Evaluation of Flow Characteristics in Physical Media

Abstract

A technique for determining flow characteristics of a fluid in a fluidic device includes a light source configured to generate a plurality of optical signals, a tracer suspended in the fluid, a plurality of photonic devices each including a photonic element and a flow path, and a measurement device configured to determine a first measurement based on the plurality of optical signals and the tracer in the flow path of a first photonic device of the plurality of photonic devices, determine a second measurement based on the plurality of optical signals and the tracer in the flow path of a second photonic device of the plurality of photonic devices, and determine a characteristic associated with the flow of the fluid or tracer based on the first measurement and the second measurement.

Description

Background Art

[0001] Conventional processes for determining the flow characteristics of a fluid in a narrowed flow path typically involve visual measurement of particles suspended in the fluid. Often, the narrowed flow path of interest is opaque (or unclear), so a vision-based measurement process is not useful for determining the flow characteristics of the flow path.

[0002] This type of process may also require special equipment, such as transparent window glass and sophisticated microscope systems, to visually inspect the flow of particles. Therefore, these processes for determining the flow characteristics of a fluid can be unnecessarily costly.

[0003] Furthermore, conventional processes typically involve sequential measurement of particles. Therefore, these processes can have relatively low performance due to slow data aggregation when inspecting particles flowing through a narrowed flow path.

Summary of the Invention

[0004] A system according to an embodiment of the present disclosure is provided. The system includes a light source configured to generate a plurality of optical signals, a tracer suspended in a fluid, a plurality of photonic devices each including a photonic element and a flow path, and a measuring device. The measuring device determines a first measurement value based on the plurality of optical signals and the tracer in the flow path of a first photonic device of the plurality of photonic devices, determines a second measurement value based on the plurality of optical signals and the tracer in the flow path of a second photonic device of the plurality of photonic devices, and is configured to determine a characteristic associated with the flow of the fluid or the tracer based on the first measurement value and the second measurement value. Advantageously, this enables determination of the flow characteristics of the flow path regardless of the opacity or visual obscurity of the flow path. Furthermore, this reduces the cost of determining the flow characteristics of a fluid in this type of flow path because the determination does not rely on special equipment, such as transparent walls and sophisticated microscope systems for visual inspection.

[0005] According to other embodiments of the present disclosure, the photonic elements of the first photonic device are aligned with the light source, enabling a plurality of optical signals to reach the flow path of the first photonic device. Advantageously, this enables the system to measure and determine the flow of the tracer without relying on visual inspection.

[0006] According to other embodiments of the present disclosure, the first photonic element of the first photonic device and the second photonic element of the first photonic device are aligned on opposite sides of the flow path of the first photonic device such that a plurality of optical signals can be transmitted from the first photonic element to the second photonic element. Advantageously, this enables the system to measure the interaction between the optical signal and the tracer so as to be able to determine the flow characteristics of the fluid.

[0007] According to other embodiments of the present disclosure, the photonic element of the first photonic device comprises a Y-splitter, the light source is disposed at the first end of the Y-splitter, the measuring device is disposed at the second end of the Y-splitter, and the third end of the Y-splitter is disposed on the flow path of the first photonic device. Advantageously, this enables the system to measure the interaction between the optical signal and the tracer so as to be able to determine the flow characteristics of the fluid.

[0008] According to other embodiments of the present disclosure, the flow path of the first photonic device extends from one end of the first photonic device to the opposite end of the first photonic device. Advantageously, this enables the fluid to flow through the first silicon-based photonic device such that the flow of the fluid in the flow path represents the flow of the fluid on the fluid device. This enables the measurements made in the flow path to accurately represent the flow within the fluid of the fluid device.

[0009] According to other embodiments of the present disclosure, each of the first measurement value and the second measurement value includes at least one of fluorescence, light reflection, refraction, absorption, or emission. Advantageously, this enables the system to measure the influence of the interaction between the optical signal and the tracer.

[0010] According to other embodiments of the present disclosure, one or more photonic devices are disposed on a first photonic device. Advantageously, this enables the system to perform parallel measurements of fluids or particles, thereby increasing the speed of data aggregation and the speed of determination of fluid characteristics.

[0011] According to other embodiments of the present disclosure, the tracer comprises at least one of a polystyrene ball containing a fluorescent molecule, an inorganic particle, a quantum dot, a molecule, an organic dye, a metal microparticle, or a metal nanoparticle. Advantageously, this enables the system to measure how the optical signal interacts with the tracer and affects the tracer, thereby enabling a functional measurement for determining the characteristics of the fluid.

[0012] The photonic device is presented according to an embodiment of the present disclosure. The photonic device comprises a substrate, a first photonic element disposed on the substrate, a flow path disposed on the substrate, and a capping layer disposed on the first photonic element and the flow path, and the first photonic element is disposed such that an optical signal can reach the flow path from the outside of the photonic device. Advantageously, this enables the measurement of the fluid flowing through the flow path, thereby enabling the determination of the characteristics of the fluid.

[0013] According to other embodiments of the present disclosure, the flow path is arranged such that the fluid can flow to a second photonic device. Advantageously, this enables the flow characteristics to be determined based on measurements at each photonic device, thereby enabling the determination of the flow characteristics of the fluid flowing between the photonic device and the second photonic device.

[0014] According to another embodiment of the present disclosure, the first photonic element and the second photonic element are aligned on opposite sides of the flow path such that an optical signal can be transmitted from the first photonic element to the second photonic element. Advantageously, this enables the system to measure the interaction between the optical signal and the tracer so that the flow characteristics of the fluid can be determined.

[0015] According to another embodiment of the present disclosure, the first photonic element includes a Y-splitter, a first end of the Y-splitter extends to a first side of the photonic device, a second end of the Y-splitter extends to the first side of the photonic device, and a third end of the Y-splitter is disposed on the flow path. Advantageously, this enables the system to measure the interaction between the optical signal and the tracer so that the flow characteristics of the fluid can be determined.

[0016] According to another embodiment of the present disclosure, the photonic device is disposed on at least one other photonic device. Advantageously, this enables the system to perform parallel measurements of fluids or particles, thereby increasing the rate of data aggregation and the rate of determination of fluid characteristics.

[0017] A method according to an embodiment of the present disclosure is provided. The method includes determining a first measurement value based on a plurality of optical signals and the flow of a tracer in the flow path of a first photonic element via a measuring device , assuming that the first flow path and the second flow path are fluidly connected, determining a second measurement value based on a plurality of optical signals and the flow of a tracer in the flow path of a second photonic element via the measuring device determining and determining a characteristic associated with the flow of the tracer based on the first measurement value and the second measurement value via the measuring device. Advantageously, this enables the determination of the flow characteristics of the flow path regardless of the opacity or visual obscurity of the flow path. Further, this reduces the cost of determining the flow characteristics of the fluid in this type of flow path because the determination does not rely on special equipment, such as transparent walls and sophisticated microscope systems for visual inspection.

[0018] According to other embodiments of the present disclosure, determining the flow characteristics further includes determining the macroscopic flow velocity (U) of the fluid containing the tracer. Advantageously, this enables the determination of the flow characteristics within a specific flow path of the fluid device.

[0019] According to other embodiments of the present disclosure, the macroscopic flow velocity (U) is determined as a function of the fluid flow rate (Q) across the cross-sectional area (A) of the fluid device, where Q is due to the applied pressure gradient (∇P) and U = Q / A. Advantageously, this enables the determination of the flow characteristics within a specific flow path of the fluid device.

[0020] According to other embodiments of the present disclosure, the macroscopic flow velocity (U) is determined as a function of the distance (Δx) traveled by a plurality of tracers and the average time (<Δt>) required for the travel of the distance (Δx), and the macroscopic flow velocity (U) is the flow path length (L) traveled by a plurality of tracers and the average flight time (<T F > ) required for the travel of the said flow path length (L), and U = Q / A = Δx / <Δt> = L / <T F >. Advantageously, this enables the determination of the flow characteristics within a specific flow path of the fluid device.

[0021] According to other embodiments of the present disclosure, determining the flow characteristics further includes determining the permeability (κ) of the flow path of the fluid device based on the fluid viscosity (μ), the macroscopic flow velocity (U), and the pressure gradient (∇P), where κ = μU / (-∇P). Advantageously, this enables the determination of the flow characteristics within a specific flow path of the fluid device.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

[0023] Embodiments of the present disclosure are directed to a measurement system for determining the flow characteristics of fluids within microfluidic or nanofluidic devices. As described above, conventional processes for determining flow characteristics rely on visual inspection of particles in the fluid and thus are not useful for opaque or unclear flow channels. Further, conventional processes typically implement a high-cost microscope system to perform visual inspection of particles in the fluid. Additionally, conventional processes may have relatively low performance due to the sequential inspection of particles in the fluid.

[0024] In one embodiment of the present disclosure, the measurement system includes a scalable flow unit disposed on or within a fluid device such that fluid of the fluid device flows through flow channels of each scalable flow unit. In one embodiment, each scalable flow unit includes a photonic element that enables light to reach the flow channels of the scalable flow unit. The measurement system tracks a tracer suspended in the fluid of the fluid device as the fluid flows through the flow channels. The measurement system also determines a light measurement value based on an interaction between the tracer and the light reaching the flow channels. The flow characteristics of the fluid are determined based on the light measurement value.

[0025] Advantages of the above-described embodiments over conventional processes for determining flow characteristics include the ability to determine the flow characteristics of fluids within opaque or unclear flow channels, cost reduction resulting from determining flow characteristics without relying on special equipment, such as transparent walls and elaborate microscope systems for visual inspection, and increased performance resulting from parallel measurements for collecting data about the fluid flow.

[0026] Figure 1 shows a fluid device measurement system 100 according to an embodiment. In one embodiment, the fluid device measurement system 100 includes a fluid device 102 that includes a first flow path configuration 104, a second flow path configuration 106, and a third flow path configuration 108.

[0027] In the illustrated embodiment, the first flow path configuration 104 and the third flow path configuration 108 include a smooth surface texture, while the second flow path configuration 106 includes a porous flow path texture. Due to these differences in the flow path configurations, when the fluid flows from the first flow path configuration 104 to the third flow path configuration 108, the flow characteristics of the fluid may not be the same. As a non-limiting example, the fluid can flow at a first flow rate through the first flow path configuration 104, which can include a smooth surface texture, and can flow at a different second flow rate through the second flow path configuration 106, which can include a porous surface texture.

[0028] In one embodiment, one or more scalable flow units (although described in detail in FIGS. 2A - 2B and omitted in FIG. 1 so that the lower elements in the fluid device measurement system 100 can be seen) are disposed on or within the flow path configuration of the fluid device. Each scalable flow unit can include one or more photonic elements. The photonic elements can include at least one of a waveguide, a splitter, a combiner, a mixer, or an interferometer.

[0029] When the photonic element is aligned with one or more light sources 120A - 120D, the photonic element transmits light from a position external to the scalable flow unit into the flow path of the scalable flow unit or into the flow path configuration of the fluid device. In the illustrated embodiment, light sources 120A - 120D are depicted as four separate light sources disposed on a first side of fluid device 102 (e.g., along the length of fluid device 102). However, in one embodiment, light sources 120A - 120D can represent a single light source. For example, light sources 120A - 120D can be a single fluorescent light source extending across the length of the fluid device or a single light source having four outlets.

[0030] As shown, one or more measurement devices 130A - 130D are disposed on a second side of the fluid device, on the side opposite the first side. When measurement devices 130A - 130D are aligned with light sources 120A - 120D, an optical signal from light sources 120A - 120D is transmitted from light sources 120A - 120D, through one or more flow path configurations of the fluid device, to measurement devices 130A - 130D. Measurement devices 130A - 130D can be any device, instrument, or sensor system capable of detecting or measuring the optical signal. For example, measurement devices 130A - 130D can be a flow sensor, a photodiode, a photometer, an exposure meter, a spectrometer, a computing system, or a microcontroller connected to at least one of the above.

[0031] In one embodiment, measurement devices 130A - 130D include software for communicating measurements with each other and calculating flow characteristics based on the measurements. In other embodiments, measurement devices 130A - 130D are communicatively coupled to a computing system (not shown) that receives the measurements and calculates the flow characteristics of the fluid based on the measurements.

[0032] In the illustrated embodiments, the measuring devices 130A - 130D are depicted as four separate measuring devices. However, in one embodiment, the measuring devices 130A - 130D can represent a computing system or a micro - controller connected to at least one of a single measuring device, such as a flow sensor, a photodiode, a photometer, an exposure meter, a spectrometer, etc.

[0033] In one embodiment, the set of tracers 110 is suspended in the fluid and aids the fluid device measurement system 100 in determining the flow characteristics of the fluid as the fluid passes through each flow path configuration. In the illustrated embodiment, the tracers 110 are suspended in the fluid of the fluid device 102. The tracers 110 flow through the fluid device due to the pressure gradient (∇P) applied to the cross - sectional area (A) of the fluid device along with the fluid. As the fluid flows from the first flow path configuration 104 to the third flow path configuration 108, the tracers 110 can represent the flow characteristics of the fluid within each flow path configuration.

[0034] In one embodiment, the tracers 110 suspended in the fluid are limited in quantity such that a single tracer interacts with an optical signal from one of the light sources 120A - 120D at a given instant. One advantage of thus limiting the quantity of the tracers 110 is that the measuring device corresponding to each optical signal can more accurately measure a single tracer without interference or disruption from other tracers.

[0035] In one embodiment, the tracer 110 is smaller than at least one dimension of each flow path configuration to ensure that the tracer 110 does not obstruct or alter the flow of fluid within the fluid device. The measuring devices 130A - 130D can measure the flow characteristics of the flow path configuration both before and after the tracer is suspended in the fluid. The measuring devices 130A - 130D can compare the pre - tracer flow characteristics with the post - tracer flow characteristics and determine whether the size of the tracer 110 has altered the pre - tracer flow characteristics. If such a change occurs, a larger - sized tracer may be removed or replaced with a tracer set to an appropriate size that does not affect the pre - tracer flow characteristics.

[0036] Additional characteristics of the tracer 110 can be adapted to the measurement techniques of the fluid device measurement system 100. For example, a fluorescent tracer can be used for a measuring device that implements a fluorescence - based measurement signal. In one embodiment, the tracer comprises a polystyrene ball that includes molecules that emit fluorescence when excited by light. Therefore, the molecules are selected, designed, or dyed to absorb or reflect light corresponding to the wavelength of the fluorescence - based measurement signal. The tracer can also comprise inorganic particles, quantum dots, molecules, organic dyes, etc., regardless of the presence or absence of any polystyrene content.

[0037] The tracer can also comprise non - fluorescent substances for use with measuring devices that implement other light - based measurement signals. In one embodiment, the tracer can comprise metal microparticles or nanoparticles, such as gold nanoparticles or silver nanoparticles.

[0038] When the tracer comprises a fluorescent substance, the measuring devices 130A - 130D can measure the fluorescence of the tracer and determine the flow characteristics of the fluid within the flow path configuration. When the tracer comprises metal particles, the measuring devices 130A - 130D can measure the reflection, refraction, or absorption of the optical signal and determine the flow characteristics of the fluid within the flow path configuration.

[0039] In the illustrated embodiment, when the tracer 110 flows across the first flow path configuration 104, the tracer 110 can flow into the flow path of a first scalable flow unit (not shown). The light source 120A generates an optical signal, and the optical signal is transmitted to the photonic element of the first scalable flow unit. The photonic element of the first scalable flow unit can direct the optical signal into the flow path of the first scalable flow unit. When the tracer 110 travels through the flow path of the first scalable flow unit, the tracer 110 encounters the optical signal. During this encounter, the measuring device 130A can measure the fluorescence of the tracer 110, or the absorption, reflection, or refraction of the optical signal. In one embodiment, the measuring device 130A can determine the time point at which to measure the light intensity or the change in light intensity from the tracer 110, and communicate that time point to a computing system or other measuring device.

[0040] When the tracer 110 continues to flow across the first flow path configuration 104, the tracer 110 can flow into the flow path of a second scalable flow unit (not shown). The light source 120B generates an optical signal, and the optical signal is transmitted to the photonic element of the second scalable flow unit. The photonic element of the second scalable flow unit can direct the optical signal into the flow path of the second scalable flow unit. When the tracer 110 travels along the flow path of the second scalable flow unit, the tracer 110 encounters the optical signal. During this encounter, the measuring device 130B can measure the fluorescence of the tracer 110, or the absorption, reflection, or refraction of the optical signal. In one embodiment, the measuring device 130B can determine the time point at which to measure the light intensity or the change in light intensity from the tracer 110, and communicate that time point to a computing system or other measuring device.

[0041] In one embodiment, the computing system receives measurement values and time points (e.g., timestamps) from measurement devices 130A and 130B, and determines the average delay time (<Δt1>) between the time points. Therefore, <Δt1> can represent the average amount of time it takes for tracer 110 to travel across the first flow path configuration 104. In other embodiments, combinations of measurement devices 130A - 130D can be communicatively coupled to each other and use a process similar to the computer system process described above to determine the average delay time corresponding to the flow path configuration within fluid device 102.

[0042] In the illustrated embodiment, when tracer 110 passes through measurement devices 130A and 130B, the computing system receives measurement values corresponding to the light intensity and time points from tracer 110. The computing system can map the measurement values and time points as a function of time (I(t)) to the light intensity from tracer 110. Next, the computing system determines the time points of the peak (or inverse peak) light intensity from tracer 110, cross - correlates these time points, and can determine the delay time (Δt1) between the peak or inverse peak of the light intensity from tracer 110. The computing system can further determine <Δt1> based on Δt1. In other embodiments, combinations of measurement devices 130A - 130D can use a process similar to the computer system process described above to determine Δt1 and <Δt1>.

[0043] In the illustrated embodiment, when the tracer 110 flows across the second flow path configuration 106, the tracer 110 can flow into the flow path of a third scalable flow unit (not shown). As shown, the light source 120C generates an optical signal, which is transmitted to the photonic element of the third scalable flow unit. The photonic element of the third scalable flow unit can direct the optical signal into the flow path of the third scalable flow unit. When the tracer 110 travels along the flow path of the third scalable flow unit, the tracer 110 encounters the optical signal. During this encounter, the measuring device 130C can measure the fluorescence of the tracer 110, or the absorption, reflection, or refraction of the optical signal. In one embodiment, the measuring device 130C can determine the time point at which to measure the light intensity or the change in light intensity from the tracer 110, and communicate that time point to a computing system or other measuring device.

[0044] In one embodiment, the computing system receives measurements and time points from the measuring device 130B and the measuring device 130C, and determines the average flight time (<T F >) between the time points. Therefore, <T F > can represent the average amount of time it takes for the tracer 110 to travel across the second flow path configuration 106. In other embodiments, combinations of the measuring devices 130A - 130D can be communicatively coupled to each other and can determine <T F > using a process similar to the computer process described above.

[0045] In the illustrated embodiment, when the tracer 110 passes through the measuring device 130B and the measuring device 130C, the computing system receives the measured values and time points corresponding to the light intensity from the tracer 110. The computing system can map the measured values and time points as a function of time (I(t)) to the light intensity from the tracer 110. Next, the computing system determines the time points of the peak (or inverse peak) light intensity from the tracer 110, cross-correlates these time points, and determines the time of flight (T F ) of the tracer 110 as the delay time between the peaks or inverse peaks of the light intensity from the tracer 110. The computing system can further determine <T F > based on T F . In other embodiments, combinations of the measuring devices 130A - 130D can determine T F and <T F > using a process similar to the computer system process described above.

[0046] In the illustrated embodiment, when the tracer 110 flows across the third flow path configuration 108, the tracer 110 can flow into the flow path of a fourth scalable flow unit (not shown). As shown, the light source 120D generates an optical signal, and the optical signal is transmitted to the photonic element of the fourth scalable flow unit. The photonic element of the fourth scalable flow unit can direct the optical signal into the flow path of the fourth scalable flow unit. When the tracer 110 travels along the flow path of the fourth scalable flow unit, the tracer 110 encounters the optical signal. During this encounter, the measuring device 130D can measure the fluorescence of the tracer 110, or the absorption, reflection, or refraction of the optical signal. In one embodiment, the measuring device 130D can determine the time points at which to measure the light intensity or change in light intensity from the tracer 110, and can notify the computing system or other measuring devices of those time points.

[0047] In one embodiment, the computing system receives measurement values and time points from measurement devices 130C and 130D, and determines an average delay time (<Δt2>) between the time points. Therefore, <Δt2> can represent the average amount of time it takes for the tracer 110 to travel across the third flow path configuration 108. In other embodiments, measurement devices 130A - 130D can be communicatively coupled to each other and can determine Δt using a process similar to the computer process described above.

[0048] In the illustrated embodiment, the computing system receives measurement values corresponding to the light intensity and time points from the tracer 110 when the tracer 110 passes through measurement devices 130C and 130D. The computing system can map the measurement values and time points as a function of time (I(t)) to the light intensity from the tracer 110. Next, the computing system determines the time points of the peak (or inverse peak) light intensity from the tracer 110, cross - correlates these time points, and can determine the delay time (Δt2) between the peak or inverse peak of the light intensity from the tracer 110. The computing system can further determine <Δt2> based on Δt2. In other embodiments, combinations of measurement devices 130A - 130D can determine Δt2 and <Δt2> using a process similar to the computer system process described above.

[0049] In the illustrated embodiment, at least one dimension of the first flow path configuration 104 and the third flow path configuration 108 is equal in length. This length traveled by the tracer 110 is labeled as Δx. The length of the dimension of the second flow path configuration 106 traveled by the tracer 110 is labeled as L. The flow rate (Q) of the fluid across the cross - sectional area (A) of the fluid device is due to the applied pressure gradient (∇P). Given the information, measurement values, time points, <Δt1>, <Δt2> and <T F >, the macroscopic flow velocity (U) of the fluid within the fluid device can be determined as follows.

[0050] U = Q / A = Δx / Δt1 = Δx / Δt2 = L / T F >

[0051] When the viscosity (μ) of the fluid to be measured or observed, the macroscopic flow velocity (U), and the pressure gradient ∇P applied to the cross-sectional area (A) of the fluid device are given, additional flow characteristics can be determined. When the above-described elements are given, the permeability (κ) of the porous material in the second flow path configuration 106 can be determined as follows.

[0052] κ = μU / (-∇P)

[0053] One advantage of the above-described process for determining the flow characteristics of a fluid is that it is not necessary to measure the flow characteristics inside a given flow path configuration. Therefore, the flow characteristics can be determined when the flow path configuration is opaque (or unclear) such that visual-based measurement techniques for determining the flow characteristics in the flow path configuration are not useful.

[0054] Figures 2A and 2B show a scalable flow unit 200 according to one embodiment. Figure 2A shows a plan view of the scalable flow unit 200.

[0055] In the illustrated embodiment, the first photonic element 204, the second photonic element 206, and the flow path 208 are disposed on the first silicon-based layer 202. The second silicon-based layer (omitted in Figure 2A so that the lower elements in the scalable flow unit 200 can be seen) is disposed on the first photonic element 204, the second photonic element 206, and the flow path 208. Further, Figure 2A includes a cross-section A-A showing the cross-sectional view shown in Figure 2B.

[0056] Furthermore, as shown, the first photonic element 204 is arranged perpendicular to the first side of the flow channel 208, and the second photonic element 206 is arranged perpendicular to the second side of the flow channel 208. The first photonic element 204 and the second photonic element 206 are aligned such that an optical signal from a light source positioned outside the scalable flow unit 200 can enter the first end of the first photonic element 204 and be transmitted through the second end of the first photonic element 204 disposed on the first side of the flow channel 208.

[0057] In one embodiment, the scalable flow unit 200 is disposed on or within a fluid device such that fluid from the fluid device flows through the flow channel 208. The fluid can flow parallel to the first and second sides of the flow channel 208 or in a direction perpendicular to the first photonic element 204 and the second photonic element 206. The fluid can contain tracers that are small enough to pass through the flow channel without changing or disturbing the flow of the fluid within the flow channel or within the fluid device.

[0058] In the illustrated embodiment, the optical signal can be transmitted from the first side of the flow channel 208 to the second side of the flow channel 208 and may encounter a tracer within the flow channel 208. During this encounter, the optical signal can be partially absorbed, reflected, or refracted by the tracer. The optical signal may also cause a fluorescence effect within the tracer. The optical signal can then be transmitted to the first side of the second photonic element 206 disposed on the second side of the flow channel 208 and exit from the second side of the second photonic element 206.

[0059] Figure 2B shows a cross-sectional view of the scalable flow unit 200. In the illustrated embodiment, the scalable flow unit 200 includes a first silicon-based layer 202. In one embodiment, the first silicon-based layer 202 functions as a substrate. The first silicon-based layer 202 can include silicon oxide, silicon nitrite, or any other silicon-based insulator.

[0060] The flow channel 208 is disposed on the first silicon-based layer 202. The first and second photonic elements 204 and 206 are disposed on the first silicon-based layer 202. As shown, the first photonic element 204 is disposed on the first side of the flow channel 208 and opposite to the second photonic element 206 disposed on the second side of the flow channel 208. The photonic elements 204 and 206 can include at least one of a waveguide, a splitter, a combiner, a mixer, an interferometer, and the like.

[0061] The second silicon-based layer 210 can be disposed over the photonic elements and the flow channel 208. In one embodiment, the second silicon-based layer 210 functions as a capping layer. The second silicon-based layer 210 can include silicon oxide, silicon nitrite, or any other silicon-based insulator. In the illustrated embodiment, the second silicon-based layer 210 is disposed over the first photonic element 204, the flow channel 208, and the second photonic element 206.

[0062] Figure 3 shows a fluid device measurement system 300 having a multi-stack scalable flow unit 304 1~N in accordance with one embodiment. In one embodiment, the multi-stack scalable flow unit 304 1~N can be disposed on or within the flow channel 302 of the fluid device.

[0063] Multi-stack scalable flow unit 304 1~N comprises at least one scalable flow unit disposed on a first scalable flow unit 3041. In the illustrated embodiment, the scalable flow unit 304 N is the multi-stack scalable flow unit 304 1~N positioned at the top. The scalable flow unit 304 N can include a photonic element 306 disposed on the flow path 308. The photonic element 306 is depicted as a Y-splitter.

[0064] Furthermore, as shown, the fluid device measurement system 300 can include a light source 320 disposed at a first end of the photonic element 306 and a measurement device 330 disposed at a second end of the photonic element 306. The light source 320 and the measurement device 330 can be disposed on the same side of the scalable flow unit 304 N

[0065] In one embodiment, the light source 320 and the measurement device 330 are operable to enable the use of all scalable flow units of the multi-stack scalable flow unit 304 1~N In other embodiments, the light source 320 and the measurement device 330 are operable to enable the use of only the scalable flow unit 304 N

[0066] In one embodiment, the fluid device includes a fluid with a set of tracers 310 suspended in the fluid. When the fluid travels across the flow path 302 of the fluid device, the fluid also travels across the flow path 308 of the scalable flow unit 304 N

[0067] ​​​In the illustrated embodiment, the light source 320 can generate an optical signal that propagates through the photonic element 306 from the first end of the photonic element 306 to the flow path 308. When the optical signal reaches the flow path 308, the optical signal may encounter the tracer 310. During this encounter, the optical signal may be partially absorbed, reflected, or refracted by the tracer 310. The optical signal may also cause a fluorescence effect within the tracer 310. Next, the optical signal can propagate towards the second end of the photonic element 306 and reach the measuring device 330. The measuring device 330 can measure the optical signal and determine the flow characteristics of the fluid.

[0068] One advantage of using a multi-stack scalable flow unit is improved accuracy and time savings in determining the flow characteristics of a fluid device. The multi-stack scalable flow unit enables the measurement of the optical signal in each scalable flow unit of the multi-stack scalable flow unit, thereby allowing the data used to determine the flow characteristics to be collected in parallel.

[0069] FIG. 4 shows a method 400 for determining the flow characteristics of a fluid device according to an embodiment. In one embodiment, the method 400 includes controlling a fluid device measurement system. The fluid device measurement system can include a light source configured to generate an optical signal, a tracer suspended in the fluid of the fluid device, one or more photonic devices each including at least one photonic element and a flow path, and a measuring device. In one embodiment, the photonic element of the first photonic device is aligned with the light source to allow the optical signal to reach the flow path of the first photonic device through the photonic element of the first photonic device.

[0070] A photonic device can be disposed on or within a flow path of a fluid device. In one embodiment, the fluid of the fluid device flows within the flow path due to a pressure gradient applied to the device. The fluid can also flow through the flow path of the photonic device on or within the flow path.

[0071] Method 400 begins at block 402. At block 404, the measuring device determines a first measurement value based on an optical signal and a tracer in the flow path of the first photonic device. Referring to FIG. 1, in one embodiment, the photonic elements of the first photonic device (not shown) are aligned with the light source 120B, thereby enabling the optical signal from the light source 120B to reach the flow path of the first photonic device. As the tracer 110 travels along the flow path of the first photonic device, the tracer 110 encounters the optical signal from the light source 120B. During this encounter, the measuring device 130B can measure the fluorescence of the tracer 110, or the absorption, reflection, or refraction of the optical signal, or any change in the intensity of the optical signal. In one embodiment, the measuring device 130B can determine the time point at which it measures the light intensity or the change in light intensity from the tracer 110, and communicate that time point to a computing system or other measuring device.

[0072] At block 406, the measuring device determines a second measurement value based on an optical signal and a tracer in the flow path of the second photonic device. In one embodiment, the second photonic device is disposed at a different location on or within the fluid flow path than the first photonic device.

[0073] Referring to FIG. 1, in one embodiment, the photonic elements of a second photonic device (not shown) are aligned with the light source 120C, whereby an optical signal from the light source 120C can reach the flow path of the second photonic device. As the tracer 110 travels along the flow path of the second photonic device, the tracer 110 may encounter the optical signal from the light source 120C. During this encounter, the measuring device 130C can measure the fluorescence of the tracer 110, the absorption, reflection or refraction of the optical signal, or any change in the intensity of the optical signal. In one embodiment, the measuring device 130C can determine the time point at which it measures the light intensity or the change in light intensity from the tracer 110, and communicate that time point to a computing system or other measuring device. In one embodiment, measurements can be made in additional scalable flow units using a process similar to that described above.

[0074] In block 408, the measuring device determines a property associated with the flow of the fluid or tracer based on the first and second measurements. In one embodiment, the computing system receives the measurements and the time points and determines the average flight time (<T F >) between the time points. Therefore, <T F > can represent the average amount of time it takes for the tracer to travel from the location of the first photonic device to the location of the second photonic device. The distance between the locations of the first and second photonic devices can be represented as length L.

[0075] In one embodiment, the computing system or measuring device receives the measurements and the time points and determines the average delay time (<Δt>) between the time points. For example, <Δt> can represent the average amount of time it takes for the tracer to travel from the location of the second photonic device to the location of the third photonic device. The distance between the locations of the second and third photonic devices can be represented as Δx.

[0076] The flow rate (Q) of the fluid across the cross-sectional area (A) of the fluid device is due to the applied pressure gradient (∇P). The information, measurements, time points, Δt, and T described above F Once given, the macroscopic flow velocity (U) of the fluid within the fluid device can be determined as follows.

[0077] U = Q / A = Δx / Δt = L / T F >

[0078] Once the measured or observed viscosity (μ) of the fluid and the macroscopic flow velocity (U) are given, additional flow characteristics can be determined. Once the elements described above are given, the permeability (κ) of the second flow path configuration can be determined as follows.

[0079] κ = μU / (-∇P)

[0080] Method 400 ends at block 410. One advantage of method 400 disclosed herein is that it can determine the flow characteristics of the fluid within the fluid flow path regardless of the differences between the configurations of the fluid flow paths. For example, referring to FIG. 1, it can be measured with a scalable flow unit positioned outside the second flow path configuration 106 (including the porous region) to determine the flow characteristics inside the second flow path configuration 106. This is particularly useful when the flow path configuration is not visually accessible (e.g., the flow path configuration is opaque or unclear).

[0081] The description of the various embodiments of the present invention is presented for purposes of illustration and is not intended to be exhaustive or to limit the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terms used herein are selected to best explain the principles of the embodiments, practical applications, or technological improvements over technologies found in the market, or to enable those skilled in the art to understand the embodiments disclosed herein.

[0082] In the foregoing, reference is made to embodiments shown in this disclosure. However, the scope of the present disclosure is not limited to the specific described embodiments. Instead, any combination of features and elements, whether related to different embodiments or not, is considered for implementing and practicing the considered embodiments. Further, although the embodiments disclosed herein can achieve other possible solutions or advantages over the prior art, whether a particular advantage is achieved by a given embodiment is not a limitation on the scope of the present disclosure. Accordingly, the aspects, features, embodiments, and advantages described herein are merely illustrative unless specifically recited in the claims and should not be considered elements or limitations of the appended claims. Similarly, references to "the invention" should not be construed as generalizations of any inventive subject matter disclosed herein unless specifically recited in the claims and should not be considered elements or limitations of the appended claims.

[0083] Aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.) or an embodiment combining software and hardware aspects that may generally be referred to herein as a "circuit," "module," or "system."

[0084] The present invention may be a system, method, or computer program product, or a combination thereof. The computer program product may include a computer-readable storage medium having computer-readable program instructions for causing a processor to execute aspects of the present invention.

[0085] A computer-readable storage medium can be a tangible device that holds and stores instructions for use by an instruction execution device. A computer-readable storage medium can be, for example, without limitation, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disk read-only memory (CD-ROM), digital versatile disk (DVD), memory stick, floppy (registered trademark) disk, punch cards, mechanically encoded devices such as raised structures within grooves in which instructions are recorded, and any suitable combination of the foregoing. A computer-readable storage medium as used herein should not be construed to be a signal per se that is transient, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., an optical pulse passing through an optical fiber cable), or an electrical signal transmitted through a wire.

[0086] The computer-readable program instructions described in this specification can be downloaded from a computer-readable storage medium to respective computing / processing devices or to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, or a wireless network, or a combination thereof. The network may include a copper transmission cable, an optical transmission fiber, a wireless transmission, a router, a firewall, a switch, a gateway computer, or an edge server, or a combination thereof. The network adapter card or network interface of each computing / processing device receives the computer-readable program instructions from the network and transfers the computer-readable program instructions for storage in a computer-readable storage medium within each respective computing / processing device.

[0087] The computer-readable program instructions for carrying out the operations of the present invention may be source code or object code written in any combination of one or more programming languages, including assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state-setting data, or object-oriented programming languages such as Smalltalk® and C++, and conventional procedural programming languages such as the “C” programming language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, for example, an electronic circuit including a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA) can execute the computer-readable program instructions by utilizing the state information of the computer-readable program instructions to customize the electronic circuit for exclusive use in performing aspects of the present invention.

[0088] Aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0089] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, causing the instructions executed via the processor of the computer or other programmable data processing apparatus to create means for implementing the functions / acts specified in the flowchart, block diagram, or both blocks thereof, thereby generating a machine. These computer-readable program instructions can also be stored in a computer-readable storage medium having instructions stored therein that include a product including instructions for implementing the functions / acts specified in the flowchart, block diagram, or both blocks thereof, thereby instructing a computer, programmable data processing apparatus, or other device or combination thereof to function in a particular manner.

[0090] Also, the computer-readable program instructions can be loaded onto a computer, other programmable data processing apparatus, or other device, causing a series of operational steps to be executed on the computer, other programmable apparatus, or other device to implement the functions / acts specified in the flowchart, block diagram, or both blocks thereof, thereby generating a computer-implemented process.

[0091] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible embodiments of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagram can represent a module, segment, or portion of a module, including one or more executable instructions for implementing the specified logical function. In some alternative embodiments, the functions described in the blocks may be performed in an order different from that shown in the figures. For example, two blocks shown in succession may actually be performed substantially simultaneously, or the blocks may sometimes be performed in the reverse order depending on the functions involved. It should also be noted that each block and combination of blocks in the block diagram or flowchart, or both, can be implemented by a dedicated hardware-based system that performs the specified function or action, or a combination of dedicated hardware and computer instructions.

[0092] The foregoing is directed to embodiments of the present invention, but other and further embodiments of the invention may be devised without departing from the basic scope thereof, which is determined by the following claims.

Claims

1. A system comprising: a light source configured to generate a plurality of optical signals; a tracer suspended in a fluid; a plurality of photonic devices disposed in a fluid device having a plurality of different channel configurations, each photonic device including a photonic element and a channel; and a measuring device, wherein the measuring device: determines a first measurement value based on the tracer in the channel of a first photonic device positioned outside of one of the plurality of channel configurations of the plurality of optical signals and the plurality of photonic devices; determines a second measurement value based on the tracer in the channel of a second photonic device positioned outside of the one channel configuration of the plurality of optical signals and the plurality of photonic devices; is configured to determine a characteristic associated with the flow of the fluid or the tracer within the one channel configuration based on the first measurement value and the second measurement value. A system.

2. The system according to claim 1, wherein the photonic element of the first photonic device is aligned with the light source to enable the plurality of optical signals to reach the channel of the first photonic device.

3. The system according to claim 1 or 2, wherein the photonic element of the first photonic device comprises at least one of a waveguide, a splitter, a combiner, a mixer, or an interferometer.

4. The system according to any one of claims 1 to 3, wherein the first photonic element and the second photonic element of the first photonic device are aligned on opposite sides of the channel of the first photonic device such that the plurality of optical signals can be transmitted from the first photonic element to the second photonic element.

5. The system according to any one of claims 1 to 4, wherein the channel of the first photonic device extends from one end of the first photonic device to the opposite end of the first photonic device.

6. The system according to any one of claims 1 to 5, wherein each of the first measurement value and the second measurement value includes at least one of fluorescence, reflection of light, refraction, absorption, or emission.

7. The system according to any one of claims 1 to 6, wherein the tracer comprises at least one of a polystyrene ball containing a fluorescent molecule, an inorganic particle, a quantum dot, a molecule, an organic dye, a metal fine particle, or a metal nanoparticle. **Claim 8**: The system according to any one of claims 1 to 7, wherein the first measurement value and the second measurement value each include information on the time point of measurement, and determining the characteristic includes cross-correlating a peak or an inverse peak based on the first measurement value and the second measurement value. **Claim 9**: A system comprising: a light source configured to generate a plurality of optical signals; a tracer suspended in a fluid; a plurality of photonic devices each including a photonic element and a flow path; a measuring device, wherein the measuring device: determines a first measurement value based on the plurality of optical signals and the tracer in the flow path of a first photonic device of the plurality of photonic devices; determines a second measurement value based on the plurality of optical signals and the tracer in the flow path of a second photonic device of the plurality of photonic devices; is configured to determine a characteristic associated with the flow of the fluid or the tracer based on the first measurement value and the second measurement value, the photonic element of the first photonic device includes a Y-splitter, the light source is disposed at a first end of the Y-splitter, the measuring device is disposed at a second end of the Y-splitter, and a third end of the Y-splitter is disposed on the flow path of the first photonic device. **Claim 10**: A system comprising: a light source configured to generate a plurality of optical signals; a tracer suspended in a fluid; a plurality of photonic devices each including a photonic element and a flow path; a measuring device, wherein the measuring device: determines a first measurement value based on the plurality of optical signals and the tracer in the flow path of a first photonic device of the plurality of photonic devices; determines a second measurement value based on the plurality of optical signals and the tracer in the flow path of a second photonic device of the plurality of photonic devices; A system configured to determine a characteristic associated with the flow of the fluid or the tracer based on the first measurement value and the second measurement value, wherein one or more photonic devices are disposed on the first photonic device. **Claim 11** A photonic device comprising: a substrate; a first photonic element disposed on the substrate; a flow path disposed on the substrate; a capping layer disposed over the first photonic element and the flow path, wherein the first photonic element is arranged such that an optical signal can reach the flow path from outside the photonic device, and the photonic device is disposed on at least one other photonic device. **Claim 12** The photonic device according to claim 11, wherein the flow path is arranged such that fluid can flow to a second photonic device. **Claim 13** The photonic device according to claim 11, wherein the first photonic element comprises at least one of a waveguide, a splitter, a combiner, a mixer or an interferometer. **Claim 14** The photonic device according to claim 11, wherein the first photonic element and the second photonic element are aligned on opposite sides of the flow path such that the optical signal can be transmitted from the first photonic element to the second photonic element. **Claim 15** A photonic device comprising: a substrate; a first photonic element disposed on the substrate; a flow path disposed on the substrate; a capping layer disposed over the first photonic element and the flow path, wherein the first photonic element is arranged such that an optical signal can reach the flow path from outside the photonic device, the first photonic element comprises a Y-splitter, a first end of the Y-splitter extends to a first side of the photonic device, a second end of the Y-splitter extends to the first side of the photonic device, and a third end of the Y-splitter is disposed on the flow path. **Claim 16** A method, wherein a first photonic device and a second photonic device are arranged in a fluid device having a plurality of channel configurations with different configurations, and are positioned outside one of the plurality of channel configurations, the method comprising: determining a first measurement value based on a plurality of optical signals and the flow of a tracer in the channel of the first photonic device via a measuring device; determining a second measurement value based on the plurality of optical signals and the flow of the tracer in the channel of the second photonic device via the measuring device; determining a characteristic associated with the flow of the tracer in the one channel configuration based on the first measurement value and the second measurement value via the measuring device; A method comprising the above steps.

17. The method according to claim 16, wherein determining the characteristic further comprises determining a macroscopic flow velocity (U) of the fluid containing the tracer.

18. The method according to claim 17, wherein the macroscopic flow velocity (U) is determined as a function of the flow rate (Q) of the fluid across the cross-sectional area (A) of the fluid device, and Q is caused by an applied pressure gradient (∇P), and U = Q / A.

19. The macroscopic flow velocity (U) is determined as a function of the distance (Δx) traveled by a plurality of tracers and the average time (<Δt>) required for the travel of the distance (Δx), and the macroscopic flow velocity (U) is the flow path length (L) of the one flow path configuration traveled by the plurality of tracers and the average flight time (<T Ｆ >) required for the travel of the flow path length (L), and is determined as a function of U = Q / A = Δx / <Δt> = L / <T Ｆ >, the method according to claim 17.

20. The method according to claim 17, wherein determining the characteristic further comprises determining a permeability (κ) of a channel having the one channel configuration of the fluid device based on a fluid viscosity (μ), the macroscopic flow velocity (U) and a pressure gradient (∇P), and κ = μU / (-∇P).

Images