strong enough for a thin liquid sheet to break up and depart the solid surface in the form of highly charged spray droplets 120. Therefore, the first ring-hydraulic jump could act as an anode in an electric corona process, even without the application of an external electric field. With the speed of an impinging jet raised to about 200 m/s in an example embodiment using a smooth plate, the charge potential may then gain enough strength to overcome a break-down voltage of non-conductive liquid water and reach the free-surface of the impinging jet. The shortest distance to the free-surface appears to be the neck region 110 where the impinging jet turns to spread radially. Also, the neck area with the smallest radius of curvature is an optimal geometry to act as the second node, also known as the cathode. Note associated electric field lines 122.
It is well-known that sharp points possess higher charge concentration due to the redistribution of surface charges by the Coulomb force field. Only about one kilovolt (kV) would be required for a break-down of deionized water for a 10 micron distance between a high shear region and a neck area of a toroid since the break-down voltage of dionized water is known to be about 100M/V or 100V/micron.
In the example embodiment shown in
Another observation for system 10 involves the detection of RF emissions. Namely, in
For LiNbO3, it is notable that in contrast to the Z-cut variant, the X-cut is neither polar nor piezoelectric, while the Y-cut is nonpolar but has piezoelectric properties. This raises interesting questions regarding the possibility of coupling between the jet hydrodynamic instabilities and the material, specifically through its vibrational characteristics being able to create additional RF signal that may be put to use. One such application may be RF generation unaffected or immune to EM radiation since no electrical circuit is involved.
It is also notable that plasmas are known to oscillate in the form of Langmuir waves. These plasma oscillations are caused by density disturbances in the electron charge density caused by their interaction with the positively charged and much heavier ions. This induces electrostatic Coulomb forces that tend to restore the electron density equilibrium of the plasma. However, because electrons have a mass, the plasma starts to oscillate at a frequency that is related to the square-root of the electron density. Thus, by reversing this relation and using the RF peak values above, we find electron densities between about 1.5×106 and about 45×106 cm−3 in the subject plasmas. These values are comparable with the electron densities found in negative coronas.
Further characterization of the RF energy and its production is presented in
A multi-physics model is presented where, due to the tribo-electric effect, electrons are pumped continuously from a high-shear region to a neck region or cathode and respectively positive ions from a passage bridge to a hydraulic jump or anode. In example embodiments, the toroidal corona would reside between these two nodes as expected from the recorded and illustrated observations. Moreover, such a system—as understood and otherwise contemplated—can be adapted to function in a number of ways, non-limiting examples of which are provided below.
Examples
In a first Example shown in
However configured, a magnetic field can be applied and optionally controlled by a computer hardware module 204 such that free electrons 206 in the corona 50, produced as described in embodiments above and others, rotate within the subject plasma as indicated in
In system 200, toroidal containment and use of a plasma is achieved in an elegant manner. Namely, additional magnetic containment field equipment, such as the inclusion of toroidal magnetic field coils, found in a conventional Tokamak is not present, yet the desired and useful toroidal form factor is available, in a boundryless or uncontained format.
In a second Example illustrated in
Alternatively, a pressure head may drive pump 216 alone, where pump 216 draws water from a separate tank (not shown) of specially treated water. Such a tank may be filled with distilled or filtered reservoir water.
In some embodiments, reservoir water may be filtered, distilled or otherwise treated by a module or station 220 in-line with the pump to achieve its desired di-ionized character (e.g., by nano-filtration or others) and resistance as above, or otherwise. In some embodiments, pump 216 may be omitted a setup with a reservoir functioning alone to supply the pressure head (h) and fluid supply for jet assembly 218.
In many embodiments, a system 210 can include one or more electrodes connected to an underside of a plate 32. In an electrical circuit 230, such electrodes can serve as an anode 232 which provides or donates electrons while a cathode 234 is provided by one or more electrodes at, along, adjacent or otherwise near the top side of plate 32 as shown. The electrical potential of the corona effect described herein can thereby be harvested.
The systems and methods herein will not only produce corona light, but electrical power as well. In some embodiments, a single nozzle and plate target surfaces are employed. In other embodiments, multiple jets emanate from a head or jet assembly 218 and are directed at multiple target plate areas as indicated by the arrows in
As illustrated in
The target areas as defined by the inserts may be set apart to avoid interference between corona generation regions. A plurality of heads and, optionally, matching inserts may be employed to multiply or multiplex power generation with a maximum number limited only by available fluid or pressure supply.
Variations
In controlling systems as described above, general purpose or dedicated “firm ware” computer hardware may be used or otherwise adapted. Firmware will typically include non-transitory memory (in the form of a programmable hard drive, RAM, etc.) for the storage and execution of instructions contained therein or thereon.
The subject methods, including methods of use and/or manufacture of the hardware described, may be carried out in any order of the events which is logically possible, as well as any recited order of events. Furthermore, where a range of values is provided, it is understood that every intervening value, between the upper and lower limit of that range and any other stated or intervening value in the stated range is encompassed within the invention. Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein.
Though the invention has been described in reference to several examples, optionally incorporating various features, the invention is not to be limited to that which is described or indicated as contemplated with respect to each variation of the invention. Various changes may be made to the invention described and equivalents (whether recited herein or not included for the sake of some brevity) may be substituted without departing from the true spirit and scope of the invention.
Reference to a singular item includes the possibility that there are a plurality of the same items present. More specifically, as used herein and in the appended claims, the singular forms “a,” “an,” “said,” and “the” include plural referents unless specifically stated otherwise. In other words, use of the articles allow for “at least one” of the subject item in the description above as well as the claims below. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.
Without the use of such exclusive terminology, the term “comprising” in the claims shall allow for the inclusion of any additional element—irrespective of whether a given number of elements are enumerated in the claim, or the addition of a feature could be regarded as transforming the nature of an element set forth in the claims. Except as specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining claim validity. Accordingly, the breadth of the different inventive embodiments or aspects described herein is not to be limited to the examples provided and/or the subject specification, but rather only by the scope of the issued claim language.
This filing claims the benefit of and priority to U.S. Provisional Patent Application Nos. 62/073,919, 62/073,944, and 62/073,946, all filed Oct. 31, 2014, and all of which are incorporated by reference herein in their entireties and for all purposes.
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