Systems and methods for reducing drag on marine vessel hulls and thereby improving hydrodynamic efficiency - Patents.com

Abstract

The present invention attempts to enhance air lubrication and reduce vessel frictional resistance by creating and maintaining a superaerobic surface on the vessel's underside. Air is supplied by two different means: through vents near the bow and through a perforated superaerobic surface on the vessel's underside. Air supplied through the perforations in the superaerobic surface prevents wetting of microscopic structures on the surface and maintains its superaerobic properties. Because the superaerobic surface draws air near the vessel's surface, the present invention significantly increases the proportion of air from the bow vent in the boundary layer, improving the efficiency and effectiveness of the air lubrication system. The aerobic effect is enhanced by carbon that is trapped, filtered, and mixed into the air supplied to the plastron.

Description

[Technical Field]

[0001] The present invention is specific to marine applications, and particularly relates to the creation and maintenance of superaerobic surfaces in underwater environments to improve the efficiency of air lubrication systems, but also has other potential applications in medical and industrial fields. [Background technology]

[0002] The movement of a ship through the water is impeded by three main drag forces: wave resistance, form (pressure) resistance, and friction drag. Optimization of bulbous bows and hull shape often significantly reduces wave resistance and form drag. Friction drag, on the other hand, has traditionally depended primarily on wetted surface area and, to some extent, hull smoothness. Despite the fact that friction drag accounts for approximately 60-90% of the total drag on large ships, relatively few innovative technologies have been employed until recently.

[0003] For the past few decades, one method for reducing the frictional drag of a ship's hull has been the adoption of an air lubrication system. Air lubrication systems attempt to reduce frictional drag by injecting air bubbles into the hydrodynamic boundary layer under the ship's hull, forming a water-air mixture. Because air has a lower kinematic viscosity than water, the frictional shear stress generated by the water-air mixture on the hull is smaller than that generated under normal operating conditions.

[0004] A challenge with current air lubrication system technology is that injected air bubbles tend to detach from the hull surface after injection. Once the air bubbles leave the boundary layer, the drag reduction benefits of air injection are lost. Current solutions to this challenge include recapturing and redistributing the air at more longitudinal locations along the hull surface, optimizing the air injection nozzle, and / or increasing the pressure and volume of the supplied air. Because the air detaches from the hull, current methods require a large compressor load to provide enough air to achieve significant drag reduction. The energy required to drive the compressor reduces or negates the energy savings from drag reduction.

[0005] Therefore, there is a need in the market for a system that reduces drag on the hull of a marine vessel while providing a net reduction in energy consumption and reducing greenhouse gas emissions due to reduced fuel use, a system that incorporates replaceable surfaces that can be temporarily affixed to the hull of a marine vessel and reapplied during periodic dry docking or underwater maintenance, and a system that recycles exhaust gases into an anti-friction gas layer that can reduce drag on the hull of the vessel. Summary of the Invention [Means for solving the problem]

[0006] The invention disclosed herein provides a system for reducing frictional drag on the hull of a marine vessel. The system includes a multi-layer air lubrication system. The multi-layer air lubrication system has at least three layers, including an outermost layer having a laser-ablated, hyperaerobic-inducing surface, a porous layer that promotes gas supply exchange with the outermost layer, and a contact layer for bonding the multi-layer air lubrication system to the hull of the marine vessel. The system also includes at least one gas injection point in the porous layer for receiving the gas supply, and an air distribution and make-up system that provides the gas supply to the porous layer. The air distribution and make-up system supplies gas at a pressure slightly higher than the pressure exerted by the water on the air plastron and includes a compressor to ensure continuous promotion of air distribution.

[0007] The present disclosure also provides a super-aerobic induction surface for use in reducing hydrodynamic drag on a marine vessel hull. The surface comprises a metal surface having a plurality of super-aerobic induction microscopic / nanoscopic structures etched into the metal surface by laser ablation. Each super-aerobic induction microscopic structure of the plurality of super-aerobic induction microscopic / nanoscopic structures defines a trench and ridge shape. Each super-aerobic induction nanoscopic structure of the plurality of super-aerobic induction microscopic / nanoscopic structures defines a trench and ridge shape in each sidewall of the super-aerobic induction microscopic structure. The metal surface has a plurality of openings at least at the innermost points of the trench and ridge shapes of the super-aerobic induction microscopic structure, each opening of the plurality of openings configured to pass a supply of air from the interior of the metal structure to the wet side of the metal structure, thereby generating an air plastron upon engagement.

[0008] The invention disclosed herein also provides a method for reducing frictional drag on a hull of a marine vessel, thereby improving its efficiency, the method comprising configuring the hull of the marine vessel to reduce frictional drag by providing a super-aerobic induction surface, the super-aerobic induction surface comprising a metal surface having a plurality of super-aerobic induction microscopic-nanoscopic structures etched into the metal surface by laser ablation, each super-aerobic induction microscopic structure of the plurality of super-aerobic induction microscopic-nanoscopic structures defining a trench and ridge shape, each super-aerobic induction nanoscopic structure of the plurality of super-aerobic induction microscopic-nanoscopic structures defining a trench and ridge shape in a respective sidewall of the super-aerobic induction microscopic structure, the metal surface comprising a plurality of openings at least at an innermost point of the trench and ridge shapes of the super-aerobic induction microscopic structures, each opening of the plurality of openings configured to pass a supply of air from an interior of the metal structure to a wetted side of the metal structure, thereby generating an air plastron upon engagement.

[0009] The present invention also provides a system for reducing drag on a marine vessel hull, thereby improving hydrodynamic efficiency. The system includes a three-layer replenishable composite surface, which is supplied with an air lubrication system and maintains an air plastron. The three-layer replenishable composite surface includes a superaerobic layer, a middle porous layer, and a contact layer for assembly to the hull. The superaerobic layer is configured to have a micro- and nanoscale topography that exhibits aerobic and hydrophobic properties. The superaerobic layer is configured with perforations for air supply and air plastron maintenance on the water-facing surface. The air lubrication system further supplies carbon-rich air to the three-layer replenishable composite surface, which diffuses through the middle porous layer and the permeable superaerobic layer, thereby improving and maintaining the air plastron and superaerobic properties of the surface, even when submerged for extended periods.

[0010] SUMMARY OF THE INVENTION It is an object of the present invention to provide a system that is able to reduce drag on the hull of a marine vessel.

[0011] Another object of the present invention is to provide a replaceable surface that can be temporarily applied to the hull of a marine vessel and reapplied during periodic drydocking or underwater maintenance.

[0012] A further object is to provide a system that recycles exhaust gases into an anti-friction gas layer that can reduce drag on the hull of a vessel.

[0013] It is yet another object of the present invention to provide a system that improves the fuel efficiency of a vessel and reduces greenhouse gas emissions by reducing the amount of energy required to propel the vessel.

[0014] The drawings and specific descriptions of the drawings, and the specific or alternative embodiments described, are intended to be read in conjunction with the entire disclosure. The present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided for illustrative purposes only, so as to thoroughly, completely, and fully convey the disclosure so that it can be understood by those skilled in the art. These and other objects and advantages of the present invention will become apparent from the following brief description of the drawings, detailed description, and appended claims. [Brief explanation of the drawings]

[0015] [Figure 1A] This is a conceptual diagram of a surface that is superhydrophilic in air and superanaerobic in water. [Figure 1B] This is a conceptual diagram of a surface that is hydrophilic in air and anaerobic in water. [Figure 1C] This is a conceptual diagram of a surface that is hydrophobic in air and aerobic in water. [Figure 1D] This is a conceptual diagram of a surface that is superhydrophobic in air and superaerobic in water. [Figure 2A] FIG. 1 is a magnified, non-scale cross-sectional side view of a hyperaerobic surface in air. [Figure 2B] FIG. 1 is a magnified, non-scale cross-sectional side view of a submerged hyperaerobic surface. [Figure 3] FIG. 1 is a magnified, non-scale cross-sectional side view of a hyperaerobic surface submerged in water and supplemented with air plastrons. [Figure 4] FIG. 1 is an enlarged, non-scale cross-sectional side view of a functional surface assembly. [Figure 5] A is an enlarged, non-scale isometric view of a functional surface assembly; B is an enlarged, non-scale cross-sectional side view of a diagram of the functional surface assembly; and C is an enlarged, non-scale perspective view of a trench with plastron refill openings for a superaerobic surface. [Figure 6A] FIG. 1 is a conceptual profile diagram of a vessel with a superaerobic surface covering a portion of the vessel bottom and using air lubrication. [Figure 6B]FIG. 1 is a conceptual plan view of a vessel in which a superaerobic surface covers a portion of the vessel bottom and uses air lubrication. [Figure 7A] FIG. 1 is a conceptual profile diagram of a vessel with a superaerobic surface covering a portion of the vessel bottom and using air lubrication. [Figure 7B] FIG. 1 is a conceptual profile diagram of a vessel using an air lubrication system on an anaerobic hull. [Figure 8] FIG. 1 is a diagram of a system for carbon-enriched air lubrication supply. [Figure 9] 1 is a flow chart of a carbon enrichment process. [Figure 10] FIG. 1 is a diagram of a turbocharger with an additional exhaust gas rerouting tube. [Figure 11A] FIG. 1 is a diagram of a parasitic compressor inserted in a turbine exhaust pipe. [Figure 11B] FIG. 1 is a diagram of a parasitic compressor inserted into a turbine exhaust pipe, with its internal components shown in phantom (dashed lines). [Figure 12A] FIG. 1 is an exploded isometric view of the major components of the filter assembly. [Figure 12B] FIG. 1 is a side view of the main components of the filter assembly, with the internal configuration shown in phantom (dashed lines). [Figure 13] FIG. 1 is a diagram of a two-stage apparatus for introducing gas into a system. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention provides a solution to the increasing demands on energy and fuel efficiency in the marine industry. Tightening regulations have driven innovations in fuel efficiency, primarily in engine improvements and hull design. However, without an efficient friction-reducing coating on the hull, efficiency potential is limited. The present invention addresses these challenges by incorporating a uniquely designed system that utilizes a super-aerobic surface to repel water and draw air to the hull surface, thereby reducing drag and ensuring a continuous supply of air or carbon to ensure air plastron replenishment, significantly reducing hull drag.

[0017] As noted above, the movement of a ship through the water is impeded by three main drag forces: wave resistance, form (pressure) drag, and friction drag. Bulbous bows and hull shape optimization often significantly reduce wave resistance and form drag. Friction drag, on the other hand, has traditionally depended primarily on wetted surface area and, to some extent, hull smoothness. Despite friction drag accounting for approximately 60–90% of the total drag on large ships, until recently, relatively few innovative technologies had been employed to address it.

[0018] For the past few decades, one method for reducing frictional drag on a ship's hull has been the adoption of air lubrication systems. Air lubrication systems attempt to reduce frictional drag by injecting air bubbles into the underside of a ship's hull, forming a water-air mixture. Because air has a lower kinematic viscosity than water, the frictional shear stresses induced on the hull by the water-air mixture are less than those generated under normal operating conditions.

[0019] A challenge with current air lubrication system technology is that injected air bubbles tend to detach from the hull surface after injection. Once the air bubbles leave the boundary layer, the drag reduction benefits of air injection are lost. Current solutions to this challenge include recapturing and redistributing the air at more longitudinal locations along the hull surface, optimizing the air injection nozzle, and / or increasing the pressure and volume of the supplied air. Because the air detaches from the hull, current methods require a large compressor load to provide enough air to achieve significant drag reduction. The energy required to drive the compressor reduces or negates the energy savings from drag reduction.

[0020] The present invention solves these challenges by incorporating systems for enhancing marine air lubrication systems, including implementing engineered surfaces with microscopic and nanoscopic structures and microscopic perforations, functional surface assemblies with porous interlayers that replenish air plastrons, inclusion of air distribution systems (air plastron replenishment systems) that supply air to the porous interlayers, the use of carbon to accelerate the conversion of laser-ablated surfaces to superaerobic properties, extraction of carbon from exhaust, sewage tanks, bioreactors, and galley hoods for carbon enhancement, the implementation of devices to separate particulates from gaseous carbon molecules, and the construction of superaerobic surfaces that increase the amount of air maintained within the boundary layer for air lubrication.

[0021] The present invention minimizes the amount of energy that must be used to deliver air to the underside of a ship's hull by utilizing a three-layer "functional surface assembly" with superaerobic and superhydrophobic properties. This functional surface assembly is molded and installed on the exterior surface of the hull. The surface attracts air and repels water, minimizing the amount of air delivered by the air lubrication system.

[0022] The three-layer functional surface assembly includes an outermost layer, which may be composed of a copper alloy and is known as a superaerobic surface. The copper alloy is converted to a superaerobic surface by etching microscopic and nanoscopic structures into the surface. In many embodiments, an ultrafast laser is used for the etching. Typical lasers are not suitable for performing these etches, but future technological advances may provide more capabilities. Using an ultrafast laser for laser ablation can create the required etching. While laser ablation is considered the most efficient method for creating etchings, other techniques, such as chemical vapor deposition, thermal spraying, and other methods capable of precise etching, may also be employed. The dual-scale topography allows air to penetrate and adhere to the voids in the surface. The trapped air, known as an air plastron, briefly prevents water intrusion.

[0023] However, over time, hydrostatic and hydrodynamic forces cause water to penetrate the surface, displacing air and reducing the air plastron, resulting in a loss of superaerobic properties. Slowly re-airing the air plastron maintains the surface's superaerobic properties. To achieve this, a layer of compressed air is created on the inside of the superaerobic surface. A porous intermediate layer is attached to the inner, non-ablated side of the superaerobic surface to distribute the compressed air. Microscopic holes are also drilled into the superaerobic surface by a laser, allowing compressed air to be delivered to the outer surface of the superaerobic surface, re-supplying the air plastron.

[0024] The final layer of the functional surface assembly is the contact layer. This layer is used to bond the entire functional surface assembly to the hull. The combination of the porous intermediate layer and the contact layer provides dielectric properties that prevent galvanic corrosion between the hull and the copper alloy.

[0025] To maintain the super-aerobic properties of the functional surface assembly, air is constantly supplied to the compressed air layer within the porous interlayer. Additionally, when the vessel is underway, an air lubrication system provides more air near the bow.

[0026] Surfaces with microscopic and nanoscopic structures, such as the ultra-aerobic surfaces described above, exhibit minimal aerobic properties after construction, and in some cases even anaerobic properties. These surfaces become increasingly aerobic and hydrophobic over time when exposed to air. This occurs because carbon atoms present in air bind to the surface. Due to the limited carbon content in air, the carbon deposition process can take anywhere from 2 to 4 weeks.

[0027] Therefore, to enhance the aerobic and hydrophobic properties of the surface, carbon is extracted from ship engine exhaust, wastewater tanks, galley hood exhaust, or bioreactors and supplied to the air plastron. Carbon oxides such as carbon dioxide (CO2) and carbon monoxide (CO) in the exhaust, as well as hydrocarbons such as methane (CH4) from wastewater (human waste) tanks, galley hood exhaust, or bioreactors, are filtered to extract the carbon-based molecules. Without such filtration, the micro-perforations of the ultra-aerobic surface would quickly become clogged, preventing the invention from functioning properly.

[0028] The present invention not only reduces the frictional drag of the hull, but also prevents the growth of marine organisms on the hull through the formation of an air plastron, which is inhospitable to marine organisms that require water to grow, making the dry environment of a hyperaerobic surface unsuitable for their habitat.

[0029] In connection with the creation and maintenance of a submerged superaerobic surface, the present invention creates and maintains a superaerobic surface in an aquatic environment. While the primary purpose of the present invention is to improve the efficiency of air lubrication systems for ship hulls, the surfaces described below have other applications.

[0030] An aerobic surface attracts air or gas when submerged in liquid, while a hydrophobic surface repels water when surrounded by air. A surface that exhibits aerobic properties is also hydrophobic. The more aerobic and hydrophobic a surface is, the lower its surface free energy.

[0031] The aerobicity of a surface submerged in water and the hydrophobicity of the same surface surrounded by air are measured by contact angle. The concept of contact angle is illustrated in Figures 1A-1D. For a hydrophobic surface with a water droplet surrounded by air, a very large contact angle forms a "superhydrophobic surface." For an aerobic surface with an air pocket in water, a very small contact angle forms a "superaerobic surface." If the contact angle of water with a surface in air is greater than 150°, it is considered superhydrophobic. If the same surface is exposed to an air bubble in water, the contact angle of the air bubble will be less than 5° and it is considered superaerobic.

[0032] The present invention utilizes a dual-scale topography, with microscopic and nanoscopic structures, as shown in Figures 2A and 2B. When submerged in liquid, air is trapped within the voids of the engineered structure, forming a layer between the superaerobic surface and the liquid. The air between the water and the superaerobic surface is known as an air plastron. The air plastron acts as a protective layer that inhibits wetting of the superaerobic surface. The superaerobic surface repels water and attracts air, provided by an air lubrication system. Conversely, when this surface is exposed to air, water droplets on the surface become approximately spherical, reducing the surface's wettability and creating a hydrophobic surface.

[0033] In air, the surface remains hydrophobic for extended periods. When submerged in water, the air plastron diminishes, resulting in a surface that is less aerobic and less hydrophobic. Contributing factors to air plastron decline include the degree to which the hyperaerobic surface is exposed to hydrostatic pressure exerted on the air plastron, the flow of water over the surface creating hydrodynamic pressure, and the pressure compressing the air trapped within the microstructure voids and the water subsequently displacing that air.

[0034] Forces opposing air plastron loss include air pressure within the void space, air loss from the void space and plastron, reduced pressure contributing to more rapid air plastron loss, capillary pressure at the curved air-liquid interface, and capillary pressure at the submerged aerobic surface, which is exerted away from the surface due to the convexity of the interface.

[0035] To maintain the aerobic properties of the superaerobic surface, the present invention actively resupplies pressurized air to the air plastron by forming a compressed air layer between the superaerobic surface and the hull. Microscopic perforations in the superaerobic surface allow air from this layer to quickly replenish air lost due to hydrostatic and hydrodynamic pressures. Figure 3 shows the supply of air from the compressed air layer to the dual-scale structure surface.

[0036] As more air is supplied to the voids of the hyperaerobic surface, the pressure within the air plastron increases, further opposing the hydrostatic and hydrodynamic pressures. As a result, the rates of air diffusion and replenishment reach equilibrium, at which point the air plastron stabilizes.

[0037] To further explain the functional surface assembly, the manufactured superaerobic surface will not remain superaerobic in water unless an air plastron is continuously resupplied from a layer of compressed air inside the superaerobic surface, as previously mentioned. Furthermore, the alloy surface described above cannot be directly applied to a ship's hull due to problems related to galvanic corrosion. To solve these problems, the present invention forms a three-layer "functional surface assembly." A cross-sectional view of the functional surface assembly is shown in Figure 4.

[0038] The layers include an outermost layer, an intermediate layer, and an innermost layer. The outermost layer is the superaerobic surface, which has been extensively described above. The intermediate layer is porous. The porosity of this layer allows the necessary compressed air to be evenly distributed inside the superaerobic surface. This layer is known as the porous intermediate layer. Air is continuously supplied to the porous intermediate layer at a low flow rate. The air within the porous intermediate layer must be at a pressure slightly higher than that of the air plastron, allowing air to move through the microscopic perforations in the superaerobic surface. The innermost layer is the contact layer. This layer allows the entire functional surface assembly to adhere to the hull without penetrating the porous intermediate layer. The contact layer should not be porous to any degree. The combination of the contact layer and porous intermediate layer must be dielectric to prevent galvanic corrosion between the steel hull and the copper alloy. Figures 5(A)-5(C) show three-dimensional views of a water-repellent functional surface assembly.

[0039] The porous interlayer structure must withstand the forces applied to the functional surface assembly while being permeable to distribute airflow evenly across the entire underside of the superaerobic surface. The porous interlayer is bonded to the copper alloy prior to laser ablation. This bond provides a strong bond to the alloy surface while maintaining high porosity. The porosity of the material is high to minimize pressure loss over the distance between the air plastron supply system and the microscopic perforations. The smaller this pressure change, the more evenly the air is distributed across the superaerobic surface. During normal operation, the porous interlayer and its connection to the superaerobic surface counterbalance the internal stresses caused by compressed air pressure and the external shear forces caused by vessel motion, sinking, and squat effects. In the event of a failure of the air plastron supply system, the porous interlayer will be temporarily exposed to high compressive forces caused by hydrostatic pressure. It must withstand these forces and be sufficiently resistant to permanent deformation.

[0040] The contact layer is the surface that bonds easily and securely to the hull. It may provide a pressure-sensitive surface for attachment to the hull, or it may be a harder substrate to which an industrial strength adhesive can bond. The contact layer does not allow the adhesive to penetrate the porous intermediate layer.

[0041] The overall system includes a system for supplying air to the compressed gas within the porous interlayer. A system for supplying air to the compressed gas within the porous interlayer is required. This is known as an air plastron refueling system. This is a separate system used in addition to the ship's air lubrication system. A check valve is included to prevent pressure loss within the porous interlayer if the air plastron refueling system fails. If the porous interlayer is sufficiently porous to allow uniform air distribution, the air plastron refueling system can have a single injection site into the porous interlayer. If the pressure loss through the porous interlayer is too great to achieve uniform distribution, a series of small-diameter tubes can be drilled through the porous interlayer to aid in air distribution. Alternatively, a series of channels can be cut into the porous interlayer to aid in even air distribution.

[0042] Regarding the fabrication of the functional surface assembly, the functional surface assembly is manufactured as a series of sheets that can be applied directly to the underside of the hull. These sheets can be made small, approximately 4 feet by 8 feet, to accommodate the possibility of divers installing the functional surface assembly. Preferably, the functional surface assembly is applied to the hull at the shipyard, in which case each sheet should be approximately 8 feet by 100 feet in scale. Fewer sheets are preferred, as compressed air in the porous interlayer is less likely to leak through the seams in the sheets than through microscopic perforations. Additionally, fewer sheets also result in fewer penetrations into the hull.

[0043] Once the three layers are bonded together, the alloy surface is laser ablated to form a superaerobic surface. Laser ablation is used to create the microscopic and nanoscopic surface structures described above. The advantage of laser ablation is that material is removed quickly enough to avoid melting adjacent material. This allows for deeper cuts on a very small scale. In this embodiment, laser ablation is employed in a precision engineering process to create microscopic grooves on the alloy surface. The laser ablation process creates laser-induced periodic surface structures that add a second structural layer on a nanoscopic scale.

[0044] A laser is used to drill microscopic holes through the alloy surface at predetermined intervals within the microscopic groove recesses. These holes allow compressed air to be delivered from the porous interlayer to the superaerobic surface. By connecting the porous interlayer to the alloy surface before ablation of the superaerobic surface, the laser-drilled holes in the alloy surface can also penetrate the porous interlayer. This ensures that the air in the porous interlayer has a clear path to the microscopic perforations in the superaerobic surface.

[0045] Laser-induced periodic surface structures and drilled microscopic holes are created by adjusting the laser parameters to obtain an optimal material removal process. Adjustable laser parameters for laser ablation include speed, focal length, and fluence (energy per unit area). These parameters also contribute to the drilling process, and the number of pulses per hole is also a factor. Each type of alloy requires fine-tuning of these parameters.

[0046] The contact layer is preferably attached to the hull by a dielectric compatibility method. One such embodiment uses an adhesive or sticky backing. This can include a solid contact layer that is dielectric and coated with a resin or another strong adhesive. In this case, the contact layer must be solid enough to prevent the adhesive from penetrating the porous interlayer. Alternatively, the contact layer can be coated with a pressure-sensitive adhesive and applied to the hull like a sticker. Another embodiment utilizes a mechanical method using fasteners. Additionally, for newbuildings, the contact layer can be omitted entirely. The porous interlayer can be attached directly to the newbuilding block or ground block using an appropriate adhesive that does not excessively penetrate the porous interlayer. The choice of alloy can improve antifouling and corrosion resistance, which is advantageous for ocean-going vessel applications. Copper alloys offer these benefits. For non-marine applications requiring ultra-aerobic or ultra-hydrophobic surfaces, other alloys can be selected depending on their properties.

[0047] If superhydrophobic or superaerobic surfaces are required for applications other than improving the efficiency of air lubrication systems on ships, the superaerobic surface can be applied to any surface. For underwater applications, a porous interlayer containing compressed air must also be applied.

[0048] The principle of air lubrication on a superaerobic surface is applied. Because air has a lower dynamic viscosity than water, the friction resistance of the hull portion with an air layer is reduced. The superaerobic surface allows the air from the air lubrication system to adhere more easily to the hull, as shown in Figures 6A and 6B.

[0049] Injecting air bubbles reduces the average dynamic viscosity of the fluid within the hull's boundary layer, reducing the hull's frictional resistance. Bubbles that leave the boundary layer do not contribute to reducing frictional drag. Creating and maintaining an aerobic and hydrophobic surface extends the time bubbles remain within the boundary layer, reducing the amount of air required to supply the hull's bottom. Bubbles injected into a non-aerobic surface tend to "bounce" off the hull. To compensate for bubbles that leave the boundary layer, existing air lubrication system installations inject large amounts of air under the hull's bottom, which requires a large amount of compressor power for operation. The power savings from drag reduction are offset by parasitic compressor power losses. An air lubrication system with an aerobic surface reduces compressor airflow, increasing net power savings. Figures 7A and 7B show a conventional air bubble air lubrication system and the enhanced air lubrication system of the present invention side by side.

[0050] In summary, the present invention reduces the amount of air that an air lubrication system must supply by using a superaerobic surface to attract the air distributed by the air lubrication system. A perfectly formed air sheet maximizes friction drag reduction compared to air bubbles. The greater drag reduction and reduced compressor power requirements result in increased net power savings.

[0051] Regarding the carbon-enriched air in the aerobic enhancement aspect, the present invention can use carbon-enriched air to enhance the aerobic and hydrophobic properties of the superaerobic surface. This embodiment enhances the superaerobic properties of the functional surface assembly, but is not required for the invention to exhibit superaerobic properties.

[0052] Many experiments have been conducted using microscopically structured surfaces to create aerobic and hydrophobic surfaces. In many cases, surfaces that were minimally hydrophobic or even hydrophilic in air were found to become more hydrophobic over time as carbon molecules were introduced to the surface. Further analysis revealed that carbon atoms in the air naturally attached to the surface, lowering the surface free energy and making the surface more hydrophobic and aerobic.

[0053] In this invention, carbon-enriched air is supplied to the compressed air layer of the porous interlayer, thereby utilizing the binding effect of carbon to enhance the effectiveness of the superaerobic surface. Because the pores in the superaerobic surface that transport air from the porous interlayer to the microstructured surface are small, carbon-containing molecules such as carbon dioxide (CO2) and carbon monoxide (CO) are filtered out, and only carbon molecules need to be supplied to the porous interlayer.

[0054] Regarding the carbon-enriched air supply system, the present invention separates carbon molecules from engine exhaust, waste tank exhaust, or galley hood exhaust and uses the filtered carbon molecules to supply carbon-enriched gas to a functional surface assembly. The carbon supply enhances the aerobic and hydrophobic properties of the ultra-aerobic surface. Figure 8 shows an example of a simplified piping diagram, and Figure 9 shows a flowchart of the carbon filtration and supply process.

[0055] Engine exhaust contains carbon oxides such as carbon monoxide (CO) and carbon dioxide (CO2). In engines using heavy fuel oil, CO2 accounts for approximately 600,000 ppm (6%) of exhaust, while CO accounts for 60 ppm (0.00006%). CO2 accounts for a much higher proportion of exhaust gas, but is a stable molecule, making it difficult to extract carbon atoms. CO is present in smaller amounts, but is unstable, making it easy to extract individual carbon atoms.

[0056] Normal air contains only trace amounts of CO, with a CO2 composition of only 0.033%. The high concentrations of carbon oxides found in ships' waste streams are a highly available and efficient source of carbon for air plastron replenishment.

[0057] Hydrocarbons such as methane (CH4) from wastewater tanks, bioreactors, and galley hoods are also utilized. The methane content in these exhausts varies widely, but is generally high enough to extract useful amounts of carbon. When methane exceeds 5% by volume in air, it becomes explosive. Many shipboard accidents have occurred as a result. An additional benefit of the present invention is that it minimizes the amount of methane buildup in wastewater tanks.

[0058] The present invention seeks to provide a solution to these problems by rerouting carbon-rich engine exhaust to replenish the air plastron. This is done by utilizing the engine's waste heat to reroute the vessel's exhaust gases through a turbocharger and into a functional surface assembly. As shown in Figure 10, the turbocompressor is driven by the vessel's engine exhaust, which it recycles and compresses to provide carbon-rich gas for the air plastron. The carbon activates the vessel's aerobic surface properties. To build this turbocompressor, flexible, heat-resistant tubing or precisely sized solid piping that fits the turbine-compressor assembly is used to connect the turbine output to the compressor input. The connection point must be properly sealed to prevent exhaust gases from leaking out.

[0059] If engine boost is also required and only a small amount of carbon-rich gas is required, a parasitic compressor can be incorporated into a conventional engine turbocharger, immediately after the turbine, in the exhaust pipe connected to the turbine. A parasitic compressor can be created by modifying a standard automotive turbocharger. The central shaft is extended to power a second, smaller compressor installed in the turbine's exhaust pipe, which draws air from the turbine's exhaust. Figures 11A and 11B show conceptual diagrams of this embodiment. Turbine exhaust gas not used by the parasitic compressor must flow freely around the parasitic compressor housing. Therefore, the parasitic turbocharger must be smaller than shown in Figures 11A and 11B to avoid excessively restricting the turbine exhaust flow and creating a backpressure effect. Alternatively, the exhaust pipe diameter of the section containing the parasitic compressor can be enlarged. A parasitic compressor is best used when only a small amount of carbon-rich air is required and space is a concern. It should also be noted that a larger parasitic compressor reduces the output pressure of a conventional turbocharger.

[0060] To construct this device, the central shaft is extended into the exhaust pipe and the parasitic turbo compressor is attached to the extension. Next, the location of the parasitic compressor's output port is marked on the (not yet attached) exhaust pipe. An appropriately shaped hole is drilled into the exhaust pipe wall. The exhaust pipe is slid over the parasitic compressor, with the parasitic compressor's output port exiting the exhaust pipe through the drilled hole, aligned with the turbine output port. The gap is sealed by welding an upper sleeve over it. This sleeve must be attached to the exhaust pipe before installation and then slid into the gap and welded after installation. The parasitic compressor's output is welded to the exhaust pipe wall. If possible, this welding operation is performed with the exhaust pipe in a vertical position to avoid bending moments on the central shaft due to gravity acting on the parasitic compressor. If vertical welding is not possible, this bending moment must be compensated for in other ways, or the shaft alignment may not be ideal. Depending on the weight of the parasitic compressor, the diameter and stiffness of the central shaft, misalignment can cause excessive friction or even prevent the shaft from rotating at all.

[0061] Adding a carbon filter to separate carbon-containing gases from the rest of the exhaust increases the carbon concentration. It is important that the carbon-rich gas delivered to the hyperaerobic surface does not contain particles large enough to clog the laser-ablated microscopic perforations. Unfiltered exhaust gases are likely to clog these perforations, resulting in the degradation and failure of the hyperaerobic surface.

[0062] The carbon filter is shown in Figures 12A and 12B. Referring to Figures 12A and 12B, gas enters the outer casing through a lid with a permanently attached intake tube. Pressure within the intake tube forces the gas against a carbon-sensitive membrane attached to the inner chamber. The membrane allows carbon-containing molecules to pass through. The remaining gas fills the inner chamber, flows from the top around the sides to the bottom, and is discharged through the carbon-reducing outlet. The carbon-reducing outlet tube is permanently welded to the outer chamber, ensuring a permanent and complete seal. Carbon-rich gas leaves the inner chamber through the carbon-rich gas outlet.

[0063] It is crucial that the intake air provides enough pressure to force the gas through the membrane, but not so excessive that damage occurs from gas impact. A pressure relief valve must also be installed at the carbon reduction outlet. This maintains the pressure in the chamber necessary to force the gas through the membrane, while releasing any gas that does not pass through the membrane, preventing overpressurization of the chamber. The gas released through the carbon reduction outlet still contains carbon dioxide, but at a much lower concentration than the original exhaust.

[0064] The inner chamber containing the carbon membrane is replaceable, allowing for filter replacement and improving efficiency over the life of the system. Three threaded connections within the filter require good sealing. The lid threaded connection has an integrated O-ring and a push-to-open locking mechanism. The other two threaded connections comprise the section where the carbon-rich outlet tube passes through the outer and inner casings. These two connections require the application of high-temperature thread sealant. The inner chamber threads are smaller than the outer casing threads, preventing the thread sealant used to seal the inner chamber from being removed as it passes through the outer casing. A leak from the inner chamber into the outer casing through the carbon-rich outlet tube would result in the loss of carbon-rich gas returning to the carbon-reduced air, reducing the efficiency of the filter. A leak through the outer casing through either the lid or the carbon-rich outlet tube is equivalent to a leak through the exhaust pipe. Regular inspection and replacement of the O-rings is required.

[0065] If CO levels on a vessel could become dangerously high, a double-pipe system can be utilized. The space between the outer and inner pipes is evacuated to below atmospheric pressure and a pressure sensor is installed. Any CO leakage from the inner pipe will cause a pressure increase and activate an alarm. In this case, an automatic valve can shut off the exhaust supply, allowing temporary air plastron make-up using non-carbon-enriched outside air.

[0066] There are other benefits and uses for the system described herein. In addition to improving the efficiency of air lubrication systems and reducing hull friction drag, the present invention has anti-fouling properties. Marine organisms require moisture to grow on surfaces, and hyperaerobic surfaces remain dry and inhospitable to marine life. Reduced anti-fouling further reduces drag, thereby improving efficiency over the life of the vessel.

[0067] Air bubble curtains along the underwater hull of a ship have been demonstrated to provide a reduction in radiated noise. The present invention contributes to the reduction of noise pollution from ships and has potential military applications.

[0068] Thus, the present invention provides a system and method for reducing drag on a vessel's hull, thereby improving hydrodynamic efficiency, that reduces drag on the vessel's hull, provides a replaceable surface that can be temporarily affixed to the vessel's hull and reapplied during periodic dry-docking or underwater maintenance, and is used to recycle exhaust gases into an anti-friction gas layer that can reduce drag on the vessel's hull, thereby improving the vessel's energy efficiency and reducing greenhouse gas emissions due to reduced fuel consumption. The present device and system are specifically shown in Figures 1A-13.

[0069] 1A-1D illustrate the concept of contact angle as it relates to aerobic and hydrophobic properties of surfaces. FIG. 1A shows a surface that is superhydrophilic 102 in air and superanaerobic in water. In the top diagram, the contact angle of a water droplet on the surface surrounded by air is θ<5°. In the bottom diagram, the contact angle of an air pocket on the same surface surrounded by water is θ>150°. FIG. 1B shows a surface that is hydrophilic 104 in air and anaerobic in water. In the top diagram, the contact angle of a water droplet on the surface surrounded by air is 5°<θ<90°. In the bottom diagram, the contact angle of an air pocket on the same surface surrounded by water is 90°<θ<150°. FIG. 1C shows a surface that is hydrophobic 106 in air and aerobic in water. In the top diagram, the contact angle of a water droplet on the surface surrounded by air is 90°<θ<150°. In the bottom image, the contact angle of an air pocket on the same surface surrounded by water is 5°<θ<90°. Figure 1D shows a surface that is superhydrophobic in air and superaerobic in water. In the top image, the contact angle of a water droplet on the surface surrounded by air is θ>150°. In the bottom image, the contact angle of an air pocket on the same surface surrounded by water is θ<5°.

[0070] Figures 2A and 2B show non-scale representations of the surface topography of a laser-ablated alloy with microscopic and nanoscopic structures that form a superaerobic surface. Figure 2A shows this surface in air, while Figure 2B shows this surface surrounded by water. As can be seen in Figures 2A and 2B, there are microscopic ridges 110 remaining after the laser-ablated grooves are formed, laser-induced nanoscopic structures 112, air 114 in the embodiment shown in Figure 2A, air plastrons 116 that form, air bubbles 118 that penetrate the microscopic and nanoscopic surface and can repel water, and water 120 in the embodiment shown in Figure 2B. Additionally, there are also water droplets 122 present on the surface surrounded by air. This form of water droplet 122 has a very small interface with the surface, minimizing surface wetting. The air within the grooves helps prevent water from seeping out of the grooves.

[0071] Figure 3 shows a non-scale super-aerobic surface with a microscopic-nanoscopic surface structure, formed so that air plastrons are replenished through the microscopic perforations. Figure 3 shows a super-aerobic surface 124 with a microscopic-nanoscopic surface structure, a compressed air layer 126 present inside the surface 124, laser-drilled microscopic holes 128 through which the compressed air can pass, a microbubble air plastron 116 formed on the surface 124, water 120 present on the surface, and air particles 118 that have escaped from the air plastron 116 due to hydrostatic and hydrodynamic pressure.

[0072] Figure 4 shows the resulting functional surface assembly. This assembly is attached to a hull and has three layers. Figure 4 shows the hull 130, the outermost layer 132, which is a super-aerobic surface with microscopic and nanoscopic scale structures and microscopic perforations, and the porous middle layer 134. This porous middle layer 134 allows compressed air to be retained and then delivered to the super-aerobic surface through the microscopic perforations. Finally, the innermost layer 136, which is a contact layer, is shown. The contact layer 136 allows the entire functional surface assembly to be attached to the hull without adhesive penetrating the porous middle layer 134.

[0073] Figures 5A-5C show conceptual renderings of the resulting functional surface assembly applied to the bottom of a ship's hull. An air layer exists between the outermost layer, the superaerobic surface, and the water. Figure 5A shows an isometric view of the superaerobic surface topography, Figure 5B shows a side view, and Figure 5C shows a close-up. Figures 5A-5C show the hull 130, the contact layer 136, the porous intermediate layer 134, the superaerobic surface 124, the water 120 on which the ship floats, the microscopic-scale structures 110, the nanoscopic-scale structures 112, the microscopic pores 128 that allow compressed air in the porous intermediate layer to penetrate the superaerobic surface and join the air layer, and the air layer 116, or air plastron, present in the grooves and valleys of the microscopic- and nanoscopic-scale structures. This air layer prevents the surface from wetting.

[0074] Figure 6A shows a profile view of a vessel utilizing air lubrication with a superaerobic surface covering a portion of the vessel bottom, and Figure 6B shows a plan view. After initial injection, air tends to remain attached to the superaerobic surface of the vessel. Figures 6A and 6B show the vessel hull 601, air bubbles 118 released during injection, air 116 adhering to the vessel hull 130 in the area covered by the superaerobic surface, and surrounding water 120.

[0075] Figure 7A shows an air lubrication system used on a vessel with a hyperaerobic surface, and Figure 7B shows an air lubrication system on an anaerobic hull. As can be seen in Figures 7A and 7B, there is shown a hull 130, an air injection site 138, an air plastron 116 maintained on the hull 130 with a hyperaerobic surface, and air bubbles 118 bouncing off the hull using air lubrication on a conventional hull bottom.

[0076] Figure 8 shows a simplified system for carbon-enriched air lubrication. Figure 8 shows the hull 130, main engine 140, wastewater tank 142a / bioreactor 142b, galley exhaust system 146, piping 148 supplying carbon-enriched air to the air plastron make-up system, carbon filter 150, gas injection site 152 for the carbon-enriched air supplied to the air plastron of the functional surface assembly, conventional air compressor 144 / 176 for the vessel's air lubrication system, air injection site 138 for air lubrication, and air sheet 116 formed on the hull. Also shown is an air compressor 144 that routes exhaust from the main engine and wastewater tank, bioreactor, and galley to the air plastron make-up system.

[0077] Figure 9 shows a flow chart of the carbon enrichment process. As can be seen in Figure 8, there are shown engine exhaust gas 156 and carbon-rich gases 158a / 158b / 158c from other onboard sources, such as the dirty water tank, grey water tank, and galley. Also shown is a mixture 160 of carbon-rich gases 158a / 158b / 158c that have passed through the turbo compressor and the exhaust from the engine exhaust gas 156. Also shown is carbon-enriched air 162 that has passed through a carbon filter and carbon-enriched air 164 that is supplied to the bottom of the hull.

[0078] Figure 10 shows a simplified diagram of a conventional turbocharger with the addition of an exhaust gas rerouting pipe. As can be seen in Figure 10, there is an exhaust gas inlet 166, a turbine 168, a first exhaust rerouting pipe 170, a second exhaust rerouting pipe 172, a compressor air intake 174, a compressor 176, and an outlet 178 to an air plastron make-up. Exhaust enters through intake 166, spins turbine 168, and is exhausted from the turbine through first exhaust rerouting pipe 170. The exhaust then travels through second exhaust rerouting pipe 172 to compressor inlet 174. The exhaust is compressed in compressor 176 and is exhausted through outlet 178 to the air plastron make-up.

[0079] 11A and 11B illustrate how a parasitic compressor can be inserted into a turbine exhaust pipe to harness the rotational energy generated by the turbine and utilize the turbine exhaust as intake air. As can be seen in FIGS. 11A and 11B, there is an engine exhaust 180 entering the turbine intake, a turbine 182, a central shaft 184, a turbine exhaust pipe 186, a parasitic compressor intake 188 drawing in the turbine exhaust, a parasitic compressor 190, a parasitic compressor output 192 to the functional surface assembly, a conventional compressor intake 194 drawing in clean air, a conventional compressor 196, and a conventional compressor output 198 to the engine air intake. The output 192 produces compressed carbon-rich air that can be used to maintain the functional surface assembly. The parasitic compressor is exaggerated for illustrative purposes. The central shaft 184 may have a smaller radius on the parasitic compressor side than on the conventional compressor 196 side. A typical compressor takes in clean air at an intake 194 and outputs compressed clean air to the engine air intake through an output 198. The turbine 182 is driven by engine exhaust 180 entering the turbine intake.

[0080] Figures 12A and 12B show the major components of the filter assembly. Figure 12A is an assembly diagram, and Figure 12B is a side view of the assembled filter, with the internal components shown in phantom (dashed lines). Figures 12A and 12B show the intake port 200, lid 202, carbon-permeable membrane 204, internal chamber 206, outer casing 208, bypass outlet 210, and carbon-rich air outlet 212. The outer casing 208 is open at the top and has holes in the bottom and side to allow for the insertion of the outlet tubes 210 / 212. The lid 202 screws securely onto the outer casing. The lid is equipped with an O-ring and a push-to-open locking mechanism (not shown) to ensure a secure, airtight seal. Inside the outer casing is the internal chamber 206. The inner chamber is offset from the bottom and sides by some means, such as small standoffs attached to the outer wall of the inner chamber to center the chamber within the outer casing. The inner chamber is also open at the top and has a hole in its side that aligns with a hole in the side of the outer casing, both of which are located at the bottom of the inner chamber. A carbon-sensitive membrane 204 is inserted into the inner chamber. This membrane is located above the side hole and allows carbon-rich air to pass through while blocking other components. Three pipe connections are provided. The first connection, air intake 200, is inserted from the top and permanently welded to the lid. This allows exhaust gas to enter the inner chamber, creating enough pressure to push carbon molecules in the exhaust through the membrane, but not so much that it damages the membrane. A second pipe, air outlet 212, is connected to the inner chamber through the side. This pipe allows the carbon-rich air that has passed through the membrane to be exhausted. A third pipe 210 is connected at the bottom through the outer casing only, to vent any air that does not pass through the membrane. This outlet pipe should be fitted with a pressure relief valve (not shown) to prevent over-pressurisation of the filter chamber.

[0081] Figure 13 shows an example of a two-stage system where wastewater, bioreactor, or galley hood exhaust is added in the first stage and includes a carbon filter between stages 1 and 2. In the second stage, the pressure increases beyond the limit imposed by the carbon filter. As can be seen in Figure 11, there is an engine exhaust input 214, a first-stage turbine 216, an exhaust rerouting pipe 218, a mixing area 220 where additional gases (from the wastewater, bioreactor, or galley exhaust) are mixed, a first-stage compressor 222, a filter inlet 200, a carbon filter 150, a filter bypass outlet 210, an area 224 where carbon-rich gas enters the second-stage turbine, a second-stage turbine 168, a gas rerouting pipe 172, a second-stage compressor 176, and an outlet 178 to the air plastron make-up. Engine exhaust enters through engine exhaust input 214, drives first-stage turbine 216, travels through exhaust gas rerouting pipe 218, and is mixed with additional gases via intake mixing area 220. These combined gases enter first-stage compressor 222 and are directed to carbon filter 150 via filter inlet 200. After separation, unfiltered gases are discharged through bypass outlet 210, and carbon-rich gases are discharged through outlet area 224. The carbon-rich gases enter second-stage turbine 168. After rotating second-stage turbine 168, these carbon-rich gases travel through rerouting pipe 172 to second-stage compressor 176 and are discharged to air plastron make-up outlet 178.

[0082] 1A-13 , a system for reducing frictional drag on a marine vessel hull is disclosed. The system includes a multi-layer air lubrication system 236. The multi-layer air lubrication system 236 has at least three layers 132 / 134 / 136, including an outermost layer 132 having a constructed super-aerobic induction surface 124, a porous layer 134 that promotes gas supply exchange to the outermost layer 132, and a contact layer 136 for bonding the multi-layer air lubrication system 236 to the marine vessel hull 130. In some embodiments, the contact layer 136 is a solid material secured to the marine vessel hull 130 with an adhesive or sticky backing. The constructed super-aerobic induction surface may be laser ablated, but in other embodiments, it may be constructed using chemical vapor deposition, thermal spraying, or other techniques capable of precisely etching a surface. In some embodiments, the contact layer 136 is coated with a pressure sensitive adhesive for securing to the hull 130 of the marine vessel.

[0083] The system also includes at least one gas injection point 138 in the porous layer 134 for receiving the gas supply, and an air distribution and make-up system 234, shown in Figure 8 and seen in more detail in Figures 5A, 5B, and 5C, for providing the gas supply to the porous layer 134. In some embodiments, the injection point may include multiple smaller injection tubes to provide even distribution throughout the porous layer 134. The air distribution and make-up system 234 includes a compressor 144 / 176 to provide gas at a pressure slightly higher than that exerted by the water 120 on the air plastron 116 and to ensure continuous, enhanced air distribution.

[0084] In some embodiments, the super-aerobic-induced surface 124 of the multi-layer air lubrication system 236 of the system for reducing frictional drag on a marine vessel hull also includes a metal surface 115. In some embodiments, the metal surface is constructed of copper to provide antifouling properties. The metal surface 115 has a plurality of super-aerobic-induced microscopic structures 110 and nanoscopic structures 112 etched into the metal surface 115 by laser ablation. Each super-aerobic-induced microscopic structure 110 of the plurality of super-aerobic-induced microscopic and nanoscopic structures defines a trench 113a and ridge 109a shape. Each super-aerobic-induced nanoscopic structure 112 of the plurality of super-aerobic-induced microscopic and nanoscopic structures defines a trench 113b and ridge 109b shape on each sidewall 111 of the super-aerobic-induced microscopic structure 110. As can be seen in Figures 4, 5A, 5B, and 5C, the metal surface 115 has a plurality of openings 128 at least at the innermost point 129 of the trench 113a and ridge 109a shape of the ultra-aerobic induction microscopic structure, and each opening 128 of the plurality of openings is configured to pass supplied air from the inside 230 of the metal structure 115 to the wet side 232 of the metal structure 115, thereby generating an air plastron 116 when engaged.

[0085] In some embodiments, the gas supply comprises filtered carbonaceous gases, including at least carbon dioxide, carbon monoxide, and methane, to enhance the aerobic and hydrophobic properties of the hyperaerobic surface. The gas supply is obtained from at least one of the external atmosphere, the engine 140 exhaust 156, the wastewater tank 142a exhaust 158a, the bioreactor 142b exhaust 158b, and the galley hood 146 exhaust 158c, and the gas supply is rerouted from at least one of the external atmosphere, the engine exhaust, the wastewater tank exhaust, the bioreactor exhaust, and the galley hood exhaust through a turbocharger 248 to the compressor input 174 of the compressor 176, which then supplies the air distribution and make-up system 234. This can be seen in FIG. 10, which also shows airflow 228.

[0086] In some embodiments, the system for reducing frictional drag on a marine vessel hull further comprises a carbon filter 150. In some embodiments, the carbon filter 150 has at least an outer casing 208, a lid 202, an intake tube 200, and a replaceable carbon-sensitive membrane 204 configured to allow carbon molecules to pass through the replaceable carbon-sensitive membrane 204, with the remaining gas molecules that cannot pass through the replaceable carbon-sensitive membrane 204 passing around an upper portion 238 and a side portion 240 to a lower portion 242 where the molecules are collected and filtered, from where they are discharged through the carbon-reduction outlet 212. This can be seen in FIGS. 12A and 12B .

[0087] In some embodiments, the system for reducing frictional drag on the hull of a marine vessel further comprises a valve (not shown, but understandable to one skilled in the art) in the air make-up system 234 to prevent loss of pressure in the event of a failure of the air make-up system 234.

[0088] In another exemplary embodiment of the present invention, as shown in FIGS. 2A-5C , a super-aerobic-inducing surface 124 for use in reducing hydrodynamic drag on a marine vessel hull is disclosed. The super-aerobic-inducing surface 124 for use in reducing hydrodynamic drag on a marine vessel hull comprises a metal surface 115. The metal surface 115 has a plurality of super-aerobic-inducing microscopic structures 110 and nanoscopic structures 112 etched into the metal surface 115 by laser ablation. Each super-aerobic-inducing microscopic structure 110 of the plurality of super-aerobic-inducing microscopic and nanoscopic structures defines a trench 113 a and ridge 109 a shape. Each super-aerobic-inducing nanoscopic structure 112 of the plurality of super-aerobic-inducing microscopic and nanoscopic structures defines a trench 113 b and ridge 109 shape on each sidewall 111 of the super-aerobic-inducing microscopic structure 110. The metal surface 115 also has a plurality of openings 128 at least at the innermost points 129 of the trench and ridge shapes of the ultra-aerobic inducing microscopic structure, each opening 128 of the plurality of openings configured to allow supplied air to pass from an interior 230 of the metal structure 115 to a wet side 232 of the metal structure 115, thereby generating an air plastron 116 upon engagement. Copper may be used as the material for the metal surface 115 to further promote anti-fouling properties.

[0089] In some embodiments, the porous layer 134 is configured to withstand the pressure exerted by the air plastron 116 and the surrounding water 120 while maintaining a shape that allows the free flow of gas into the plurality of openings 128.

[0090] In yet another embodiment, a method for reducing frictional drag on a marine vessel hull 130, thereby improving its efficiency, is disclosed. As shown in FIGS. 2A-5C, the method includes configuring the marine vessel hull 130 to reduce frictional drag by providing at least a super-aerobic induction surface 124, the super-aerobic induction surface 124 comprising a metal surface 115 having a plurality of super-aerobic induction microscopic structures 110 and nanoscopic structures 112 etched into the metal surface 115 by laser ablation, each super-aerobic induction microscopic structure 110 of the plurality of super-aerobic induction microscopic and nanoscopic structures defining a trench 113a and ridge 109a shape, and the plurality of super-aerobic induction microscopic and nanoscopic structures defining a trench 113a and ridge 109a shape. Each super-aerobic induction nanoscopic structure 112 of the induction microscopic-nanoscopic structure defines a trench 113b and ridge 113b shape in each sidewall 111 of the super-aerobic induction microscopic structure 110, and the metal surface 115 has a plurality of openings 128 at least at an innermost point 129 of the trench 113a and ridge 109a shape of the super-aerobic induction microscopic structure 110, and each opening 128 of the plurality of openings is configured to pass supplied air from an inside 230 of the metal structure 115 to a wet side 232 of the metal structure 115, thereby generating an air plastron 116 when engaged.

[0091] In some embodiments of a method for reducing frictional drag on a marine vessel hull 130, the super aerobic induction surface 124 is applied in a process of configuring the marine vessel hull 130 to reduce frictional drag by providing the super aerobic induction surface 124. The surface 124 is formed by a) bonding together at least three layers 132 / 134 / 136, the at least three layers 132 / 134 / 136 including an outermost super aerobic induction surface layer 132 / 124, a middle porous layer 134, and an inner contact layer 136, thereby forming a functional surface assembly 250; and b) laser ablating the outermost super aerobic induction surface layer 132 / 115 to form the super aerobic surface 124, the super aerobic properties being achieved by a microscopic surface structure 110 and a nanoscopic surface structure 115 comprising grooves 244 etched into the surface 115. c) creating a laser-induced periodic surface structure 124, thereby adding a second structural layer at the nanoscopic scale; d) using a laser to form a plurality of openings 128 by drilling evenly spaced microscopic holes through the outermost super-aerobic-inducing surface layer 124 within the depressions formed by the trench 113a and ridge 109a shapes of the microscopic-scale grooves 244; and d) configuring at least one gas injection point 152 in the intermediate porous layer for receiving a gas supply.

[0092] In some embodiments, the method further includes applying the ultra-aerobic surface 124 to the marine vessel hull 130 by engaging the adhesive applied to the contact layer 136 with the marine vessel hull 130.

[0093] In some embodiments, the method further includes providing an air distribution and make-up system 234 that supplies gas to the air plastron 116 at a pressure slightly higher than that exerted by the water 120 to ensure continuous aeration, and a piping system 148 connecting the gas supply to the compressor 144. This can be seen in Figures 8-13.

[0094] In some embodiments, the method further includes providing a continuous gas supply from an air distribution and make-up system 234 to at least one gas injection point 152 in the middle porous layer 134 .

[0095] In some embodiments, the method further includes using a carbon-based gas to accelerate the conversion of the laser-ablated superaerobic-inducing surface 124 to a laser-ablated superaerobic-inducing surface 124 with improved aerobic and hydrophobic properties.

[0096] In some embodiments, the method further includes configuring the air distribution and make-up system 234 to receive a gaseous supply of carbon from at least one of the external atmosphere 246, the engine exhaust 156, the wastewater tank exhaust 158a, the bioreactor exhaust 158b, and the galley hood exhaust 158c, wherein the gaseous supply is rerouted from at least one of the external atmosphere 246, the engine exhaust 156, the wastewater tank exhaust 158a, the bioreactor exhaust 158b, and the galley hood exhaust 158c through the turbocharger 248 to the compressor input 174 of the compressor 144 / 176, thereby causing the compressor 144 / 176 to supply the air distribution and make-up system 234.

[0097] In some embodiments, the method further includes providing a carbon filter 150 having at least an outer casing 208, a lid 202, an intake tube 200, and a replaceable carbon-sensitive membrane 204, wherein the replaceable carbon-sensitive membrane 204 is configured to allow carbon molecules to pass through the replaceable carbon-sensitive membrane 204, and the remaining gas molecules that cannot pass through the replaceable carbon-sensitive membrane 204 are collected and filtered around an upper portion 238 and a side portion 240 to a lower portion 242 where the molecules are discharged through a carbon-reducing outlet 212.

[0098] In some embodiments, the method further includes configuring metal surface 115 with anti-fouling properties by selecting copper as the material for metal surface 115, thereby reducing the accumulation of dirt and keeping opening 128 clean for gas replenishment and distribution.

[0099] The disclosed systems and methods can be employed to improve the fuel efficiency of marine vessels or other vehicles affected by hydrodynamic drag, while employing methods and components that minimize the energy used to operate the system, resulting in a net increase in fuel efficiency and a reduction in greenhouse gas emissions.

[0100] While preferred embodiments of the invention have been shown and described above, it is to be understood that the invention may be embodied other than as particularly shown and described herein, and that certain changes may be made in the form and arrangement of parts without departing from the underlying spirit or principles of the invention as set forth in the appended claims.

Claims

1. 1. A system for reducing frictional drag on a hull of a marine vessel, comprising: Equipped with a multi-layer air lubrication system, The multi-layer air lubrication system has at least three layers, including an outermost layer having a constructed super-aerobic induction surface, a porous layer that promotes exchange of gas supply to the outermost layer, and a contact layer for joining the multi-layer air lubrication system to the hull of a marine vessel. system.

2. The constructed ultra-aerobic induction surface further comprises a metal surface; the metal surface has a plurality of hyperaerobic-induced microscopic and nanoscopic structures etched into the metal surface by laser ablation; each hyper-aerobic-induced microscopic structure of the plurality of hyper-aerobic-induced microscopic-nanoscopic structures defines a trench and ridge shape; each super-aerobic-induced nanoscopic structure of the plurality of super-aerobic-induced microscopic-nanoscopic structures defines a trench and ridge shape in a sidewall of each of the super-aerobic-induced microscopic structures; 2. The system for reducing frictional drag on a hull of a marine vessel as described in claim 1, wherein the metal surface has a plurality of openings at least at the innermost points of the trench and ridge shapes of the hyperaerobic-inducing microscopic structure, each opening of the plurality of openings configured to pass supplied air from the inside of the metal structure to the wet side of the metal structure, thereby generating an air plastron upon engagement.

3. 3. The system for reducing frictional drag on a marine vessel hull as set forth in claim 2, wherein the metal surface comprises copper and is used for anti-fouling functions to inhibit the accumulation of fouling.

4. at least one gas injection point within said porous layer for receiving a gas supply; an air distribution and replenishment system that provides the gas supply to the porous layer; Further provided with 10. The system for reducing frictional drag on a marine vessel hull as described in claim 1, wherein the air distribution and make-up system includes a compressor for supplying gas at a pressure slightly higher than that exerted by the water on the air plastron to ensure continuous promotion of air dispersion.

5. 5. The system for reducing frictional drag on a hull of a marine vessel as described in claim 4, wherein the gas supply consists of filtered carbon-based gases including at least carbon dioxide, carbon monoxide, and methane to enhance the aerobic and hydrophobic properties of the superaerobic surface.

6. 6. A system for reducing frictional drag on a hull of a marine vessel as described in claim 5, wherein the gas supply is obtained from at least one of the external atmosphere, an engine exhaust, a wastewater tank exhaust, a bioreactor exhaust, and a galley hood exhaust, and the gas supply is rerouted from the at least one of the external atmosphere, the engine exhaust, the wastewater tank exhaust, the bioreactor exhaust, and the galley hood exhaust through a turbocharger to a compressor input of the compressor, whereby the compressor supplies the air distribution and make-up system.

7. 7. The system for reducing frictional drag on a hull of a marine vessel according to claim 6, further comprising a carbon filter.

8. 8. The system for reducing frictional drag in a hull of a marine vessel as described in claim 7, wherein the carbon filter has at least an outer casing, a lid, an intake pipe, and a replaceable carbon-sensitive membrane configured to allow carbon molecules to pass through the replaceable carbon-sensitive membrane, and remaining gas molecules that cannot pass through the replaceable carbon-sensitive membrane are collected and filtered through an upper and side periphery to a lower part where the molecules are discharged through a carbon reduction outlet.

9. 5. The system for reducing frictional drag in a hull of a marine vessel as described in claim 4, wherein the at least one gas injection point in the porous layer for receiving a gas supply further comprises a plurality of smaller injection tubes to provide uniform distribution throughout the porous layer.

10. 10. The system for reducing frictional drag on a marine vessel hull as set forth in claim 1, wherein the contact layer is a solid material secured to the marine vessel hull by an adhesive or sticky backing.

11. 10. The system for reducing frictional drag on a marine vessel hull as set forth in claim 1, wherein the contact layer is coated with a pressure sensitive adhesive.

12. 10. The system for reducing frictional drag on a hull of a marine vessel as set forth in claim 1, further comprising a valve in the air make-up system to prevent loss of pressure in the event of a failure of the air make-up system.

13. 1. A superaerobic induction surface for use in reducing hydrodynamic drag on a hull of a marine vessel, comprising: With a metal surface, the metal surface has a plurality of hyperaerobic-induced microscopic and nanoscopic structures etched into the metal surface by laser ablation; each hyper-aerobic-induced microscopic structure of the plurality of hyper-aerobic-induced microscopic-nanoscopic structures defines a trench and ridge shape; each super-aerobic-induced nanoscopic structure of the plurality of super-aerobic-induced microscopic-nanoscopic structures defines a trench and ridge shape in a sidewall of each of the super-aerobic-induced microscopic structures; The metal surface has a plurality of openings at least at the innermost points of the trench and ridge shapes of the ultra-aerobic induction microscopic structure, and each opening of the plurality of openings is configured to pass supplied air from the inside of the metal structure to the wet side of the metal structure, thereby generating an air plastron when engaged, the ultra-aerobic induction surface.

14. 14. The super aerobic induction surface for use in reducing hydrodynamic drag on a hull of a marine vessel as described in claim 13, wherein the porous layer is configured to withstand pressure exerted by the air plastron and the water surrounding it while maintaining a shape that allows free flow of gas into the plurality of openings.

15. 14. The super aerobic induction surface for use in reducing hydrodynamic drag on a marine vessel hull as set forth in claim 13, wherein the metal surface comprises copper and is used for an anti-fouling function to inhibit the accumulation of fouling.

16. 1. A method of reducing frictional drag on a hull of a marine vessel, thereby improving its efficiency, comprising: configuring a hull of a marine vessel to reduce frictional drag by providing a superaerobic guidance surface; the super-aerobic induction surface comprises a metal surface having a plurality of super-aerobic induction microscopic and nanoscopic structures etched into the metal surface by laser ablation; each super-aerobic-inducing microscopic structure of the plurality of super-aerobic-inducing microscopic-nanoscopic structures defines a trench and ridge shape; each super-aerobic-inducing nanoscopic structure of the plurality of super-aerobic-inducing microscopic-nanoscopic structures defines a trench and ridge shape in a sidewall of each of the super-aerobic-inducing microscopic structures; and the metal surface comprises a plurality of openings at least at innermost points of the trench and ridge shapes of the super-aerobic-inducing microscopic structures; each opening of the plurality of openings is configured to pass a supply of air from an interior of the metal structure to a wet side of the metal structure, thereby creating an air plastron upon engagement; method.

17. In the step of configuring a hull of a marine vessel to reduce frictional drag by providing a superaerobic induction surface, the superaerobic induction surface comprises: bonding at least three layers together, the at least three layers including an outermost ultra-aerobic inducing surface layer, a middle porous layer, and an inner contact layer, thereby forming a functional surface assembly; forming a superaerobic surface by laser ablation of the outermost superaerobic-inducing surface layer, wherein the superaerobic properties are achieved by creating microscopic and nanoscopic surface structures including grooves etched into the surface; creating a laser-induced periodic surface structure, thereby adding a second structural layer at the nanoscopic scale; forming the plurality of openings by drilling regularly spaced microscopic holes through the outermost ultra-aerobic inducing surface layer using a laser within the recesses formed by the trenches and ridges of the microscopic grooves; configuring at least one gas injection point within said intermediate porous layer for receiving a gas supply; 17. A method of reducing frictional drag on a hull of a marine vessel and thereby improving its efficiency as claimed in claim 16, applied by:

18. applying the ultra-aerobic surface to the hull of the marine vessel by engaging the adhesive applied to the contact layer against the hull of the marine vessel.

20. The method of reducing frictional drag on a hull of a marine vessel, thereby improving its efficiency, as set forth in claim 17, further comprising:

19. providing an air distribution and make-up system, said air distribution and make-up system comprising a compressor for supplying gas to said air plastron at a pressure slightly higher than that exerted by the water to ensure continuous promotion of air distribution, and a piping system connecting a gas supply to said compressor; 17. The method of reducing frictional drag on a hull of a marine vessel, thereby improving its efficiency, as set forth in claim 16, further comprising:

20. providing a continuous gas supply from said air distribution and make-up system to said at least one gas injection point within the intermediate porous layer.

20. The method of reducing frictional drag on a hull of a marine vessel, thereby improving its efficiency, as set forth in claim 19, further comprising:

21. using a carbon-based gas to accelerate the conversion of the laser-ablated superaerobic-inducing surface to a laser-ablated superaerobic-inducing surface having improved aerobic and hydrophobic properties; 21. The method of reducing frictional drag on a hull of a marine vessel, thereby improving its efficiency, as set forth in claim 20, further comprising:

22. configuring the air distribution and makeup system to receive a carbon gas supply from at least one of the outside atmosphere, an engine exhaust, a wastewater tank exhaust, a bioreactor exhaust, and a galley hood exhaust, wherein the gas supply is rerouted from at least one of the outside atmosphere, the engine exhaust, the wastewater tank exhaust, the bioreactor exhaust, and the galley hood exhaust through a turbocharger to a compressor input of the compressor, whereby the compressor supplies the air distribution and makeup system; 22. The method of reducing frictional drag on a hull of a marine vessel, thereby improving its efficiency, as set forth in claim 21, further comprising:

23. providing a carbon filter having at least an outer casing, a lid, an intake pipe, and a replaceable carbon-sensitive membrane configured to allow carbon molecules to pass through the replaceable carbon-sensitive membrane, and the remaining gas molecules that cannot pass through the replaceable carbon-sensitive membrane are collected and filtered through a top and side periphery to a bottom where the molecules are discharged through a carbon-reducing outlet; 23. The method of reducing frictional drag on a hull of a marine vessel, thereby improving its efficiency, as set forth in claim 22, further comprising:

24. configuring the metal surface to have antifouling properties by selecting copper as the material of the metal surface, thereby reducing the accumulation of dirt and keeping the opening clean for gas replenishment and distribution; 17. The method of reducing frictional drag on a hull of a marine vessel, thereby improving its efficiency, as set forth in claim 16, further comprising:

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