Non-invasive flow rate profile measuring device for measuring flow rate profile of fluid in pipe

Abstract

Disclosed is a non-invasive flow rate profile measuring device for non-invasively measuring the flow rate profile of a fluid in a pipe. The non-invasive flow rate profile measuring device disclosed herein includes a 1-1st sensor unit and a 1-2nd sensor unit that are disposed spaced apart from each other in, or adjacent to, a central portion of the outer surface of a pipe through which a fluid passes. The 1-1st sensor unit includes a 1-1st ultrasonic transducer and a 1-1st medium unit disposed between the 1-1st ultrasonic transducer and the pipe. The 1-1st medium unit includes: a first sensor including a 1-1st meta structure for converting the type of ultrasonic waves; and a 2-1st sensor unit and a 2-2nd sensor unit that are disposed spaced apart from each other on the outer surface of the pipe and spaced apart from the first sensor. The 2-1st sensor unit includes a 2-1st ultrasonic transducer and a 2-1st medium unit disposed between the 2-1st ultrasonic transducer and the pipe. The 2-1st medium unit may include a second sensor including a 2-1st meta-structure for converting the type of ultrasonic waves.

Description

Non-invasive velocity profile measuring device for measuring the velocity profile of fluid in a pipe

[0001] The present invention relates to a device and method for measuring a flow velocity profile, and more particularly, to a non-invasive flow velocity profile measuring device and measuring method for non-invasively measuring a flow velocity profile of a fluid in a pipe.

[0002] Fluid passing through a pipe can have different velocities (flow rates) depending on location and area. Furthermore, the fluid volume within the pipe can also vary depending on the location. To accurately obtain fluid flow rate information, it is necessary to measure the velocity profile of the fluid passing through the pipe.

[0003] Conventional ultrasonic sensors in velocity profile measurement devices are installed invasively, either by drilling a hole in the pipe to be measured or by fabricating a special pipe and installing it between the cut pipes. However, these methods present challenges in manufacturing and installing velocity profile measurement devices, and in applying them to existing pipes.

[0004] In addition, the existing proposed multi-line ultrasonic flow sensor uses a non-invasive method that simply has a plastic wedge structure and is installed on the outer wall of a pipe. However, if a plastic wedge is simply used, the ultrasonic propagation path of the auxiliary sensor among the multi-line ultrasonic flow sensors cannot help but be set quite close to the ultrasonic propagation path of the central sensor, which makes it difficult to measure a complete flow velocity profile over a wide range.

[0005] Therefore, a device and technique are required that can obtain 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.

[0006] The technical problem to be achieved by the present invention is to provide a non-invasive velocity profile measuring device that can non-invasively measure the velocity profile of a fluid passing through a pipe through simple installation and can accurately and completely (substantially completely) measure the velocity profile of a wide area within the pipe.

[0007] The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned can be understood by those skilled in the art from the description below.

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

[0009] 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 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 ultrasonic wave propagated toward the pipe into a shear wave type ultrasonic wave or to convert a shear wave type ultrasonic wave transmitted from the pipe into a longitudinal wave type ultrasonic wave.

[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 1-1 medium portion or the 2-1 medium portion.

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

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

[0014] The 1-1 sensor unit may further include a 1-1 insertion medium portion disposed between the 1-1 medium portion and the pipe and in contact with the pipe; and a 1-1 additional meta-structure formed within the 1-1 insertion medium portion to increase ultrasonic transmittance from the pipe to the inside thereof. The 2-1 sensor unit may further include a 2-1 insertion medium portion disposed between the 2-1 medium portion and the pipe and in contact with the pipe; and a 2-1 additional meta-structure formed within the 2-1 insertion medium portion to increase ultrasonic transmittance from the pipe to the inside thereof.

[0015] The above 1-1 medium portion and the 2-1 medium portion may be formed of plastic, and the above 1-1 insert medium portion and the above 2-1 insert medium portion 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 sensors may be provided in numbers of 2n (where n is a positive integer), and the non-invasive velocity 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 is provided, which is disposed at a center or adjacent portion of an outer surface of a pipe through which a fluid passes, and which comprises a first sensor unit and a first sensor unit spaced apart from each other, wherein the first sensor unit includes a first ultrasonic transducer and a first medium portion disposed between the first ultrasonic transducer and the pipe, and wherein the first medium portion includes a first metastructure for reducing the speed of sound of ultrasonic waves; And a non-invasive velocity profile measuring device for non-invasively measuring a velocity profile of a fluid in a pipe is provided, comprising a 2-1 sensor unit and a 2-2 sensor unit spaced apart from each other and arranged on an outer surface of the pipe, the 2-1 sensor unit including a 2-1 ultrasonic transducer and a 2-1 medium portion arranged between the 2-1 ultrasonic transducer and the pipe, the 2-1 medium portion including a second sensor including a 2-1 metastructure for reducing the speed of sound of ultrasonic waves.

[0018] 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 may be greater than 0.18D. Here, D is the inner diameter of the pipe.

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

[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 1-1 medium portion or the 2-1 medium portion.

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

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

[0023] The 1-1 sensor unit may further include a 1-1 insertion medium portion disposed between the 1-1 medium portion and the pipe and in contact with the pipe; and a 1-1 additional meta-structure formed within the 1-1 insertion medium portion to increase ultrasonic transmittance from the pipe to the inside thereof. The 2-1 sensor unit may further include a 2-1 insertion medium portion disposed between the 2-1 medium portion and the pipe and in contact with the pipe; and a 2-1 additional meta-structure formed within the 2-1 insertion medium portion to increase ultrasonic transmittance from the pipe to the inside thereof.

[0024] The above 1-1 medium portion and the 2-1 medium portion may be formed of plastic, and the above 1-1 insert medium portion and the above 2-1 insert medium portion 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 sensors may be provided in numbers of 2n (where n is a positive integer), and the non-invasive velocity profile measuring device may be a multi-line measuring device having 2n+1 lines.

[0026] According to embodiments of the present invention, a non-invasive velocity profile measuring device can be implemented that can not only non-invasively measure the velocity profile of a fluid passing through a pipe through simple installation, but can also accurately and completely (substantially) measure the velocity profile of a wide area within the pipe. In particular, the non-invasive velocity profile measuring device according to embodiments can obtain a more accurate and complete (substantially complete) velocity profile by increasing the distance between the ultrasonic propagation path of the central sensor and the ultrasonic propagation path of the auxiliary sensor by using a metastructure, i.e., a metaslab. In addition, since the non-invasive velocity profile measuring device according to embodiments can be installed in a simple manner in various pipes, 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 expanded in various ways without departing from the technical spirit and scope of the present invention.

[0028] FIG. 1 is a perspective view showing a non-invasive velocity profile measuring device for non-invasively measuring the velocity profile of a fluid in a pipe, according to one embodiment of the present invention.

[0029] FIG. 2 is a perspective view exemplarily showing a 1-1 sensor unit that can be applied to a non-invasive velocity profile measuring device according to one embodiment of the present invention.

[0030] FIG. 3 is a cross-sectional view illustrating a path design of a first sensor that can be applied to a non-invasive flow profile measurement device according to one embodiment of the present invention.

[0031] Figure 4 shows the transverse / longitudinal wave mode conversion ratio (T) according to the incidence angle (θ1) of Figure 3. S-L ) is a graph showing the

[0032] FIG. 5 is a cross-sectional view illustrating a path design of a second sensor that can be applied to a non-invasive flow profile measurement device according to one embodiment of the present invention.

[0033] FIG. 6 is a cross-sectional view illustrating an elliptical region of a pipe through which ultrasonic waves are transmitted by the second sensor of FIG. 5 and a path design related thereto.

[0034] FIG. 7 is a drawing for explaining an elliptical region (cross-sectional view of a propagation path) of a pipe through which ultrasonic waves are propagated by a second sensor that can be applied to a non-invasive velocity profile measuring device according to one embodiment of the present invention, and a path design related thereto.

[0035] FIG. 8 is a drawing showing the velocity distribution of a fluid flowing inside a pipe to which a non-invasive velocity profile measuring device according to one embodiment of the present invention can be applied.

[0036] FIG. 9 is a drawing showing an ultrasonic path by a first sensor that can be applied to a non-invasive flow profile measuring device according to one embodiment of the present invention.

[0037] Figure 10 is a graph showing the flow rate measurement results measured by the first sensor of Figure 9.

[0038] FIG. 11 is a drawing showing an ultrasonic path by a second sensor that can be applied to a non-invasive flow profile measuring device according to one embodiment of the present invention.

[0039] Figure 12 is a graph showing the flow rate measurement results measured by the second sensor of Figure 11.

[0040] FIG. 13 is a cross-sectional view showing a case where a first sensor and a second sensor applicable to a non-invasive flow profile measuring device according to one embodiment of the present invention are installed in a pipe.

[0041] Figures 14 and 15 are graphs showing the results of an ultrasonic path confirmation experiment (3D ultrasonic path confirmation experiment) for a non-invasive flow profile measuring device according to one embodiment of the present invention.

[0042] FIG. 16 is a cross-sectional view exemplarily showing a second sensor that can be applied to a non-invasive flow profile measurement device according to one embodiment of the present invention.

[0043] Fig. 17 is simulation data showing a mode (type) conversion phenomenon between longitudinal and transverse waves by a unit pattern structure that can be applied to the metastructure of Fig. 2.

[0044] Figure 18 is a graph showing the results of measuring the rate at which longitudinal waves are converted into transverse waves (i.e., energy conversion rate) by the unit pattern structure of Figure 17.

[0045] FIG. 19 is a drawing for explaining an elliptical region (cross-sectional view of a propagation path) of a pipe through which ultrasonic waves are propagated by a second sensor that can be applied to a non-invasive velocity profile measuring device according to an embodiment of the present invention, and a path design related thereto.

[0046] Figures 20 and 21 are cross-sectional views for explaining the transmission characteristics of ultrasonic waves in structures according to comparative examples and embodiments, respectively.

[0047] FIG. 22 is a drawing for explaining a second sensor that can be applied to a non-invasive flow profile measurement device according to another embodiment of the present invention.

[0048] Fig. 23 is a cross-sectional view illustrating a 1-1 sensor unit that can be applied to a non-invasive velocity profile measuring device according to a comparative example.

[0049] FIG. 24 is a cross-sectional view illustrating a 1-1 sensor unit that can be applied to a non-invasive velocity profile measuring device according to another embodiment of the present invention.

[0050] FIG. 25 is a cross-sectional view illustrating a 1-1 sensor unit that can be applied to a non-invasive flow profile measuring device according to another embodiment of the present invention.

[0051] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0052] The embodiments of the present invention described below are provided to more clearly explain the present invention to a person having ordinary skill in the art, and the scope of the present invention is not limited by the following embodiments, and the following embodiments can be modified in various other forms.

[0053] The terminology used herein is used to describe particular embodiments and is not intended to limit the present invention. The singular forms used herein may include the plural forms unless the context clearly dictates otherwise. In addition, the terms "comprise" and / or "comprising" used herein specify the presence of a stated feature, step, number, operation, element, element, and / or group thereof, but do not exclude the presence or addition of one or more other features, steps, numbers, operations, elements, elements, and / or groups thereof. In addition, the term "connected" used herein not only means that certain elements are directly connected, but also includes a concept that indirectly connects elements by interposing another element between them.

[0054] In addition, when it is said in this specification that a certain element is located "on" another element, this includes not only cases where a certain element is in contact with another element, but also cases where another element exists between the two elements. The term "and / or" as used in this specification includes any one of the listed items and any and all combinations of one or more of them. In addition, terms of degree such as "about", "substantially", etc. as used in this specification are used to mean a range of or close to the numerical value or degree, taking into account inherent manufacturing and material tolerances, and are used to prevent infringers from unfairly using the disclosure that mentions exact or absolute numbers provided to help the understanding of this specification.

[0055] Some technical terms used in this specification are briefly explained below.

[0056] Metamaterial: Also called a metastructure. Metamaterials are materials engineered to possess properties not found in nature. Metamaterials can be composed of periodic arrangements of engineered unit structures, and their properties can be determined by their structure. Utilizing metamaterials allows for extreme wave control.

[0057] 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 mode of ultrasonic waves propagating in an elastic medium from longitudinal waves to transverse waves or from transverse waves to longitudinal waves with an energy efficiency of about 90% or more or about 99% or more. By engineering the unit structure of the metamaterial and controlling its anisotropy, ultrasonic waves incident on the metamaterial as longitudinal waves (or transverse waves) can be converted into transverse waves (or longitudinal waves) and transmitted.

[0058] Perfect elastic wave penetration: This refers to the use of metamaterials to transmit ultrasound waves entering the boundary of different elastic media with 100% (or approximately 90% or more) energy efficiency without reflection. By engineering the unit structure of the metamaterial to satisfy phase-matching and impedance-matching conditions, the transmittance of ultrasound (both longitudinal and transverse waves) at the boundary of different media can be maximized.

[0059] Snell's Law: When two different media are in contact and an elastic wave passes through the two media, the speed of sound is different for each medium (υ1 and υ2, respectively), so the angle of penetration is different. If the angle of incidence and the angle of penetration are expressed as angles on the plane of incidence, they are θ1 and θ2. At this time, Snell's Law is defined as in mathematical equation 1 below.

[0060]

[0061] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The sizes and thicknesses of areas or parts illustrated in the attached drawings may be somewhat exaggerated for clarity and convenience of explanation. Like reference numbers designate like components throughout the detailed description.

[0062] FIG. 1 is a perspective view showing a non-invasive velocity profile measuring device for non-invasively measuring the velocity profile of a fluid in a pipe, according to one embodiment of the present invention.

[0063] Referring to FIG. 1, a non-invasive velocity profile measuring device (hereinafter, velocity profile measuring device) according to an embodiment of the present invention may be a device for non-invasively measuring a velocity profile of a fluid (F10) within a pipe (P10). The pipe (P10) may have, for example, a cylindrical structure (pipe structure). The velocity profile measuring device may be configured to measure an average velocity through a multi-circuit path and then calculate a velocity profile in order to measure the velocity profile of the fluid (F10) flowing within the pipe (P10).

[0064] The above-described velocity profile measuring device may include a first sensor (S10) arranged at the center or adjacent portion of the outer surface of a pipe (P10) through which a fluid (F10) passes, and a second sensor (S20) arranged on the outer surface of the pipe (P10) and spaced apart from the first sensor (S10). Here, the first sensor (S10) may be a central sensor, and the second sensor (S20) may be an auxiliary sensor. The number of auxiliary sensors may be 2n (where n is a positive integer). The above-described velocity profile measuring device may further include a third sensor (S30) arranged on the outer surface of the pipe (P10) and spaced apart from the first sensor (S10), and the third sensor (S30) may also correspond to the auxiliary sensor. One of the second sensor (S20) and the third sensor (S30) may be positioned above the first sensor (S10), and the other may be positioned below the first sensor (S10). Accordingly, the second sensor (S20) and the third sensor (S30) may be positioned at a position spaced apart from the center of the pipe (P10). The positions of the second sensor (S20) and the third sensor (S30) may be swapped. The velocity profile measuring device may be a multi-line measuring device having 2n+1 lines. For example, the velocity profile measuring device may be a measuring device having 3 lines, 5 lines, 7 lines, 9 lines, or more lines.

[0065] The first sensor (S10) may include a first-first sensor unit (SU11) and a second-second sensor unit (SU12) that are spaced apart from each other. Similarly, the second sensor (S20) may include a second-first sensor unit (SU21) and a second-second sensor unit (SU22) that are spaced apart from each other. Furthermore, the third sensor (S30) may include a third-first sensor unit (SU31) and a third-second sensor unit (not shown) that are spaced apart from each other.

[0066] The 1-1 sensor unit (SU11) and the 1-2 sensor unit (SU12) may function as an ultrasonic transmitter and an ultrasonic receiver. For example, when the 1-1 sensor unit (SU11) is in charge of ultrasonic transmission, the 1-2 sensor unit (SU12) may be in charge of ultrasonic reception, and when the 1-2 sensor unit (SU12) is in charge of ultrasonic transmission, the 1-1 sensor unit (SU11) may be in charge of ultrasonic reception. The 1-1 sensor unit (SU11) and the 1-2 sensor unit (SU12) may be installed on the outer wall of the pipe (P10) so as to face each other with the pipe (P10) interposed therebetween, and may be installed at a certain distance apart from each other along the length 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 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 function as an ultrasonic transmitter and an ultrasonic receiver, and may be installed to face each other with the pipe (P10) interposed therebetween, and may be installed to be spaced apart from each other by a certain distance along the length direction of the pipe (P10). In addition, the 3-1 sensor unit (SU31) and the 3-2 sensor unit may function as an ultrasonic transmitter and an ultrasonic receiver, and may be installed to face each other with the pipe (P10) interposed therebetween, and may be installed to be spaced apart from each other by a certain distance along the length direction of the pipe (P10).

[0067] Each sensor unit (SU11, SU12, SU21, SU22, SU31) may include a type of wedge structure and may use a guide rail, jig, chain, etc. to enable accurate installation at a given location in the pipe (P10).

[0068] FIG. 2 is a perspective view exemplarily showing a 1-1 sensor unit (SU11) that can be applied to a non-invasive flow profile measuring device according to one embodiment of the present invention.

[0069] Referring to FIG. 2, when a flow 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 1-1 sensor unit (SU11) may have a configuration as shown. The pipe is 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.

[0070] The 1-1 sensor unit (SU11) may include a 1-1 ultrasonic transducer (T11) and a 1-1 medium portion (A11) disposed between the 1-1 ultrasonic transducer (T11) and the pipe, and the 1-1 medium portion (A11) may include a 1-1 metastructure (M11) for converting the type of ultrasonic waves.

[0071] The 1-1 ultrasonic transducer (T11) may include a piezoelectric element. For example, the piezoelectric element may include, but is not limited to, an oxide or compound of, for example, a piezoelectric material such as PZT (lead zirconate titanate) or other materials such as barium (Ba), calcium (Ca), titanium (Ti), zirconium (Zr), and manganese (Mn) between opposing electrodes, and these may have a single-layer structure or may be multilayered by alternately arranging the electrodes, and may have a three-dimensional shape using a thin film or MEMS (micro-electromechanical system) technology. The 1-1 ultrasonic transducer (T11) may be installed in a groove formed on the rear surface of the 1-1 medium portion (A11), but in some cases, the groove may not be formed.

[0072] In one embodiment, the 1-1 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 1-1 ultrasonic transducer (T11) generates longitudinal wave type ultrasonic waves, the 1-1 medium section (A11) may include a 1-1 metastructure (M11) for converting the longitudinal wave type ultrasonic waves into transverse wave type ultrasonic waves.

[0073] In one embodiment, the first metastructure (M11) may include a unit pattern structure (n10) for mode (type) conversion of ultrasonic waves. The first metastructure (M11) may be considered a type of metamaterial, and may induce mode conversion of ultrasonic waves through a material configuration based on a geometric structure without electrical conversion. In addition, the first metastructure (M11) may be considered a type of metaslab.

[0074] The first-first 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-first medium section (A11) may have a structure in which a portion of a rectangular column structure is cut off, and the cut surface may have the curved area. The curved area may be arranged to contact (make contact with) the first area of ​​the pipe. The first-first medium section (A11) may be referred to as a type of 'wedge structure.'

[0075] The first-first medium section (A11) may include or be formed of a plastic material. The plastic material may be, for example, polyether ether ketone (PEEK) or may include PEEK. However, the type of the plastic material is merely exemplary and is not limited to the aforementioned, and various materials may be employed. Furthermore, in some cases, the first-first medium section (A11) may be formed of the same plastic material as the pipe.

[0076] The metamaterial (metastructure) mentioned in the above description may refer to a material that is engineered to have properties that do not exist in nature. A metamaterial may be composed of a periodic arrangement of engineered unit structures (unit pattern structures), and the properties of the metamaterial may be determined by the structure. Using metamaterials, the wave mode (type) of ultrasonic waves (elastic waves) propagating in an elastic medium can be converted from longitudinal waves (or transverse waves) to transverse waves (or longitudinal waves) with an energy efficiency of about 90% or more or about 99% or more. By engineering the unit structure (unit pattern structure) of the metamaterial to control its anisotropy, ultrasonic waves incident on the metamaterial as longitudinal waves (or transverse waves) can be converted into transverse waves (or longitudinal waves) and transmitted therethrough. Such metamaterials may be referred to as 'anisotropic metamaterials.'

[0077] The 1-1 metastructure (M11) may include a unit pattern structure (n10) for mode (type) conversion of ultrasonic waves. A plurality of unit pattern structures (n10) may be regularly arranged. For example, a plurality of unit pattern structures (n10) may be arranged in a row with a predetermined distance between them in a direction parallel to the 1-1 ultrasonic transducer (T11).

[0078] The unit pattern structure (n10) may be a through hole (through hole region) having a predetermined shape formed in the 1-1 medium portion (A11). The through hole may be easily formed by making a hole in the 1-1 medium portion (A11) using a method 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 1-1 medium portion (A11).

[0079] By using this 1-1 meta-structure (M11), mode conversion of almost 100% between longitudinal and transverse waves can be possible. In addition, depending on the structure, shape, size, etc. of the unit pattern structure (n10) constituting the 1-1 meta-structure (M11), the target frequency range of the ultrasonic waves to be converted between longitudinal and transverse waves can vary. In the embodiment of Fig. 2, the cross-section of the unit pattern structure (n10) can have a kind of heart shape or a similar shape. In other words, the cross-section of the unit pattern structure (n10) can be said to have a deformed triangle shape in which three vertex areas are rounded. Through this shape design, longitudinal-type ultrasonic waves can be converted into transverse-type ultrasonic waves. However, the specific structure, shape, size, etc. of the unit pattern structure (n10) can be varied in various ways.

[0080] Although not shown, the 1-2 sensor unit (SU12) of FIG. 1 may have a structure symmetrical to the 1-1 sensor unit (SU11) of FIG. 2. The 1-2 sensor unit (SU12) may include a 1-2 ultrasonic transducer and a 1-2 medium portion disposed between the 1-2 ultrasonic transducer and the pipe, and the 1-2 medium portion may include a 1-2 meta-structure for converting the type of ultrasonic waves. When the 1-2 sensor unit (SU12) is used for ultrasonic reception, the 1-2 meta-structure may serve to convert a transverse wave type ultrasonic wave transmitted from the pipe into a longitudinal wave type ultrasonic wave, and the longitudinal wave type ultrasonic wave may be transmitted to the 1-2 ultrasonic transducer.

[0081] 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 ultrasonic waves. The 2-1 sensor unit (SU21) may have a structure identical to or nearly identical to the 1-1 sensor unit (SU11) of FIG. 2, except for a curved structure at an end of the 2-1 medium portion. When the 2-1 sensor unit (SU21) is used for ultrasonic transmission, the 2-1 metastructure can serve to convert longitudinal wave type ultrasonic waves transmitted from the 2-1 ultrasonic transducer into transverse wave type ultrasonic waves, and the transverse wave type ultrasonic waves can be transmitted to the pipe.

[0082] Although not shown, the 2-2 sensor unit (SU22) of FIG. 1 may have a structure symmetrical to the 2-1 sensor unit (SU21) described above. The 2-2 sensor unit (SU22) may include a 2-2 ultrasonic transducer and a 2-2 medium portion disposed between the 2-2 ultrasonic transducer and the pipe, and the 2-2 medium portion may include a 2-2 metastructure for converting the type of ultrasonic waves. When the 2-2 sensor unit (SU22) is used for ultrasonic reception, the 2-2 metastructure may serve to convert a transverse wave type ultrasonic wave transmitted from the pipe into a longitudinal wave type ultrasonic wave, and the longitudinal wave type ultrasonic wave may be transmitted to the 2-2 ultrasonic transducer.

[0083] Additionally, although not shown, the 3-1 sensor unit (SU31) and the 3-2 sensor unit of FIG. 1 may have the same or similar structure as the 2-1 sensor unit (SU21) and the 2-2 sensor unit (SU22) described above, respectively.

[0084] 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 portion) to a pipe, when ultrasonic waves are transmitted as transverse waves from the pipe to the internal fluid, the difference in sound speed between the pipe and the internal fluid can be reduced, and transmission can be achieved at a larger transmission angle. Accordingly, the distance (minimum distance between the centers of paths) (i.e., height difference) between the propagation path of ultrasonic waves within the pipe by the first sensor (S10 of FIG. 1) and the propagation path of ultrasonic waves within the pipe by the second sensor (S20 of FIG. 1) can be increased.

[0085] FIG. 3 is a cross-sectional view illustrating a path design of a first sensor (S10) that can be applied to a non-invasive flow profile measurement device according to one embodiment of the present invention.

[0086] Referring to FIG. 3, the first sensor (S10) may include a 1-1 sensor unit (SU11) and a 1-2 sensor unit (SU12). For convenience, the 1-1 sensor unit (SU11) and the 1-2 sensor unit (SU12) are simply illustrated. Here, θ1 represents an incident angle of ultrasonic waves from the 1-1 sensor unit (SU11) to the pipe (P10), and α1 represents a transmission angle of ultrasonic waves from the 1-1 sensor unit (SU11) to the fluid (F10) in the pipe (P10). The incident angle (θ1) and the transmission angle (α1) may be angles with respect to a line perpendicular to the pipe (P10).

[0087] Figure 4 shows the transverse / longitudinal wave mode conversion ratio (T) according to the incidence angle (θ1) of Figure 3. S-L ) is a graph showing the

[0088] Referring to Fig. 4, the ultrasonic transducer of the first sensor (S10 of Fig. 3) is set to an incident angle of θ1 = 36.5° at which the maximum energy transmittance is obtained, and at this time, the transmission angle in the fluid inside the pipe is α1 = 54.5°. The transmitter (e.g., SU11 of Fig. 3) and the receiver (e.g., SU12 of Fig. 3) of the first sensor (S10) are installed on opposite sides of the pipe with a certain installation distance between them, and the installation positions can be determined by the incident angle and transmission angle in each medium section and the dimensions of the sensor unit and the pipe.

[0089] FIG. 5 is a cross-sectional view illustrating a path design of a second sensor (S20) that can be applied to a non-invasive flow profile measurement device according to one embodiment of the present invention.

[0090] 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 2-1 sensor unit (SU21) and a 2-2 sensor unit (SU22). For convenience, the 2-1 sensor unit (SU21) and the 2-2 sensor unit (SU22) are simply illustrated. The 2-1 sensor unit (SU21) and the 2-2 sensor unit (SU22) may be installed at opposite sides of the pipe (P10) with a certain installation distance between them. Here, β represents a cross-sectional determination angle. The cross-sectional determination angle (β) may be determined by the positions of the 2-1 sensor unit (SU21) and the 2-2 sensor unit (SU22). In other words, the cross-sectional determination angle (β) may be the angle formed by a 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).

[0091] The region where the path for ultrasonic waves to propagate in the fluid (F10) inside the pipe (P10) by the second sensor (S20) can be viewed as an elliptical region. The cross-sectional shape of the ultrasonic wave propagation path can be determined by the cross-sectional determination angle (β). The cross-sectional determination angle (β) can be arbitrarily selected, but in this embodiment, it is set to 65° as an example.

[0092] FIG. 6 is a cross-sectional view illustrating an elliptical region of a pipe (P10) through which ultrasonic waves are transmitted by the second sensor (S20) of FIG. 5 and a path design related thereto.

[0093] Referring to FIG. 6, the ultrasonic waves converted into transverse waves by the 2-1 sensor unit (SU21 of FIG. 5) of the 2nd sensor (S20 of FIG. 5) can be propagated as longitudinal waves in the fluid (F10) inside the pipe (P10). The ultrasonic waves can be propagated in the form of longitudinal waves in the fluid (F10). Here, θ2 represents the angle of incidence of the ultrasonic waves from the 2-1 sensor unit (SU21) to the pipe (P10), and α2 represents the angle of transmission of the ultrasonic waves from the 2-1 sensor unit (SU21) to the fluid (F10) inside the pipe (P10). The angle of incidence (θ2) and the angle of transmission (α2) can be angles with respect to a line (normal) perpendicular to the tangent line of the pipe (P10) at the point of incidence. In addition, h represents the distance (minimum distance between the centers of the paths) (i.e., height difference) between the propagation path of the ultrasonic wave in the pipe (P10) by the first sensor (S10) and the propagation path of the ultrasonic wave in the pipe (P10) by the second sensor (S20), r' represents the inner radius in the short axis direction of the elliptical region, and r" represents the inner radius in the long axis direction of the elliptical region. The inner diameter (D) of the pipe (P10) may be 2r'.

[0094] The above α1, α2, θ2, r' and h can be determined as in mathematical equations 2 to 6 below.

[0095]

[0096]

[0097]

[0098]

[0099]

[0100] In the above mathematical equations 2 and 4, C w is the transverse wave velocity of ultrasonic waves in a plastic material medium (wedge), and C l 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.

[0101] In the case of a conventional ultrasonic wedge, since the wave is incident longitudinally from the wedge to the pipe, there is a limit to the distance between the path of the central sensor and the path of the auxiliary sensor. However, using a non-invasive velocity profile measuring device according to an embodiment of the present invention, theoretically, the distance (h) between the path of the first sensor (the central sensor) and the path of the second sensor (the auxiliary sensor) can be any distance. According to an embodiment of the present invention, the distance (h) between the propagation path of the ultrasonic wave within the pipe by the first sensor and the propagation path of the ultrasonic wave within the pipe by the second sensor can be greater than about 0.18D (where D is the inner diameter of the pipe), and therefore, the velocity profile of a wide area within the pipe can be accurately and completely (substantially completely) measured.

[0102] FIG. 7 is a drawing for explaining an elliptical region (cross-sectional view of a propagation path) of a pipe through which ultrasonic waves are propagated by a second sensor that can be applied to a non-invasive velocity profile measuring device according to one embodiment of the present invention, and a path design related thereto.

[0103] Referring to Fig. 7, when measuring a velocity profile in a pipe (P10) (e.g., PVC pipe), for example, the penetration angle α2 in the fluid (F10) can be calculated as 65° to set an ultrasonic path by a second sensor (i.e., an auxiliary sensor) at a path that is located at a distance of h = (2 / 3)r' from the ultrasonic path by the first sensor (i.e., the center sensor) by a cross-sectional determination angle of β = 65°. Here, a tan represents the reciprocal of tan. In addition, since the impedance difference with the internal fluid (F10) can be reduced when the ultrasonic wave is incident from a plastic (e.g., PEEK) medium (wedge) to the pipe (P10) (e.g., PVC pipe) as a shear wave, the medium (wedge) can be designed to be 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.

[0104] FIG. 8 is a drawing showing the velocity distribution of a fluid (F10) flowing inside a pipe (P10) to which a non-invasive velocity profile measuring device according to one embodiment of the present invention can be applied.

[0105] Referring to Fig. 8, in order to verify the average velocity measurement performance of the non-invasive velocity profile measuring device according to an embodiment of the present invention along the ultrasonic propagation path, the velocity distribution of the fluid (F10) was simulated for a PVC pipe (P10) having a diameter of 30 mm and a thickness of 2 mm. The average velocity of the fluid (F10) along the ultrasonic path by the first sensor was approximately 20.02 m / s, and the average velocity of the fluid (F10) along the ultrasonic path by the second sensor was approximately 15.67 m / s.

[0106] Figure 9 is a diagram showing an ultrasonic path by a first sensor (S10) applicable to a non-invasive velocity profile measurement 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.

[0107] Fig. 10 is a graph showing the results of the flow rate measurement measured by the first sensor (S10) of Fig. 9.

[0108] Figure 11 is a diagram showing an ultrasonic path by a second sensor (S20) that can be applied to a non-invasive velocity profile measurement 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.

[0109] Fig. 12 is a graph showing the flow rate measurement results measured by the second sensor (S20) of Fig. 11.

[0110] Referring to FIGS. 9 to 12, the average velocity calculated from the upstream and downstream signals in the ultrasonic path of the first sensor (S10) had an error of 3.3% from the average velocity set to about 20.67 m / s. In addition, the average velocity calculated from the upstream and downstream signals in the ultrasonic path of the second sensor (S20) had an error of 3.8% from the average velocity set to about 16.27 m / s. In this way, a velocity profile can be obtained by the average velocity measured in multiple circuits. It can be confirmed from the simulation results that both the first sensor (S10) and the second sensor (S20) can transmit / transmit ultrasonic waves along the designed path and accurately measure the velocity at a desired location.

[0111] To verify whether ultrasonic waves actually propagate along the path designed according to the embodiment within the pipe (P10), an ultrasonic path verification experiment was conducted as shown in Figs. 13 to 15. At this time, the pipe (P10) was a PVC pipe.

[0112] FIG. 13 is a cross-sectional view showing a case where a first sensor (S10) and a second sensor (S20) applicable to a non-invasive velocity profile measurement device according to one embodiment of the present invention are installed in a pipe (P10).

[0113] 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 represents an ultrasonic propagation path located at a distance of (2 / 3)r' from the center of the pipe (P10) by the second sensor (S20). To confirm whether the ultrasonic waves propagate along the designed path, the path was blocked using a 30 mm long epoxy block, and the magnitude of the received signal was compared depending on the presence or absence of the block. The results are as shown in Figs. 14 and 15.

[0114] Figures 14 and 15 are graphs showing the results of an ultrasonic path confirmation experiment (3D ultrasonic path confirmation experiment) for a non-invasive flow profile measuring device according to one embodiment of the present invention.

[0115] Referring to Fig. 14, in the case of path 1, it can be confirmed that when the ultrasonic path is blocked using an epoxy block, the size of the received signal is greatly reduced compared to before.

[0116] Referring to Fig. 15, in the case of path 2, when the lower and upper parts of the pipe were each blocked using epoxy blocks, the size of the received signal in the lower part was almost similar to when there was no block, and the signal size in the upper part was significantly reduced compared to when there was no block. From the experimental results of Figs. 14 and 15, it can be confirmed that the ultrasonic waves are well propagated along the designed path.

[0117] FIG. 16 is a cross-sectional view exemplarily showing a second sensor (S20) that can be applied to a non-invasive flow profile measurement device according to one embodiment of the present invention.

[0118] Referring to FIG. 16, the second sensor (S20) may include a 2-1 sensor unit (SU21) and a 2-2 sensor unit (SU22) that are spaced apart from each other. The 2-1 sensor unit (SU21) may include a 2-1 ultrasonic transducer (T21) and a 2-1 medium portion (A21) disposed between the 2-1 ultrasonic transducer (T21) and the pipe (P10), and the 2-1 medium portion (A21) may include a 2-1 metastructure (M21) for converting the type of ultrasonic waves. The second-second sensor unit (SU22) may include a second-second ultrasonic transducer (T22) and a second-second medium section (A22) disposed between the second-second ultrasonic transducer (T22) and the pipe (P10), and the second-second medium section (A22) may include a second-second metastructure (M22) for converting the type of ultrasonic waves. In this embodiment, the pipe (P10) may be a non-metallic pipe, for example, a plastic pipe, and the fluid (F10) flowing inside the pipe (P10) may be a liquid.

[0119] 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 wave type ultrasonic waves. When an ultrasonic transducer that generates longitudinal wave type ultrasonic waves is used, energy efficiency can be improved and costs can be reduced.

[0120] The second-first medium section (A21) may include a second-first metastructure (M21) for converting the type of ultrasonic waves between longitudinal and transverse waves. In addition, the second-second medium section (A22) may include a second-second metastructure (M22) for converting the type of ultrasonic waves between longitudinal and transverse waves. The metastructures (M21, M22) may be shaped to enable nearly 100% mode conversion between longitudinal and transverse waves at a specific frequency (e.g., 200 kHz), and may be designed as a monolayer to be processed into a single unit hole for convenience of manufacturing.

[0121] The distance (h) between the ultrasonic propagation path by the second sensor (S20) and the ultrasonic propagation path (center path) by the first sensor can be theoretically 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 about 0.18D (wherein D is the inner diameter of the pipe). Therefore, by using the non-invasive velocity profile measuring device according to the embodiment, the velocity profile of a wide area within the pipe (P10) can be accurately and completely (substantially completely) measured.

[0122] Fig. 17 is simulation data showing a mode (type) conversion phenomenon between longitudinal and transverse waves by a unit pattern structure (n10) that can be applied to the metastructure (M11) of Fig. 2.

[0123] Referring to Fig. 17, longitudinal wave type ultrasonic waves can be converted into transverse wave type ultrasonic waves as they pass through the unit pattern structure (n10). Also, in the opposite case, transverse wave type ultrasonic waves can be converted into longitudinal wave type ultrasonic waves as they pass through the unit pattern structure (n10).

[0124] Fig. 18 is a graph showing the results of measuring the rate at which longitudinal waves are converted into transverse waves (i.e., energy conversion rate) by the unit pattern structure (n10) of Fig. 17.

[0125] Referring to Fig. 18, when the frequency of the ultrasonic wave is about 200 kHz, the ratio of longitudinal waves converted into transverse waves by the unit pattern structure (n10 in Fig. 17), i.e., the mode conversion rate, can be as high as about 97.5%. Therefore, mode conversion close to 100% can be possible using ultrasonic waves having a specific frequency. However, the specific frequency (200 kHz) disclosed herein is merely exemplary, and the target frequency range may vary depending on design conditions. In addition, the shape of the unit pattern structure (n10 in Fig. 17) is not limited to that illustrated in Fig. 17, and may vary in various ways.

[0126] If the pipe is formed of metal, i.e., if a metal pipe is used, it may be difficult to secure an ultrasonic path as shown in Fig. 16, etc.

[0127] FIG. 19 is a drawing illustrating an elliptical region (cross-sectional view of a propagation path) of a pipe through which ultrasonic waves are propagated by a second sensor applicable to a non-invasive velocity profile measurement 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, for example, steel.

[0128] Referring to Fig. 19, the second sensor is also configured to set 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). The ultrasonic waves should be transmitted at an angle of α2=65°. However, even if the ultrasonic waves are incident on the metal pipe (P20) as transverse waves, a critical angle may occur due to the difference in the speed of sound between the ultrasonic waves 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 the ultrasonic waves along the desired set path inside the fluid (F10).

[0129] For metal pipes, when using a metal wedge, there is a problem that the ultrasonic waves of the auxiliary sensor cannot transmit through a path away from the central sensor due to a critical angle caused by the difference in the speed of sound of the ultrasonic waves in the metal pipe and the internal fluid. In addition, for metal pipes, when using a plastic wedge, there is a problem that the ultrasonic transmittance 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 transmit through a path away from the central sensor. However, according to another embodiment of the present invention, by using a separate meta-structure that takes the thickness of the metal pipe into account, i.e., an additional meta-slab, both the critical angle and transmittance problems can be overcome, and the ultrasonic waves of the auxiliary sensor (second sensor) can be transmitted and propagated through a path set within the metal pipe.

[0130] Figures 20 and 21 are cross-sectional views for explaining the transmission characteristics of ultrasonic waves in structures according to comparative examples and embodiments, respectively. Figure 20 shows a structure according to a comparative example, and Figure 21 shows a structure according to an embodiment. In Figure 20, a plastic wedge portion (A10) is in direct contact with a metal pipe (P20), and in Figure 21, a metal wedge portion (B10) including an additional metastructure (N10) is arranged between the plastic wedge portion (A10) and the metal pipe (P20).

[0131] Referring to FIG. 20, when ultrasonic waves are transmitted from a plastic wedge (A10) through a metal pipe (P20) to a fluid (F10), the energy ratio of the ultrasonic waves transmitted into the fluid (F10) may be very low.

[0132] Referring to Fig. 21, the additional metastructure (N10) can serve to transmit ultrasonic waves propagated from the plastic wedge portion (A10) into the fluid (F10) with an energy efficiency close to 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) can have a refracted bar shape or a similar shape. The shape of the unit pattern structure can be varied in various ways.

[0133] When measuring the flow profile of the internal fluid in a metal pipe, to solve the problem of ultrasonic penetration due to the critical angle, an anisotropic meta-slab that takes the pipe thickness into account can be used to ensure that ultrasonic waves are transmitted along a set path within the pipe. When using a conventional plastic wedge, the critical angle may exist due to the difference in the speed of sound of ultrasonic waves in the plastic wedge and the metal pipe, which may result in very low ultrasonic penetration. In addition, the difference in the ultrasonic speed and impedance between the metal pipe and the internal fluid may cause the ultrasonic waves to not be transmitted along the desired path. When using an assembled ultrasonic meta-transducer that takes the pipe thickness into account (i.e., a sensor unit including the anisotropic meta-slab) can overcome both the critical angle and the penetration problem, thereby ensuring that ultrasonic waves are transmitted along the set path within the pipe.

[0134] Figure 22 is a drawing illustrating a second sensor (S20') applicable to a non-invasive velocity profile measurement 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.

[0135] 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 velocity profile measurement device (hereinafter, the velocity profile measurement 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.

[0136] The second sensor (S20') may include a second-first sensor unit (SU21') and a second-second sensor unit (SU22') that are spaced apart from each other. The second-first sensor unit (SU21') may include a second-first ultrasonic transducer (T21) and a second-first medium portion (A21) disposed between the second-first ultrasonic transducer (T21) and the pipe (P20), and the second-first medium portion (A21) may include a second-first metastructure (M21) for converting the type of ultrasonic waves. In addition, the 2-1 sensor unit (SU21') may further include a 2-1 insertion medium portion (B21) disposed between the 2-1 medium portion (A21) and the pipe (P20) and in contact with the pipe (P20), and a 2-1 additional meta-structure (N21) formed within the 2-1 insertion medium portion (B21) to increase ultrasonic transmittance from the pipe (P20) to the inside thereof. The 2-1 insertion medium portion (B21) and the 2-1 additional meta-structure (N21) may constitute one additional meta-slab. The 2-1 additional meta-structure (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 portion (B21).

[0137] The 2-2 sensor unit (SU22') may include a 2-2 ultrasonic transducer (T22) and a 2-2 medium portion (A22) disposed between the 2-2 ultrasonic transducer (T22) and the pipe (P20), and the 2-2 medium portion (A22) may include a 2-2 meta-structure (M22) for converting the type of ultrasonic waves. In addition, the 2-2 sensor unit (SU22') may further include a 2-2 insertion medium portion (B22) disposed between the 2-2 medium portion (A22) and the pipe (P20) and in contact with the pipe (P20), and a 2-2 additional meta-structure (N22) formed within the 2-2 insertion medium portion (B22) to increase ultrasonic transmittance from the pipe (P20) to the inside thereof. The second-second insertion medium portion (B22) and the second-second additional metastructure (N22) can form one additional metaslab. The second-second additional metastructure (N22) can include a periodic arrangement of unit pattern structures, and the unit pattern structures can be, for example, through holes (through hole regions) having a predetermined shape formed in the second-second insertion medium portion (B22).

[0138] According to one embodiment, the 2-1 medium portion (A21) and the 2-2 medium portion (A22) may be formed of plastic, and the 2-1 insertion medium portion (B21) and the 2-2 insertion medium portion (B22) may be formed of metal. The 2-1 insertion medium portion (B21) and the 2-2 insertion medium portion (B22) may be formed of the same metal as the pipe (P20), or may be formed of a different metal.

[0139] Although not illustrated in FIG. 22, the first sensor may include a 1-1 sensor unit and a 1-2 sensor unit that are spaced apart from each other. The 1-1 sensor unit may include a 1-1 ultrasonic transducer and a 1-1 medium portion disposed between the 1-1 ultrasonic transducer and a pipe (P20), and the 1-1 medium portion may include a 1-1 metastructure for converting a type of ultrasonic wave. In addition, the 1-1 sensor unit may further include a 1-1 insertion medium portion disposed between the 1-1 medium portion and the pipe (P20) and in contact with the pipe (P20), and a 1-1 additional metastructure formed within the 1-1 insertion medium portion to increase ultrasonic transmittance from the pipe (P20) to the interior thereof. The 1-1 insertion medium portion and the 1-1 additional metastructure may constitute one additional metaslab. The above 1-1 additional metastructure 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 1-1 insertion medium portion.

[0140] The above 1-2 sensor unit may include a 1-2 ultrasonic transducer and a 1-2 medium portion disposed between the 1-2 ultrasonic transducer and a pipe (P20), and the 1-2 medium portion may include a 1-2 meta-structure for converting a type of ultrasonic wave. In addition, the 1-2 sensor unit may further include a 1-2 insertion medium portion disposed between the 1-2 medium portion and the pipe (P20) and in contact with the pipe (P20), and a 1-2 additional meta-structure formed within the 1-2 insertion medium portion to increase ultrasonic transmittance from the pipe (P20) to the inside thereof. The 1-2 insertion medium portion and the 1-2 additional meta-structure may constitute one additional meta-slab. The above 1-2 additional metastructure 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 1-2 insertion medium portion.

[0141] In one embodiment, the first-first medium portion and the first-second medium portion may be formed of plastic, and the first-first insertion medium portion and the first-second insertion medium portion may be formed of metal. The first-first insertion medium portion and the first-second insertion medium portion may be formed of the same metal as the pipe (P20), or may be formed of a different metal.

[0142] Additionally, the flow 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').

[0143] According to one embodiment, the sensor unit considering the pipe thickness in the flow profile measuring device may be composed of a part made of a plastic (for a non-limiting example, PEEK) material and a part made of a metal (for a non-limiting example, steel) material including 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 be propagated 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 the pipe thickness, when θ2 is 30°, the height (h) of the propagation path is 0.29D. The right drawing of Fig. 22 includes a simulation result in a three-dimensional propagation cross-section. As can be seen from the simulation result, it can be seen that the longitudinal wave transmitted into the internal fluid (F10) is well propagated to the receiver (i.e., S20') at the set path height of 0.29D. When θ2 is greater than 30°, the height of the ultrasonic propagation path can be larger, and theoretically, the height of the propagation path can be set to any height.

[0144] When the fluid flowing inside the pipe is gas, the longitudinal wave velocity in the plastic medium (wedge) is much faster than the longitudinal wave velocity in the gas, so the difference in the speed of sound of the ultrasonic waves in the plastic medium (wedge) and the fluid (gas) can be very large, which can make it difficult to establish a propagation path of the ultrasonic waves.

[0145] Fig. 23 is a cross-sectional view illustrating a 1-1 sensor unit (SU11a) that can be applied to a non-invasive flow profile measuring device according to a comparative example.

[0146] Referring to FIG. 23, the 1-1 sensor unit (SU11a) according to the comparative example may have a 1-1 ultrasonic transducer (T11a) and a 1-1 medium portion (A11a) disposed between the 1-1 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 the 1-1 sensor unit (SU11a) according to the comparative example is used, since the longitudinal wave velocity in the 1-1 medium portion (A11a) formed of plastic is much faster than the longitudinal wave velocity in gas (air), the transmission angle θ1 in the pipe (P20) may be much smaller than the incident angle θ0 in the 1-1 medium portion (A11a) according to Snell's law. When the internal gas is air, the maximum penetration angle (θ1) in the air is 6.2°, but in order to perform the flow rate measurement function, the penetration angle needs to be set to 30° or more, just like when the internal gas is liquid. In addition, when the 1-1 sensor unit (SU11a) according to the comparative example is used, there is a problem in that the energy penetration rate is very low and the signal cannot be detected at the receiving unit due to the impedance difference between the 1-1 medium portion (A11a) formed of plastic and the pipe (P20) formed of metal, and between the metal pipe (P20) and the internal fluid (gas) (F20), especially, the very large impedance difference between the metal pipe (P20) and the internal fluid (gas) (F20).

[0147] Figure 24 is a cross-sectional view illustrating a 1-1 sensor unit (SU11b) applicable to a non-invasive flow profile measurement 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.

[0148] Referring to FIG. 24, the 1-1 sensor unit (SU11b) may include a 1-1 ultrasonic transducer (T11b) and a 1-1 medium portion (A11b) disposed between the 1-1 ultrasonic transducer (T11b) and a pipe (P20), and the 1-1 medium portion (A11b) may include a 1-1 metastructure (M11b) for reducing the speed of sound of ultrasonic waves. Additionally, the 1-1 sensor unit (SU11b) may further include a 1-1 insertion medium portion (B11b) disposed between the 1-1 medium portion (A11b) and the pipe (P20) and in contact with the pipe (P20), and a 1-1 additional metastructure (N11b) formed within the 1-1 insertion medium portion (B11b) to increase ultrasonic transmission from the pipe (P20) to the inside thereof.

[0149] The 1-1 metastructure (M11b) can play a role in lowering the speed of sound of ultrasonic waves in the 1-1 medium portion (A11b). The 1-1 metastructure (M11b) can be formed uniformly (or substantially uniformly) throughout the ultrasonic propagation region within the 1-1 medium portion (A11b). Since the speed of sound of ultrasonic waves in the 1-1 medium portion (A11b) can be proportional to the density, the speed of sound of ultrasonic waves in the 1-1 medium portion (A11b) can be reduced by reducing the density of the 1-1 medium portion (A11b) using the 1-1 metastructure (M11b). As a result, the difference between the speed of sound of ultrasonic waves in the 1-1 medium portion (A11b) and the speed of sound of ultrasonic waves in a fluid (gas) (F20) can be significantly reduced. Meanwhile, the 1-1 additional metastructure (N11b) can play a role in increasing the ultrasonic penetration rate into the inside of the pipe (P20) similarly to the additional metastructures (N21, N22) described in FIG. 22.

[0150] In one embodiment, the first-first medium portion (A11b) may be formed of plastic, and the first-first insertion medium portion (B11b) may be formed of metal. The first-first insertion medium portion (B11b) may be formed of the same metal as the pipe (P20), or may be formed of a different metal.

[0151] The first-first sensor unit (SU11b) may be referred to as an assembled ultrasonic meta-transducer. The first-first sensor unit (SU11b) may be composed of a wedge part (i.e., A11b) made of a plastic material and a wedge part (i.e., B11b) made of the same metal material as the pipe (P20) including an anisotropic meta-slab (i.e., N11b). The first-first meta-structure (M11b) applied within the wedge part (i.e., A11b) made of a 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 may be refracted (θ0<θ1) after passing through the pipe (P20) and thus no critical angle may exist. Additionally, the low permeability problem can also be solved by inserting a first-first 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, as in the case where the pipe (P20) is a metal pipe and the internal fluid is a liquid.

[0152] The first sensor of the non-invasive velocity profile measuring device according to the embodiment of FIG. 24 may further include a 1-2 sensor unit arranged corresponding to the 1-1 sensor unit (SU11b). The 1-2 sensor unit may have a structure symmetrical with respect to the 1-1 sensor unit (SU11b). In addition, the non-invasive velocity 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 2-1 sensor unit and a 2-2 sensor unit spaced apart from each other. The 2-1 sensor unit and the 2-2 sensor unit may have configurations similar to those of the 1-1 sensor unit (SU11b) and the 1-2 sensor unit. In addition, the non-invasive velocity 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.

[0153] According to one embodiment, in the non-invasive velocity profile measuring device according to the embodiment of FIG. 24, the distance (h) between the propagation path of the ultrasonic wave in the pipe (P20) by the first sensor and the propagation path of the ultrasonic wave in the pipe (P20) by the second sensor may be greater than 0.18D (wherein, D is the inner diameter of the pipe).

[0154] In addition, the configurations and features of the non-invasive velocity profile measuring devices according to the embodiments described with reference to FIGS. 1 to 19, 21 and 22 may all be applied to the non-invasive velocity profile measuring devices according to the embodiment of FIG. 24 within a range that is not contradictory.

[0155] Figure 25 is a cross-sectional view illustrating a 1-1 sensor unit (SU11c) applicable to a non-invasive flow profile measurement 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.

[0156] Referring to FIG. 25, when the pipe (P10) is a plastic pipe and the fluid (F20) is a gas, the use of the 1-1 insertion medium portion (B11b) and the 1-1 additional meta-structure (N11b) in the embodiment of FIG. 24 may be excluded. The 1-1 sensor unit (SU11c) of the present embodiment may include a 1-1 ultrasonic transducer (T11c) and a 1-1 medium portion (A11c) disposed between the 1-1 ultrasonic transducer (T11c) and the pipe (P10), and the 1-1 medium portion (A11c) may include a 1-1 meta-structure (M11c) for reducing the speed of sound of ultrasonic waves.

[0157] The first sensor of the non-invasive velocity profile measuring device according to the embodiment of FIG. 25 may further include a 1-2 sensor unit arranged corresponding to the 1-1 sensor unit (SU11c). The 1-2 sensor unit may have a structure symmetrical with respect to the 1-1 sensor unit (SU11c). In addition, the non-invasive velocity 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 2-1 sensor unit and a 2-2 sensor unit spaced apart from each other. The 2-1 sensor unit and the 2-2 sensor unit may have configurations similar to those of the 1-1 sensor unit (SU11c) and the 1-2 sensor unit. In addition, the non-invasive velocity 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.

[0158] According to one embodiment, in the non-invasive velocity profile measuring device according to the embodiment of FIG. 25, the distance (h) between the propagation path of the ultrasonic wave in the pipe (P10) by the first sensor and the propagation path of the ultrasonic wave in the pipe (P10) by the second sensor may be greater than 0.18D (wherein D is the inner diameter of the pipe).

[0159] In addition, the configurations and features of the non-invasive velocity profile measuring devices according to the embodiments described with reference to FIGS. 1 to 19, FIG. 21, FIG. 22, and FIG. 24 may all be applied to the non-invasive velocity profile measuring devices according to the embodiment of FIG. 25 within a range that is not contradictory.

[0160] According to the embodiments of the present invention described above, a non-invasive velocity profile measuring device can be implemented that can not only non-invasively measure the velocity profile of a fluid passing through a pipe through a simple installation, but can also accurately and completely (substantially) measure the velocity profile of a wide area within the pipe. In particular, the non-invasive velocity profile measuring device according to the embodiments can obtain a more accurate and complete (substantially complete) velocity profile by increasing the gap between the ultrasonic propagation path of the central sensor and the ultrasonic propagation path of the auxiliary sensor by using a metastructure, i.e., a metaslab. In addition, since the non-invasive velocity profile measuring device according to the embodiments can be installed in a simple manner in various pipes, it can have significant advantages in terms of installation and measurement methods.

[0161] In this specification, preferred embodiments of the present invention have been disclosed, and although specific terms have been used, they have been used in a general sense only to easily explain the technical contents of the present invention and to help the understanding of the invention, and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of ​​the present invention are possible in addition to the embodiments disclosed herein. Those skilled in the art will appreciate that the non-invasive flow profile measuring device for non-invasively measuring the flow profile of a fluid in a pipe according to the embodiments described with reference to FIGS. 1 to 25 can be variously substituted, changed, and modified without departing from the technical idea of ​​the present invention. Therefore, the scope of the invention should not be defined by the described embodiments, but by the technical idea described in the claims.

[0162] Embodiments of the present invention can be applied to devices and methods for measuring flow profiles. Embodiments of the present invention can be applied to non-invasive flow profile measurement devices and methods for non-invasively measuring the flow profile of a fluid in a pipe.

Claims

1. A first sensor disposed at the center of or adjacent to the outer surface of a pipe through which a fluid passes, comprising a 1-1 sensor unit and a 1-2 sensor unit spaced apart from each other, wherein the 1-1 sensor unit includes a 1-1 ultrasonic transducer and a 1-1 medium portion disposed between the 1-1 ultrasonic transducer and the pipe, and wherein the 1-1 medium portion includes a 1-1 metastructure for converting the type of ultrasonic waves; and A 2-1 sensor unit and a 2-2 sensor unit are disposed on the outer surface of the pipe and spaced apart from the first sensor, and 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 second sensor including a 2-1 metastructure for converting the type of ultrasonic waves. A non-invasive velocity profile measuring device for non-invasively measuring the velocity profile of a fluid in a pipe.

2. In paragraph 1, A non-invasive flow profile measuring device in which 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 is greater than 0.18D, where D is the inner diameter of the pipe.

3. In paragraph 1, A non-invasive flow profile measuring device, wherein at least one of the first-first metastructure and the second-first metastructure is configured to convert a longitudinal wave type ultrasonic wave propagated toward the pipe into a shear wave type ultrasonic wave or to convert a shear wave type ultrasonic wave transmitted from the pipe into a longitudinal wave type ultrasonic wave.

4. In paragraph 1, At least one of the above 1-1 metastructure and the above 2-1 metastructure includes a unit pattern structure, A non-invasive flow profile measuring device wherein the unit pattern structure includes a through hole region formed in the first-first medium portion or the second-first medium portion.

5. In paragraph 1, The above pipe is formed of plastic, The above fluid is a non-invasive flow profile measuring device for liquids.

6. In paragraph 1, The above pipe is formed of metal, The above fluid is a non-invasive flow profile measuring device for liquids.

7. In paragraph 6, The 1-1 sensor unit further includes a 1-1 insertion medium portion disposed between the 1-1 medium portion and the pipe and in contact with the pipe; and a 1-1 additional meta-structure formed within the 1-1 insertion medium portion to increase ultrasonic transmittance from the pipe to the inside thereof. A non-invasive flow profile measuring device, wherein the 2-1 sensor unit further comprises a 2-1 insertion medium portion disposed between the 2-1 medium portion and the pipe and in contact with the pipe; and a 2-1 additional meta-structure formed within the 2-1 insertion medium portion to increase ultrasonic transmission from the pipe to the inside thereof.

8. In paragraph 7, The above 1-1 medium portion and the above 2-1 medium portion are formed of plastic, A non-invasive velocity profile measuring device in which the first-first insertion medium section and the second-first insertion medium section are formed of metal.

9. In paragraph 1, The above first sensor is a center sensor, The above second sensor is an auxiliary sensor, The above auxiliary sensors are provided in 2n units (where n is a positive integer), The above non-invasive velocity profile measuring device is a non-invasive velocity profile measuring device that is a multi-line measuring device having 2n+1 lines.

10. A first sensor disposed at the center of or adjacent to the outer surface of a pipe through which a fluid passes, comprising a 1-1 sensor unit and a 1-2 sensor unit spaced apart from each other, wherein the 1-1 sensor unit includes a 1-1 ultrasonic transducer and a 1-1 medium portion disposed between the 1-1 ultrasonic transducer and the pipe, and wherein the 1-1 medium portion includes a 1-1 metastructure for reducing the speed of sound of ultrasonic waves; and A second sensor unit and a second sensor unit are disposed spaced apart from the first sensor on the outer surface of the pipe, and the second sensor unit includes a second sensor unit including a second ultrasonic transducer and a second medium portion disposed between the second ultrasonic transducer and the pipe, and the second medium portion includes a second sensor including a second metastructure for reducing the speed of sound of ultrasonic waves. A non-invasive velocity profile measuring device for non-invasively measuring the velocity profile of a fluid in a pipe.

11. In paragraph 10, A non-invasive flow profile measuring device in which 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 is greater than 0.18D, where D is the inner diameter of the pipe.

12. In paragraph 10, The above 1-1 metastructure is uniformly formed throughout the ultrasonic propagation region within the 1-1 medium section, The above 2-1 metastructure is a non-invasive velocity profile measuring device formed uniformly throughout the ultrasonic propagation region within the 2-1 medium section.

13. In paragraph 10, At least one of the above 1-1 metastructure and the above 2-1 metastructure includes a unit pattern structure, A non-invasive flow profile measuring device wherein the unit pattern structure includes a through hole region formed in the first-first medium portion or the second-first medium portion.

14. In paragraph 10, The above pipe is formed of plastic, The above fluid is a non-invasive flow profile measuring device in which the fluid is a gas.

15. In paragraph 10, The above pipe is formed of metal, The above fluid is a non-invasive flow profile measuring device in which the fluid is a gas.

16. In paragraph 15, The 1-1 sensor unit further includes a 1-1 insertion medium portion disposed between the 1-1 medium portion and the pipe and in contact with the pipe; and a 1-1 additional meta-structure formed within the 1-1 insertion medium portion to increase ultrasonic transmittance from the pipe to the inside thereof. A non-invasive flow profile measuring device, wherein the 2-1 sensor unit further comprises a 2-1 insertion medium portion disposed between the 2-1 medium portion and the pipe and in contact with the pipe; and a 2-1 additional meta-structure formed within the 2-1 insertion medium portion to increase ultrasonic transmission from the pipe to the inside thereof.

17. In paragraph 16, The above 1-1 medium portion and the above 2-1 medium portion are formed of plastic, A non-invasive velocity profile measuring device in which the first-first insertion medium section and the second-first insertion medium section are formed of metal.

18. In paragraph 10, The above first sensor is a center sensor, The above second sensor is an auxiliary sensor, The above auxiliary sensors are provided in 2n units (where n is a positive integer), The above non-invasive velocity profile measuring device is a non-invasive velocity profile measuring device that is a multi-line measuring device having 2n+1 lines.

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