Non-invasive flow velocity profile measuring apparatus for non-invasively measuring flow velocity profile of fluid in pipe

Abstract

A non-invasive flow velocity profile measuring device for non-invasively measuring the flow velocity profile of a fluid within a pipe is disclosed. The disclosed non-invasive flow rate profile measuring device comprises a mutually spaced first-1 sensor unit and a first-2 sensor unit disposed at the center or adjacent portion of the outer surface of a pipe through which fluid passes, wherein the first-1 sensor unit comprises a first-1 ultrasonic transducer and a first-1 medium portion disposed between the first-1 ultrasonic transducer and the pipe, wherein the first-1 medium portion comprises a first sensor including a first-1 metastructure for converting the type of ultrasound, and a mutually spaced second-1 sensor unit and a second-2 sensor unit disposed on the outer surface of the pipe at a distance from the first sensor, wherein the second-1 sensor unit comprises a second-1 ultrasonic transducer and a second-1 medium portion disposed between the second-1 ultrasonic transducer and the pipe, and wherein the second-1 medium portion may comprise a second sensor including a second-1 metastructure for converting the type of ultrasound. there is.

Description

Technology Field

[0001] The present invention relates to an apparatus and method for measuring a flow velocity profile, and more specifically, to a non-invasive flow velocity profile measuring apparatus and method for non-invasively measuring the flow velocity profile of a fluid within a pipe. Background Technology

[0002] Fluid passing through a pipe can have different velocities (flow rates) depending on its location or region. Additionally, the flow rate at a given location can vary depending on the fluid volume within the pipe. To accurately obtain fluid flow rate information, it is necessary to measure the flow rate profile of the fluid passing through the pipe.

[0003] Conventional ultrasonic sensors in flow velocity profile measuring devices employ an invasive method, either by drilling a hole in the pipe to be measured or by fabricating a special pipe and installing it between cut sections. However, this presents challenges in manufacturing and installing the device, as well as difficulties in applying it to existing pipes.

[0004] In addition, existing multi-line ultrasonic flow sensors utilize a non-invasive method in which they simply have a plastic wedge structure and are installed on the outer wall of the pipe. However, when using a simple plastic wedge, the ultrasonic propagation path of the auxiliary sensor among the multi-line ultrasonic flow sensors is inevitably set to be significantly close to the ultrasonic propagation path of the central sensor, which has the disadvantage of making it difficult to measure a complete flow velocity profile over a wide range.

[0005] Therefore, there is a need for a device and technique that can acquire an accurate and complete flow velocity profile by increasing the gap between the ultrasonic propagation path of the central sensor and the ultrasonic propagation path of the auxiliary sensor while being non-invasive. The problem to be solved

[0006] The technical problem that the present invention aims to solve is to provide a non-invasive flow velocity profile measuring device capable of non-invasively measuring the flow velocity profile of a fluid passing through a pipe through simple installation, and capable of accurately and completely (generally completely) measuring the flow velocity profile of a wide area within the pipe.

[0007] The problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be understood by those skilled in the art from the description below. means of solving the problem

[0008] According to one embodiment of the present invention, a first sensor comprises a mutually spaced first-1 sensor unit and a first-2 sensor unit disposed at the center or an adjacent portion of the outer surface of a pipe through which a fluid passes, wherein the first-1 sensor unit comprises a first-1 ultrasonic transducer and a first-1 medium portion disposed between the first-1 ultrasonic transducer and the pipe, and the first-1 medium portion comprises a first-1 metastructure for converting the type of ultrasound. A non-invasive flow velocity profile measuring device for non-invasively measuring the flow velocity profile of a fluid in a pipe is provided, comprising a mutually spaced 2-1 sensor unit and a 2-2 sensor unit disposed spaced apart from the 1 sensor on the outer surface of the pipe, wherein the 2-1 sensor unit comprises a 2-1 ultrasonic transducer and a 2-1 medium portion disposed between the 2-1 ultrasonic transducer and the pipe, and the 2-1 medium portion comprises a 2 sensor including a 2-1 metastructure for converting the type of ultrasound.

[0009] The distance (h) between the propagation path of the ultrasonic wave inside the pipe by the first sensor and the propagation path of the ultrasonic wave inside the pipe by the second sensor may be greater than 0.18D. Here, D is the inner diameter of the pipe.

[0010] At least one of the above 1-1 metastructure and the above 2-1 metastructure may be configured to convert a longitudinal wave type ultrasound propagating toward the pipe into a shear wave type ultrasound, or to convert a shear wave type ultrasound transmitted from the pipe into a longitudinal wave type ultrasound.

[0011] At least one of the above 1-1 metastructure and the above 2-1 metastructure may include a unit pattern structure, and the unit pattern structure may include a through-hole region formed in the above 1-1 medium part or the above 2-1 medium part.

[0012] The above piping may be formed of plastic, and the fluid may be a liquid.

[0013] The above piping may be formed of metal, and the fluid may be a liquid.

[0014] The first-1 sensor unit may further include a first-1 insertion medium portion disposed between the first-1 medium portion and the pipe and in contact with the pipe; and a first-1 additional metastructure formed within the first-1 insertion medium portion to increase the ultrasonic transmittance from the pipe into its interior. The second-1 sensor unit may further include a second-1 insertion medium portion disposed between the second-1 medium portion and the pipe and in contact with the pipe; and a second-1 additional metastructure formed within the second-1 insertion medium portion to increase the ultrasonic transmittance from the pipe into its interior.

[0015] The above 1-1 medium part and the above 2-1 medium part may be formed of plastic, and the above 1-1 insert medium part and the above 2-1 insert medium part may be formed of metal.

[0016] The first sensor may be a central sensor, the second sensor may be an auxiliary sensor, and the auxiliary sensor may be provided in 2n (where n is a positive integer), and the non-invasive flow rate profile measuring device may be a multi-line measuring device having 2n+1 lines.

[0017] According to another embodiment of the present invention, a first sensor comprises a mutually spaced first-1 sensor unit and a first-2 sensor unit disposed at the center or an adjacent portion of the outer surface of a pipe through which a fluid passes, wherein the first-1 sensor unit comprises a first-1 ultrasonic transducer and a first-1 medium portion disposed between the first-1 ultrasonic transducer and the pipe, and the first-1 medium portion comprises a first-1 metastructure for reducing the sound velocity of the ultrasound. A non-invasive flow velocity profile measuring device for non-invasively measuring the flow velocity profile of a fluid in a pipe is provided, comprising a mutually spaced 2-1 sensor unit and a 2-2 sensor unit disposed spaced apart from the 1 sensor on the outer surface of the pipe, wherein the 2-1 sensor unit comprises a 2-1 ultrasonic transducer and a 2-1 medium portion disposed between the 2-1 ultrasonic transducer and the pipe, and the 2-1 medium portion comprises a 2 sensor including a 2-1 metastructure for reducing the sound velocity of the ultrasound.

[0018] The distance (h) between the propagation path of the ultrasonic wave inside the pipe by the first sensor and the propagation path of the ultrasonic wave inside the pipe by the second sensor may be greater than 0.18D. Here, D is the inner diameter of the pipe.

[0019] The above 1-1 metastructure can be formed uniformly throughout the ultrasonic propagation region within the above 1-1 medium part, and the above 2-1 metastructure can be formed uniformly throughout the ultrasonic propagation region within the above 2-1 medium part.

[0020] At least one of the above 1-1 metastructure and the above 2-1 metastructure may include a unit pattern structure, and the unit pattern structure may include a through-hole region formed in the above 1-1 medium part or the above 2-1 medium part.

[0021] The above piping may be formed of plastic, and the fluid may be a gas.

[0022] The above piping may be formed of metal, and the fluid may be a gas.

[0023] The first-1 sensor unit may further include a first-1 insertion medium portion disposed between the first-1 medium portion and the pipe and in contact with the pipe; and a first-1 additional metastructure formed within the first-1 insertion medium portion to increase the ultrasonic transmittance from the pipe into its interior. The second-1 sensor unit may further include a second-1 insertion medium portion disposed between the second-1 medium portion and the pipe and in contact with the pipe; and a second-1 additional metastructure formed within the second-1 insertion medium portion to increase the ultrasonic transmittance from the pipe into its interior.

[0024] The above 1-1 medium part and the above 2-1 medium part may be formed of plastic, and the above 1-1 insert medium part and the above 2-1 insert medium part may be formed of metal.

[0025] The first sensor may be a central sensor, the second sensor may be an auxiliary sensor, and the auxiliary sensor may be provided in 2n (where n is a positive integer), and the non-invasive flow rate profile measuring device may be a multi-line measuring device having 2n+1 lines. Effects of the invention

[0026] According to embodiments of the present invention, a non-invasive flow velocity profile measuring device can be implemented that not only non-invasively measures the flow velocity profile of a fluid passing through a pipe through simple installation, but also accurately and completely (generally completely) measures the flow velocity profile of a wide area within the pipe. In particular, the non-invasive flow velocity profile measuring device according to the embodiments utilizes a metastructure, namely a metaslab, to increase the distance between the ultrasonic propagation path of the central sensor and the ultrasonic propagation path of the auxiliary sensor, thereby obtaining a more accurate and complete (generally complete) flow velocity profile. Furthermore, since the non-invasive flow velocity profile measuring device according to the embodiments can be installed in various pipes in a simple manner, it can have significant advantages in terms of installation and measurement methods.

[0027] However, the effects of the present invention are not limited to the above effects and can be extended in various ways without departing from the technical concept and scope of the present invention. Brief explanation of the drawing

[0028] FIG. 1 is a perspective view showing a non-invasive flow velocity profile measuring device for non-invasively measuring the flow velocity profile of a fluid in a pipe, according to one embodiment of the present invention. FIG. 2 is a perspective view exemplarily showing a first-1 sensor unit that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating the path design of a first sensor that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention. FIG. 4 shows the transverse / longitudinal mode conversion rate (T) according to the angle of incidence (θ1) of FIG. 3. S-L This is a graph showing ). FIG. 5 is a cross-sectional view illustrating the path design of a second sensor that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating the elliptical region of the pipe through which ultrasound is propagated by the second sensor of FIG. 5 and the associated path design. FIG. 7 is a drawing for explaining an elliptical region (cross-sectional view of the propagation path) of a pipe through which ultrasound is propagated by a second sensor that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention, and a path design related thereto. FIG. 8 is a diagram showing the flow velocity distribution of a fluid flowing inside a pipe to which a non-invasive flow velocity profile measuring device according to one embodiment of the present invention can be applied. FIG. 9 is a diagram showing an ultrasonic path by a first sensor that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention. Figure 10 is a graph showing the flow rate measurement results measured by the first sensor of Figure 9. FIG. 11 is a diagram showing an ultrasonic path by a second sensor that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention. Figure 12 is a graph showing the flow rate measurement results measured by the second sensor of Figure 11. FIG. 13 is a cross-sectional view showing a case where a first sensor and a second sensor, which can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention, are installed in a pipe. FIGS. 14 and 15 are graphs showing the results of an ultrasonic path verification experiment (three-dimensional ultrasonic path verification experiment) for a non-invasive flow rate profile measuring device according to one embodiment of the present invention. FIG. 16 is a cross-sectional view illustrating an exemplary second sensor that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention. Figure 17 is simulation data showing the mode (type) conversion phenomenon between longitudinal and transverse waves by a unit pattern structure that can be applied to the metastructure of Figure 2. Figure 18 is a graph showing the results of measuring the ratio (i.e., energy conversion rate) at which a longitudinal wave is converted into a transverse wave by the unit pattern structure of Figure 17. FIG. 19 is a drawing for explaining an elliptical region (cross-sectional view of the propagation path) of a pipe through which ultrasound is propagated by a second sensor that can be applied to a non-invasive flow rate profile measuring device according to an embodiment of the present invention, and a path design related thereto. FIGS. 20 and FIGS. 21 are cross-sectional views illustrating the transmission characteristics of ultrasound in structures according to comparative examples and embodiments, respectively. FIG. 22 is a drawing illustrating a second sensor that can be applied to a non-invasive flow rate profile measuring device according to another embodiment of the present invention. FIG. 23 is a cross-sectional view illustrating a first-1 sensor unit that can be applied to a non-invasive flow rate profile measuring device according to a comparative example. FIG. 24 is a cross-sectional view illustrating a first-1 sensor unit that can be applied to a non-invasive flow rate profile measuring device according to another embodiment of the present invention. FIG. 25 is a cross-sectional view illustrating a first-1 sensor unit that can be applied to a non-invasive flow rate profile measuring device according to another embodiment of the present invention. Specific details for implementing the invention

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0030] The embodiments of the present invention described below are provided to more clearly explain the present invention to those skilled in the art, and the scope of the present invention is not limited by the following embodiments, and the following embodiments may be modified in various other forms.

[0031] The terms used herein are for describing specific embodiments and are not intended to limit the invention. Terms used herein in the singular form may include plural forms unless the context clearly indicates otherwise. Additionally, the terms “comprise” and / or “comprising” used herein specify the presence of the mentioned features, steps, numbers, actions, components, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, steps, numbers, actions, components, elements, and / or groups thereof. Furthermore, the term “connected” used herein means not only that components are directly connected, but also includes the concept of indirectly connecting components through the interposition of additional components between them.

[0032] Furthermore, when a component is described in this specification as being located "on" another component, this includes not only cases where a component is in contact with another component, but also cases where another component exists between the two components. The term "and / or" as used in this specification includes any one of the listed items and all combinations of one or more thereof. Additionally, terms of degree such as "about" and "substantially" as used in this specification are used to mean a range of numerical values ​​or degrees or approximate values, taking into account inherent manufacturing and material tolerances, and are used to prevent an infringer from unfairly exploiting the disclosures in which precise or absolute figures provided to aid in understanding this specification are mentioned.

[0033] Some technical terms used in this specification are briefly explained as follows.

[0034] Metamaterial: Also known as metastructure. Metamaterials are materials engineered to possess properties that do not exist in nature. Metamaterials can be composed of a periodic arrangement of engineered unit structures, and their properties can be determined by that structure. By utilizing metamaterials, extreme control of waves becomes possible.

[0035] Elastic Wave Mode Conversion: Elastic waves can be ultrasound. Elastic wave mode conversion can also be called elastic wave type conversion. It is a technology that utilizes metamaterials to convert the wave modes of ultrasound propagating in an elastic medium from longitudinal waves to transverse waves or from transverse waves to longitudinal waves with an energy efficiency of over 90% or over 99%. By engineering the unit structure of a metamaterial and controlling its anisotropy, ultrasound incident on the metamaterial as a longitudinal wave (or transverse wave) can be converted into a transverse wave (or longitudinal wave) and transmitted.

[0036] Complete elastic wave transmission: This refers to transmitting ultrasound entering the boundary between different elastic media with 100% (or approximately 90% or more) energy efficiency without reflection by utilizing metamaterials. By engineering the unit structure of the metamaterial to satisfy phase matching and impedance matching conditions, the transmission rate of ultrasound (both longitudinal and transverse waves are possible) at the boundary between different media can be maximized.

[0037] Snell's Law: When two different media are in contact and an elastic wave passes through them, the speed of sound differs in each medium (υ1 and υ2, respectively), so the angles of transmission differ. When expressed as angles on the plane of incidence, the angles of incidence and transmission are θ1 and θ2. In this case, Snell's Law is defined as shown in Equation 1 below.

[0038]

[0039] Embodiments of the present invention will be described in detail below with reference to the attached drawings. The sizes or thicknesses of the areas or parts depicted in the attached drawings may be slightly exaggerated for the clarity of the specification and convenience of explanation. Throughout the detailed description, the same reference numerals indicate the same components.

[0040] FIG. 1 is a perspective view showing a non-invasive flow velocity profile measuring device for non-invasively measuring the flow velocity profile of a fluid in a pipe, according to one embodiment of the present invention.

[0041] Referring to FIG. 1, a non-invasive flow velocity profile measuring device (hereinafter, flow velocity profile measuring device) according to an embodiment of the present invention may be a device for non-invasively measuring the flow velocity profile of a fluid (F10) within a pipe (P10). The pipe (P10) may have, for example, a cylindrical structure (pipe structure). The flow velocity profile measuring device may be configured to measure the average flow velocity through a multi-circuit path and then calculate the flow velocity profile in order to measure the flow velocity profile of the fluid (F10) flowing within the pipe (P10).

[0042] The above flow velocity profile measuring device may include a first sensor (S10) disposed in the center or adjacent portion of the outer surface of a pipe (P10) through which fluid (F10) passes, and a second sensor (S20) disposed spaced apart from the first sensor (S10) on the outer surface of the pipe (P10). Here, the first sensor (S10) may be a central sensor, and the second sensor (S20) may be an auxiliary sensor. The auxiliary sensor may be provided in 2n (where n is a positive integer). The above flow velocity profile measuring device may further include a third sensor (S30) disposed spaced apart from the first sensor (S10) on the outer surface of the pipe (P10), and the third sensor (S30) may also correspond to the auxiliary sensor. Either one of the second sensor (S20) and the third sensor (S30) may be positioned above the first sensor (S10), and the other below the first sensor (S10). Thus, the second sensor (S20) and the third sensor (S30) may be positioned at a location spaced apart from the center of the pipe (P10). The positions of the second sensor (S20) and the third sensor (S30) may be reversed. The flow velocity profile measuring device may be a multi-line measuring device having 2n+1 lines. For example, the flow velocity profile measuring device may be a measuring device having 3 lines, 5 lines, 7 lines, 9 lines, or more lines.

[0043] The first sensor (S10) may include a mutually spaced first-1 sensor unit (SU11) and a first-2 sensor unit (SU12). Similarly, the second sensor (S20) may include a mutually spaced second-1 sensor unit (SU21) and a second-2 sensor unit (SU22). Additionally, the third sensor (S30) may include a mutually spaced third-1 sensor unit (SU31) and a third-2 sensor unit (not shown).

[0044] The first-1 sensor unit (SU11) and the first-2 sensor unit (SU12) can serve as an ultrasonic transmitter and an ultrasonic receiver. For example, if the first-1 sensor unit (SU11) is responsible for ultrasonic transmission, the first-2 sensor unit (SU12) can be responsible for ultrasonic reception, and if the first-2 sensor unit (SU12) is responsible for ultrasonic transmission, the first-1 sensor unit (SU11) can be responsible for ultrasonic reception. The first-1 sensor unit (SU11) and the first-2 sensor unit (SU12) can be installed on the outer wall of the pipe (P10) so as to face each other with the pipe (P10) in between, and can be installed spaced apart from each other by a certain distance along the longitudinal direction of the pipe (P10). These features may be the same or similar for the 2-1 sensor unit (SU21) and the 2-2 sensor unit (SU22), and may also be the same or similar for the 3-1 sensor unit (SU31) and the 3-2 sensor unit. The 2-1 sensor unit (SU21) and the 2-2 sensor unit (SU22) may serve as an ultrasonic transmitter and an ultrasonic receiver, and may be installed facing each other with the pipe (P10) in between, and may be installed spaced apart from each other by a certain distance along the longitudinal direction of the pipe (P10). Additionally, the 3-1 sensor unit (SU31) and the 3-2 sensor unit may serve as an ultrasonic transmitter and an ultrasonic receiver, and may be installed facing each other with the pipe (P10) in between, and may be installed spaced apart from each other by a certain distance along the longitudinal direction of the pipe (P10).

[0045] Each sensor unit (SU11, SU12, SU21, SU22, SU31) may include a wedge structure and may use a guide rail, jig, chain, etc. to accurately install it at a given location in the pipe (P10).

[0046] FIG. 2 is a perspective view exemplarily showing a first-1 sensor unit (SU11) that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention.

[0047] Referring to FIG. 2, when a flow rate profile measuring device according to an embodiment of the present invention is applied to a plastic pipe and the fluid flowing inside the pipe is a liquid, the first-1 sensor unit (SU11) may have a configuration as illustrated. The pipe may be a non-metallic pipe and, as a non-limiting example, may be formed of a plastic such as PVC (polyvinyl chloride), and the fluid flowing inside the pipe may be a liquid.

[0048] The first-1 sensor unit (SU11) may include a first-1 ultrasonic transducer (T11) and a first-1 medium section (A11) disposed between the first-1 ultrasonic transducer (T11) and the pipe, and the first-1 medium section (A11) may include a first-1 metastructure (M11) for converting the type of ultrasound.

[0049] The first-1 ultrasonic transducer (T11) may include a piezoelectric element. For example, the piezoelectric element may include, between opposing electrodes, oxides or compounds such as barium (Ba), calcium (Ca), titanium (Ti), zirconium (Zr), manganese (Mn), or other materials ranging from piezoelectric material PZT (lead zirconate titanate) to other materials. These may have a single-layer structure or be multilayered by alternating the electrodes, and may have a thin film or a three-dimensional shape through MEMS (micro-electromechanical system) technology. The first-1 ultrasonic transducer (T11) may be installed in a groove formed on the rear surface of the first-1 medium part (A11), but in some cases, the groove may not be formed.

[0050] In one embodiment, the first-1 ultrasonic transducer (T11) may be configured to generate longitudinal wave type ultrasonic waves. Here, the longitudinal wave may be referred to as a tensile wave. When the first-1 ultrasonic transducer (T11) generates longitudinal wave type ultrasonic waves, the first-1 medium part (A11) may include a first-1 metastructure (M11) for converting the longitudinal wave type ultrasonic waves into transverse wave type ultrasonic waves.

[0051] In one embodiment, the first-1 metastructure (M11) may include a unit pattern structure (n10) for mode (type) conversion of ultrasound. The first-1 metastructure (M11) may be a type of metamaterial and can induce mode conversion of ultrasound through material configuration via geometric structure without electrical conversion. Additionally, the first-1 metastructure (M11) may be a type of metaslab.

[0052] The first-1 medium section (A11) may have a wedge structure having a curved area corresponding to the curved surface of the outer surface of the pipe. For example, the first-1 medium section (A11) may have a structure in which a part of it is cut off from a rectangular column structure, and the cut surface may have the curved area. The curved area may be positioned to be in contact with the first area of ​​the pipe. The first-1 medium section (A11) may be described as a kind of 'wedge structure'.

[0053] The first-1 medium section (A11) may include a plastic material or be formed of a plastic material. The plastic material may be, for example, polyether ether ketone (PEEK) or may include PEEK. However, the types of plastic materials are exemplary and are not limited to those described above, and various materials may be employed. Additionally, in some cases, the first-1 medium section (A11) may be formed of the same plastic material as the pipe.

[0054] The metamaterial (metastructure) mentioned in the above description may refer to a material engineered to possess properties that do not exist in nature. Metamaterials can be composed of a periodic arrangement of engineered unit structures (unit pattern structures), and the properties of the metamaterial can be determined by its structure. By utilizing metamaterials, the wave mode (type) of ultrasound (elastic wave) propagating in an elastic medium can be converted from a longitudinal wave (or transverse wave) to a transverse wave (or longitudinal wave) with an energy efficiency of approximately 90% or more, or approximately 99% or more. By engineering the unit structure (unit pattern structure) of the metamaterial to control its anisotropy, ultrasound incident on the metamaterial as a longitudinal wave (or transverse wave) can be converted into a transverse wave (or longitudinal wave) and transmitted. Such metamaterials may be referred to as 'anisotropic metamaterials'.

[0055] The first-1 metastructure (M11) may include a unit pattern structure (n10) for converting the mode (type) of the ultrasound. A plurality of unit pattern structures (n10) may be arranged regularly. For example, a plurality of unit pattern structures (n10) may be arranged in a line spaced apart from each other by a predetermined distance in a direction parallel to the first-1 ultrasound transducer (T11).

[0056] The unit pattern structure (n10) may be a through hole (through hole region) having a predetermined shape formed in the first-1 medium part (A11). The through hole can be easily formed by making a hole in the first-1 medium part (A11) using methods such as wire cutting or laser cutting. The through hole may be an empty region, but in some cases, it may be filled with a material different from the material of the first-1 medium part (A11).

[0057] By using this first-1 metastructure (M11), nearly 100% mode conversion between longitudinal and transverse waves may be possible. Additionally, depending on the structure, shape, and size of the unit pattern structure (n10) constituting the first-1 metastructure (M11), the target frequency range of the ultrasound to be converted between longitudinal and transverse waves may vary. In the embodiment of FIG. 2, the cross-section of the unit pattern structure (n10) may have a heart shape or a similar shape. In other words, the cross-section of the unit pattern structure (n10) may have a modified triangular shape with three vertex regions rounded. Through this shape design, longitudinal type ultrasound can be converted into transverse type ultrasound. However, the specific structure, shape, and size of the unit pattern structure (n10) may vary.

[0058] Although not illustrated, the first-2 sensor unit (SU12) of FIG. 1 may have a structure symmetrical to the first-1 sensor unit (SU11) of FIG. 2. The first-2 sensor unit (SU12) may include a first-2 ultrasonic transducer and a first-2 medium section disposed between the first-2 ultrasonic transducer and the pipe, and the first-2 medium section may include a first-2 metastructure for converting the type of ultrasonic wave. When the first-2 sensor unit (SU12) is used for receiving ultrasonic waves, the first-2 metastructure may serve to convert transverse type ultrasonic waves transmitted from the pipe into longitudinal type ultrasonic waves, and the longitudinal type ultrasonic waves may be transmitted to the first-2 ultrasonic transducer.

[0059] Although not illustrated, the 2-1 sensor unit (SU21) of FIG. 1 may have a structure similar to the 1-1 sensor unit (SU11) of FIG. 2. The 2-1 sensor unit (SU21) may include a 2-1 ultrasonic transducer and a 2-1 medium portion disposed between the 2-1 ultrasonic transducer and the pipe, and the 2-1 medium portion may include a 2-1 metastructure for converting the type of ultrasound. The 2-1 sensor unit (SU21) may have a structure identical or nearly similar to the 1-1 sensor unit (SU11) of FIG. 2, except for the curved structure of the end portion of the 2-1 medium portion. When the 2-1 sensor unit (SU21) is used for ultrasonic transmission, the 2-1 metastructure can convert longitudinal type ultrasonic waves transmitted from the 2-1 ultrasonic transducer into transverse type ultrasonic waves, and the transverse type ultrasonic waves can be transmitted to the pipe.

[0060] Although not illustrated, the second-2 sensor unit (SU22) of FIG. 1 may have a structure symmetrical to the second-1 sensor unit (SU21) described above. The second-2 sensor unit (SU22) may include a second-2 ultrasonic transducer and a second-2 medium section disposed between the second-2 ultrasonic transducer and the pipe, and the second-2 medium section may include a second-2 metastructure for converting the type of ultrasound. When the second-2 sensor unit (SU22) is used for receiving ultrasound, the second-2 metastructure may serve to convert transverse-type ultrasound transmitted from the pipe into longitudinal-type ultrasound, and the longitudinal-type ultrasound may be transmitted to the second-2 ultrasonic transducer.

[0061] Additionally, although not illustrated, the 3-1 sensor unit (SU31) and the 3-2 sensor unit of FIG. 1 may each have the same or similar structure as the 2-1 sensor unit (SU21) and the 2-2 sensor unit (SU22) described above.

[0062] According to an embodiment of the present invention, by using a metastructure to cause ultrasonic waves to be incident as transverse waves from a wedge structure (i.e., a medium part) into a pipe, when ultrasonic waves are transmitted as transverse waves from the pipe into an internal fluid, the difference in sound speed between the pipe and the internal fluid can be reduced, and transmission can be made at a larger angle of transmission. Accordingly, the distance (minimum distance between the centers of the paths) (i.e., height difference) between the propagation path of ultrasonic waves inside the pipe by the first sensor (S10 in FIG. 1) and the propagation path of ultrasonic waves inside the pipe by the second sensor (S20 in FIG. 1) can be increased.

[0063] FIG. 3 is a cross-sectional view illustrating the path design of a first sensor (S10) that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention.

[0064] Referring to FIG. 3, the first sensor (S10) may include a first-1 sensor unit (SU11) and a first-2 sensor unit (SU12). For convenience, the first-1 sensor unit (SU11) and the first-2 sensor unit (SU12) are simply illustrated. Here, θ1 represents the angle of incidence of the ultrasound from the first-1 sensor unit (SU11) to the pipe (P10), and α1 represents the angle of transmission of the ultrasound from the first-1 sensor unit (SU11) to the fluid (F10) inside the pipe (P10). The angle of incidence (θ1) and the angle of transmission (α1) may be angles with respect to a line perpendicular to the pipe (P10).

[0065] FIG. 4 shows the transverse / longitudinal mode conversion rate (T) according to the angle of incidence (θ1) of FIG. 3. S-L This is a graph showing ).

[0066] Referring to FIG. 4, the ultrasonic transducer of the first sensor (S10 in FIG. 3) is set to an incident angle of θ1 = 36.5°, at which maximum energy transmittance occurs, and the transmission angle in the fluid inside the pipe is α1 = 54.5°. The transmitter (e.g., SU11 in FIG. 3) and receiver (e.g., SU12 in FIG. 3) of the first sensor (S10) are each installed on opposite sides of the pipe with a certain installation distance between them, and the installation position can be determined by the incident angle and transmission angle in each medium and the dimensions of the sensor unit and the pipe.

[0067] FIG. 5 is a cross-sectional view illustrating the path design of a second sensor (S20) that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention.

[0068] Referring to FIG. 5, in order to measure the average flow velocity at a location away from the center of the pipe (P10), a second sensor (S20) may be installed at a location away from the center of the pipe (P10). The second sensor (S20) may include a second-1 sensor unit (SU21) and a second-2 sensor unit (SU22). For convenience, the second-1 sensor unit (SU21) and the second-2 sensor unit (SU22) are simply illustrated. The second-1 sensor unit (SU21) and the second-2 sensor unit (SU22) may be installed on opposite sides of the pipe (P10) with a certain installation distance between them. Here, β represents the cross-section determining angle. The cross-section determining angle (β) may be determined by the positions of the second-1 sensor unit (SU21) and the second-2 sensor unit (SU22). In other words, the cross-section determination angle (β) may be the angle formed by the line segment connecting the center of the 2-1 sensor unit (SU21) and the center of the 2-2 sensor unit (SU22) with respect to a line perpendicular to the pipe (P10).

[0069] The region where the path for ultrasonic waves propagating in the fluid (F10) inside the pipe (P10) is formed by the second sensor (S20) can be viewed as an elliptical region. The shape of the cross-section of the ultrasonic wave propagation path can be determined by the cross-section determining angle (β). The cross-section determining angle (β) can be selected arbitrarily, but in this embodiment, it was set to 65° as an example.

[0070] FIG. 6 is a cross-sectional view illustrating an elliptical region of a pipe (P10) through which ultrasonic waves propagate by the second sensor (S20) of FIG. 5 and a path design associated therewith.

[0071] Referring to FIG. 6, the ultrasound converted into a transverse wave by the second-1 sensor unit (SU21 in FIG. 5) of the second sensor (S20 in FIG. 5) can propagate as a longitudinal wave in the fluid (F10) inside the pipe (P10). In the fluid (F10), the ultrasound can propagate in the form of a longitudinal wave. Here, θ2 represents the angle of incidence of the ultrasound from the second-1 sensor unit (SU21) to the pipe (P10), and α2 represents the angle of transmission of the ultrasound from the second-1 sensor unit (SU21) to the fluid (F10) inside the pipe (P10). The angle of incidence (θ2) and the angle of transmission (α2) may be angles relative to a line (normal) perpendicular to the tangent of the pipe (P10) at the point of incidence. Additionally, h represents the distance (minimum distance between the centers of the paths) (i.e., height difference) between the propagation path of the ultrasonic waves within the pipe (P10) by the first sensor (S10) and the propagation path of the ultrasonic waves within the pipe (P10) by the second sensor (S20), r' represents the inner radius in the minor axis direction of the elliptical region, and r" represents the inner radius in the major axis direction of the elliptical region. The inner diameter (D) of the pipe (P10) may be 2r'.

[0072] The above-mentioned α1, α2, θ2, r', and h can be determined as shown in mathematical formulas 2 to 6 below.

[0073]

[0074]

[0075]

[0076]

[0077]

[0078] C in the above mathematical formulas 2 and 4 w is the transverse wave velocity of ultrasound in a plastic medium (wedge), and C l ε is the longitudinal wave velocity of ultrasound in a fluid (liquid). In Equation 6, h can be (2 / 3)r', but h can be set arbitrarily.

[0079] In the case of conventional ultrasonic wedges, since longitudinal waves are incident from the wedge into the pipe, there is a limit to the distance between the path of the central sensor and the path of the auxiliary sensor. However, by using the non-invasive flow velocity profile measuring device according to the embodiment of the present invention, theoretically, the distance (h) between the path of the first sensor (central sensor) and the path of the second sensor (auxiliary sensor) can be any distance. According to the embodiment of the present invention, the distance (h) between the propagation path of the ultrasonic waves within the pipe by the first sensor and the propagation path of the ultrasonic waves within the pipe by the second sensor can be greater than approximately 0.18D (where D is the inner diameter of the pipe), and thus, the flow velocity profile of a wide area within the pipe can be measured accurately and completely (generally completely).

[0080] FIG. 7 is a drawing for explaining an elliptical region (cross-sectional view of the propagation path) of a pipe through which ultrasound is propagated by a second sensor that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention, and a path design related thereto.

[0081] Referring to FIG. 7, when measuring the flow velocity profile in a pipe (P10) (e.g., PVC pipe), for example, the transmission angle in the fluid (F10) α2 = 65° can be calculated to establish the ultrasonic path by the second sensor (i.e., auxiliary sensor) at a distance of h = (2 / 3)r' from the ultrasonic path by the first sensor (i.e., center sensor) by first determining the cross-section angle β = 65°. Here, a tan represents the reciprocal of tan. Additionally, since the impedance difference with the internal fluid (F10) can be reduced when a shear wave is incident from a plastic (e.g., PEEK) medium (wedge) into the pipe (P10) (e.g., PVC pipe), the medium (wedge) can be designed so that the wave is incident at θ2 = 40.2° from the plastic medium (wedge). However, the path design described in Fig. 7 is merely exemplary and may vary depending on the case.

[0082] FIG. 8 is a diagram showing the flow velocity distribution of a fluid (F10) flowing inside a pipe (P10) to which a non-invasive flow velocity profile measuring device according to one embodiment of the present invention can be applied.

[0083] Referring to FIG. 8, in order to verify the average flow velocity measurement performance in the ultrasonic propagation path of a non-invasive flow velocity profile measuring device according to an embodiment of the present invention, the flow velocity distribution of a fluid (F10) was simulated for a PVC pipe (P10) having a diameter of 30 mm and a thickness of 2 mm. The average flow velocity of the fluid (F10) in the ultrasonic path by the first sensor was approximately 20.02 m / s, and the average flow velocity of the fluid (F10) in the ultrasonic path by the second sensor was approximately 15.67 m / s.

[0084] FIG. 9 is a drawing showing an ultrasonic path by a first sensor (S10) that can be applied to a non-invasive flow rate profile measuring device according to an embodiment of the present invention. The left drawing is a front view of a cut area, and the right drawing is a perspective view corresponding to the left drawing.

[0085] FIG. 10 is a graph showing the flow rate measurement results measured by the first sensor (S10) of FIG. 9.

[0086] FIG. 11 is a drawing showing an ultrasonic path by a second sensor (S20) that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention. The left drawing is a front view of a cut area, and the right drawing is a perspective view corresponding to the left drawing.

[0087] FIG. 12 is a graph showing the flow rate measurement results measured by the second sensor (S20) of FIG. 11.

[0088] Referring to FIGS. 9 to 12, the average flow velocity calculated from the upstream and downstream signals in the ultrasonic path of the first sensor (S10) had an error of 3.3% compared to the average flow velocity set to approximately 20.67 m / s. Additionally, the average flow velocity calculated from the upstream and downstream signals in the ultrasonic path of the second sensor (S20) had an error of 3.8% compared to the average flow velocity set to approximately 16.27 m / s. In this way, a flow velocity profile can be obtained by the average flow velocity measured by multiple lines. Based on the simulation results, it can be confirmed that both the first sensor (S10) and the second sensor (S20) propagate / transmit ultrasonic waves along the design path and can accurately measure the flow velocity at a desired location.

[0089] In order to verify whether ultrasound actually propagates along the path designed according to the embodiment within the pipe (P10), an ultrasound path verification experiment as shown in FIGS. 13 to 15 was conducted. At this time, the pipe (P10) was a PVC pipe.

[0090] FIG. 13 is a cross-sectional view showing a case where a first sensor (S10) and a second sensor (S20) that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention are installed in a pipe (P10).

[0091] Referring to FIG. 13, path 1 represents an ultrasonic propagation path passing through the center of the pipe (P10) by the first sensor (S10). Path 2 is an ultrasonic propagation path by the second sensor (S20) located at a distance of (2 / 3)r' from the center of the pipe (P10). To verify whether the ultrasonic waves propagate along the designed path, the path was blocked using an epoxy block 30 mm in length, and the magnitude of the received signal was compared with and without the block. The results were as shown in FIG. 14 and FIG. 15.

[0092] FIGS. 14 and 15 are graphs showing the results of an ultrasonic path verification experiment (three-dimensional ultrasonic path verification experiment) for a non-invasive flow rate profile measuring device according to one embodiment of the present invention.

[0093] Referring to Fig. 14, in the case of path 1, it can be seen that the magnitude of the received signal is significantly reduced compared to the conventional one when the ultrasonic path is blocked using an epoxy block.

[0094] Referring to Fig. 15, in the case of path 2, when the lower and upper parts of the pipe were blocked using epoxy blocks, it was confirmed that the magnitude of the received signal in the lower part was almost the same as when there were no blocks, and the magnitude of the signal in the upper part was significantly reduced compared to when there were no blocks. From the experimental results of Figs. 14 and 15, it can be confirmed that ultrasound propagates well along the designed path.

[0095] FIG. 16 is a cross-sectional view illustrating an exemplary second sensor (S20) that can be applied to a non-invasive flow rate profile measuring device according to one embodiment of the present invention.

[0096] Referring to FIG. 16, the second sensor (S20) may include a second-1 sensor unit (SU21) and a second-2 sensor unit (SU22) spaced apart from each other. The second-1 sensor unit (SU21) may include a second-1 ultrasonic transducer (T21) and a second-1 medium section (A21) disposed between the second-1 ultrasonic transducer (T21) and the pipe (P10), and the second-1 medium section (A21) may include a second-1 metastructure (M21) for converting the type of ultrasound. The second-2 sensor unit (SU22) may include a second-2 ultrasonic transducer (T22) and a second-2 medium part (A22) disposed between the second-2 ultrasonic transducer (T22) and the pipe (P10), and the second-2 medium part (A22) may include a second-2 metastructure (M22) for converting the type of ultrasound. In this embodiment, the pipe (P10) may be a non-metallic pipe, e.g., a plastic pipe, and the fluid (F10) flowing inside the pipe (P10) may be a liquid.

[0097] In one embodiment, at least one of the 2-1 ultrasonic transducer (T21) and the 2-2 ultrasonic transducer (T22) may be configured to generate longitudinal type ultrasonic waves. When using an ultrasonic transducer that generates longitudinal type ultrasonic waves, energy efficiency can be increased and costs can be reduced.

[0098] The 2-1 medium section (A21) may include a 2-1 metastructure (M21) for converting the type of ultrasound between longitudinal and transverse waves. Additionally, the 2-2 medium section (A22) may include a 2-2 metastructure (M22) for converting the type of ultrasound between longitudinal and transverse waves. The metastructures (M21, M22) may be designed in a shape that enables nearly 100% mode conversion between longitudinal and transverse waves at a specific frequency (e.g., 200 kHz), and may be designed as a monolayer so that they can be processed into a single unit hole for ease of manufacturing.

[0099] The distance (h) between the ultrasonic propagation path by the second sensor (S20) and the ultrasonic propagation path (central path) by the first sensor can theoretically be set arbitrarily. According to one embodiment, the distance (h) between the ultrasonic propagation path by the first sensor and the ultrasonic propagation path by the second sensor (S20) may be greater than approximately 0.18D (where D is the inner diameter of the pipe). Therefore, by using the non-invasive flow velocity profile measuring device according to the embodiment, the flow velocity profile of a wide area within the pipe (P10) can be measured accurately and completely (generally completely).

[0100] Figure 17 is simulation data showing the mode (type) conversion phenomenon between longitudinal and transverse waves by a unit pattern structure (n10) that can be applied to the metastructure (M11) of Figure 2.

[0101] Referring to FIG. 17, longitudinal type ultrasound can be converted into transverse type ultrasound while passing through a unit pattern structure (n10). Also, in the opposite case, transverse type ultrasound can be converted into longitudinal type ultrasound while passing through a unit pattern structure (n10).

[0102] Figure 18 is a graph showing the results of measuring the ratio (i.e., energy conversion rate) at which a longitudinal wave is converted into a transverse wave by the unit pattern structure (n10) of Figure 17.

[0103] Referring to FIG. 18, when the frequency of the ultrasound is approximately 200 kHz, the ratio at which a longitudinal wave is converted into a transverse wave by the unit pattern structure (n10 in FIG. 17), i.e., the mode conversion rate, can be as high as approximately 97.5%. Therefore, it may be possible to achieve nearly 100% mode conversion using ultrasound having a specific frequency. However, the specific frequency (200 kHz) disclosed herein is merely exemplary, and the target frequency range may vary depending on the design conditions. Furthermore, the shape of the unit pattern structure (n10 in FIG. 17) described above is not limited to that shown in FIG. 17 and can be varied in many ways.

[0104] If the piping is formed of metal, that is, if metal piping is used, it may be difficult to secure an ultrasonic path as illustrated in Fig. 16, etc.

[0105] FIG. 19 is a drawing for explaining an elliptical region (cross-sectional view of the propagation path) of a pipe through which ultrasound is propagated by a second sensor that can be applied to a non-invasive flow rate profile measuring device according to an embodiment of the present invention, and a path design related thereto. In this embodiment, the pipe (P20) may be formed of metal, and the fluid (F10) flowing within the pipe (P20) may be a liquid. The metal may be steel, as a non-limiting example.

[0106] Referring to FIG. 19, the second sensor, in order to establish an ultrasonic propagation path in a path (2 / 3)r' away from the ultrasonic path of the first sensor (center sensor) for a pipe (P20) formed of metal, in the fluid (F10) Ultrasound must be transmitted at α2 = 65°. However, even if ultrasound is incident on the metal pipe (P20) as a transverse wave, a critical angle may occur due to the difference in the speed of sound of the ultrasound in the internal fluid (F10) and the pipe (P20). That is, the angle of incidence (θ2) in the pipe (P20) may be greater than 90°. In other words, it may be difficult to propagate ultrasound along the desired set path inside the fluid (F10).

[0107] Regarding metal pipes, when using a metal wedge, there is a problem in that the ultrasonic waves of the auxiliary sensor cannot penetrate through a path away from the center sensor due to the existence of a critical angle caused by the difference in the speed of sound between the metal pipe and the internal fluid. Additionally, regarding metal pipes, when using a plastic wedge, there is a problem in that the ultrasonic transmission rate is very low due to the impedance difference between the plastic wedge and the metal pipe, and between the metal pipe and the internal fluid, and the ultrasonic waves of the auxiliary sensor cannot penetrate through a path away from the center sensor. However, according to another embodiment of the present invention, by using a separate metastructure that takes into account the thickness of the metal pipe, that is, an additional metaslab, both the critical angle and transmission rate problems can be overcome, and the ultrasonic waves of the auxiliary sensor (second sensor) can be transmitted and propagated through a set path within the metal pipe.

[0108] FIGS. 20 and FIGS. 21 are cross-sectional views illustrating the transmission characteristics of ultrasound in structures according to a comparative example and an embodiment, respectively. FIG. 20 is a structure according to a comparative example, and FIG. 21 is a structure according to an embodiment. In FIG. 20, a plastic wedge portion (A10) is in direct contact with a metal pipe (P20), and in FIG. 21, a metal wedge portion (B10) including an additional metastructure (N10) is disposed between the plastic wedge portion (A10) and the metal pipe (P20).

[0109] Referring to FIG. 20, when ultrasound is transmitted from the plastic wedge portion (A10) through the metal pipe (P20) to the fluid (F10), the ratio of the energy of the ultrasound transmitted to the fluid (F10) can be very low.

[0110] Referring to FIG. 21, the additional metastructure (N10) can transmit ultrasound propagating from the plastic wedge portion (A10) into the fluid (F10) with an energy efficiency of nearly 100%. The metaslab including the additional metastructure (N10) and the metal wedge portion (B10) can be designed considering the thickness of the metal pipe (P20). The metal wedge portion (B10) on which the additional metastructure (N10) is formed can be referred to as an anisotropic matching layer. The cross-section of the unit pattern structure of the additional metastructure (N10) may have a refracted bar shape or a similar shape. The shape of the unit pattern structure may vary in many ways.

[0111] When measuring the flow velocity profile of an internal fluid in a metal pipe, an anisotropic metaslab that takes pipe thickness into account can be used to resolve the problem of ultrasonic transmission being blocked by the critical angle, thereby enabling ultrasonic transmission along a set path within the pipe. When using conventional plastic wedges, the ultrasonic transmission rate may be very low due to the existence of a critical angle caused by the difference in sound speed between the plastic wedge and the metal pipe. Additionally, there is a problem where ultrasonic transmission cannot go along the desired path due to the difference in sound speed and impedance between the metal pipe and the internal fluid. By using an assembled ultrasonic metatransducer that takes pipe thickness into account (i.e., a sensor unit including the aforementioned anisotropic metaslab), both the critical angle and transmission rate issues can be overcome, allowing ultrasonic transmission along a set path within the pipe.

[0112] FIG. 22 is a drawing for explaining a second sensor (S20') that can be applied to a non-invasive flow rate profile measuring device according to another embodiment of the present invention. The drawing on the right is a front view of a cut area, and the drawing on the left is a perspective view corresponding to the drawing on the right.

[0113] Referring to FIG. 22, the present embodiment may be a case where the pipe (P20) is a metal pipe and the fluid (F10) flowing within the pipe (P20) is a liquid. The non-invasive flow velocity profile measuring device (hereinafter, flow velocity profile measuring device) according to the present embodiment may include a first sensor (not shown) and a second sensor (S20') spaced apart from the first sensor. The first sensor may be a central sensor, and the second sensor (S20') may be an auxiliary sensor.

[0114] The second sensor (S20') may include a second-1 sensor unit (SU21') and a second-2 sensor unit (SU22') spaced apart from each other. The second-1 sensor unit (SU21') may include a second-1 ultrasonic transducer (T21) and a second-1 medium section (A21) disposed between the second-1 ultrasonic transducer (T21) and the pipe (P20), and the second-1 medium section (A21) may include a second-1 metastructure (M21) for converting the type of ultrasound. Additionally, the 2-1 sensor unit (SU21') may further include a 2-1 insertion medium part (B21) disposed between the 2-1 medium part (A21) and the pipe (P20) and in contact with the pipe (P20), and a 2-1 additional metastructure (N21) formed within the 2-1 insertion medium part (B21) to increase the ultrasonic transmission rate from the pipe (P20) into the interior thereof. The 2-1 insertion medium part (B21) and the 2-1 additional metastructure (N21) may constitute a single additional metaslab. The 2-1 additional metastructure (N21) may include a periodic arrangement of unit pattern structures, and the unit pattern structures may be, for example, through holes (through hole regions) having a predetermined shape formed in the 2-1 insertion medium part (B21).

[0115] The second-2 sensor unit (SU22') may include a second-2 ultrasonic transducer (T22) and a second-2 medium section (A22) disposed between the second-2 ultrasonic transducer (T22) and the pipe (P20), and the second-2 medium section (A22) may include a second-2 metastructure (M22) for converting the type of ultrasound. Additionally, the second-2 sensor unit (SU22') may further include a second-2 insertion medium section (B22) disposed between the second-2 medium section (A22) and the pipe (P20) and in contact with the pipe (P20), and a second-2 additional metastructure (N22) formed within the second-2 insertion medium section (B22) to increase the ultrasonic transmission rate from the pipe (P20) into its interior. The second-2 insertion medium part (B22) and the second-2 additional metastructure (N22) may form an additional metaslab. The second-2 additional metastructure (N22) may include a periodic arrangement of unit pattern structures, and the unit pattern structures may be, for example, through holes (through hole regions) having a predetermined shape formed in the second-2 insertion medium part (B22).

[0116] According to one embodiment, the 2-1 medium part (A21) and the 2-2 medium part (A22) may be formed of plastic, and the 2-1 insert medium part (B21) and the 2-2 insert medium part (B22) may be formed of metal. The 2-1 insert medium part (B21) and the 2-2 insert medium part (B22) may be formed of the same metal as the pipe (P20) or may be formed of a different metal.

[0117] Although not illustrated in FIG. 22, the first sensor may include a first-1 sensor unit and a first-2 sensor unit spaced apart from each other. The first-1 sensor unit may include a first-1 ultrasonic transducer and a first-1 medium portion disposed between the first-1 ultrasonic transducer and a pipe (P20), and the first-1 medium portion may include a first-1 metastructure for converting the type of ultrasound. Additionally, the first-1 sensor unit may further include a first-1 insertion medium portion disposed between the first-1 medium portion and the pipe (P20) and in contact with the pipe (P20), and a first-1 additional metastructure formed within the first-1 insertion medium portion to increase the ultrasonic transmission rate from the pipe (P20) into its interior. The first-1 insertion medium portion and the first-1 additional metastructure may constitute a single additional metaslab. The above-mentioned 1-1 additional metastructure may include a periodic arrangement of unit pattern structures, and the unit pattern structure may be, for example, a through hole (through hole region) having a predetermined shape formed in the above-mentioned 1-1 insertion medium.

[0118] The first-2 sensor unit may include a first-2 ultrasonic transducer and a first-2 medium portion disposed between the first-2 ultrasonic transducer and the pipe (P20), and the first-2 medium portion may include a first-2 metastructure for converting the type of ultrasound. Additionally, the first-2 sensor unit may further include a first-2 insertion medium portion disposed between the first-2 medium portion and the pipe (P20) and in contact with the pipe (P20), and a first-2 additional metastructure formed within the first-2 insertion medium portion to increase the ultrasonic transmission rate from the pipe (P20) into its interior. The first-2 insertion medium portion and the first-2 additional metastructure may constitute a single additional metaslab. The above-mentioned first-second additional metastructure may include a periodic arrangement of unit pattern structures, and the unit pattern structure may be, for example, a through hole (through hole region) having a predetermined shape formed in the above-mentioned first-second insertion medium.

[0119] According to one embodiment, the first-1 medium part and the first-2 medium part may be formed of plastic, and the first-1 insertion medium part and the first-2 insertion medium part may be formed of metal. The first-1 insertion medium part and the first-2 insertion medium part may be formed of the same metal as the pipe (P20) or may be formed of a different metal.

[0120] Additionally, the above flow rate profile measuring device may further include one or more auxiliary sensors, and the one or more auxiliary sensors may have the same or similar configuration as the second sensor (S20').

[0121] According to one embodiment, the sensor unit considering pipe thickness in the flow velocity profile measuring device may be composed of a part made of plastic (a non-limiting example, PEEK) and a part made of metal (a non-limiting example, steel) containing an anisotropic metaslab that is the same material as the pipe (P20). When using a conventional plastic wedge, the maximum height (height from the center) of the ultrasonic path that can propagate within the pipe (P20) is 0.18D (D: inner diameter of the pipe), whereas in the case of the sensor unit according to the embodiment considering pipe thickness, when θ2 is 30°, the height (h) of the propagation path is 0.29D. The right-hand diagram of FIG. 22 includes simulation results in a three-dimensional propagation cross-section. As can be seen from the simulation results, the longitudinal wave transmitted into the internal fluid (F10) propagates well to the receiver (i.e., S20') at a set path height of 0.29D. When θ2 is greater than 30°, the height of the ultrasonic propagation path can be increased, and theoretically, the height of the propagation path can be set to any height.

[0122] When the fluid flowing inside the pipe is a gas, the longitudinal wave velocity in the plastic medium (wedge) is much faster than the longitudinal wave velocity in the gas; therefore, the difference in the speed of sound of the ultrasound between the plastic medium (wedge) and the fluid (gas) can be very large, which can make it difficult to establish the propagation path of the ultrasound.

[0123] FIG. 23 is a cross-sectional view illustrating a first-1 sensor unit (SU11a) that can be applied to a non-invasive flow rate profile measuring device according to a comparative example.

[0124] Referring to FIG. 23, the first-1 sensor unit (SU11a) according to the comparative example may have a first-1 ultrasonic transducer (T11a) and a first-1 medium section (A11a) disposed between the first-1 ultrasonic transducer (T11a) and a pipe (P20). Here, the pipe (P20) may be a metal pipe, and the fluid (F20) may be a gas. When using the first-1 sensor unit (SU11a) according to the comparative example, since the longitudinal wave velocity in the first-1 medium section (A11a) formed of plastic is much faster than the longitudinal wave velocity in gas (air), the transmission angle θ1 within the pipe (P20) may be much smaller than the incidence angle θ0 in the first-1 medium section (A11a) according to Snell's law. When the internal gas is air, the maximum transmission angle (θ1) in air is 6.2°, but in order to perform the flow rate measurement function, it is necessary to set the transmission angle to 30° or more, just as when the internal gas is liquid. In addition, when using the first-1 sensor unit (SU11a) according to the above comparative example, there is a problem in that the energy transmittance is very low and the signal cannot be detected at the receiver due to the impedance difference between the first-1 medium part (A11a) formed of plastic and the pipe (P20) formed of metal, and between the metal pipe (P20) and the internal fluid (gas) (F20), particularly the very large impedance difference between the metal pipe (P20) and the internal fluid (gas) (F20).

[0125] FIG. 24 is a cross-sectional view illustrating a first-1 sensor unit (SU11b) that can be applied to a non-invasive flow rate profile measuring device according to another embodiment of the present invention. Here, the pipe (P20) may be a metal pipe, and the fluid (F20) may be a gas.

[0126] Referring to FIG. 24, the first-1 sensor unit (SU11b) may include a first-1 ultrasonic transducer (T11b) and a first-1 medium section (A11b) disposed between the first-1 ultrasonic transducer (T11b) and a pipe (P20), and the first-1 medium section (A11b) may include a first-1 metastructure (M11b) for reducing the sound velocity of the ultrasound. Additionally, the first-1 sensor unit (SU11b) may further include a first-1 insertion medium section (B11b) disposed between the first-1 medium section (A11b) and the pipe (P20) and in contact with the pipe (P20), and a first-1 additional metastructure (N11b) formed within the first-1 insertion medium section (B11b) to increase the ultrasonic transmission rate from the pipe (P20) into the interior thereof.

[0127] The first-1 metastructure (M11b) can serve to reduce the sound speed of ultrasound in the first-1 medium section (A11b). The first-1 metastructure (M11b) can be formed uniformly (or generally uniformly) throughout the ultrasound propagation area within the first-1 medium section (A11b). Since the sound speed of ultrasound in the first-1 medium section (A11b) may be proportional to the density, the sound speed of ultrasound in the first-1 medium section (A11b) can be reduced by using the first-1 metastructure (M11b) to reduce the density of the first-1 medium section (A11b). As a result, the difference between the sound speed of ultrasound in the first-1 medium section (A11b) and the sound speed of ultrasound in the fluid (gas) (F20) can be significantly reduced. Meanwhile, the 1-1 additional metastructure (N11b) can serve to increase the ultrasonic penetration into the pipe (P20), similar to the additional metastructures (N21, N22) described in FIG. 22.

[0128] According to one embodiment, the first-1 medium part (A11b) may be formed of plastic, and the first-1 insertion medium part (B11b) may be formed of metal. The first-1 insertion medium part (B11b) may be formed of the same metal as the pipe (P20) or may be formed of a different metal.

[0129] The first-1 sensor unit (SU11b) can be described as an assembled ultrasonic metatransducer. The first-1 sensor unit (SU11b) may be composed of a wedge part (i.e., A11b) made of plastic material and a wedge part (i.e., B11b) made of the same metal material as the pipe (P20) containing an anisotropic metaslab (i.e., N11b). The first-1 metastructure (M11b) applied within the wedge part (i.e., A11b) made of plastic material is designed to reduce the difference between the longitudinal wave velocity in the plastic wedge part (i.e., A11b) and the longitudinal wave velocity in the gas, so that the ultrasonic waves are refracted (θ0 < θ1) as they pass through the pipe (P20), and thus no critical angle may exist. In addition, the problem of low transmittance can also be solved by inserting a first-1 additional metastructure (N11b) between the metal pipe (P20) and the plastic wedge (i.e., A11b) so that wave energy is completely transmitted at the interface, just as in the case where the pipe (P20) is a metal pipe and the internal fluid is a liquid.

[0130] The first sensor of the non-invasive flow rate profile measuring device according to the embodiment of FIG. 24 may further include a first-2 sensor unit positioned corresponding to a first-1 sensor unit (SU11b). The first-2 sensor unit may have a structure symmetrical to the first-1 sensor unit (SU11b). Additionally, the non-invasive flow rate profile measuring device according to the embodiment of FIG. 24 may further include a second sensor spaced apart from the first sensor, and the second sensor may include a second-1 sensor unit and a second-2 sensor unit spaced apart from each other. The second-1 sensor unit and the second-2 sensor unit may have a configuration similar to the first-1 sensor unit (SU11b) and the first-2 sensor unit. Furthermore, the non-invasive flow rate profile measuring device according to the embodiment of FIG. 24 may include 2n auxiliary sensors and may be a multi-line measuring device having 2n+1 lines.

[0131] According to one embodiment, in a non-invasive flow rate profile measuring device according to the embodiment of FIG. 24, the distance (h) between the propagation path of the ultrasound within the pipe (P20) by the first sensor and the propagation path of the ultrasound within the pipe (P20) by the second sensor may be greater than 0.18D (where D is the inner diameter of the pipe).

[0132] In addition, the configurations and features of the non-invasive flow rate profile measuring device according to the embodiments described with reference to FIGS. 1 to 19, FIG. 21, and FIG. 22 may all be applicable to the non-invasive flow rate profile measuring device according to the embodiment of FIG. 24 within a range that is not contradictory.

[0133] FIG. 25 is a cross-sectional view illustrating a first-1 sensor unit (SU11c) that can be applied to a non-invasive flow rate profile measuring device according to another embodiment of the present invention. Here, the pipe (P10) may be a plastic pipe, and the fluid (F20) may be a gas.

[0134] Referring to FIG. 25, when the pipe (P10) is a plastic pipe and the fluid (F20) is a gas, the use of the first-1 insertion medium part (B11b) and the first-1 additional metastructure (N11b) in the embodiment of FIG. 24 may be excluded. The first-1 sensor unit (SU11c) of the present embodiment may include a first-1 ultrasonic transducer (T11c) and a first-1 medium part (A11c) disposed between the first-1 ultrasonic transducer (T11c) and the pipe (P10), and the first-1 medium part (A11c) may include a first-1 metastructure (M11c) for reducing the sound speed of the ultrasound.

[0135] The first sensor of the non-invasive flow rate profile measuring device according to the embodiment of FIG. 25 may further include a first-2 sensor unit positioned corresponding to a first-1 sensor unit (SU11c). The first-2 sensor unit may have a structure symmetrical to the first-1 sensor unit (SU11c). Additionally, the non-invasive flow rate profile measuring device according to the embodiment of FIG. 25 may further include a second sensor spaced apart from the first sensor, and the second sensor may include a second-1 sensor unit and a second-2 sensor unit spaced apart from each other. The second-1 sensor unit and the second-2 sensor unit may have a configuration similar to the first-1 sensor unit (SU11c) and the first-2 sensor unit. Furthermore, the non-invasive flow rate profile measuring device according to the embodiment of FIG. 25 may include 2n auxiliary sensors and may be a multi-line measuring device having 2n+1 lines.

[0136] According to one embodiment, in a non-invasive flow rate profile measuring device according to the embodiment of FIG. 25, the distance (h) between the propagation path of ultrasound within the pipe (P10) by the first sensor and the propagation path of ultrasound within the pipe (P10) by the second sensor may be greater than 0.18D (where D is the inner diameter of the pipe).

[0137] In addition, the configurations and features of the non-invasive flow rate profile measuring device according to the embodiments described with reference to FIGS. 1 to 19, FIGS. 21, FIGS. 22, and FIGS. 24 may all be applicable to the non-invasive flow rate profile measuring device according to the embodiment of FIG. 25 within a range that is not contradictory.

[0138] According to the embodiments of the present invention described above, a non-invasive flow velocity profile measuring device can be implemented that not only non-invasively measures the flow velocity profile of a fluid passing through a pipe through simple installation, but also accurately and completely (generally completely) measures the flow velocity profile of a wide area within the pipe. In particular, the non-invasive flow velocity profile measuring device according to the embodiments utilizes a metastructure, namely a metaslab, to increase the distance between the ultrasonic propagation path of the central sensor and the ultrasonic propagation path of the auxiliary sensor, thereby obtaining a more accurate and complete (generally complete) flow velocity profile. Furthermore, since the non-invasive flow velocity profile measuring device according to the embodiments can be installed in various pipes in a simple manner, it can have significant advantages in terms of installation and measurement methods.

[0139] This specification discloses preferred embodiments of the present invention. Although specific terms have been used, they are used merely in a general sense to facilitate the explanation of the technical content of the invention and to aid in understanding the invention, and are not intended to limit the scope of the invention. It is obvious to those skilled in the art that, in addition to the embodiments disclosed herein, other variations based on the technical concept of the present invention are possible. Those skilled in the art will understand that a non-invasive flow velocity profile measuring device for non-invasively measuring the flow velocity profile of a fluid within a pipe according to the embodiments described with reference to FIGS. 1 to 25 can be variously substituted, changed, and modified within the scope of the technical concept of the present invention. Therefore, the scope of the invention should not be determined by the described embodiments but by the technical concept described in the claims. Explanation of the symbols

[0140] * Explanation of symbols for major parts of the drawing * A11 : 1-1 Medium Section A21 : Section 2-1 Medium A22 : Section 2-2 of the medium B21: Section 2-1 Insertion Medium B22 : 2-2 Insertion medium section F10, F20: Fluid M11 : Section 1-1 Metastructure M21 : Section 2-1 Metastructure M22 : Section 2-2 Metastructure N21: Section 2-1 Additional Metastructure N22 : Section 2-2 Additional Metastructure P10, P20: Piping S10: 1st sensor S20: Second sensor S30: 3rd sensor SU11: 1-1 Sensor Unit SU12: 1st-2nd Sensor Unit SU21: 2-1 Sensor Unit SU22: 2-2 Sensor Unit SU31: 3-1 Sensor Unit T11: 1-1 Ultrasonic transducer T21: 2-1 Ultrasonic transducer T22: 2-2 Ultrasonic transducer

Claims

Claim 1 A first sensor unit and a second sensor unit spaced apart from each other with respect to a first direction, disposed at the center or adjacent portion of the outer surface of a pipe through which fluid passes, wherein the first sensor unit comprises a first ultrasonic transducer and a first medium portion disposed between the first ultrasonic transducer and the pipe, and the first medium portion comprises a first metastructure for converting the type of ultrasound, and the first sensor unit and the second sensor unit form a first ultrasonic propagation path through which ultrasound propagates between them;and, based on a second direction perpendicular to the first direction, is disposed spaced apart from the first sensor on the outer surface of the pipe and includes a mutually spaced 2-1 sensor unit and a 2-2 sensor unit, wherein the 2-1 sensor unit includes a 2-1 ultrasonic transducer and a 2-1 medium portion disposed between the 2-1 ultrasonic transducer and the pipe, and the 2-1 medium portion includes a 2-1 metastructure for converting the type of ultrasound, and the 2-1 sensor unit and the 2-2 sensor unit include a second sensor forming a second ultrasonic propagation path through which ultrasound propagates between them, and the 1-1 metastructure determines a first position of the first ultrasonic propagation path within the pipe, and the 2-1 metastructure determines a second position of the second ultrasonic propagation path within the pipe, and the first position and the second position are such that the ultrasound A non-invasive flow velocity profile measuring device in which the angle of incidence entering the pipe and the angle of transmission into the pipe are designed to be different from each other to have different positions, and the flow velocity of the fluid within the pipe is calculated by measuring the flow velocity for the first ultrasonic propagation path and the flow velocity for the second ultrasonic propagation path, respectively, and the distance (h) between the first ultrasonic propagation path and the second ultrasonic propagation path is greater than 0.18D, where D is the inner diameter of the pipe. Claim 2 A non-invasive flow rate profile measuring device according to claim 1, wherein the flow rate for the first ultrasonic propagation path is the average flow rate calculated from the upstream and downstream signals of the first ultrasonic propagation path, and the flow rate for the second ultrasonic propagation path is the average flow rate calculated from the upstream and downstream signals of the second ultrasonic propagation path. Claim 3 A non-invasive flow velocity profile measuring device according to claim 1, wherein at least one of the 1-1 metastructure and the 2-1 metastructure is configured to convert longitudinal wave type ultrasound propagated toward the pipe into shear wave type ultrasound or to convert shear wave type ultrasound transmitted from the pipe into longitudinal wave type ultrasound. Claim 4 A non-invasive flow velocity profile measuring device according to claim 1, wherein at least one of the 1-1 metastructure and the 2-1 metastructure comprises a unit pattern structure, and the unit pattern structure comprises a through-hole region formed in the 1-1 medium portion or the 2-1 medium portion. Claim 5 A non-invasive flow velocity profile measuring device according to claim 1, wherein the piping is formed of plastic and the fluid is a liquid. Claim 6 A non-invasive flow velocity profile measuring device according to claim 1, wherein the piping is formed of metal and the fluid is a liquid. Claim 7 A non-invasive flow rate profile measuring device according to claim 6, wherein the first-1 sensor unit further comprises: a first-1 insertion medium portion disposed between the first-1 medium portion and the pipe and in contact with the pipe; and a first-1 additional metastructure formed within the first-1 insertion medium portion to increase ultrasonic transmittance from the pipe into its interior, and the second-1 sensor unit further comprises: a second-1 insertion medium portion disposed between the second-1 medium portion and the pipe and in contact with the pipe; and a second-1 additional metastructure formed within the second-1 insertion medium portion to increase ultrasonic transmittance from the pipe into its interior. Claim 8 A non-invasive flow rate profile measuring device according to claim 7, wherein the first-1 medium part and the second-1 medium part are formed of plastic, and the first-1 insertion medium part and the second-1 insertion medium part are formed of metal. Claim 9 In claim 1, the first sensor is a central sensor and the second sensor is an auxiliary sensor, and the auxiliary sensor is provided in 2n (where n is a positive integer), and the non-invasive flow velocity profile measuring device is a multi-line measuring device having 2n+1 lines. Claim 10 A first sensor unit and a second sensor unit spaced apart from each other with respect to a first direction, disposed at the center or adjacent portion of the outer surface of a pipe through which fluid passes, wherein the first sensor unit comprises a first ultrasonic transducer and a first medium portion disposed between the first ultrasonic transducer and the pipe, and the first medium portion comprises a first metastructure for reducing the sound speed of the ultrasound, and the first sensor unit and the second sensor unit form a first ultrasonic propagation path through which ultrasound propagates between them;and, based on a second direction perpendicular to the first direction, is disposed spaced apart from the first sensor on the outer surface of the pipe and includes a mutually spaced 2-1 sensor unit and a 2-2 sensor unit, wherein the 2-1 sensor unit includes a 2-1 ultrasonic transducer and a 2-1 medium portion disposed between the 2-1 ultrasonic transducer and the pipe, and the 2-1 medium portion includes a 2-1 metastructure for reducing the sound speed of the ultrasound, and the 2-1 sensor unit and the 2-2 sensor unit include a second sensor forming a second ultrasonic propagation path through which ultrasound propagates between them, and the 1-1 metastructure determines a first position of the first ultrasonic propagation path within the pipe, and the 2-1 metastructure determines a second position of the second ultrasonic propagation path within the pipe, and the first position and the second position are such that the ultrasound A non-invasive flow velocity profile measuring device in which the angle of incidence entering the pipe and the angle of transmission into the pipe are designed to be different from each other to have different positions, and the flow velocity of the fluid within the pipe is calculated by measuring the flow velocity for the first ultrasonic propagation path and the flow velocity for the second ultrasonic propagation path, respectively, and the distance (h) between the first ultrasonic propagation path and the second ultrasonic propagation path is greater than 0.18D, where D is the inner diameter of the pipe. Claim 11 A non-invasive flow rate profile measuring device according to claim 10, wherein the flow rate for the first ultrasonic propagation path is the average flow rate calculated from the upstream and downstream signals of the first ultrasonic propagation path, and the flow rate for the second ultrasonic propagation path is the average flow rate calculated from the upstream and downstream signals of the second ultrasonic propagation path. Claim 12 A non-invasive flow rate profile measuring device according to claim 10, wherein the 1-1 metastructure is formed uniformly over the ultrasonic propagation region within the 1-1 medium section, and the 2-1 metastructure is formed uniformly over the ultrasonic propagation region within the 2-1 medium section. Claim 13 A non-invasive flow velocity profile measuring device according to claim 10, wherein at least one of the 1-1 metastructure and the 2-1 metastructure comprises a unit pattern structure, and the unit pattern structure comprises a through-hole region formed in the 1-1 medium portion or the 2-1 medium portion. Claim 14 A non-invasive flow velocity profile measuring device according to claim 10, wherein the piping is formed of plastic and the fluid is a gas. Claim 15 A non-invasive flow velocity profile measuring device according to claim 10, wherein the piping is formed of metal and the fluid is a gas. Claim 16 A non-invasive flow rate profile measuring device according to claim 15, wherein the first-1 sensor unit further comprises: a first-1 insertion medium portion disposed between the first-1 medium portion and the pipe and in contact with the pipe; and a first-1 additional metastructure formed within the first-1 insertion medium portion to increase ultrasonic transmittance from the pipe into its interior, and the second-1 sensor unit further comprises: a second-1 insertion medium portion disposed between the second-1 medium portion and the pipe and in contact with the pipe; and a second-1 additional metastructure formed within the second-1 insertion medium portion to increase ultrasonic transmittance from the pipe into its interior. Claim 17 A non-invasive flow rate profile measuring device according to claim 16, wherein the first-1 medium part and the second-1 medium part are formed of plastic, and the first-1 insertion medium part and the second-1 insertion medium part are formed of metal. Claim 18 In claim 10, the first sensor is a central sensor and the second sensor is an auxiliary sensor, and the auxiliary sensor is provided in 2n (where n is a positive integer), and the non-invasive flow velocity profile measuring device is a multi-line measuring device having 2n+1 lines.

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