Liquid film measurement device

Abstract

To directly measure a state of a liquid film of a measurement object surface.SOLUTION: A liquid film measurement device includes a first electrode member having a circulation surface where measurement object liquid flows, a second electrode member of a linear body adjacently arranged facing the circulation surface of the first electrode member, excitation reception circuit means for forming an excitation reception circuit between the first electrode member and the second electrode member to acquire response of components (capacitance of an area obtained by synthesizing liquid and gas) of capacitance to an input signal, and control means for receiving information of the components of capacitance acquired by the excitation reception circuit to grasp a state of the liquid of the circulation surface of the first electrode member.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a liquid film measuring device for measuring the thickness of a liquid film.

Background Art

[0002] For example, as a heat exchanger used in a heat pump system, a falling liquid film type heat exchanger is adopted. As a falling liquid film type heat exchanger, a plurality of heat transfer tubes are arranged in a case, and a liquid refrigerant is poured over the surface of the heat transfer tube to form a liquid film of the refrigerant on the surface of the heat transfer tube, thereby exchanging heat between a fluid heat medium flowing in the heat transfer tube and the refrigerant (see, for example, Patent Document 1).

[0003] The falling liquid film type heat exchanger can reduce the filling amount of the refrigerant required for operation, and thus is useful as a heat exchanger for large equipment. On the other hand, since the effective heat transfer surface is the portion where the liquid film is formed, in order to effectively maintain the heat exchange efficiency, it is necessary to stably form the liquid film on the surface of the heat transfer tube. In order to stably form and maintain the liquid film on the surface of the heat transfer tube, it is considered effective to measure the situation of the liquid film on the surface of the heat transfer tube and grasp the situation of the liquid film (thickness, width of the liquid film, etc.).

[0004] However, since equipment is arranged in a limited space inside the falling liquid film type heat exchanger, it is currently impossible to separately provide measuring means, and there has been a demand for the emergence of a technology that can directly measure the situation of the liquid film on the surface of the heat transfer tube.

[0005] Not only in the field of falling liquid film heat exchangers, but also in the fields of liquid immersion cooling of electronic circuits and cooling of cooled members housed in a cooling water tank, it is considered effective to grasp the situation of the liquid film of the two-phase fluid on the surface of the electronic circuit, the surface of the cooled member, etc. in order to effectively maintain the cooling efficiency. Also, in the field of cooling of cooled members housed in a cooling water tank, it is considered effective to grasp the situation of the liquid film of the two-phase fluid on the surface of the cooled member, etc. in order to effectively maintain the cooling efficiency. However, as in the field of heat exchangers, the actual situation was that the emergence of a technology capable of directly measuring the situation of the liquid film on the surface of an electronic circuit or a cooled member was desired.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention has been made in view of the above situation, and an object thereof is to provide a liquid film measuring device capable of directly measuring the situation of the liquid film on the measurement target surface by measuring capacitance.

Means for Solving the Problems

[0008] The liquid film measuring device of the present invention according to claim 1 for achieving the above object includes a first electrode member (measurement electrode part) having a flow surface through which the liquid to be measured flows, a linear second electrode member arranged in proximity to and facing the flow surface of the first electrode member (measurement electrode part), excitation reception circuit means for forming an excitation reception circuit between the first electrode member and the second electrode member and obtaining a response of a capacitance component (capacitance of a region where a liquid and a gas are combined) with respect to an input signal, and control means for inputting information on the capacitance component obtained by the excitation reception circuit means and grasping the situation of the liquid on the flow surface of the first electrode member.

[0009] In the present invention according to claim 1, the excitation reception circuit means obtains the response of the capacitance component (the capacitance of the region where the liquid and gas are combined) between the first electrode member and the second electrode member. Based on the information of the capacitance component obtained by the excitation reception circuit means, the control means grasps the situation of the liquid (liquid film). For example, the thickness and flow width of the liquid film are derived (obtained by operations such as comparison with stored data).

[0010] By using a member having a flow surface through which the liquid flows as the first electrode member and arranging the second electrode member of a linear body (a wire of about several millimeters) in a device where the member is provided and the space is limited, the situation of the liquid film (such as thickness and flow width) with respect to the capacitance can be directly measured.

[0011] The liquid film measuring device of the present invention according to claim 2 is the liquid film measuring device according to claim 1, wherein the control means has a storage function for storing the situation of the liquid film with respect to a desired capacitance value, and compares the capacitance component obtained by the excitation reception circuit means and the situation of the liquid film stored in the storage function, and has an extraction function for extracting the situation of the liquid film corresponding to the capacitance component obtained by the excitation reception circuit means.

[0012] In the present invention according to claim 2, the situation of the liquid film with respect to a desired capacitance value is stored in the control means. The control means compares the capacitance component obtained by the excitation reception circuit means and the situation of the liquid film stored in the storage function, and the extraction function extracts the situation of the liquid film corresponding to the capacitance component obtained by the excitation reception circuit means.

[0013] That is, by comparing the capacitance component measured by the excitation reception circuit means with the capacitance value of the liquid film stored in advance, the data of the liquid film corresponding to the capacitance of a close value (the same value) can be extracted to evaluate the situation (thickness) of the liquid film.

[0014] And the liquid film measurement device of the present invention according to claim 3 is the liquid film measurement device according to claim 1 or claim 2, characterized in that the excitation reception circuit means includes an equivalent circuit for evaluating the capacitance of the region where the liquid and the gas are combined.

[0015] In the present invention according to claim 3, the equivalent circuit is used to evaluate the capacitance of the region where the liquid and the gas are combined, and to evaluate the situation (thickness) of the liquid film.

[0016] Also, the liquid film measurement device of the present invention according to claim 4 is the liquid film measurement device according to claim 2, characterized in that the storage function is a function in which the relationship between the information of the liquid film obtained optically and the value of the capacitance when corresponding to the obtained information of the liquid film is stored in advance.

[0017] In the present invention according to claim 4, it is possible to use the data in which the relationship between the information of the liquid film obtained optically (for example, the information of the liquid film photographed by an optical camera) and the value of the capacitance when corresponding to the obtained information of the liquid film is stored in advance.

[0018] Also, the liquid film measurement device of the present invention according to claim 5 is the liquid film measurement device according to claim 3, characterized in that the storage function obtains the value of the capacitance with respect to the information of the liquid film by a model that reproduces a liquid film with a desired thickness, and the relationship between the information of the liquid film obtained by the model and the value of the capacitance is stored in advance. The model is such that a second electrode member is disposed in a resin having a dielectric constant equivalent to that of a gas, and the liquid is enclosed between the resin and the first electrode member.

[0019] In the present invention according to claim 5, the value of the capacitance with respect to the information of the liquid film is obtained by a model that reproduces a liquid film with a desired thickness, and the data of the relationship between the information of the liquid film obtained by the model and the value of the capacitance can be used. As the model, one in which a second electrode member is disposed in a resin having a dielectric constant equivalent to that of a gas and the liquid is enclosed between the resin and the first electrode member is used.

[0020] Further, the liquid film measuring device of the present invention according to claim 6 is the liquid film measuring device according to claim 1 or claim 2, wherein a plurality of the second electrode members are arranged along the flow direction of the liquid, and the control means individually grasps a detection signal of the capacitance between the first electrode member and each of the second electrode members, and has a flow condition evaluation function of evaluating the flow condition in the flow direction of the liquid based on the delay condition of the detection signal.

[0021] In the present invention according to claim 6, the detection signals of the capacitance between the first electrode member and each of the second electrode members are individually grasped, and based on the delay condition of the detection signals (delay and the distance between the second electrodes), the flow velocity in the flow direction of the liquid can be evaluated, and / or the influence on the measurement of the film thickness by the scattered droplets can be evaluated.

[0022] Specifically, based on the delay time of the detection signals at the plurality of second electrode members and the distance between the second electrode members, the one-dimensional velocity in the flow direction of the liquid can be evaluated. Further, by comparing the shapes of the detection signals at the plurality of second electrode members, the presence or absence (scattering amount) of droplet scattering can be evaluated.

[0023] Further, the liquid film measuring device of the present invention according to claim 7 is the liquid film measuring device according to claim 1 or claim 2, wherein a plurality of the second electrode members are arranged along the flow direction of the liquid, the widths of the conductor portions (the widths of the non-insulated portions) intersecting the flow direction of the liquid are different from each other, and the control means individually grasps the components of the capacitance between the first electrode member and each of the second electrode members, and has a flow width evaluation function of evaluating the flow width in the flow direction of the liquid based on the difference state of the capacitance components.

[0024] In the present invention according to claim 7, since the widths of the energized portions of the second electrode members are different along the flow direction of the liquid, when the width of the liquid (the width of the non-insulated portion) becomes narrower than the energized portion (assuming the thickness is the same), it is affected by the gas component and the value of the capacitance becomes low. Therefore, the situation of the width of the liquid can be evaluated.

[0025] Further, the liquid film measuring device of the present invention according to claim 8 is the liquid film measuring device according to claim 1 or claim 2, wherein a plurality of the second electrode members are arranged along the flow direction of the liquid, and the positions of the conductor portions (positions of non-insulated portions) intersecting the flow direction of the liquid are different from each other, and the control means individually grasps the capacitance components between the first electrode member and each of the second electrode members, and has a flow shape evaluation function for estimating the three-dimensional shape of the liquid based on the difference state of the capacitance components.

[0026] In the present invention according to claim 8, since the positions of the conductor portions (positions of non-insulated portions) intersecting the flow direction of the liquid are different from each other, the distribution of the flow thickness in the width direction in the flow direction is evaluated, and the three-dimensional shape of the liquid can be grasped based on the distribution of the flow thickness.

[0027] Further, the liquid film measuring device of the present invention according to claim 9 is the liquid film measuring device according to claim 1 or claim 2, wherein the first electrode member is a long member, and a plurality of the second electrode members are provided to intersect at an arbitrary position in the longitudinal direction of the first electrode member.

[0028] In the present invention according to claim 9, by providing a plurality of second electrode members to intersect at an arbitrary position in the longitudinal direction of the first electrode member, it becomes possible to arrange the second electrodes in a lattice pattern with respect to the first electrode member. When a long member is applied as the first electrode member, the state (thickness) of the liquid on the peripheral surface of the member can be grasped.

[0029] In addition, by using a long first electrode member as a cylindrical member and arranging the second electrode member axially inside, based on the capacitance value, the state (thickness) of the liquid film on the inner peripheral surface of the cylindrical first electrode member can be grasped.

Advantages of the Invention

[0030] The liquid film measuring device of the present invention can directly measure the state of the liquid film on the measurement target surface by obtaining the capacitance.

Brief Description of the Drawings

[0031]

Figure 1

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Figure 8

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Figure 10

Figure 11

Figure 12

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Figure 14

Figure 15

Figure 16

Embodiments for Carrying Out the Invention

[0032] Based on FIGS. 1 to 4, the schematic configuration of a liquid film measuring device according to an exemplary embodiment of the present invention will be described.

[0033] FIG. 1 shows an overall conceptual configuration for explaining the outline of a liquid film measuring apparatus according to an exemplary embodiment of the present invention, and FIG. 2 shows a side view state for explaining the main part of the liquid film measuring apparatus according to an exemplary embodiment of the present invention.

[0034] As shown in FIGS. 1 and 2, a heat transfer tube 1 (for example, a heat transfer tube of a falling heat exchanger) having a flow surface through which a liquid flows as a measurement target is used as a first electrode member. A linear wire electrode 2 is used as a second electrode member facing the flow surface of the heat transfer tube 1. Liquid (water) 7 is supplied from a jetting means 6 to the flow surface of the heat transfer tube 1, and the water 7 flows down the flow surface of the heat transfer tube 1.

[0035] An equivalent circuit 3 (see FIG. 2: an equivalent circuit 3 composed of a resistor and a capacitor) that represents the capacitance component of water 7 and the capacitance component of gas (air) is configured between the heat transfer tube 1 and the wire electrode 2, and energization is performed between the heat transfer tube 1 and the wire electrode 2 to measure impedance, and excitation and reception circuit means 4 (measurement device) for evaluating capacitance based on the impedance is provided. The equivalent circuit 3 is set in a frequency region that dominates the capacitor.

[0036] The excitation and reception circuit means 4 constitutes an excitation and reception circuit between the heat transfer tube 1 (first electrode member) and the wire electrode 2 (second electrode member), and the impedance between the heat transfer tube 1 and the wire electrode 2 is measured to obtain a response of the capacitance component (capacitance of a region where liquid and gas are combined) to the measured input signal.

[0037] The information on the capacitance component obtained by the excitation and reception circuit means 4 is input to the control means 5, and the control means 5 grasps the situation (for example, film thickness) of the liquid (water) 7 on the flow surface of the heat transfer tube 1 based on the information on the capacitance component.

[0038] That is, the impedance between the heat transfer tube 1 (first electrode member) and the wire electrode 2 (second electrode member) is measured by the excitation reception circuit means 4, and the response of the capacitance component to the measured input signal is obtained. According to the response of the capacitance component obtained by the excitation reception circuit means 4, the control means 5 grasps the situation such as the film thickness of the water 7 on the flow surface of the heat transfer tube 1.

[0039] As a field of measurement target, in addition to the heat transfer tube 1 having a flow surface through which a liquid flows, it can be applied to the field of liquid immersion cooling of an electronic circuit and the cooling of a cooled member housed in a cooling water tank. Thereby, the situation of the liquid film of the two-phase fluid on the surface of the electronic circuit, the surface of the cooled member, etc. can be grasped, and the cooling efficiency can be effectively maintained. Further, it can also be applied to the field of cooling a cooled member (for example, a fuel rod cladding tube of a nuclear reactor, a heat transfer tube of a heat exchanger such as a condenser or a steam generator) housed in a cooling water tank. Thereby, the situation of the liquid film of the two-phase fluid on the surface of the cooled member, etc. can be grasped, and the cooling efficiency can be effectively maintained.

[0040] Based on FIGS. 3 and 4, the conceptual state of the equivalent circuit 3 will be described. FIG. 3 shows an explanation of the concept of the equivalent circuit between the first electrode member and the second electrode member, and FIG. 4 shows a graph representing the relationship between the capacitance and the liquid film thickness.

[0041] As shown in FIG. 3, an equivalent circuit 3 composed of a resistance RL and a capacitor CL of the water 7 part and a resistance RG and a capacitor CG of the air part is formed between the heat transfer tube 1 and the wire electrode 2. As can be seen from the equivalent circuit 3, when the film thickness of the water 7 increases, the impedance decreases.

[0042] Therefore, when the impedance is low, the value of the film thickness of the water 7 becomes high (there is a lot of water 7), and when the impedance is high, the value of the film thickness of the water 7 becomes low (there is little water 7 and a lot of air). Since the impedance and the capacitance have a negative correlation, when the impedance is low, the capacitance becomes high and the film thickness of the water 7 becomes thick. And when the impedance is high, the capacitance becomes low and the film thickness of the water 7 becomes thin.

[0043] That is, as shown in FIG. 4, it can be seen that as the capacitance increases, the film thickness of the water 7 becomes thicker, and as the capacitance decreases, the film thickness of the water 7 becomes thinner. According to the relationship shown in FIG. 4, the control means 5 grasps the situation such as the film thickness of the water 7 on the flow surface of the heat transfer tube 1 according to the response of the capacitance component.

[0044] The situation of the control means 5 will be described with reference to FIGS. 5 and 6. FIG. 5 shows the block configuration of the control means 5, and FIG. 6 shows the concept of the data stored in the storage function.

[0045] The control means 5 has a storage function 11 in which the situation (film thickness) of the liquid film with respect to a desired capacitance value is stored. Further, the control means 5 receives the input of the capacitance component (response data) obtained by the excitation reception circuit means 4, compares the film thickness stored in the storage function 11 with the response data (capacitance component), and has an extraction function 12 for extracting the film thickness corresponding to the capacitance component obtained by the excitation reception circuit means 4.

[0046] In the storage function 11, for example, the relationship between the image obtained by photographing the actual liquid film with an optical camera and the capacitance value corresponding to the thickness of the liquid film in the obtained image is stored in advance. That is, as shown in FIG. 6, a large number of images ABCDE... of liquid films with different thicknesses are stored, and for the stored images ABCDE..., the relationship between the capacitance value corresponding to the thickness of the liquid film is stored.

[0047] The information (response data) of the capacitance component is input to the extraction function 12, and the input response data is compared with the information stored in the storage function 11. For example, the input capacitance value and the images ABCDE... are compared, and the thickness (film thickness) of the liquid film corresponding to the input capacitance is output.

[0048] That is, in the extraction function 12, the capacitance value of the liquid film data (images ABCDE...) obtained optically is compared with the measured capacitance component (input capacitance component), and the liquid film data for the capacitance with a close value (the same value) is fitted. Thereby, the thickness of the liquid film of the heat transfer tube 1 is measured.

[0049] As a function in the memory function 11, it is also possible to apply a function in which the value of the capacitance with respect to the information of the liquid film is obtained by a model that reproduces a liquid film with a desired thickness, and the relationship between the information of the liquid film obtained by the model and the value of the capacitance is stored in advance.

[0050] Another embodiment of the memory function will be described with reference to FIG. 7. FIG. 7 shows the concept of a model that reproduces a desired film thickness.

[0051] In the memory function 11 (see FIG. 5), the information of a model in which a wire electrode 2 as a second electrode member is arranged in a resin 15 having a dielectric constant equivalent to that of air, and a liquid (water) 7 is enclosed between the resin 15 and a heat transfer tube 1 as a first electrode member is stored, and the relationship of the value of the capacitance corresponding to the thickness of the liquid film is stored for the stored model.

[0052] In addition, the capacitance of the resin 15 is determined in the form of a mathematical model using the capacitance of the resin itself and the capacitance of the water 7, and when actually measuring the capacitance, it is estimated by replacing it with the capacitance of air or vapor as the capacitance of the resin 15.

[0053] That is, as shown in the figure, the information of the model having liquid films with thicknesses d1, d2, d3, and d4 is stored, and for each model (for each of the liquid film thicknesses d1, d2, d3, and d4), the capacitance obtained by synthesizing the capacitances of the resin 15 and the water 7 is stored.

[0054] And in the extraction function 12, the input response data is compared with the information stored in the memory function 11. For example, the value of the input capacitance is compared with the value of the synthesized capacitance stored for each model (stored for each of the liquid film thicknesses d1, d2, d3, and d4), and the thickness (film thickness) of the liquid film corresponding to the input capacitance is output.

[0055] That is, in the extraction function 12, the measured capacitance component (the input capacitance component) is compared with the synthesized capacitance values stored for each model (stored for each of the liquid film thicknesses d1, d2, d3, and d4), and the data of the liquid film for the capacitance with a close value (the same value) is fitted. As a result, the thickness of the liquid film of the heat transfer tube 1 is measured.

[0056] Returning to FIG. 5, the control means 5 has a flow width evaluation function 13. The flow width evaluation function 13 is a function for evaluating the width of the flow in the flow direction of the liquid (water) 7.

[0057] Based on FIGS. 8 and 9, the configuration of the wire electrode to which the flow width evaluation function 13 is applied will be described. FIG. 8 shows a concept of a state in which three stages of wire electrodes are arranged, and FIG. 9 shows a front view of a state in which three stages of wire electrodes are arranged.

[0058] As shown in the figure, the wire electrodes 2 are arranged in a plurality of stages (three stages) along the flow direction of the water 7 (the vertical direction in the figure). And the widths of the conductor portions in the direction intersecting the flow direction of the water 7 (the left - right direction in FIG. 9) are different from each other.

[0059] That is, the wire electrodes 2 are covered with the insulating member 17, and the insulating member 17 at the portion facing the heat transfer tube 1 is removed. The widths of the portions where the wire electrodes 2 are not insulated (the widths where the insulating member 17 is removed) gradually become wider in the upper, middle, and lower stages and are different from each other.

[0060] In the flow width evaluation function 13, the capacitance components between the heat transfer tube 1 and each wire electrode 2 are individually grasped, and the flow width in the flow direction of the water 7 is evaluated based on the difference state of the capacitance components.

[0061] Specifically, when water 7 exists across the width of the non-insulated portions of the upper and middle wire electrodes 2, the capacitance components of the upper and middle portions are evaluated to be the same. When water 7 and air exist across the width of the non-insulated portion of the lower wire electrode (assuming the same thickness), the value of the capacitance component is reduced under the influence of the impedance of air.

[0062] In this state, since the values of the capacitance components of the non-insulated portions of the upper and middle wire electrodes 2 are the same and the value of the capacitance component of the non-insulated portion of the lower part is evaluated to be low, the flow width in the flow direction of water 7 is evaluated to be a value between the width of the non-insulated portion in the middle and the width of the non-insulated portion in the lower part.

[0063] Thereby, the flow width in the flow direction of water 7 is evaluated based on the difference state of the capacitance components between the heat transfer tube 1 and each wire electrode 2.

[0064] In the above embodiment, an example in which the thickness (film thickness) of the liquid film is derived using the data of the liquid film and the model of the liquid film has been described. However, it is also possible to obtain the thickness (film thickness) of the liquid film by calculation based on parameters such as the liquid to be measured and the member through which the liquid flows.

[0065] Also, in the above embodiment, the cylindrical heat transfer tube 1 has been described as an example of the first electrode member. However, as the first electrode member, other shaped members such as a prismatic member or a rectangular block-shaped member can be applied. As the first electrode member, in addition to the heat transfer tube 1 of the falling heat exchanger, it can be applied to components of an electronic circuit where liquid immersion cooling is performed, fuel rods, etc. Thereby, it is possible to apply to members arranged in a limited space or members in an environment where people cannot approach to measure the situation (thickness) of the liquid film.

[0066] Based on FIGS. 10 and 11, another embodiment of the arrangement state of the wire electrodes will be described.

[0067] FIG. 10 shows a concept of a state in which wire electrodes are arranged in a grid pattern, and FIG. 11 shows a concept of a state in which a cylindrical first electrode member is used.

[0068] As shown in FIG. 10, a plurality of wire electrodes 2 as a second electrode member are provided so as to intersect at an arbitrary position in the longitudinal direction of the heat transfer tube 1 with respect to the long heat transfer tube 1 as the first electrode member.

[0069] Therefore, by providing a plurality of wire electrodes 2 so as to intersect at an arbitrary position in the longitudinal direction of the heat transfer tube 1, it becomes possible to arrange the wire electrodes 2 in a grid pattern with respect to the heat transfer tube 1, and the film thickness of the liquid on the peripheral surface of the heat transfer tube 1 can be measured.

[0070] As shown in FIG. 11, a cylindrical member 21 is applied as the first electrode member, and the wire electrode 2 as the second electrode member can be arranged in the axial direction on the inner diameter portion (inside) of the member 21. Thereby, based on the value of the capacitance, the thickness of the liquid film on the inner peripheral surface of the cylindrical member 21 can be grasped.

[0071] Based on FIGS. 12 and 13, an embodiment of a flow state evaluation function for evaluating the flow rate of water 7 will be described.

[0072] FIG. 12 shows a front view of the arrangement state of the wire electrodes, and FIG. 13 shows the change over time of the capacitance (liquid film thickness).

[0073] As shown in FIG. 12, the wire electrodes 2 are arranged in two stages along the flow direction of water 7 (the vertical direction in the figure). For example, the widths of the conductor portions in the direction intersecting the flow direction of water 7 (the left - right direction in the figure) (the widths of the non - insulated portions) are made equal.

[0074] As shown by the solid line in FIG. 13, the capacitance at the position of the wire electrode 2 on the upstream side (for example, the upper side in the figure) is detected, and as shown by the dotted line in FIG. 13, the capacitance of water 7 at the same position as the portion detected on the upstream side is detected at the position of the wire electrode 2 on the downstream side (for example, the lower side in the figure). At this time, at the position of the wire electrode 2 on the downstream side (for example, the lower side in the figure), the capacitance is detected with a delay time τ.

[0075] Therefore, when the distance between the wire electrode 2 on the upstream side (e.g., the upper side in the figure) and the wire electrode 2 on the downstream side (e.g., the lower side in the figure) is d, the flow velocity v of the water 7 can be obtained by dividing the distance d by the delay time τ (d / τ) (flow condition evaluation function).

[0076] Based on FIGS. 14 and 15, an embodiment of the flow condition evaluation function for evaluating the condition of the droplets of the water 7 will be described.

[0077] FIG. 14 shows a side view of the arrangement state of the wire electrodes, and FIG. 15 shows the change over time of the capacitance (thickness of the liquid film).

[0078] As shown in FIG. 14(a), the wire electrodes 2 provided facing the heat transfer tube 1 are arranged in two stages along the flow direction of the water 7 (the vertical direction in the figure). For example, it is assumed that droplets 7a are formed and detached / scattered from the water 7 at the position of the wire electrode 2 on the upstream side (e.g., the upper side in the figure), and the droplets 7a are scattered at the position of the wire electrode 2 on the downstream side (e.g., the lower side in the figure) as shown in FIG. 14(b).

[0079] As shown by the thick solid line in FIG. 15, the capacitance before the droplets 7a are scattered at the position of the wire electrode 2 on the upstream side (e.g., the upper side in the figure) is detected (time t1), and as shown by the thin solid line in FIG. 15, the capacitance is detected at the position of the wire electrode 2 on the downstream side (e.g., the lower side in the figure) (time t2).

[0080] As shown by the dotted line in FIG. 15, based on the value of the capacitance component at the position of the wire electrode 2 on the upstream side (e.g., the upper side in the figure) at time t1, the value of the capacitance component at the position of the wire electrode 2 on the downstream side (e.g., the lower side in the figure) at time t2 is estimated.

[0081] At the position of the wire electrode 2 on the downstream side (e.g., the lower side in the figure) (at time t2), the volume of the water 7 through which the droplet 7a scatters and passes through the measurement unit becomes small, and the capacitance becomes low. At time t2, the value of the estimated capacitance component (shown by the dotted line in Fig. 15) is compared with the value of the capacitance component actually measured at the position of the wire electrode 2 on the downstream side (e.g., the lower side in the figure) (shown by the thin solid line in Fig. 15), and it is determined that the value of the capacitance component actually measured at the position of the wire electrode 2 on the downstream side (e.g., the lower side in the figure) (shown by the thin solid line in Fig. 15) is low.

[0082] Based on the comparison result, it is evaluated that there are droplets 7a that have detached and scattered from the water 7 between the upper and lower wire electrodes 2 (flow situation evaluation function).

[0083] When there are no droplets 7a, the value of the capacitance component at the position of the wire electrode 2 on the upstream side (e.g., the upper side in the figure) at time t3 is equal to the value of the capacitance component at the position of the wire electrode 2 on the downstream side (e.g., the lower side in the figure) at time t4, and it is evaluated that the thickness of the liquid film has not changed.

[0084] Incidentally, when droplets enter from the outside between the upper and lower wire electrodes 2, the value of the capacitance component at the position of the wire electrode 2 on the downstream side (e.g., the lower side in the figure) becomes higher than the estimated value, and it is evaluated that the thickness of the liquid film has increased due to the entry of the droplets.

[0085] Based on Fig. 16, an embodiment of the flow shape evaluation function for evaluating the flow shape of the water 7 will be described. Fig. 16 shows a front view of the arrangement state of the wire electrodes.

[0086] As shown in the figure, the wire electrodes 2 are arranged in a plurality of stages (five stages in the illustrated example) along the flow direction of the water 7 (the vertical direction in the figure). And the positions of the conductor portions in the direction intersecting the flow direction of the water 7 (the left - right direction in Fig. 16) (the positions of the non - insulated portions) are different from each other.

[0087] That is, the position of the portion where the wire electrode 2 is not insulated (the position where the insulating member is removed) is shifted to the left in the drawing from the upstream side (the upper side in the drawing) to the downstream side (the lower side in the drawing) of the flow direction of the water 7. Note that the widths of the conductor portions (the widths of the non-insulated portions) are made equal.

[0088] In the case of a plurality of stages (five stages in the illustrated example) of wire electrodes 2, the values of the capacitance components are individually grasped, and the three-dimensional shape of the water 7 is inferred based on the difference state of the values of the capacitance components (the difference state of the liquid film thickness at the measured position) (flow shape evaluation function). For this reason, since the positions of the conductor portions (the positions of the non-insulated portions) intersecting the flow direction of the water 7 are different from each other, the distribution of the flow thickness in the width direction in the flow direction is evaluated, and the three-dimensional shape of the liquid can be grasped based on the distribution of the flow thickness.

Industrial Applicability

[0089] The present invention can be used in the industrial field of a liquid film measuring device that directly measures the state of a liquid film on a measurement target surface.

Explanation of Reference Numerals

[0090] 1 Heat transfer tube 2 Wire electrode 3 Equivalent circuit 4 Excitation and reception circuit means 5 Control means 6 Jetting means 7 Liquid (water) 11 Storage function 12 Extraction function 13 Flow width evaluation function 15 Resin 17 Insulating member 21 Member

Claims

1. A first electrode member having a flow surface through which a liquid to be measured flows (measurement electrode portion), A second electrode member in the form of a linear body disposed close to and facing the flow surface of the first electrode member (measurement electrode portion), Excitation and reception circuit means for forming an excitation and reception circuit between the first electrode member and the second electrode member and obtaining a response of a capacitance component (capacitance of a region where liquid and gas are combined) to an input signal, Control means for receiving information on the capacitance component obtained by the excitation and reception circuit means and grasping the state of the liquid on the flow surface of the first electrode member. A liquid film measuring device characterized by the above.

2. In the liquid film measuring device according to Claim 1, The control means Has a storage function for storing the state of the liquid film with respect to a desired capacitance value, Compares the capacitance component obtained by the excitation and reception circuit means and the state of the liquid film stored in the storage function, and has an extraction function for extracting the state of the liquid film corresponding to the capacitance component obtained by the excitation and reception circuit means. A liquid film measuring device characterized by the above.

3. In the liquid film measuring device according to Claim 1 or Claim 2, The excitation and reception circuit means Includes an equivalent circuit for evaluating the capacitance of the region where the liquid and gas are combined. A liquid film measuring device characterized by the above.

4. In the liquid film measuring device according to Claim 2, The storage function Is a function in which the relationship between the information on the liquid film obtained optically and the capacitance value at the time corresponding to the obtained information on the liquid film is stored in advance. A liquid film measuring device characterized by the above.

5. In the liquid film measuring device according to Claim 3, The storage function Is a function in which the capacitance value for the liquid film information is obtained by a model that reproduces a liquid film of a desired thickness, and the relationship between the liquid film information obtained by the model and the capacitance value is stored in advance. The model Is one in which the second electrode member is disposed in a resin having a dielectric constant equivalent to that of gas, and the liquid is enclosed between the resin and the first electrode member. A liquid film measuring device characterized by the above.

6. In the liquid film measuring device according to Claim 1 or Claim 2, A plurality of the second electrode members are arranged along the flow direction of the liquid, The control means Individually grasps the detection signals of the capacitance between the first electrode member and each of the second electrode members, and has a flow condition evaluation function for evaluating the flow condition in the flow direction of the liquid based on the delay condition of the detection signals. A liquid film measuring device characterized by the above.

7. In the liquid film measuring device according to claim 1 or claim 2, a plurality of the second electrode members are arranged along the liquid flow direction, and widths of conductor portions (widths of non-insulated portions) intersecting the liquid flow direction are different from each other, the control means includes a flow width evaluation function of individually grasping components of capacitance between the first electrode member and each of the second electrode members and evaluating a flow width in the liquid flow direction based on a difference state of the capacitance components The liquid film measuring device is characterized by this.

8. In the liquid film measuring device according to claim 1 or claim 2, a plurality of the second electrode members are arranged along the liquid flow direction, and positions of conductor portions (positions of non-insulated portions) intersecting the liquid flow direction are different from each other, the control means includes a flow shape evaluation function of individually grasping components of capacitance between the first electrode member and each of the second electrode members and inferring a three-dimensional shape of the liquid based on a difference state of the capacitance components The liquid film measuring device is characterized by this.

9. In the liquid film measuring device according to claim 1 or claim 2, the first electrode member is a long member, the second electrode member is a plurality of which are provided to intersect at an arbitrary position in the longitudinal direction of the first electrode member The liquid film measuring device is characterized by this.

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