Multiphase measuring system with calibration value tracking and flow control arrangement

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to a fluidic arrangement that provides reference values for calibrating multiphase measurement systems. BACKGROUND

[0002] Multiphase flows are flows of heterogeneous mixtures of substances with at least one liquid or gaseous component in a pipeline. Multiphase measurement systems determine the volume or mass fractions of components (phases) of the multiphase flow and / or the volume or mass flow of at least one of the components.

[0003] US Pat. No. 9,927,270 B2 describes a tomographic method for determining the phase distribution in multiphase flows. Electrode pairs on the wall of a Venturi throttle perform capacitance measurements (ECT, electrical capacitance tomography), electrical resistance measurements (ERT, electrical resistance tomography), and / or impedance measurements (EIT, electrical impedance tomography). Reconstruction algorithms can determine the phase distribution from the measured signals. US Pat. No. 5,287,752 describes the determination of the phase distribution of oil / water / gas mixtures by measuring the complex admittance between segmented capacitive sensors on parallel plates placed along the flow direction.

[0004] Conductivity grid sensors according to DE 196 49 011 C2 determine the phase distribution of conductive phases in the pipe cross-section based on conductivity measurements at grid points within a pipe cross-sectional plane. Grid sensors according to DE 10 2006 019 178 B2, which determine the phase distribution in the pipe cross-section based on the complex electrical admittance at grid points within a pipe cross-sectional plane, enable the determination of the volume fraction of non-conductive phases. For example, US 2015 / 0 293 047 A1 determines a cross-sectionally averaged water content in oil / water mixtures based on admittance measurements between two electrodes. DE 10 2008 055 032 A1 describes a multiphase measuring system in which the entire multiphase flow is separated in sections using a channel body with capillaries.

[0005] Calibration measurements make it possible to at least partially compensate for the influence of the measuring system itself on measured values. The result of the calibration measurement typically depends on physical properties of the components of the multiphase flow, which can change during operation of the multiphase measuring system, for example, due to changes in temperature and / or the chemical composition of a component. Tracking the calibration values compensates for such influences, thereby improving the measurement accuracy of the multiphase measuring system. US Pat. No. 5,260,667 describes the determination of the water content in water / oil emulsions using a calibrated admittance measurement. The calibration values are tracked according to a temperature-related change in the conductivity of the water. For this purpose, a reference measurement is carried out in an auxiliary container filled exclusively with (liquid) water, which is located partially within the pipeline.A multiphase measuring system described in US 2017 / 0 261 357 A1 comprises an auxiliary tank designed as a branch of the pipeline. In the auxiliary tank, components of different densities are separated by gravity. The electrical conductivity of at least one of the separated components is measured within the auxiliary tank. The measured electrical conductivity value is used to adjust the calibration values of the described multiphase measuring system when the temperature and / or salinity of a component changes. The contents of the auxiliary tank are returned downstream to the pipeline via a thin line.

[0006] The present application is based on the object of providing a precise multiphase measuring system and expanding the application possibilities for multiphase measuring systems. Such a multiphase measuring system is provided by the subject matter of claim 1. A fluidic arrangement with such a multiphase measuring system is disclosed in claim 8. Advantageous embodiments are disclosed in the dependent claims.

[0007] One embodiment relates to a multiphase measurement system for a multiphase fluid. The multiphase fluid can be a mixture of at least two immiscible or only slightly miscible components, wherein at least one component is a fluid (e.g., a gas or a liquid). For example, the multiphase fluid comprises at least two fluids, at least two of which form a heterogeneous mixture. The multiphase fluid can also contain a fluid, e.g., a gas, that transports a solid. The multiphase fluid can, for example, comprise exclusively liquids or a mixture with at least one gas and at least one liquid.

[0008] For example, the multiphase fluid is a two-phase fluid, where in the case of a single-component two-phase flow, a gas and a liquid with the same chemical composition flow through a pipe, e.g., (liquid) water and (gaseous) water vapor, and in the case of a two-component two-phase flow, a gas and a liquid with different chemical compositions flow, e.g., (liquid) water and air. Examples of a three-phase fluid are mixtures containing (liquid) water, oil, and one or more gases.

[0009] Single-phase partial streams ("phases") of the multiphase fluid can flow continuously separated from each other in a multiphase flow, e.g. in the form of a stratified flow, or discontinuously, e.g. in the form of a bubble flow.

[0010] The multiphase measuring system can determine the volume and / or mass fraction of at least one of the single-phase partial streams of the multiphase fluid. Alternatively or additionally, the multiphase measuring system can determine the volume and / or mass flow of at least one of the single-phase partial streams of the multiphase fluid.

[0011] The multiphase measuring system may comprise a reference value measuring arrangement. The reference value measuring arrangement may comprise one or more capillaries and a capillary measuring device.

[0012] For reference value measurement arrangements with more than one capillary, the following information referring to a capillary applies to each of the capillaries, unless expressly stated otherwise.

[0013] The inner cross-sectional area of the capillary can be, for example, circular, oval, or square with rounded edges. The shape and size of the inner cross-sectional area and / or the capillary wall can remain constant along the length of the capillary. For example, the capillary can be designed as a straight, circular tube with a constant inner diameter and constant outer diameter.

[0014] The internal cross-sectional area and length of the capillary are dimensioned so that the phases of the partial flow of the multiphase fluid flowing through the capillary are separated by interfacial forces, z.B. Capillary forces separate the fluid in the direction of flow. For example, a two-phase fluid separates into a binary flow of the phases. This results in intermittent flow within the capillary. In other words, a section of the capillary extending along the flow direction is alternately flowed through by exactly one of the phases.

[0015] The capillary measuring device is configured to measure at least one physical property of at least one of the phases flowing through the capillary or capillaries. The physical properties include, for example, the radiological density, electrical conductivity, relative permittivity, temperature, or specific density of the phase. For example, the capillary measuring device can comprise a conductivity sensor, a contactless conductivity detector, a capacitance sensor, a needle probe, a thermocouple, a resistance thermometer, a gamma densitometer, and / or an X-ray densitometer.

[0016] In addition, the multiphase measuring system can comprise a multiphase measuring device. The multiphase measuring device can be configured to measure a volume and / or mass fraction of at least one of the phases and / or a volume and / or mass flow of at least one of the phases of the multiphase fluid through a pipeline, taking into account the physical property(ies) determined by the capillary measuring device.

[0017] The multiphase measuring device can be arranged upstream or downstream of the capillary in the pipeline or can be bridged by the capillary, with the capillary's inlet openings being located upstream of the multiphase measuring device and the capillary's outlet openings being located downstream of the multiphase measuring device. If the multiphase measuring device is arranged upstream or downstream of the capillary, the multiphase measuring device can be provided in close proximity to the capillary.

[0018] The result of the multiphase measuring device depends on the physical property or properties determined by the capillary measuring device on the capillary. For example, the capillary measuring device can directly and immediately record the physical property or properties on which the measuring principle of the multiphase measuring device is based, e.g. the electrical conductivity, the relative permittivity, the complex electrical admittance, and / or the radiological density. The physical property or properties measured or recorded by the capillary measuring device can also be different from those used by the multiphase measuring device, provided that the physical property or properties determined by the capillary measuring device can be used to determine the physical property or properties.determined physical properties allow for sufficiently accurate conclusions to be drawn about the physical property on the basis of which the multi-phase measuring device determines the volume and / or mass fraction of a phase or the volume and / or mass flow of the phase.

[0019] The measurement by the multi-phase measuring device can take into account at least one actual, current physical property of at least one of the phases. If a property of a phase that is essential for the measurement by the multi-phase measuring device changes, for example due to a change in temperature, a change in pressure, a change in the composition of the phase, e.g. due to a change in concentration or due to impurities, the calculation of the volume and / or mass fractions and / or volume and / or mass flows can be adjusted accordingly during operation without interrupting the multi-phase flow. The measurement accuracy for the volume and / or mass fractions and / or volume and / or mass flows can become less dependent on other operating parameters, e.g. parameters of the multi-phase fluids, and can be determined without complex calculations of the thermo-physical and electrical properties of the fluid flow.without additional components for temperature and / or pressure measurement. The measuring principle for the capillary measuring device is variable.

[0020] The sequential separation of the phases in the capillary enables the continuous, nearly synchronous measurement of the relevant physical property for several or all phases of the multiphase flow, each in the single-phase range. The accuracy of the multiphase measurement system can be increased by increasing the number of phases for which the relevant physical property is known.

[0021] The calibration of the multiphase measuring device can be adjusted during operation of the multiphase measuring system and with virtually no time delay to track changing parameters. Compared to multiphase measuring systems in which, for example, the conductivity or temperature of a phase is measured in auxiliary tanks or gravity separators branching off from the pipeline, the multiphase measuring system according to the present embodiments can react significantly faster and thus deliver more accurate measured values. Compared to arrangements that guide the entire flow through capillaries, the multiphase measuring system according to the present embodiments can have significantly lower flow resistance. Compared to arrangements that force a change in the flow pattern, the influence of the multiphase measuring system according to the present embodiments on the flow process can be reduced.

[0022] The multiphase measuring system can be used for virtually all technically relevant flow patterns in horizontal, vertical, and arbitrarily inclined pipelines. The measuring system can respond relatively quickly to changes in the physical properties of at least one of the phases relevant for flow measurement.

[0023] According to one embodiment, the inner cross-sectional area of the capillary is at most π*25mm 2< . For example, the inner cross-sectional area of the capillary is at most π*2.25mm 2< . For example, the inner diameter of a capillary with a circular inner cross-sectional area is at most 10mm, 5mm, or 3mm. The capillaries of a reference value measurement arrangement with more than one capillary can have different, approximately equal, or equally large inner cross-sectional areas.

[0024] According to one embodiment, the length of the capillary is at most 100 cm. For example, the length of the capillary is at most 25 cm. A reference value measurement arrangement with more than one capillary can have capillaries of different, approximately the same, or the same length.

[0025] According to one embodiment, one of the at least one physical property by which the multiphase measuring device determines the volume and / or mass fraction of at least one of the phases of the multiphase fluid and / or a volume and / or mass flow of one of the phases of the multiphase fluid through the pipeline can be the electrical conductivity or the relative permittivity. Typically, the electrical conductivity and / or the relative permittivity of the phases can be included in a calibration of the multiphase measuring device. The electrical conductivity can be determined comparatively easily, quickly, and accurately by the capillary measuring device on the capillary using a suitable measuring probe. The physical quantity determined by the capillary measuring device on the capillary can be used directly by the multiphase measuring device to adjust the calibration values.

[0026] According to one embodiment, the multiphase measuring device may comprise a sensor unit which determines the local volumetric fraction of at least one of the phases of the multiphase fluid flowing through a pipeline at several locations, e.g. at all locations in a flat cross-sectional area transverse to the flow direction.

[0027] For example, the sensor unit is a radiation tomographic sensor unit for detecting a large number of radiographic projections. The tomographic sensor unit calculates, e.g. by means of an image reconstruction algorithm, which can be carried out e.g. by a computer of the sensor unit, on the basis of a large number of locally superimposed radiographic projections thus detected, a superposition-free sectional image of the phase distribution, from which the local volumetric components of at least one phase in a cross-sectional area perpendicular to the flow direction can be extracted.

[0028] The radiation tomography sensor unit comprises, for example, an X-ray computed tomography device, an optical tomography device, a gamma-ray tomography device, or an ultrasound tomography device. According to another exemplary embodiment of a tomography sensor unit, the sensor unit comprises at least two electrode pairs for electrotomography methods such as ERT, ECT, and / or EIT.

[0029] According to a further embodiment, the sensor unit comprises a plurality of individual measuring sensors which are arranged distributed over a cross-sectional area of the flowing fluid and which determine the local proportions of a phase of the fluid at a plurality of locations based on a suitable physical property.

[0030] According to one embodiment, the multiphase measuring device can comprise a grid sensor. A grid sensor can determine the local electrical conductivity and / or the relative permittivity of a multiphase fluid flowing through a pipeline at grid points in a plane perpendicular to the flow direction.

[0031] For example, the multiphase measuring device can comprise a grid sensor that determines the electrical conductivity of a multiphase fluid flowing through a pipeline at several measuring points in a plane perpendicular to the flow direction. The measuring points can be arranged in a grid.

[0032] For example, a grid sensor can have several linear excitation electrodes and several linear detection electrodes, with the excitation electrodes arranged in an excitation plane and the detection electrodes arranged in a measurement plane. The excitation plane and measurement plane can be aligned perpendicular to the flow direction and arranged at a comparatively small measurement distance from each other in the flow direction. The excitation electrodes and the detection electrodes are arranged at an angle to each other, for example, at an angle of 90 degrees.

[0033] Each detection electrode can cross each excitation electrode at a measuring distance, with the excitation electrodes arranged in or against the flow direction at a distance from the detection electrodes and - in the absence of a conductive fluid - electrically separated from each other. The excitation electrodes can be individually excited one after the other at short intervals of time, for example by voltage pulses. A current can occur in each detection electrode that is proportional to the average conductance of the measuring medium in the vicinity of the intersection point between the respective detection electrode and the excited excitation electrode. The local volumetric fraction of a phase can be determined from the current intensity in the detection electrode, provided the electrical conductivity of at least one of the phases is known.If an alternating voltage is applied to the excitation electrode instead of a voltage pulse, the permittivity at the crossing point can be determined instead of the conductance, which makes it possible to quantify the phase components even in combinations of non-conductive media.

[0034] The continuous tracking of the actual value for the electrical conductivity and / or for the relative permittivity of one, several or all phases in the multi-phase measuring system increases the accuracy and enables the use of sensor units for determining the local volumetric fraction of a phase, e.g. grid sensors for applications in which the temperature and / or the composition of the phases are subject to rapid and / or strong fluctuations, e.g. in the production of crude oil and / or gases or in the measurement of the steam content in direct evaporation solar power plants.

[0035] According to one embodiment, the multiphase measuring system can comprise a data processing unit. The data processing unit can be configured to provide reference values for the multiphase measuring device based on the physical property(ies) determined by the capillary measuring device. The data processing unit can be connected to the capillary measuring device and the multiphase measuring device via data technology. For example, the data processing unit can determine interval-related global minima and maxima of all capillaries from the time course of the measurement data acquired in the capillaries and provide these as reference values for the multiphase measuring device.

[0036] Instead of global measured values, the data processing unit of the multiphase measuring device can also provide local calibration values in the case of a reference value measuring arrangement with more than one capillary. In conjunction with a multiphase measuring device with a sensor unit that determines the local volumetric fraction of at least one of the phases of the multiphase fluid at multiple locations in a flat cross-sectional area perpendicular to the flow direction, the data processing unit can assign different calibration values to the different locations.

[0037] For example, if the sensor unit has several individual measuring sensors that are distributed over a cross-sectional area of the flowing fluid, the data processing unit can assign a separate calibration value to each measuring sensor, for example to each grid point of a grid sensor.

[0038] The calibration values in the multiphase measuring system can therefore be adjusted automatically and during operation, whereby the phase distribution and / or phase volume flows or phase mass flows can be correctly determined despite changing properties of the phases.

[0039] The data processing unit for providing the reference values can be an integral part of a data processing unit for controlling and evaluating electrical signals for the multiphase measuring device. Alternatively, the data processing unit for providing the reference values and the data processing unit for controlling and evaluating electrical signals for the multiphase measuring device can be implemented separately.

[0040] According to one embodiment, the multiphase measuring system can comprise a single capillary, the inlet opening of which can be located at the geometric center of a flow cross-section, for example, a pipeline cross-section. For example, the pipeline and capillary are arranged coaxially. A multiphase measuring system with only one capillary can be sufficient, for example, for applications in which only bubbly flows, such as vertical bubbly flows, occur or are expected. An embodiment with only one capillary generates only a small pressure drop and can also be used in flows with a comparatively small cross-section.

[0041] According to another embodiment, the multiphase measuring system can comprise exactly two capillaries. The inlet openings of the two capillaries can be arranged approximately or exactly in the same cross-sectional plane of the pipeline or in two cross-sectional planes spaced apart along the flow direction.

[0042] In both cases, the inlet opening of one capillary can be arranged in the geometric center of the flow cross-section, e.g. the pipe cross-section, and the inlet opening of the other capillary at a distance from the geometric center. The distance of the other capillary from the geometric center can, for example, be greater than half the mean inner radius of the pipe. For example, the other capillary can be attached to an inner wall of the pipe. A multi-phase measuring system with two capillaries arranged in this way can, for example, be sufficient for applications in which only concentric flows occur or are expected. According to another embodiment of a multi-phase measuring system with exactly two capillaries, the inlet openings of the two capillaries can be arranged opposite each other at the geometric center of the pipe cross-section, e.g. on the inner wall of the pipe.For example, one capillary can be arranged at the base of a horizontal pipeline and the other at the zenith. A multiphase measuring system with two capillaries arranged in this way may be sufficient for applications where only stratified flows are expected, such as horizontally stratified flows.

[0043] According to one embodiment, the multiphase measuring system can have at least three capillaries whose cross-section and length are dimensioned such that, when the fluid flows through the capillaries, an at least binary flow pattern is established in each capillary. The capillaries can be designed and arranged such that they are assigned to different volumetric partial flows of the multiphase fluid. In other words, during operation of the multiphase measuring system, the at least three capillaries are each flowed through by different volumetric partial flows of the multiphase fluid. The inlet openings of the capillaries can be arranged in a plane or approximately in a plane perpendicular to the flow direction, or with an individual axial offset from such a plane.In other words, the three capillaries can be arranged in the same cross-sectional plane, or in two or three cross-sectional planes spaced apart along the flow direction. The maximum distance between two cross-sectional planes with inlet openings, for example, is a maximum of twice the length of a capillary arranged between the two cross-sectional planes, or is equal to or less than the length of the capillary in question.

[0044] The longitudinal axis of each capillary can be aligned parallel to the main flow direction, for example, along a tube axis. The capillaries can have different internal cross-sectional areas and / or lengths. According to one embodiment, the capillaries can have the same internal cross-sectional area and / or the same length.

[0045] A multiphase measuring system with three or more than three capillaries can enable use in applications where the flow pattern of the multiphase fluid is unknown or where the multiphase flow alternates between at least two flow patterns.

[0046] According to a further embodiment, the multiphase measuring system can be an integral component of a fluidic arrangement. The fluidic arrangement can also comprise a pipeline. The pipeline can comprise a rigid or flexible pipe, a flexible hose, or another flow-conducting vessel or container. The multiphase fluid flows through the pipeline. An inlet opening of the at least one capillary can be arranged in a cross-sectional plane of the pipeline.

[0047] According to one embodiment, an inlet opening of one of three or more capillaries can be arranged at the geometric center of a pipeline cross-section. An inlet opening of another of the at least three capillaries can be arranged at a first distance from the geometric center of the pipeline cross-section that is greater than half the mean radius of the pipeline, for example, on an inner wall of the pipeline. A multiphase measuring system in which the inlet opening of one of several capillaries is arranged at the geometric center can, for example, be suitable for applications in which, in addition to other flow patterns, concentric flows can also occur or are expected.

[0048] According to one embodiment, at least one of the additional capillaries can be adjacent to an inner wall of the pipeline. For example, two of exactly three or more capillaries are adjacent to the inner wall of the pipeline, with all capillaries, for example all three capillaries, being arranged along a diameter of the pipeline. With such an arrangement, reference values for the calibration value tracking of a multiphase measuring device can be provided for most common flow patterns. In particular, the flow type of the multiphase flow in the pipeline can change almost arbitrarily during operation of the multiphase measuring system without negatively affecting the precision of the measurement of the multiphase measuring device.

[0049] According to one embodiment, the capillaries can be arranged entirely within the pipeline. No openings in the pipeline wall are required for the capillaries. This can result in an economical design, particularly for embodiments of the multiphase measurement system with two opposing capillaries on the inner wall of the pipeline.

[0050] According to another embodiment, at least one of the capillaries can be partially formed outside the pipeline. For example, a capillary with an inlet opening in the geometric center of the pipeline cross-section can be directed to the outside. Such an arrangement can enable reliable measurement of the physical property(ies) of a phase that flows only or almost exclusively in the center of the pipeline. If all capillaries are directed to the outside, this enables the use of a variety of different measuring sensors for the capillary measuring device.

[0051] According to one embodiment, the capillary or capillaries can be configured and arranged such that flow through the capillaries is achieved solely by a pressure difference between the inlet and outlet openings of the respective capillaries. This results in a simple and maintenance-free arrangement of the capillaries in the multiphase measuring system.

[0052] For example, a static or variable flow resistance device can be arranged in the pipeline upstream of the capillary outlets and downstream of the capillary inlets, creating a sufficient pressure difference between the inlet and outlet openings to ensure sufficient flow through the capillaries. Alternatively, the flow through the capillaries can be assisted by an auxiliary device, such as a pump.

[0053] According to one embodiment, the inner cross-sectional area of the capillary is a maximum of 5% of the inner cross-sectional area of the pipeline in the cross-sectional plane of the capillary inlet opening. Capillaries with a small inner cross-sectional area only influence the fluid flow to a minimal extent.

[0054] According to one embodiment, the length of the at least one capillary is a maximum of ten times a maximum diameter of the pipeline in the cross-sectional plane of the inlet opening of the capillary.

[0055] Further features and advantages of the disclosed subject matter will become apparent to the person skilled in the art from the following detailed description and from the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The accompanying drawings provide a more in-depth understanding of embodiments of a multiphase measurement system with calibration value tracking and a fluidic arrangement, are incorporated in and constitute a part of this disclosure. The drawings merely illustrate embodiments and, together with the description, serve to explain the principles thereof. The multiphase measurement system described herein and the fluidic arrangement with a multiphase measurement system are not limited to these by the description of the embodiments. Other embodiments and intended advantages will become apparent from an understanding of the following detailed description and from combinations of the embodiments described below, even if not explicitly described. The elements and structures shown in the drawings are not necessarily drawn to scale with respect to one another.Like reference symbols refer to like or corresponding elements and structures. FIG. 1 shows a schematic longitudinal section through a pipeline with a multiphase measuring system with multiphase measuring device and with a capillary measuring device on a capillary according to one embodiment. FIG. 2 shows a schematic time diagram for a time-dependent measured value determined by the capillary measuring device for the capillary. FIG. 3A-3C show schematic longitudinal sectional views of a pipeline and a multiphase measuring system with differently arranged capillaries according to further embodiments. FIG. 4A-4B show schematic perspective representations of a section of a pipeline with capillaries and a capillary according to an embodiment of a capillary measuring device for detecting the electrical conductivity of a phase. FIG. 5A-5D combine schematic longitudinal sectional representations of a pipeline with a multiphase measuring system according to one embodiment for different flow patterns with time diagrams for measured values determined at the capillaries according to further embodiments. FIG. 6 shows a schematic representation of a multiphase measuring system according to an embodiment with a tomographic multiphase measuring device. DETAILED DESCRIPTION

[0057] In the following detailed description, reference is made to the accompanying drawings, which form a part of the disclosure and in which specific embodiments of a multiphase measurement system and a fluidic arrangement are shown for illustrative purposes. The existence of further embodiments is to be understood. Likewise, it is to be understood that structural and / or logical changes may be made to the embodiments without departing from the scope of the invention. The description of the embodiments is not limiting in this respect. In particular, features of embodiments described below may be combined with features of other described embodiments, unless the context indicates otherwise.

[0058] The FIG. 1 shows a section of a pipeline 200 with components of a multiphase measuring system 100. For simplicity, the multiphase measuring system 100 is described below in connection with the evaluation for a two-phase fluid 205.

[0059] The pipeline 200 can have a square, oval, circular, or nearly circular cross-section with a diameter ranging from a few centimeters to over one meter. The pipeline 200 is sealed against the two-phase fluid 205 flowing within the pipeline 200. The two-phase fluid 205 flows through the pipeline 200 in the direction of the arrow as a two-phase flow consisting of a phase (L) of lower electrical conductivity and a phase (H) of higher electrical conductivity. The term "phase" is used below to denote a single-phase fluid.

[0060] A multi-phase measuring device 130 determines, at grid points of a cross-sectional plane oriented transversely to the flow direction, instantaneous local volume fractions α i , j , k e.g. of the phase (L) of lower electrical conductivity, resolved after a unit of time according to equation #1: α i , j , k = U i , j H − U i , j , k meas U i , j H − U i , j L

[0061] Here, i and j denote the orthogonal position variables of the grid points in the cross-sectional plane. U i,j,k represents the magnitude of an output signal of the multiphase measuring device 130 (e.g., an analog electrical voltage or the output value of an analog / digital converter) at grid point i,j at time k. The output signal U i,j,k is, for example, proportional to the electrical conductivity of the medium located at grid point i,j at time k. U i , j H and U i , j L describe the local reference values of two single-phase calibration matrices of the phases with higher (H) and lower (L) electrical conductivity.

[0062] The single-phase calibration matrices can be initialized, for example, during a base calibration (B) with single-phase flow. During the base calibration, the values of the initial base calibration matrices U i , j , B H and U i , j , B L the multiphase measuring device 130.

[0063] In addition, basic calibration values U m , B H and U m , B L of m reference measuring points and, if applicable, the electrical conductivities σ B H and σ B L the phases (L) and (H) are determined by means of a reference value measuring arrangement 160.

[0064] The reference value measuring arrangement 160 comprises one or more capillaries 110 and a capillary measuring device 120. The capillary measuring device 120 can detect, for example, signals at the reference measuring points assigned to the capillaries, the amplitude change of which is proportional to a relative change in the electrical conductivity and / or (in the case of single-phase flow) the electrical conductivities σ B H and σ B L of phases (L) and (H) can be determined directly.

[0065] The reference measuring points are located in the capillaries 110, whereby each capillary 110 can be assigned to a different reference measuring point. Each capillary 110 is dimensioned such that interfacial forces or capillary forces in the capillary 110 separate a multiphase flow, and the phases flow through the capillaries one after the other. For example, a two-phase system in the pipeline 200 becomes a binary flow pattern in the capillary 110. The reference value measuring arrangement 160 can therefore continuously determine current values of a physical quantity, for example, current values of the electrical conductivity of each phase of the multiphase fluid, independently of the other phase.

[0066] The reference value measuring arrangement 160 may comprise one, two, three or more capillaries 110, each of which has at least one reference measuring point with a corresponding measuring sensor.

[0067] The continuous adjustment of the calibration matrices of the multiphase measuring device 130 can be based on the determination of the relative change in the electrical properties of the single-phase fluids at the reference measuring points.

[0068] From the updated local reference values, a data processing unit can, for example, determine the local volume fractions of the phase (L) of lower electrical conductivity α i, j, k using updated values for the calibration matrices U i , j H and U i , j L determine.

[0069] Fig. 2 shows a possible temporal course of the measured value U m (t) as an example for any reference measuring point m.Due to the binary flow pattern in the capillary, the measured value U m (t) alternately reaches the measured values characteristic of the individual phases. Based on the maximum value U m,max (Δt) occurring in a sliding time window Δt and the minimum value U m,min (Δt) occurring in the same time window Δt, measuring point-specific key figures can be calculated according to equations #2 and #3. f m H and f m L be determined: f m H = U m , max Δ t U m , B H , f m L = U m , min Δ t U m , B L

[0070] If the phase (L) of lower electrical conductivity is fundamentally non-conductive, such as in the case of gases, the corresponding values of the calibration matrix can be set to zero and adjustment of this calibration matrix can be omitted without any loss of accuracy.

[0071] Then, according to equations #4 and #5, global tracking factors can be calculated from, for example, three reference measuring points m = 1, 2, 3 f H< and f L< be determined: f H = max f 1 H f 2 H f 3 H , f L = min f 1 L f 2 L f 3 L

[0072] The global tracking factors f H< and f L< describe the relative change in the electrical conductivity of the single-phase fluids compared to the base calibration. Due to the direct proportionality of the measured value and electrical conductivity, the new reference values for the multiphase measuring device 130 can be determined according to equations 6 and 7: σ H = f H ⋅ σ B H , σ L = f L ⋅ σ B L

[0073] In the present embodiment, the values in the calibration matrices can be updated analogously according to equations #8 and #9 due to the identical measuring principle: U i , j H = σ H σ B H ⋅ U i , j , B H , U i , j L = σ L σ B L ⋅ U i , j , B L

[0074] In the present embodiment, a direct use of the global tracking factors generated by the reference value measuring arrangement is f H< and f L< possible, as shown in equations #10 and #11: U i , j H = f H ⋅ U i , j , B H , U i , j L = f L ⋅ U i , j , B L

[0075] This allows the measurement of electrical conductivity σ B H and σ B L during the basic calibration.

[0076] In order to achieve a short response time of the tracking - especially with decreasing maximum values or increasing minimum values of the conductivities - the aim is to select the time window Δt as small as possible.

[0077] For multiphase flows with two or more conductive phases, a minimum time window size can be defined such that, considering all reference measuring points used, each phase is present at least once within the time window Δt. As shown below, such a condition for a lower limit of the time window is only relevant for certain flow patterns, such as intermittent flow and bubbly flow. Furthermore, this condition does not apply for a non-conductive phase for which no calibration matrix is maintained.

[0078] If the reference value measuring arrangement has more than one capillary, the calibration value tracking can be carried out according to equations #6 to #9 or #10 and #11 instead of the global tracking factors f H< and f L< from equations #4, #5 also local tracking factors f i , j H , f i , j L to use.

[0079] Each local tracking factor f i , j H , f i , j L can consist of exactly one of the measuring point-specific key figures f m H and f m L , e.g. the reference measuring point of the capillary whose inlet opening is closest to the respective grid point i,j in terms of the cross-sectional area. Alternatively, the calculation of each local tracking factor f i , j H , f i , j L two or more measuring point-specific key figures f m H and f m L where the weighting of each key figure decreases with increasing distance between the capillary inlet opening, for example the center of the capillary inlet opening, and the respective grid point i,j, e.g. decreases continuously.

[0080] The local tracking factors enable more accurate measurements, especially when key properties of the same phase, e.g. temperature and / or density, vary within the flow cross-section.

[0081] The FIG. 3A-3C show different possibilities for arranging the capillaries 110 in the pipe 200. In all examples of Figuren 3A-3C The reference value measuring arrangement 160 has similar, straight capillaries 110 and is arranged downstream of the multiphase measuring device 130, thereby avoiding any influence on the flow upstream of the multiphase measuring device 130. Inlet openings 118 of the capillaries 110 are arranged in a cross-sectional plane of the pipeline 200 perpendicular to the flow direction.

[0082] The multiphase measuring device 130 has a grid sensor 133 that determines the local electrical conductance of a multiphase fluid flowing through the pipeline 200 at grid "points" between two planes perpendicular to the flow direction. The grid sensor 133 has, for example, several linear, parallel excitation electrodes 131 and several linear, parallel detection electrodes 132. The excitation electrodes 131 are arranged in an excitation plane, and the detection electrodes 132 are arranged in a measurement plane. The excitation plane and measurement plane are aligned perpendicular to the flow direction and arranged at a comparatively small measurement distance from each other in the flow direction. The excitation electrodes 131 and the detection electrodes 132 are arranged rotated relative to each other, for example, at an angle of 90 degrees.Each detection electrode 132 crosses each excitation electrode 131 at the measuring distance, with all electrodes 131, 132 being spatially separated from one another and—in the absence of a conductive fluid—electrically separated from one another. An evaluation and control unit 135 of the multiphase measuring device 130 excites the excitation electrodes 131 individually, one after the other, at short intervals, for example, by means of voltage pulses. A current can occur in each detection electrode 132 that is proportional to the average conductance of the measuring medium in the vicinity of the grid point between the respective detection electrode 132 and the respectively excited excitation electrode 131.From the current intensity in the detection electrode 132, the evaluation and control unit 135 determines the local volumetric fraction of a phase. The evaluation and control unit 135 of the multiphase measuring device 130 receives current reference values for the electrical conductivity of the phases from a data processing unit 140 for calibration value tracking. For this purpose, the data processing unit 140 evaluates measurement signals from the capillary measuring device 120, for example, in the manner described above.

[0083] FIG. 3A shows three straight capillaries 110 arranged within the pipe 200 and parallel to the pipe axis. One of the capillaries 110 is arranged coaxially with the pipe 200. The other two capillaries 110 are arranged on opposite sides of the inner wall 201 of the pipe 200, e.g., at the highest and lowest positions when the pipe 200 is arranged horizontally, and each flush with the inner wall 201 or at a distance from the inner wall 201.

[0084] In FIG. 3B A first capillary 110 is arranged coaxially to the pipe 200, wherein an inlet opening 118 of the capillary 110 is located in the geometric center of the cross section of the pipe 200. A second capillary 110 is arranged at a distance from the first capillary 110 that is greater than half the average radius of the pipe 200. In the embodiment shown, the second capillary 110 is located on the inner wall 201 of the pipe 200. An arrangement with exactly two capillaries 110 according to FIG. 3B For example, it may be sufficiently suitable for concentric flow profiles, e.g., annular flow profiles. Pipeline 200 may be a vertical pipe.

[0085] In FIG. 3C Exactly two capillaries 110 are arranged opposite each other on the inner wall 201 of the pipe 200. An arrangement with exactly two capillaries 110 according to FIG. 3C may be sufficient, for example, for stratified flows in horizontal pipelines 200.

[0086] FIG. 4A und 4B show details of a reference value measuring device 160 with a capillary measuring device 120 for determining the electrical conductivity of phases sequentially separated in capillaries 110.

[0087] In FIG. 4A The multiphase measuring system 100 comprises, in addition to a multiphase measuring device (not shown), three straight capillaries 110. One of the capillaries 110 is arranged coaxially with the pipeline 200. The other two capillaries 110 are arranged on opposite sections of the inner wall 201 of the pipeline 200 and can be attached to the inner wall 201. The inlet openings 118 of the capillaries 110 are arranged along the same pipe cross-sectional plane. The capillaries 110 are approximately the same or exactly the same length and have approximately the same or exactly the same internal cross-sectional area and cross-sectional shape.

[0088] The capillary measuring device 120 shown has a linear excitation electrode 121 that is guided through the cross-section of each of the capillaries 110. The capillary measuring device 120 shown also has three linear detection electrodes 122, each linear detection electrode 122 being guided through exactly one of the capillaries 110. According to another embodiment not shown, the capillary measuring device 120 has exactly one linear detection electrode 122 that is guided through the cross-section of each of the capillaries 110, and three linear excitation electrodes 121, each linear excitation electrode 122 being guided through exactly one of the capillaries 110. According to a further embodiment not shown, the capillary measuring device 120 has three linear detection electrodes 122 and three linear excitation electrodes 121, wherein a different excitation electrode 121 and a different detection electrode 121 are guided through each capillary 110.

[0089] FIG. 4B shows that the excitation and detection electrodes 121, 122 are exposed in each capillary 110 and are guided past each other in an intersection region 126 within the capillary 110 at a distance of a few micrometers to millimeters. Outside the capillaries 110, a dielectric sheath 125 insulates the excitation and detection electrodes 121, 122 from the multiphase fluid 205 in the pipeline 200. If a current is impressed by the excitation electrode 121, a current will also flow through the detection electrode 122 if the phase conductivity in the intersection region 126 of the capillary 110 is sufficient, whereby the current intensity in the detection electrode 122 is proportional to the phase conductivity in the intersection region 126.

[0090] The FIG. 5A-5D refer to horizontal pipelines 200 with a multiphase measuring device 130, which has a grid sensor, and with a reference value measuring arrangement 160 with three capillaries 111, 112, 113 and a capillary measuring device 120 assigned to the three capillaries 111, 112, 113, which according to the FIG. 4A-4B can be designed. The time courses 211, 221, 231, 241 each show a possible course of the time-dependent measured value U(t) for the upper capillary 111. The time courses 212, 222, 232, 242 each show a possible course of the time-dependent measured value U(t) for the coaxial capillary 112. The time courses 213, 223, 233, 243 each show a possible course of the time-dependent measured value U(t) for the lower capillary 111. The measured value U(t) for one of the phases of a two-phase fluid, e.g. the phase with the higher conductivity, changes abruptly at t=t1.

[0091] FIG. 5A shows the time courses 211, 212, 213 for a two-phase bubble flow. In applications where the conductivity of both phases can fluctuate, the time window Δt can be selected such that each of the two phases is evaluated once in at least one of the capillaries 111, 112, 113 within the time window Δt. The length of the time window Δt determines the response time of the multiphase measuring system 100 to a change in the conductivity of one of the phases.

[0092] In the case of FIG. 5B In the stratified flow shown, the arrangement of the capillaries 111, 112, 113 shown alone ensures that both phases can be evaluated simultaneously at any time during operation, since the denser phase flows through the lower capillary 113 at any time and the less dense phase flows through the upper capillary 111 at any time.

[0093] According to FIG. 5C In the case of an intermittent flow, the same applies as for the bubble flow according to FIG. 5A .

[0094] In case of FIG. 5D In the annular flow shown, the arrangement of the capillaries 111, 112, 113 shown enables both phases to be evaluated simultaneously at any time, since in the operating state the denser phase flows through at least one of the outer capillaries 111, 113 at any time and the less dense phase flows through the coaxial capillary 112 at any time.

[0095] FIG. 6shows a multiphase measuring system 100 with three capillaries 111, 112, 113 in a vertical pipeline 200, in which a two-phase fluid 205 flows from bottom to top in a vertical direction. In this exemplary embodiment, the inlet openings 118 of the three capillaries 111, 112, 113 are arranged upstream of a multiphase measuring device 130 in a cross-sectional plane of the pipeline 200. The capillaries 111, 112, 113 are guided outward through first bores 115 in the pipe wall 202. The first bores 115 can be guided obliquely to the pipeline 200 at a shallow angle deviating from the flow direction. The capillaries 111, 112, 113 open further downstream and upstream of a multiphase measuring device 130 through second bores 116 into the pipeline 200. The second bores 116 can be perpendicular to the pipe wall 202.The external capillaries 111, 112, 113 enable measurement of the relevant physical quantity(s) by measuring means 127 outside the pipeline 200.

[0096] A flow resistance device 150 can be arranged in the pipeline 200 between the first bores 115 and the second bores 116, e.g., directly upstream of the second bores 116. The flow resistance of the flow resistance device 150 can be selected such that the capillaries 111, 112, 113 are flowed through sufficiently quickly without additional aids, even at the lowest flow velocity assumed in the application in the pipeline 200. The flow resistance of the flow resistance device 150 can be adjustable. For example, the flow resistance device 150 has an iris diaphragm with a variable opening.

[0097] The capillary measuring device 120 has, for example, three needle probes 127. Each needle probe 127 measures, for example, the instantaneous electrical conductivity of both phases as well as the instantaneous relative permittivity of both phases and transmits the measured values in a suitable form to a data processing unit 140. The data processing unit 140 determines global minimum and maximum values in the three capillaries based on the information received from the capillary measuring device 120 and transmits these as updated reference values for calibration value tracking to a multiphase measuring device 130.

[0098] The multiphase measuring device 130 has a tomographic sensor head 138, which, for example, determines spatially resolved information about the multiphase flow. An evaluation and control unit 135 of the multiphase measuring device 130 receives the updated reference values from the data processing unit 140 as well as the spatially resolved information about the multiphase flow from the sensor head 138 and calculates from both a volume and / or mass fraction of at least one of the phases and / or a volume and / or mass flow of at least one of the phases.

Claims

1. A multi-phase measurement system (100) for a multi-phase fluid (205), comprising: a reference value measurement assembly (160), which comprises at least one capillary (110) and a capillary measurement device (120), wherein the inner cross-sectional area and the length of the capillary (110) are dimensioned such that the phases of the multi-phase fluid (205) separate in the flow direction when flowing through the capillary (110), and wherein the capillary measurement device (120) is configured for determining at least one physical property of at least one of the phases flowing through the capillary (110); and a multi-phase measurement device (130), which is configured for measuring a volume and / or mass fraction of at least one phase of the multi-phase fluid and / or for measuring a volume and / or mass flow of at least one of the phases of the multi-phase fluid taking into account the physical property determined by the capillary measurement device (120), wherein the at least one physical property determined by the capillary measurement device (120) allows a physical property to be inferred, on the basis of which the multi-phase measurement device (130) determines the volume and / or mass fraction of at least one of the phases or the volume and / or mass flow of at least one of the phases.

2. The multi-phase measurement system according to claim 1, wherein the inner cross-sectional area of the capillary (110) is at most π*25 mm2.

3. The multi-phase measurement system according to any one of the preceding claims, wherein the length of the capillary (110) is at most 100 cm.

4. The multi-phase measurement system according to any one of the preceding claims, wherein the physical property is the electrical conductivity and / or the relative permittivity.

5. The multi-phase measurement system according to any one of the preceding claims, wherein the multi-phase measurement device (130) comprises a grating sensor (133).

6. The multi-phase measurement system according to any one of the preceding claims, further comprising: a data processing unit (140), which provides at least one reference value for the multi-phase measurement device (130) on the basis of the physical property or properties measured by the capillary measurement device (120).

7. The multi-phase measurement system according to any one of the preceding claims, wherein the multi-phase measurement system (100) comprises at least three capillaries (110), the cross-section and length of which are dimensioned such that a binary flow is established in the capillaries (110) when two phases of the multi-phase fluid (205) flow through the capillaries (110), the capillaries (110) being assigned to different partial flows of the multi-phase fluid (205).

8. A fluidic assembly, comprising: the multi-phase measurement system (100) for a multi-phase fluid (205) according to any one of the preceding claims; and a conduit (200), wherein an inlet opening (118) of the at least one capillary (110) is arranged in a cross-sectional plane of the conduit (200).

9. The fluidic assembly according to the preceding claim, wherein an inlet opening (118) of one of the capillaries (110) is arranged in a geometric center of the cross-section of the conduit (200) and an inlet opening (118) of a further one of the capillaries (110) is arranged at a distance from the geometric center of the cross-section of the conduit (200).

10. The fluidic assembly according to any one of the two preceding claims, wherein at least one of the capillaries (110) is arranged on an inner wall (201) of the conduit (200).

11. The fluidic assembly according to any one of the three preceding claims, wherein the capillaries (110) are arranged completely in the conduit (200).

12. The fluidic assembly according to any one of the four preceding claims, wherein at least one of the capillaries (110) is arranged partially outside the conduit (200).

13. The fluidic assembly according to any one of the five preceding claims, wherein the at least one capillary (110) is configured and arranged such that a flow through the capillary (110) results from a pressure difference between the inlet opening (118) and the outlet opening of the capillary (110).

14. The fluidic assembly according to any one of the six preceding claims, wherein the inner cross-sectional area of the at least one capillary (110) is at most 5% of an inner cross-sectional area of the conduit (200) in the cross-sectional plane of the inlet opening (118).

15. The fluidic assembly according to any one of the seven preceding claims, wherein the length of the at least one capillary (110) is at most ten times a maximum inner diameter of the conduit (200) in the cross-sectional plane of the inlet opening (118).