Method and system for measuring the kinematic viscosity of a free fluid stream

Abstract

1. A computer-implemented method for measuring viscosity of a fluid stream flowing through an orifice at a constant acceleration, comprising: The method comprises: receiving as input at least one image of a region of interest of the fluid flow, a cross-section s0 of the aperture, and an output volumetric flow rate U0 of the fluid flow from the aperture; The method provides as an output the viscosity of the fluid, η; The method comprises the steps of: (a) Modeling the geometric profile of the fluid flow through digital processing of the input images; (b) calculating the viscosity of the fluid from the modeled geometric profile, cross section s0, and output volumetric flow rate U0 using a mathematical or physical model; 4. A computer-implemented method comprising:

Description

[Technical field]

[0001] The present disclosure relates to a method for determining the viscosity of a free fluid flow in an industrial environment, in particular in industrial processes for glass production, more particularly in industrial processes for the production of inorganic glass fiber based materials, such as mineral wool, e.g. glass wool or stone wool. [Background technology]

[0002] In a mineral wool production line, the molten glass coming from the glass melting furnace is conveyed through a forehearth to feed the fiberization tool. From the forehearth to the fiberization tool, the molten glass flows through what is called a bushing. A bushing is generally designed as an opening extended by a nozzle or drain pan and terminated by a hole through which the molten glass flows by gravity. Depending on its size and diameter, the bushing controls the flow rate of the molten glass to the fiberization tool.

[0003] The fiberizing tool typically includes a high-speed rotating device, called a centrifuge, spinner, or spinning plate, which is made of an annular wall with metering holes drilled in it. When fed with molten glass emerging from a bushing, the high-speed rotating device forces the molten glass to shoot through the drilled holes to cast glass threads.

[0004] The fiberizing tool also has a ring or annular burner that projects a gas stream or jet of elevated temperature substantially tangentially to the annular wall, thereby drawing down the cast glass threads. This drawing stream or jet heats and draws the glass threads, allowing them to form glass fibers.

[0005] One requirement for obtaining a high-quality product, such as stone wool or glass wool, is that the glass threads need to be properly stretched while being cast and pulled down from the rotating device. The stretching operation must not be too vigorous or too fast to allow sufficiently elongated glass fibers to be formed, but to avoid their breakage. Otherwise, the final product, such as stone wool or glass wool, will not meet the technical requirements, such as with regard to thickness and barrier properties. This product must be discarded, resulting in economic losses for the manufacturer.

[0006] And because the flow rate of the molten glass depends on its temperature and its chemistry, it is current practice to periodically take samples of the molten glass in front of the bushing for chemical analysis. It is also common to periodically measure or continuously monitor the temperature of the molten glass near the bushing, e.g., before, after, and inside the bushing.

[0007] In the short term, the flow rate of the molten glass during the drawing operation can be controlled by changing its temperature near the bushing. This temperature regulation can be done through an adaptive heating operation, for example Joule heating by passing an electric current through a metallic bushing. In the long term, the chemistry of the molten glass can also be changed by adapting the chemistry of the raw materials in the melting process.

[0008] WO 83 / 004437 [GULLFIBER AB [SE]] 22.12.1983 discloses a method for measuring the flow velocity of a freely falling molten glass stream, which relies on measuring the time interval between pulse-like signals generated by inhomogeneities in the stream and detected by two separate radiation detectors.

[0009] US Patent No. 4,877,436 [SHEINKOP ISAC [US]], October 31, 1989, discloses a method for controlling the flow rate and viscosity of molten glass during production, which relies on the calculation of the viscosity of the molten glass by the Hagen-Poiseuille method, which requires prior knowledge of the density of the molten glass.

[0010] US Patent No. 5,170,438 [GRAHAM FIBER GLASS LTD [CA]] 1992.12.08 discloses an apparatus for determining the volumetric flow rate of a viscous fluid flow, such as a molten glass flow, which digitally processes an image of the fluid flow to measure its width, from which the flow rate is calculated, taking into account both geometrical considerations of the shape of the fluid flow, and the velocity and density of the fluid. Summary of the Invention [Problem to be solved by the invention]

[0011] Changing the temperature of the molten glass near the bushing may be a desirable action when a rapid adjustment in flow rate is required, however, to assess whether the temperature should be increased or decreased, it may be necessary to first assess the actual viscosity or flow rate of the molten glass.

[0012] A common practice for assessing the viscosity or flow rate of molten glass is to rely on the assumption of constant glass density and / or constant viscosity, such as the Hagen-Poiseuille method. The density of the molten glass depends on both its chemistry and temperature, and if assumptions were made or measured based on the chemistry of the molten glass, the density would likely be estimated from a measurement of the temperature near the bushing.

[0013] Measuring the temperature of the molten glass near the bushing can be a difficult task. Due to the elevated temperature and the difficulty of access, the measurement is generally performed with optical methods based on blackbody radiation, such as pyrometers. However, this type of measurement can be overly sensitive to the acquisition conditions, such as the surface radiation of the molten glass, the emissivity of the surface, the light reflection of the surrounding environment, etc. Since the molten glass can be inhomogeneous in temperature, the measurements can be very inaccurate and can vary depending on the acquisition zone of the molten glass. The density values ​​can be unreliable and the density-viscosity or flow rate relationships, such as the Hagen-Poiseuille method, can break down or provide unrealistic values ​​for the viscosity of the flow rate.

[0014] Besides these drawbacks, another disadvantage of current viscosity-flow relationships, especially those based on the Hagen-Poiseuille law, is that they require laminar flow and uniform viscosity and / or uniform density in the bushings, which must have simple geometries. In fact, the Hagen-Poiseuille law is only valid for fluids that have laminar flow through tubes or pipes, i.e., fluids that do not have a free surface.

[0015] However, it is common to heat the bushing by the Joule effect. This operation generates spatial and temporal temperature gradients in the molten glass and thus spatial and temporal changes in the viscosity of the molten glass. Changes in the flow regime of the molten glass, e.g. pressure loss, can occur in the vicinity of the bushing; viscosity-flow relationships may not apply or may provide unrealistic values ​​for the viscosity.

[0016] It is also worth mentioning that the Hagen-Poiseuille laws do not apply to free-flowing fluids, i.e., flowing fluids with free surfaces unconstrained by tubes or pipes, etc., since they require laminar flow and uniform viscosity and / or uniform density within bushings of simple geometries, as explained above.

[0017] Perhaps one of the most detrimental effects of the aforementioned problems is that they can lead to misregulation of the temperature of the molten glass, which in turn can cause insidious damage to the production tools. For example, excessive temperature can shorten the life of the fiberization tools.

[0018] There is clearly a need for a method of measuring the viscosity of a fluid stream, particularly one that does not rely on measuring the temperature of the fluid and that can overcome the limitations of the current prior art, which is primarily based on density-viscosity or flow rate relationships, such as the Hagen-Poiseuille method, etc. The method would ideally be on-line, allowing for fast and reliable measurements that can then be used for real-time adjustments of the manufacturing process. [Means for solving the problem]

[0019] In a first aspect of the present disclosure, two alternative computer implemented methods for measuring the kinematic viscosity of a fluid flow are provided, as set forth in claim 1 and claim 2, with the dependent claims being advantageous embodiments.

[0020] In a second aspect of the disclosure, there is provided a data processing apparatus, a computer program and a computer readable medium for implementing the method of the first aspect.

[0021] In a third aspect of the present disclosure, a process for measuring the kinematic viscosity of a fluid stream is provided.

[0022] In a fourth aspect of the present disclosure, a system for measuring the kinematic viscosity of a fluid stream is provided.

[0023] The methods, processes, data processing apparatus and systems according to the first, second, third and fourth aspects of the present disclosure may be used in the manufacturing process or installation of glass fibres. Effect of the Invention

[0024] A first distinct advantage of the present invention is that the viscosity of a fluid stream may be rapidly measured without reliance on measuring the temperature of the fluid, overcoming the limitations of current prior art techniques, which are primarily based on the use of density-viscosity or flow rate relationships.

[0025] A second distinct advantage of the present invention is that the viscosity of the fluid is measured in a non-contact manner. Continuous monitoring of the viscosity of the fluid stream is possible without disturbing or disrupting it, which can save time and costs in the manufacturing process of products, such as fiberglass based products.

[0026] A third advantage of the present invention is that it may be easily implemented in existing production lines, provided that the configuration of the production line allows for the use of an image recording device to capture images of the fluid stream. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a schematic diagram showing an example of a glass fiber production line.

[0028] [Diagram 2] FIG. 2 is a schematic cross-sectional view of an example of a bushing and fiberizing tool of Detail I of FIG.

[0029] [Diagram 3] FIG. 3 is a schematic diagram of detail II of FIG.

[0030] [Figure 4] FIG. 4 is a data flow diagram of a computer-implemented method according to one embodiment of the first aspect of the invention.

[0031] [Diagram 5] FIG. 5 is a data flow diagram of a computer-implemented method according to a second embodiment of the first aspect of the present invention.

[0032] [Figure 6]FIG. 6 is a data flow diagram of a computer implemented method according to an embodiment of the first aspect of the invention.

[0033] [Figure 7] Figure 7 is a plot of the geometrical profile of fluid flow for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U0 of 6.3 m3 / day at a cross section s0 of 4.5 cm2.

[0034] [Figure 8] Figure 8 is a plot of the geometrical profile of fluid flow for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U0 of 8.4 m3 / day at a cross section s0 of 4.5 cm2.

[0035] [Figure 9] Figure 9 is a plot of the geometrical profile of fluid flow for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U09.6 m3 / day at a cross section s0 of 4.5 cm2.

[0036] [Figure 10] Figure 10 is a plot of the geometrical profile of fluid flow for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U06.3 m3 / day at a cross section s0 of 8 cm2.

[0037] [Figure 11] FIG. 11 is a plot of the geometrical profile of fluid flow for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U0 of 8.4 m3 / day at a cross section s0 of 8 cm2.

[0038] [Figure 12] FIG. 12 is a plot of the geometrical profile of fluid flow for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U09.6 m3 / day at a cross section s0 of 8 cm2.

[0039] [Figure 13] FIG. 13 is a plot of the fluid flow velocity profile for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U0 of 6.3 m3 / day at a cross section s0 of 4.5 cm2.

[0040] [Figure 14] FIG. 14 is a plot of the fluid flow velocity profile for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U0 of 8.4 m3 / day at a cross section s0 of 4.5 cm2.

[0041] [Figure 15] FIG. 15 is a plot of the fluid flow velocity profile for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U09.6 m3 / day at a cross section s0 of 4.5 cm2.

[0042] [Figure 16] FIG. 16 is a plot of the fluid flow velocity profile for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U06.3 m3 / day at a cross section s0 of 8 cm2.

[0043] [Figure 17] FIG. 17 is a plot of the fluid flow velocity profile for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U0 of 8.4 m3 / day at a cross section s0 of 8 cm2.

[0044] [Figure 18] FIG. 18 is a plot of the fluid flow velocity profile for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U09.6 m3 / day at a cross section s0 of 8 cm2.

[0045] [Figure 19]FIG. 19 is a plot comparing example experimental data of fluid flow velocity profiles for an output volumetric flow rate U of 9.6 m / day at a cross section s of 5.7 cm.

[0046] [Figure 20] FIG. 20 is a plot comparing example experimental data of fluid flow velocity profiles for an output volumetric flow rate U of 9.6 m / day at a cross-section s of 5.7 cm.

[0047] [Figure 21] FIG. 21 is a physical data flow diagram of a processing data system for implementing the method according to the first and / or second aspect of the present disclosure.

[0048] [Figure 22] FIG. 22 is a schematic diagram of a system for measuring the kinematic viscosity of a fluid stream flowing through an orifice at a constant acceleration.

[0049] [Diagram 23] FIG. 23 is a plot of the geometrical profile of fluid flow for values ​​of kinematic viscosity varying from 87 to 614 for an output volumetric flow rate U0 of 6.3 m3 / day at a cross section s0 of 4.5 cm2.

[0050] [Figure 24] FIG. 24 is a plot of the geometrical profile of fluid flow for values ​​of kinematic viscosity varying from 87 to 614 for an output volumetric flow rate U09.6 m3 / day at a cross section s0 of 8.0 cm2.

[0051] [Diagram 25] FIG. 25 is a plot of the fluid flow velocity profile for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U0 of 6.3 m3 / day at a cross section s0 of 4.5 cm2.

[0052] [Figure 26]FIG. 26 is a plot of the fluid flow velocity profile for values ​​of kinematic viscosity varying from 87 to 614 Stokes for an output volumetric flow rate U09.6 m3 / day at a cross section s0 of 8 cm2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] 1, a glass fiber production line 1000 may generally include a silo 1001 for storing raw materials 1001a, such as inorganic compounds and / or cullet, a glass melting furnace 1002 for melting the raw materials 1001a conveyed by a conveyor 1003 from the silo 1001, and one or more fiberizing tools 1005a, 1005b, 1005c to which molten glass 1006 is supplied via a forehearth 1004. The forehearth is usually designed as an open or closed channel, which is provided with an opening directly above each fiberizing tool 1005a, 1005b, 1005c, thereby supplying each of them with molten glass 1006.

[0054] 2, the opening 2001 of the forehearth 1004 may be provided with a bushing 2002, here illustrated as an opening 2002a extended by a nozzle or drain pan 2002b and terminated by another opening 2002c, from which the molten glass 1006 flows by gravity as a fluid stream 2003 to the fiberizing tool 1005c located below. The fiberizing tool 1005c may have a spinner 2004, which is made of a bucket 2003a with a side opening and an annular wall 2004b provided with a number of metering holes. Under high speed rotation, the molten glass 1006 emerges from the bushing 2002 as a fluid stream 2003, falls into the bucket 2004a, shoots out of its side opening towards the inner surface of the annular wall 2004b, then shoots out through the metering holes to cast the glass thread 2005.

[0055] The fiberizing tool 1005c may also have a ring burner 2006 that emits an elevated temperature gas stream or jet substantially tangential to the annular wall, thereby drawing down the cast glass threads 2005, thereby heating and strengthening them, and forming glass fibers 2007. It may also have a gas blower 2008 located below the ring burner 2005, thereby preventing the glass fibers 2007 from straying too far from the axis of rotation of the spinner 2004.

[0056] As illustrated in Figures 2 and 3, when molten glass 1006 flows by gravity out of opening 2002c of bushing 2002, molten glass 1006 flows freely as a free fluid stream 2003 having a constant acceleration.

[0057] 3 and 4, in a first aspect of the present disclosure, there is provided a computer-implemented method 4000 for measuring the kinematic viscosity of a free fluid stream 2003 flowing at a constant acceleration from an opening 2002c, said method 4000 taking as input at least one image I4001 of a region of interest A3001 of the fluid stream 2003, a cross-section s0 of said opening 2002c, and an output volumetric flow rate U0 of the fluid stream 2003 from said opening 2002c; wherein said method 4000 provides as output the kinematic viscosity η of the fluid; wherein said method 4000 comprises the steps of: (a) S4001, which models the geometric profile GP of the fluid flow 2003 through digital processing operations of an input image I4001; (b) S4002, which calculates the kinematic viscosity of the fluid from the modeled geometric profile GP, cross section s0, and output volumetric flow rate U0 with a mathematical or physical model.

[0058] In the context of the present disclosure, a free fluid stream is understood as a free-flowing fluid, i.e. a flowing fluid having a free surface, not constrained by an external surface, such as from a tube or pipe.

[0059] In the context of the present disclosure, the geometric profile GP should be understood as any dimensional measurement that represents or allows to derive the variation of a geometric dimension, such as width, cross section, diameter, etc., of the fluid flow 2003 in the flow direction.

[0060] In an exemplary embodiment, for a fluid flow having a circular cross-section, as shown by the reference X, Z axes in Figure 3, the geometric profile can be the change in cross-section, diameter, or radius in the X direction along the flow direction Z. The origin of the X, Z axes can be the opening 2002c.

[0061] For example, due to radiation of the fluid flow 2003, such as a fluid flow of molten inorganic glass at elevated temperature, or the industrial surroundings of the opening 2002c, it may happen that at least one input image I4001 is corrupted or ruined by too much noise, which does not allow accurate modeling of the geometric profile GP.

[0062] Instead of measuring modeling the geometric profile GP, it may be advantageous to model the flow velocity of the fluid vapor 2003, i.e., the velocity of the fluid flow at discrete locations of the fluid flow along the flow direction, e.g., along the Z direction in Fig. 3. This may help to overcome the limitation of the input image I4001 being too noisy.

[0063] Thus, in an alternative advantageous embodiment, and with reference to Figures 3, 4 and 5, a method 5000 has as input a first image I4001 of a region of interest A3001 of the fluid flow 2003, a cross section s0 of said opening 2002c and an output volumetric flow rate U0 of the fluid flow 2003 from said opening 2002c, a second time-shifted image I5001 of at least two features F3001, F3002 of the fluid flow 2003, wherein said features F3001, F3002 are present in the provided first image I4001, The method 5000 provides as an output the dynamic viscosity of the fluid, η; The method 5000 includes the following steps: - S5001 carrying out digital processing of the first and second images I4001, I5001 to measure the displacement of said features F3001, F3002; - calculating S5002 the velocity V1, V2 of each of said features F3001, F3002 from the measurements of the displacement over the time shift between the first and second images I4001, I5001; and S4002, calculating the kinematic viscosity of the fluid from the velocities V1, V2, cross section s0, and output volumetric flow rate U0 using a mathematical or physical model.

[0064] The velocities V1, V2 of the features F3001, F3002 may be considered as two different measurements of the flow velocity FV of the fluid stream. In the calculation step S4002, each of these two velocities V1, V2 may be used independently to calculate the value of the dynamic velocity. Such an approach may advantageously provide relatively good accuracy in the measurement of viscosity, especially when several velocities are calculated from several features in the fluid stream.

[0065] Advantageously, the more velocities are calculated for the flow velocity FV, the better the accuracy of the method may be. Thus, the velocities of a number of features may be calculated, for example at least 10 features, preferably at least 50 features, more preferably at least 100 features. The calculation may be performed on many more input images than the two input images I4001, I5001.

[0066] The feature F3001, F3002 or multiple features of the fluid flow 2003 may be any feature of the fluid flow 2003 that moves with the fluid flow 2003 and shows a certain persistence between the first and second images I4001, I5001, so that their displacement over time, and therefore their velocity, can be measured.

[0067] In certain embodiments, the at least two features F3001, F3002 can be defects in the fluid stream 2003. For example, in the case of molten glass, the defects can be bubbles, unmelted particles, such as refractory stones or unmelted raw materials, or other non-uniformities. The defects can be on the surface of the fluid stream or in the mass. In the case of transparent molten glass, defects in the mass can be easily detected due to the transparency.

[0068] The fluid stream 2003 may at times exhibit uniform quality and may be free of visible defects. Artificial defects may be introduced upstream, for example, using a bubbling device or solid particles in a molten glass forehearth.

[0069] The cross section s0 of the opening 2002c can either be provided as an independent value from the technical specifications of the opening 2002c or be measured directly through image processing of the first image I4001 of the area A3001.

[0070] The output volumetric flow rate U0, provided as input, can be measured independently of the method according to the first aspect of the invention. For example, it can be measured automatically by a dedicated flow meter placed directly under the opening 2002c, for example by the method and device as described in WO 83 / 004437 [GULLFIBER AB [SE]] 1983.12.22, provided that the cross section of the fluid flow 3001 is known or can be measured. It can also be measured manually from timed sampling.

[0071] Alternatively or supplementarily, the method according to the first aspect of the disclosure may also be adapted to measure an output volumetric flow rate U0. Thus, in one embodiment, and with reference to Figures 3, 4 and 6, the method 6000 further comprises the steps of: taking as input a second time-shifted image I6001 of at least one feature F3001 of the fluid flow 2003, said feature F3001 being present in the first image I4001 provided as input, and wherein the output volumetric flow rate U0 of the fluid flow 2003 from said opening 2002c is calculated, after a modelling step S4001, by the following steps: - S6001 carrying out digital processing of the first and second images I4001, I6001 to measure the displacement of said feature F3001; - calculating S6002 a velocity V of the feature F3002 from measurements of the displacement over the time shift between the first and second images I4001, I6001; - Calculating S6003 an output flow rate U0 by multiplying the calculated velocity V by a cross section s1 of the modelled geometric profile GP of the fluid flow 3001 at the location of the feature F3001 in the first image I6001.

[0072] 3, the cross section s0 of the opening (2002c) is fixed. However, the cross section s of the fluid flow 2003 varies in the Z direction depending on the position of the feature F3001 within the fluid flow 2003 in said Z direction. Thus, the cross section s1 of the modeled geometric profile of the fluid flow 2003 will vary accordingly.

[0073] In certain embodiments, to improve the accuracy of the measurement, the output volumetric flow rate U0 may be calculated using multiple features of the fluid stream 2003, thereby calculating the mean output volumetric flow rate Umean. The calculation may be performed on many more input images than just the two input images I4001, I6001.

[0074] It should be noted that, according to the law of conservation of mass, the output mass flow rate should not change in the falling direction, i.e., Z direction, of the fluid stream 2003 at steady state. Thus, at steady state, which occurs in most cases if the temperature and thus the density do not change, or at least change within a very limited and negligible range, the calculated output volume flow rate Umean is a representative measure of the true output volume flow rate U0 of the fluid stream 2003 from the opening 2002c.

[0075] The feature F3001 may be of the same nature as described above in the context of the alternative embodiment of Fig. 5. Furthermore, when the alternative embodiment of Fig. 5 is implemented, steps S6001 and S6002 may advantageously be replaced by steps S5001 and S5002. Input image I6001 may be replaced by input image I5001. This may limit extra steps and may save time.

[0076] The area of ​​interest A3001 may be any area of ​​the fluid stream 2003. Due to the constant acceleration, the fluid stream 2003 may be relatively thin as it moves away from the opening 2002c. It may therefore be advantageous for the fluid stream 2003 to exhibit a constant width, for the digital processing operations of steps S4001, S5001, S6001 to operate efficiently on the input images I4001, I5001, I6001. Images of the thinnest areas of the fluid stream 2003, e.g. the lowest areas of the fluid stream, should then be avoided. In fact, the area of ​​interest A3001 may extend from the opening 2002c up to a length two times, preferably three times, the diameter of the opening 2002c. And the width of the fluid stream in the input images I4001, I5001, I6001 may be large enough for the digital processing operations.

[0077] In the modeling step S4001, the geometric profile GP may be calculated using any adapted edge detection algorithm for image processing, such as: the marching squares algorithm; the Canny edge detector; thresholding; edge operators based on Prewitt, Sobel, or Scharr filters, etc.

[0078] In the calculation step S4002, according to certain embodiments, the mathematical or physical model can be an empirical and / or simulated relationship, e.g., a chart, between the geometric profile of the fluid flow, its output volumetric flow rate, its viscosity, and the cross-section of the opening.

[0079] As an exemplary embodiment, the chart can be derived from previous experiments in which a surrogate fluid, such as cold oil, whose kinematic viscosity can be easily modified, is made to flow at different volumetric flow rates through orifices with different cross sections as a stream with constant acceleration. The kinematic viscosity can be altered by changing the temperature of the fluid or its composition, such as by diluting it in water. Images acquired from multiple tests performed with different values ​​for kinematic viscosity, orifice cross section and volumetric flow rate make it possible to build a chart in which kinematic viscosity values ​​correspond to a given geometric profile, a given volumetric flow rate and a given orifice cross section. The data of the chart can be experimental data or a model derived from experimental data.

[0080] Example charts for different values ​​of cross section s0 of opening 2002c, different values ​​of output volumetric flow rate U0, and different values ​​of kinematic viscosity are shown in FIGS.

[0081] 7-12 show the geometric profile of a circular fluid, expressed as the change in its radius R in the flow direction Z. 2 Three values ​​of the output volume flow rate U0 at the cross section s0 of 6.3 m 3 / day, 8.4m 3 / day, and 9.6m 3 10-12 show this change in terms of kinematic viscosity for a range of 87 to 614 stokes (cm2 / s) per day. 2 Three values ​​of the output volume flow rate U0 at the cross section s0 of 6.3 m 3 / day, 8.4m 3 / day, and 9.6m 3 This change is expressed in terms of kinematic viscosity values ​​which vary from 87 to 614 stokes (cm2 / s) and in terms of viscosity per unit time per day.

[0082] 13 to 18 show the change in the flow velocity FV of the fluid flow in the flow direction Z. 2 Three values ​​of the output volume flow rate U0 at the cross section s0 of 6.3 m 3 / day, 8.4m 3 / day, and 9.6m 3 16-18 show this change in terms of viscosity per day and in terms of values ​​of kinematic viscosity varying from 87 to 614 stokes (cm2 / s). 2 Three values ​​of the output volume flow rate U0 at the cross section s0 of 6.3 m 3 / day, 8.4m 3 / day, and 9.6m 3 This change is expressed in terms of kinematic viscosity values ​​which vary from 87 to 614 stokes (cm2 / s) and in terms of viscosity per unit time per day.

[0083] 7 to 18, the origin of the flow direction Z is the outlet of the opening 2002c.

[0084] The values ​​of the cross section s0 of the opening 2002c, the values ​​of the output volume flow rate U0, the values ​​of the dynamic viscosity, the geometrical profile and the flow velocity profile provided on Figures 7 to 18 are all representative of the actual industrial conditions, especially the fluid flow of molten glass for producing glass fibers for glass wool or stone wool. And the skilled person can directly use these charts to determine the dynamic viscosity of the fluid flow of molten glass falling in the fiberizing tool. If necessary, intermediate values ​​can be extrapolated from the data of Figures 7 to 18.

[0085] As an example, FIGS. 19 and 20 show a comparison of different flow velocities, FV, and geometric profiles, i.e., radii R, of the molten glass fluid flow, respectively. 2 10 and 20 provide experimental data obtained under industrial conditions for an output volumetric flow rate U0 of 9.6 m3 / day at cross section s0 of 1000 s. Both Figures 10 and 20 show near perfect agreement between the modeled profile and the experimental data, demonstrating that the chart according to the present disclosure allows for accurate and precise measurement of kinematic viscosity in fluid streams in industrial environments or conditions.

[0086] As another alternative or supplemental exemplary embodiment, the mathematical or physical model may be a numerical resolution of the Navier-Stokes equations, which are applied to a free-falling fluid flow for different conditions, e.g., different values ​​of kinematic viscosity, aperture, and volumetric flow rate. The relationships of kinematic viscosity, aperture, and volumetric flow rate may be simulated as a geometric or flow velocity profile and may be represented as a chart, e.g., a given kinematic viscosity value corresponds to a given geometric or flow velocity profile, a given volumetric flow rate, and a given aperture. Alternatively, the Navier-Stokes equations may be used as mathematical functions to fit or model the geometric or flow velocity profile of the fluid flow.

[0087] As an illustrative example, and with reference to FIGS. 2 and 3, the Navier-Stokes equations applied to a freely falling fluid stream 2003 from an opening 2002c may be written as follows:

number

[0088] where v is the dynamic viscosity, s0 is the cross section of the opening (2002c), FV is the velocity of the fluid flow (2003), g is the acceleration constant, and z is the coordinate in the flow direction Z from the opening 2003, i.e., perpendicular to the opening.

[0089] To solve the above equations numerically, two boundary conditions can be used, namely:

number

[0090] (2) Viscous stresses at the ends of the fluid flow can be neglected, i.e.,

number

[0091] This equation can be numerically solved for different values ​​of the kinematic viscosity ν, the cross section s0, the opening 2002c, and the output volumetric flow rate U0 using a solver for solving boundary value problems, such as the bpv_solve solver in the scipy python package.

[0092] Figures 23 and 24 show the variation of the fluid flow velocity FV in the flow direction Z, as can be obtained from such a numerical resolution. 2 The output volume flow rate U0 is 6.3 m 3 This change is shown in Fig. 24 for the cross section s0 of 8.0 cm2 / day and for the value of the kinematic viscosity which varies from 87 to 614 stokes (cm2 / s). 2 Three values ​​of the output volume flow rate U0, 9.6 m 3 This variation is shown in terms of viscosity per day and for values ​​of kinematic viscosity which vary from 87 to 614 stokes (cm2 / s).

[0093] Figures 25 and 26 show the geometrical profiles of a circular fluid flow, expressed as a change in radius R in the flow direction Z, as can be obtained from the same numerical resolution. Figure 25 shows a circular fluid flow with a cross-sectional area s of 4.5 cm 2 Three values ​​of the output volume flow rate U0, 6.3 m 3 This change is shown in Fig. 26 for a cross section s0 of 8.0 cm2 / s and for values ​​of kinematic viscosity which vary from 87 to 614 stokes (cm2 / s). 2 Three values ​​of the output volume flow rate U0, 9.6 m 3 This change is expressed in terms of kinematic viscosity per day and in terms of kinematic viscosity values ​​which vary from 87 to 614 stokes (cm2 / s).

[0094] 23 to 26, the origin of the flow direction Z is the outlet of the opening 2002c.

[0095] In the context of the present disclosure, the cross-section of the opening 2002c may have any geometric shape that allows the fluid flow 2003 to flow therethrough. In a particular embodiment, the cross-section of the opening 2002c and therefore the cross-section of the fluid flow 2003 may be circular; since this geometric configuration corresponds to the case in current industrial lines. The cross-section of the opening 2002c may then be calculated from its diameter.

[0096] In a preferred embodiment, the fluid stream 2003 is a stream of molten inorganic glass.

[0097] In a second aspect of the present disclosure, referring to FIG. 21, there is provided a data processing system 21000 having means 21001 for performing the methods 4000, 5000, 6000 according to any one of the embodiments of the first aspect of the present invention, and a computer program I21001, which may include instructions that, when executed by a computer, cause the computer to perform the method according to any one of the embodiments of the first aspect of the present invention.

[0098] The data processing system 21000 comprises means 21001 for performing a method according to any one of the embodiments of the first aspect of the present invention. An example of the means 21001 may be a device that can be instructed to automatically perform a sequence of arithmetic or logical operations to perform a task or action. Such a device, also called a computer, may have one or more central processing units (CPUs) and at least a controller device adapted to perform those operations.

[0099] It may further have other electronic components, such as an input / output interface 21003, a non-volatile or volatile storage device 21002, and a bus, which is a communication system for data transfer between components within or between computers, etc. One of the input / output devices may be a user interface for human-machine interaction, such as a graphical user interface for displaying human-understandable information.

[0100] Since calculations can require a lot of computing power to process significant amounts of data, the data processing system may advantageously have one or more graphical processing units (GPUs), particularly for image processing, whose parallel structure makes them more efficient than CPUs.

[0101] The computer program I21001 may be written through any kind of programming language, which may be either compiled or interpreted to perform the steps of the method according to any embodiment of the first aspect of the invention. The computer program I21001 may be part of a software solution, i.e. part of a collection of executable instructions, code, scripts, etc., and / or part of a database.

[0102] In certain embodiments, a computer readable storage device or medium 21002 may also be provided that contains instructions that, when executed by a computer, cause the computer to perform a method according to any embodiment of the first aspect of the invention.

[0103] The computer readable storage device 21002 may preferably be a non-volatile, non-transitory storage device or memory, such as a hard disk drive or a solid state drive, etc. The computer readable storage device may be a removable or non-removable storage medium as part of the computer.

[0104] Alternatively, the computer readable storage device may be a volatile memory in a removable medium.

[0105] The computer readable storage device 21002 may be part of a computer used as a server to which executable instructions may be downloaded which, when executed by the computer, may cause the computer to perform a method according to any of the embodiments described herein.

[0106] Alternatively, the program I21001 may be implemented in a distributed computing environment, such as cloud computing. The instructions may be executed on a server to which a client computer may connect and provide encoded data as input to the method. Once the data is processed, the output may be downloaded and decoded or transmitted directly, such as, for example, as instructions, to the client computer. This type of implementation may be advantageous since it may be realized in a distributed computing environment, such as, for example, a cloud computing solution.

[0107] In a third aspect of the disclosure, with reference to Figs. 3, 21 and 22, there is provided a process for measuring the dynamic viscosity η of a fluid stream 2003 flowing from opening 2002c at a constant acceleration, comprising: Here, the above steps include the following steps: (a) acquiring at least one image of a region of interest A3001 of the fluid stream 3001 using an image recording device 22001; (b) using the data processing means 21000, modelling the geometric profile of the fluid flow through digital processing of the acquired images; (c) Using the data processing means 21000, the dynamic viscosity η of the fluid is calculated from the modelled geometric profile, the cross section s0 of the opening and the output volumetric flow rate U0 of the fluid stream 3001 using a mathematical or physical model.

[0108] All embodiments described above in the context of the first aspect of the invention may be applied to the process according to the third aspect of the invention. More precisely, all embodiments relating to methods 4000, 5000 may be applied in the process, in particular in the process relating to steps (b) and (c) of said process.

[0109] In a fourth aspect of the present disclosure, with reference to Figs. 3, 21 and 22, there is provided a system 22000 for measuring the kinematic viscosity η of a fluid stream 2003 flowing from an opening 2002c at a constant acceleration, said system including: - an image recording device 22001 configured to acquire at least one image of a region of interest A3001 of the fluid flow 2003; A data processing device 21000 according to a second aspect of the present disclosure, configured to receive images from an image recording device 22001.

[0110] In certain embodiments, the image recording device 22001 can be a digital camera, such as a CCD or CMOS digital camera. The image resolution of the image recording device can depend on the desired accuracy for measuring the kinematic viscosity. In general, the smaller the width of the fluid stream 2003, the higher the image resolution.

[0111] In advantageous embodiments, the image resolution of the digital camera is such that the width resolution of the acquired image of the area of ​​interest A3001 of the fluid stream 2003 is at least 200 pixels / cm, preferably at least 400 pixels / cm. These embodiments may be compatible with most of the prerequisites of current production lines.

[0112] In a preferred embodiment, the digital camera may further be a high speed digital camera, such as a high speed digital camera having a frame rate of at least 50 frames per second (fps), preferably at least 100 fps. A high frame rate may be advantageous for acquiring a sequence of images which may then be fed to the data processing device 21000. The data processing device 21000 may then be further configured to calculate an average or representative image of the area of ​​interest A3001 of the fluid flow 2003 from said sequence of images. The average image may then be used to model the geometric profile GP relatively accurately and precisely.

[0113] A high frame rate may also be advantageous for calculating the output volume flow U0 from an image of a feature or features as described in the context of the first aspect of the invention.

[0114] As shown in Fig. 22, the image recording device 22001 may be oriented perpendicular to the flow direction of the fluid stream 2003. In certain embodiments, the image recording device 22001 may be oriented at an angle or tilted from the flow direction when there is not enough space in the vicinity of the opening 2002c and the fluid stream to place the image recording device 22001 perpendicular to the flow direction, as may occur in an industrial environment. The tilt angle may be taken into account when processing the acquired images, thereby correcting for optical distortions induced in the images.

[0115] The distance from the fluid stream 2003 at which the image recording device 22001 may be placed may depend on the focal length of the device, e.g. 50 cm to 1 m. In certain embodiments, depending on the temperature of the fluid stream 2003 and / or its thermal radiation, the image recording device may be placed at a relatively high distance from the fluid stream, thereby protecting its electronics from heat. A heat shield may be placed around the camera.

[0116] The processes, data processing devices, and systems according to the second, third, and fourth aspects of the present disclosure may be advantageously used in a fiberglass manufacturing line to monitor the kinematic viscosity of molten glass 1006 flowing by gravity through bushing 2002. The manufacturing line may have any type of fiberizing tool, such as a fiberizing tool with a spinner as previously described, or a fiberizing tool with a bottom-closed spinner.

[0117] In a further embodiment, the monitored viscosity may be incorporated into a feedback process to adjust the temperature of the molten glass 1006 in the vicinity of the bushing 2002 .

[0118] In this context, in certain embodiments, the system 22000 may further include a controller device configured to set or modify one or more parameters of one or more components of the production line that may affect the temperature of the molten glass. In some exemplary embodiments, if the kinematic viscosity deviates from a set point value, the controller device may act on a cooling and / or heating device associated with the forehearth 1004, thereby increasing or decreasing the temperature of the molten glass in front of the bushing 2002. In other exemplary embodiments, the controller device may send a visual signal on a display device, thereby alerting a human operator to adjust the chemistry of the molten glass.

[0119] All embodiments described herein, whether relating to the first, second, third or fourth aspect of the invention, may be combined by a person skilled in the art, unless they are considered technically incompatible.

[0120] Furthermore, while the present invention has been described in connection with preferred embodiments, it should be understood that various modifications, additions, and alterations may be made thereto by those skilled in the art without departing from the spirit and scope of the invention as defined in the claims.

Claims

1. 1. A computer-implemented method (4000) for measuring the kinematic viscosity of a free fluid stream (2003) flowing from an opening (2002c) at a constant acceleration, comprising: The method (4000) comprises: acquiring at least one image (I4001) of a region of interest (A3001) of the fluid flow (2003); ０ , and the output volumetric flow rate U of said fluid flow (2003) from said opening (2002c). ０ With the input, The method (4000) provides as an output the dynamic viscosity η of the fluid; The method (4000) comprises the steps of: (a) modeling (S4001) the geometric profile GP of said fluid flow (2003) by digital processing of said input image (I4001); (b) modeling the dynamic viscosity of the fluid using a mathematical or physical model, the geometric profile GP, the cross section s ０ , and the output volume flow rate U ０ (S4002), A computer-implemented method (4000).

2. A computer-implemented method (5000), comprising: The method comprises: capturing a first image (I4001) of a region of interest (A3001) of a fluid flow (2003); ０ , and the output volumetric flow rate U of said fluid flow (2003) from said opening (2002c). ０ a second time-shifted image I5001 of at least two features F3001, F3002 of the fluid flow 2003, the features F3001, F3002 being present in the first image I4001 provided as input; the method (5000) providing as an output the dynamic viscosity η of the fluid; The method (5000) comprises the steps of: - digital processing of said first and second images I4001, I5001 to measure the displacement of said features F3001, F3002 (S5001); - calculating (S5002) the velocity V1, V2 of each of said features F3001, F3002 from measurements of the displacement over the time shift between said first and second images I4001, I5001; The dynamic viscosity of the fluid is calculated using a mathematical or physical model in accordance with the velocities V1, V2, the cross section s ０ , and the output volume flow rate U ０ (S4002), A computer-implemented method (5000).

3. 3. The computer-implemented method of claim 1 or 2, further comprising: receiving as input a second time-shifted image (I6001) of at least one feature (F3001) of the fluid flow (2003), said feature (F3002) being present in the first image (I4001) provided as input; and determining the output volumetric flow rate U of the fluid flow (2003) from the opening (2002c). ０ However, after the modeling step (S4001), the following steps are performed: - digital processing (S6001) of said first and second images (I4001, I6001) to measure the displacement of said features (F3001); - calculating (S6002) the velocity V of said feature (F3002) from measurements of displacement over the time shift between said first and second images (I4001, I6001); an output flow rate U is calculated by multiplying the calculated velocity V by a cross section s1 of the modeled geometric profile GP of the fluid flow (3001) at the location of the feature (F3001) in the first image (I6001); ０ Calculating (S6003), The computer-implemented method (6000) is calculated by:

4. The output volume flow rate U ０ is calculated using a number of characteristics of the fluid flow (2003), thereby determining the average output volumetric flow rate U ｍｅａｎ The computer-implemented method (6000) of claim 3, further comprising:

5. The computer-implemented method (5000, 6000) of claim 2 or claim 3, wherein the feature (F3001, F3002) is a defect in the fluid flow (2003).

6. The computer-implemented method (4000, 5000, 6000) of any one of claims 1 to 5, wherein the mathematical or physical model is an experimental and / or simulation chart of the relationship between the fluid flow, its output volumetric flow rate, its viscosity, and the geometric profile for the cross-section of the opening.

7. The computer-implemented method (4000, 5000, 6000) of any one of claims 1 to 6, wherein a cross-section of the opening (2002c) and a cross-section of the fluid flow (2003) are circular.

8. A data processing apparatus (21000) having means for performing the method (4000, 5000, 6000) according to any one of claims 1 to 7.

9. A computer program (I21001) comprising instructions that, when the program is executed by a computer, cause the computer to carry out the method (4000, 5000, 6000) according to any of claims 1 to 7.

10. A computer readable medium (21002) comprising instructions which, when executed by a computer, cause the computer to carry out the method (4000, 5000, 6000) of any one of claims 1 to 7.

11. A process for measuring the dynamic viscosity η of a fluid stream (2003) flowing from an opening (2002c) at a constant acceleration, comprising: The process comprises the following steps: (a) acquiring at least one image of a region of interest (A3001) of a fluid flow (3001) using an image recording device (22001); (b) using a data processing device (21000) to model the geometric profile of said fluid flow through digital processing of the acquired images; (c) using a data processing device (21000), the dynamic viscosity η of the fluid is calculated using a mathematical or physical model, the geometric profile modeled, the cross section s of the opening ０ , and the output volumetric flow rate U of the fluid stream (2003) ０ To calculate from The process includes:

12. 1. A system (22000) for measuring a kinematic viscosity η of a fluid stream (2003) flowing from an opening (2002c) at a constant acceleration, the system comprising: an image recording device (22001) configured to acquire at least one image of a region of interest (A3001) of the fluid flow (2003); and A data processing device (21000) according to claim 8, adapted to receive an image from said image recording device (22001). A system (22000) having the above configuration.

13. 12. Use of the process of claim 11 in a fiberglass manufacturing line to monitor the kinematic viscosity of molten glass (1006) flowing by gravity through a bushing (2002).

14. 14. The use of claim 13, wherein the monitored kinematic viscosity is incorporated into a feedback process to regulate a temperature of the molten glass (1006) in the vicinity of the bushing (2002).

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