WO2020118389A1

WO2020118389A1 - Device for reducing dynamic drag

Info

Publication number: WO2020118389A1
Application number: PCT/BR2018/050459
Authority: WO
Inventors: Paul Gaiser
Original assignee: Paul Gaiser
Priority date: 2018-12-13
Filing date: 2018-12-13
Publication date: 2020-06-18
Also published as: BR112021011039A2

Abstract

The present invention relates to a device (100) for reducing dynamic drag in a fluid medium (400), comprising a main body (200) provided with a plurality of oblique through holes (210), that is fastened to the surface of the element for which the device is intended, at a distance (h) from this surface, the side holes and other holes thereof being joined to the surface by means of closing flaps (230, 240) such that the holes are perfectly sealed about the entire device (100), except in an air-intake region (220).

Description

DYNAMIC DRAG REDUCER DEVICE

Application field

[001] The present invention belongs to the field of devices for vessels, ships, subsea equipment and ships, with respect to its hydrodynamic, aerodynamic and flotation resources; and the field of devices for vehicles and equipment on the ground, aircraft in general and wind turbines, with respect to their aerodynamic resources.

Introduction

[002] The present invention relates to a dynamic drag reducing device in fluid medium, composed of a main body with openings, which causes interposition of air between the fluid medium and the rigid surfaces in dynamic contact, so that the drag (frictional force) decreases with the intervening air.

State of the art

[003] Currently, several solutions are known from the state of the art aiming to improve the aero and / or hydrodynamics of means of transport and equipment of the nature treated here.

[004] An example is the solution revealed by patent document WO201006491 1, concerning a microbubble generator in the hull of a ship. This document reveals a method for generating a layer of bubbles in a vessel's hull, which comprises the steps of: i) providing a cavity in the bottom of the vessel, with a length of at least 1 m, and no more than 30 % of vessel L length along the bottom, preferably not more than 25%, more preferably not more than 10% of vessel L length, and with an upper surface spaced at least 50 cm from the lower plane, preferably at least 1 m from the lower plane; ii) supply air in the cavity by means of a compressor device at a pressure greater than the atmospheric pressure to empty at least partially the water in the cavity; iii) providing a water / air interface in the cavity to form a mixing region; iv) generate a plurality of air bubbles in the mixing region and; v) provide a bubble outlet at or near the back of the cavity to allow bubbles to flow along the hull towards the rear of the vessel.

[005] As it is possible to deduce from the patent document WO201006491 1, the revealed bubble generator has, as one of its main problems, the requirement of a form of active bubble generation based on the pumping of air through a compressor device . Such configuration necessarily requires the installation of equipment specific to the vessel, which, in addition to being expensive, uses space from the boat, adds weight and consumes extra energy, in addition to requiring additional management of resources. Its versatility is compromised due to the fact that different types of vessels are not suitable for their use, in addition to no mention being made, in WO201006491 1, to their use in other types of means of transport that could use technologies of this type. nature.

[006] Another example of the state of the art is the solution revealed by the patent document US 9,376,167, relating to a device for reducing frictional resistance for ships. Said device is based on means of control of gas injection that carry out control reflecting in variation in the speed of the vessel over time without adversely affecting its main engine. That is, it avoids that the gas is consumed too much and, thus, that the gas supply or the air load does not become insufficient, that the efficiency of the main engine decreases, that the exhaust gas is deteriorated and that similar events occur. . In it are provided: a main engine that acquires propulsion energy for a vessel and a turbocharger that is driven by the exhaust gas from the main engine and that blows pressurized gas into the main engine. A portion of the pressurized gas and / or the exhaust gas is extracted between the turbocharger and the main engine. The pressurized gas removed and / or the exhaust gas is / are injected (s) in the vicinity of the hull above or below the water line, and the extraction rate of the pressurized gas and / or the exhaust gas is controlled based on in a physical quantity related to a heat load on the main engine and the characteristics of the turbocharger.

[007] Once again, it is possible to deduce from the patent document US 9,376,167 that the revealed bubble generator has, as one of its main problems, the requirement for a form of active bubble generation based on the pumping of air or gas through a compressor. In addition to being expensive, such a configuration necessarily requires the installation of equipment specific to the vessel so that it is possible to manage the use of air or gas and be able to inject it into the outlets responsible for reducing the vessel's friction. Its versatility is also compromised in view of different types of vessels, particularly smaller vessels. In addition, no mention is made in US 9,376,167 of its use in other types of means of transport that could use technologies of this nature.

[008] Other state-of-the-art documents that fail to solve problems such as those mentioned above include US 4,989,534, US 5,456,201, US 2009/0031937 and US 6,789,491. In addition to the problems mentioned above, other disadvantages present in solutions such as those mentioned here include drastic changes made to vessels and high installation and maintenance costs embedded in the devices or devices. Such patent documents bring little discussion about the materials suitable for such applications, in which the devices will necessarily be exposed to conditions widely known to be aggressive and intensive, such as humidity, high pressure, high levels of salinity, in addition to damage caused by debris found in water and aquatic life forms.

[009] It should be noted, therefore, that there is a demand for a device of the aforementioned nature that will solve the problems of the state of the art, especially a device that offers a better cost-benefit ratio, which also allows easy adaptation to and / or installation in types of vessels and means of transport and which, in addition, has high resistance to bad weather and adverse conditions associated with circumstances such as those described above and do not consume extra energy to those offered and used “in situ”.

Objectives of the invention

[010] One of the objectives of the present invention is to provide a dynamic drag reduction device, superimposed on the carcass of a ship or equipment, whatever the types they may be, moving in a fluid medium, in which such device comprises a main body provided of slanting and passing openings fixed on the body of the ships or equipment with a certain distance or spacing, in which said spacing is sufficient to allow air to flow, in which it will travel there by force of suction by the part in laminar friction in the largest areas in contact with the fluid medium and by force of pressure in the air intake opening to the direction of movement, caused by the displacement of the ship or equipment. Brief description of the figures

[01 1] For a better understanding and visualization of the object of the present invention, it will now be described with reference to the attached figures, representing the technical effect obtained through an exemplary modality not limiting the scope of the present invention, in which:

Figure 1: schematically shows a side view in partial section of the central body of a dynamic drag reduction device according to the invention for liquid media, installed on a vessel;

Figure 1 a: schematically shows a front view in partial section of the central body of a dynamic drag reduction device according to the invention for liquid media, installed on a vessel;

Figure 2: schematically shows an enlarged side view of detail A of figure 1; Figure 3: schematically shows an enlarged side view of detail B of figure 1;

Figure 4: shows a bottom view of the main body of the dynamic drag reduction device;

Figure 5: schematically shows a side view in partial section of the dynamic drag reduction device according to the invention for vehicles and equipment on the ground, recording air flows, catchment opening and closures;

Figure 6: schematically shows a side view in partial section of the dynamic drag reduction device according to the invention for vehicles and equipment on the ground or overhead, recording air flows, catchment opening and closures;

Figure 7: schematically presents a side view in partial section of the dynamic drag reduction device according to the invention for round or rounded parts of vehicles and ground and aerial equipment, traveling in the air, recording air flows, intake opening and closings; and

Figure 8: schematically shows a side view in partial section of the dynamic drag reduction device according to the invention for underwater vessels, recording air flows, catchment opening and closures.

Detailed description of the invention

[012] The present invention will now be described in detail based on the aforementioned figures, but not limited to them.

[013] The dynamic drag reduction device (100) according to the invention basically comprises a main body (200) provided with a plurality of oblique openings (210), wherein said main body (200) is attached to the surface of the element for which it is intended.

[014] This element can be the watertight housing (300) of a vessel (500), a vehicle (600), an aircraft (700) or any other construction element, accessory or object (800), but always a element in dynamic contact with a fluid medium (400).

[015] The dynamic drag reduction device (100), or only device (100), is superimposed on the element for which it is intended at a distance or height (h), where this height (h) will vary according to the application, especially according to the medium, the speed, the pressure of the medium and the contact area. The height (h) will usually vary between 0.5 mm and 2.000 mm, being able to be uniform or not, that is, being able to vary along the surface of the element for which it is intended, having, however, its dimensional constancy determined and guaranteed by a or more spacer elements (250), of material, consistency, shape and other characteristics suitable for each application.

[016] It should be noted that the main body (200) of the device (100) has its side openings and other openings joined to the watertight housing (300) by means of closing flaps (230, 240) so that the openings are perfectly sealed around the entire device (100), except in the air intake region (220). The main body (200) of the device (100) must be properly secured and positioned in relation to the main body (200) of the device (100), and there must always be an opening for air inlet (220), that is, pressure positive, which can be arranged on the upper sides and / or on the front or attack surface of the element for which it is intended and / or in the form of ducts and / or channels and / or chimneys and the like. This opening may be arranged in the dry front part of a vessel (500), of a vehicle (600), of an aircraft (700) or of any other constructive element, accessory or object (800), and in the form of capture chimneys or suction (260) in the case of underwater vessels (900), but always in elements that are in displacement and in dynamic contact with the fluid medium (400). [017] The main body (200) of the dynamic drag reduction device (100) has a shape suitable for the surface of the element for which it is intended, and may be, for example, a flat and / or three-dimensional surface and / or free in shape of blade or plate, being composed of suitable material, preferably a light material and, in particular, lighter (less dense) than the material of the element for which it is intended, preferably a polymeric material suitable for the application, without, however, being limited to that kind of material.

[018] The main body (200) according to the present invention has a thickness that can vary from 1 mm to 5,000 mm, according to the depth and size of the contact area in liquid medium or with the size and the contact area in air, without, however, being limited to such values. For each case there are ideal thickness and distance or height (h) measurements, depending on the different pressures in the depths and the displacement speeds imposed by the existing driving forces.

[019] The oblique openings (210) are perforated in the thickness of the main body (200) of the device (100), through it and being in contact with the fluid on both the upper and lower faces of the main body (200) .

[020] The important distances for the oblique openings (210) are the longitudinal distance (a), the transverse distance (b) and the transverse spacing (c), and vary depending on the fluid medium, pressure, displacement speed of the element and the diameter (or cross-section) of the oblique openings (210), which may vary, between one and the other, from 1 mm to 30,000 mm taking into account, in these minimum and maximum values, the existence of small boats (drones ) and vessels up to 500 meters in length. In addition, it should be noted that the oblique openings (210) can have a cross section of any desired shape, the easiest and simplest being round or oval or oblong, but it can also have any polygonal shape suitable for the application, including sections square, triangular, polyhedral, etc. [021] The oblique openings (210) act as suction-generating “chambers” and are capable of allowing passive air flows by simply moving the element in a fluid medium.

[022] Therefore, the oblique angles of the orifices relative to the direction of the dynamic contact between the fluid medium (400) and solid surfaces in contact, will range from 1 to 89 °, according to the positioning surfaces relation to the flow direction, the pressures of the fluid medium and the size of the areas of the solid parts in contact with the fluid medium, since the air flows must be as free as possible within the space generated by the heights (h) between the drag reduction device (100) and the rigid surfaces of the elements for which it is intended.

[023] The oblique openings (210) or “suction chambers” at the end of each orifice and the opening should also be sized so that they supply the air in the amount necessary for said property to passively insert a layer of air between the solid surfaces and fluid media (400), whether liquid or gaseous. This amount of air required depends on the speed, pressure of the fluid medium and the contact area.

[024] In order to obtain the desired effect, the oblique angle must be more accentuated, as this causes a larger volume “chamber”, which provides a greater suction force (vacuum), allowing suction to greater depths , for example, on vessels (500).

[025] The device (100) of the present invention takes advantage of the physical phenomenon already described by Bernoulli and later by Venturi: the device (100) being installed in superposition to a rigid surface of a moving body with empty space (air) between both (ie, the height (h)) maintained by means of spacer elements (250), the device (100) being provided with oblique openings (210) for permanent air access, there will be a tendency for the fluid to occupy the entire area larger of the main body surface (200), passing through the openings (210) and, thereby, causing low pressure zones in these oblique openings (210) (“suction chambers”) that connect the two faces of the main body (200) . Since the lower face of the main body (200) is also facing a space equally occupied by a fluid, this fluid is moved towards the side with the least pressure between the two sides of the oblique opening (210).

[026] This phenomenon results in fluid drainage. In the present case, water in the initial phase of the movement until it drains, or air in the working regime phase, so that the device (100) then starts to suck air permanently, causing the air to interpose in the relation of friction between main body (200) in motion and the fluid. In this way, the friction becomes partly of the main body (200) with the air and the fluid, and no longer only of the main body (200) with the fluid.

[027] Thus, for example, if the fluid is water on both sides of the main body (200), that fluid must be exhausted until it is replaced by air. It is the air that must then interpose in the form of bubbles between the rigid surfaces of the device (100) submerged in water, with much of the friction occurring between air and water. If the fluid is air from both sides of the main body (200), the air is sucked in on one side, resulting in swirling micro-vortices, of higher density than the air passing laminarly to the other, causing this swirling air to interpose together to the surface, passing much of the friction between air and air.

[028] In this way, the friction of the moving element is significantly reduced by the device (100), resulting in an improvement in the displacement performance of this object, reduction of the energy needed to maintain a certain displacement speed, etc.

[029] It should be noted that, being the oblique openings (210) (holes without protrusion or reliefs), the device (100) according to the invention becomes even more efficient, since, being its main body (200) , of at least one plane, has better aero or hydrodynamic performance, in addition to protrusions or raised surfaces that are subject to flattening and shocks in different contexts (such as the encounter with some rigid submerged obstacle, for example). Even so, the present invention should not be understood as limited to flat or smooth surfaces, and may also be provided with flaps or nozzles or protuberances at the exit of the oblique openings (210), that is, on the side of the oblique openings (210) facing the external face of the main body.

[030] The person skilled in the art will also understand that if the dynamic drag reduction device (100) is preferably made of polymeric material, especially of material with a density less than or equal to 1.0 g / cm ³ , it will not add unwanted weight to the element for which it is intended.

[031] A minimum possible density value for the main body (200) of the device (100) is given by the requirement of a minimum thickness capable of enabling the execution of oblique openings (210), to ensure that they have adequate volume for creation the low pressure necessary for the suction of the fluid (water or air) at the beginning of the movement, that is, the suction of the fluid that is occupying the space between the device (100) and the housing (300).

[032] Among the polymeric materials on the market, among those that preferentially best adapt to compose the main body of the dynamic drag reducer, object of the present invention, we highlight those with a polyethylene base, such as UHMW-PE (ultra high polyethylene) molecular weight) and HDPE (high density polyethylene), and the chemical industry has increasingly developed different types of engineering polymers, with different mechanical, chemical and physical characteristics. The lighter and more resistant they are, the more qualified they are to fulfill the desired function of reducing dynamic drag in a technically and economically viable way.

[033] Thus, the use of the dynamic drag reduction device (100) according to the invention and according to the modality illustrated by the attached figures is able to solve, simultaneously, several problems of the state of the art.

[034] The dynamic drag reduction device (100) therefore makes it possible to improve the performance of a means of transport without the addition of compressors and other expensive systems for air injection or other type of gas, reducing its weight and its cost. [035] The present dynamic drag reduction device (100) also solves the serious problem of the lack of versatility in the solutions provided by the state of the art. As illustrated in the figures, its suitability for different types of vessels allows this device (100) to be placed on vessels of different sizes without difficulties of installation or removal in future situations. Its easy installation and removal provide several advantages such as, for example, the possibility of easy maintenance and the non-devaluation in the sale value of the means of transport (which often suffers depreciation for having undergone some form of modification).

[036] As discussed above, some of the state of the art solutions do not cover other means of transport, such as aircraft, such as their objects. The person skilled in the art will understand that the present invention can be installed in the housing of vehicle parts, and can cover wind turbine blades, aircraft wings, truck chests, high-speed trains, among others. For this purpose, the main body (200) of the device (100) can be both rigid and flexible, without departing from the scope of protection of the present invention.

[037] Finally, the person skilled in the art will understand that the device (100) according to the present invention has adequate resistance to various situations foreseen for its use, including the actions of the weather and several adverse conditions associated with circumstances such as those described above.

Conclusion

[038] It will be easily understood by those skilled in the art that modifications can be made in the present invention, without departing, with this, from the concepts exposed in the description above. Such modifications should be considered to be within the scope of the present invention. Consequently, the particular embodiments described in detail above are only illustrative and exemplary and are not limiting as to the scope of the present invention, which should be given the full extent of the appended claims and any and all equivalents thereof.

Claims

1. Dynamic drag reduction device (100), characterized in that it comprises a main body (200) with a plurality of oblique openings (210) and through, being fixed to the surface of the element for which it is intended for a distance or distance (h ) of this surface, with its side openings and other openings joined to the surface by means of closing flaps (230, 240) so that the openings are perfectly sealed around the entire device (100), except in an entrance region of air (220).

Device according to claim 1, characterized in that the spacing (h) can be uniform or vary across the surface of the element for which it is intended, the respective measurement being determined by one or more spacing elements (250).

Device according to claim 1, characterized in that the air inlet region (220) is a region of positive pressure.

4. Device according to claim 1, characterized in that the oblique angle of the oblique apertures (210) relative to the direction of the dynamic contact between the fluid medium (400) and solid surfaces in contact, ranging from 1 to 89 °.