JP2004077338A - Sensor, liquid film measurement device, and equipment with flowing liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique which can measure the thickness of an object to be detected such as a liquid film and so forth in real-time, and which can measure the velocity and the direction of a vapor-liquid interface. <P>SOLUTION: The sensor 10 is composed of an approximately cylindrical casing 11, a shaft 12 disposed at the central part of the casing 11, two pairs of sensor parts 13A and 13B disposed between the casing 11 and the shaft 12, a filler 14 filled into the spacing among the casing 11, the shaft 12, and the sensor parts 13A and 13B. Each of the sensor parts 13A and 13B is composed of a pair of two electrodes 15a and 15b. By providing such a sensor 10 to a heat transfer tube 3 of a steam generator, the thickness of the liquid film L or the velocity of the vapor-liquid interface can be measured. Further, the flow of the vapor and the liquid in a group of the tubes of the vapor generator can be controlled by a controller 30. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sensor, a liquid film measuring device, and the like suitable for measuring a liquid film thickness and the like.
[0002]
[Prior art]
In a steam generator of a nuclear power plant, water passes between a number of pipes (tube groups) through which hot water produced in a nuclear reactor passes, and at this time, water evaporates by performing heat exchange with the hot water in the pipes, Generates steam.
Therefore, in the space between the tube groups, there is a so-called gas-liquid two-phase flow in which water (liquid) and steam (gas) flow in a mixed manner. In this state, the liquid flows along the outer surface of the tube.
With such a steam generator, the interior cannot be visualized. Therefore, in order to control the generation state of the vapor in real time, it is desired to measure the liquid film in the gas-liquid two-phase flow.
[0003]
[Problems to be solved by the invention]
Conventionally, various techniques for measuring the thickness of a liquid film have been provided, but an effective technique capable of measuring the thickness of the liquid film in real time in a high-temperature, high-pressure steam generator environment. The reality was that no technology was provided. Furthermore, there is no problem in that there is no technique for measuring the gas-liquid interface speed and its direction for grasping the flow of the liquid film.
The present invention has been made based on such a technical problem, and can measure the thickness of a detection target such as a liquid film in real time, and furthermore, measure the gas-liquid interface velocity and its direction. The purpose is to provide technology that enables it.
[0004]
[Means for Solving the Problems]
For this purpose, in the sensor of the present invention, a predetermined voltage is applied between the power-supply-side electrode and the ground-side electrode which are arranged at an interval, and the predetermined voltage is applied at a predetermined interval therebetween. A potential difference between a power supply side electrode, a ground side electrode, and a detection target contacted by the pair of two detection electrodes is detected by a sensor unit including a pair of two detection electrodes. An insulating portion is filled between the power supply side electrode, the ground side electrode, and the pair of two detection electrodes.
As described above, the thickness of the detection target can be measured by detecting the potential difference of the detection target with the pair of two detection electrodes. In this case, the detection target is not limited to the fluid, and may be any object as long as the potential difference varies according to the thickness.
Alternatively, two pairs of sensor units may be provided, and each of the sensor units may be arranged such that two pairs of detection electrodes are arranged along one predetermined direction. Here, "disposing in one predetermined direction" means that one pair of two detection electrodes are disposed along the same direction in one sensor unit and the other sensor unit. In other words, this includes the case where two pairs of detection electrodes of one sensor unit and the other sensor unit are arranged not only on the same straight line but also on two straight lines parallel to each other.
Thus, by providing two pairs of sensor units, the thickness of the detection target can be measured at two locations, and the moving speed of the detection target can be measured based on the phase difference of the fluctuation.
Furthermore, if two pairs of such sensor units are provided, and one pair and two pairs of detection electrodes are arranged along directions different from each other in one pair and the other pair, the moving speed of the detection target in two directions is improved. Can be measured, and based on this, the moving direction of the detection target can also be measured.
[0005]
Incidentally, in the above-described sensor, it is preferable that the detection electrode is formed of platinum. This is because durability can be improved when the sensor is used in a high-temperature, high-pressure environment or the like. Further, when the insulating portion is formed of an insulating material such as a glass-based material or a belo metal, heat resistance can be improved.
[0006]
In addition, the present invention can be regarded as a liquid film measurement device that performs measurement on a liquid film. Such a liquid film measurement device includes a sensor unit configured by arranging a pair of two detection electrodes at a predetermined interval between a casing and a center member at the center of the casing. Then, the casing, the center member, and the pair of two detection electrodes are arranged so that their respective tips face the flow path of the liquid film to be detected. Furthermore, an insulating layer is formed between the casing, the center member, and the sensor unit, and when a predetermined voltage is applied between the casing and the center member by a power source, a pair of two electrodes is detected by an electrometer. The potential difference between the electrodes is detected.
In this case, by providing a plurality of pairs of two detection electrodes, it becomes possible to detect the gas-liquid interface speed of the liquid film, the moving direction thereof, and the like.
Such a liquid film measuring device is suitable for performing measurement on a liquid film of a liquid flowing in contact with a gas, for example, on an inner peripheral surface or an outer peripheral surface of a tubular body, or on another wall surface or the like. The flow of the liquid along it can be measured, and it can be used for setting conditions of various facilities.
Further, in addition to this, as will be described later, it can be attached to equipment having a flow path for gas-liquid two-phase flow or equipment in which liquid flows in contact with gas, and used for controlling the operation.
[0007]
That is, the equipment of the present invention includes a flow path having a wall through which a liquid flows in contact with a gas, a sensor for detecting the flow of the liquid on the wall of the flow path, and a flow path based on the detection result of the sensor. And a controller for controlling the flow of the liquid to the controller. The sensor is disposed at an interval and has a power supply side electrode and a ground side electrode to which a predetermined voltage is applied, and a sensor for measuring the liquid film thickness of the liquid flowing on the wall surface by detecting the voltage. The sensor unit includes a pair of detection electrodes, a power supply side electrode, a ground side electrode, and an insulating portion filled between the pair of detection electrodes.
In such equipment, by providing the sensor unit at a plurality of locations on the wall, the controller detects the flow rate of the liquid on the wall based on the variation of the liquid film thickness detected by each of the sensor units at the plurality of locations. can do.
Further, the controller can detect the flow direction of the liquid on the wall surface by detecting the flow velocity of the liquid on the wall surface in at least two directions.
Examples of such equipment include steam generators that have high temperatures and high pressures.In addition to the steam generators that are particularly severe in such conditions, there are other equipment in which liquid flows along the wall surface in contact with gas. Any equipment is acceptable. For example, there are an absorption refrigerator, a boiler, an air conditioner, and the like that can supply cold heat by efficiently using steam.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
[First embodiment]
FIG. 1 is a diagram for explaining a schematic configuration of the steam generator according to the present embodiment. As shown in FIG. 1, the steam generator (equipment) 1 includes a tube group 4 including a large number of substantially U-shaped heat transfer tubes 3 inside a container 2. In the steam generator 1, water supplied from the water supply inlet 5 into the container 2 passes between the tube groups 4 to generate steam, and the steam (water) and the steam (gas) are generated by the steam separator 6. After the separation is performed, only the generated steam is discharged from the steam outlet 7.
In such a configuration, water flows along the surface of the heat transfer tubes 3 constituting the tube group 4 in a region where a gas-liquid two-phase flow in which water and steam coexist is formed.
[0009]
Now, as shown in FIGS. 2 and 3, a sensor 10 is mounted on all or some of the heat transfer tubes 3 constituting the tube group 4.
The sensor 10 is mounted in a hole 3 a formed in the tube wall of the heat transfer tube 3, and its detection surface 10 a is substantially flush with the outer peripheral surface (wall surface, flow path) 3 b of the heat transfer tube 3.
The sensor 10 includes a substantially cylindrical casing (ground-side electrode) 11, a shaft (power-supply-side electrode, center member) 12 disposed at the center of the casing 11, and a sensor disposed between the casing 11 and the shaft 12. Parts 13A and 13B, a casing 11, a shaft 12, and a filler (insulating part) 14 filled in the gaps between the sensor parts 13A and 13B. Each of the sensor parts 13A and 13B has two pairs of electrodes ( (Detection electrodes) 15a and 15b. Here, the tips of the electrodes 15a and 15b constituting the casing 11, the shaft 12, and the sensor portions 13A and 13B are exposed on the detection surface 10a, and thereby face the liquid film L flowing on the outer peripheral surface 3b of the heat transfer tube 3. It has become.
[0010]
The electrodes 15a and 15b constituting the casing 11, the shaft 12, and the sensor sections 13A and 13B are each formed of a conductive material, and the filler 14 is formed of an insulating material. As a conductive material constituting the casing 11, the shaft 12, and the electrodes 15a and 15b, for example, copper (Cu) is generally used, but as the sensor 10 provided in the steam generator 1 under a high-temperature and high-pressure environment, It is preferable to use platinum (Pt). For the same reason, it is preferable to use a silicon (Si) -based glass material or a belo metal material having excellent heat resistance and insulation properties as the insulating material forming the filler 14.
[0011]
As shown in FIG. 3, the casing 11 is grounded by being in contact with the metal heat transfer tube 3 or via a separately provided wiring (not shown). On the other hand, a power supply 20 is connected to the shaft 12, and a predetermined voltage is applied from the power supply 20. As a result, a predetermined voltage is applied between the shaft 12 and the casing 11.
The electrodes 15a and 15b constituting the sensor sections 13A and 13B, respectively, are arranged such that their tips are separated by a predetermined distance, and are connected to the electrometers 21A and 21B to detect a voltage generated between the electrodes 15a and 15b. I can do it.
The voltage values detected by the electrometers 21A and 21B of the sensor units 13A and 13B are transmitted to the controller 30, and the controller 30 controls the water flow along the outer peripheral surface 3b of the heat transfer tube 3 based on the voltage values. The measurement for the film L is performed. Further, the controller 30 controls the operation of the steam generator 1 such as the amount of water supplied to the tube group 4 and various temperature conditions based on the measurement result.
[0012]
FIG. 4 is a diagram for explaining the principle of measurement in the sensor units 13A and 13B.
As shown in FIG. 4A, when a predetermined voltage is applied from the power supply 20 to the shaft 12 in a state where the liquid film L (the flow direction is the direction of the arrow in the drawing) exists on the outer peripheral surface 3b of the heat transfer tube 3, the shaft A potential difference V ₀ is generated between the casing 12 and the grounded casing 11.
At this time, in each of the sensor sections 13A and 13B, the potential difference between the electrodes 15a and 15b is detected by the electrometers 21A and 21B.
Then, as shown in FIG. 4 (b), the potential difference V detected by the respective potentiometer 21A, 21B, there is a correlation between the thickness t _f of the liquid film L, and advance the potential difference V by knowing the correlation between the thickness t _f of the liquid film L by experiment or the like, the controller 30 can determine the thickness t _f of the liquid film L from the detected potential difference V. In practice, since the liquid film L there is a flow, the thickness t _f of the liquid film L varies with time. Therefore, the average value t _fav of the thickness t _f of the liquid film L detected within a predetermined time set in advance can be used as the thickness of the liquid film L.
[0013]
In the sensor 10, the sensor units 13A and 13B are separated by a predetermined dimension S (see FIG. 3A) along the flow direction of the liquid film L. Therefore, as shown in FIG. 4 (c), the sensor unit and the waveform (1) showing the thickness t _f of the liquid film L detected by 13A, the thickness t of the liquid film L detected by the sensor unit 13B in the waveform (2) showing a is _f, the phase difference [delta] _t results.
The controller 30, and the phase difference [delta] _t, the sensor unit 13A, the dimension S (known) between 13B, it is possible to obtain the gas-liquid interfacial velocity U by the following equation.
U = S / δ _t
[0014]
By providing the sensor 10 as described above in the heat transfer tubes 3, it is possible to measure the thickness t _f of the liquid film L in real time in an environment of steam generator 1 having a high temperature and high pressure. In particular, by forming the casing 11, the shaft 12, and the electrodes 15a and 15b from platinum (Pt), the corrosion resistance and the durability can be improved, and the filler 14 is made of a silicon (Si) -based glass material. Alternatively, by using an insulating material such as a belo metal, the heat resistance can be improved.
Further, the sensor 10, two pairs of the sensor unit 13A, since a configuration with a 13B, measure the thickness t _f of the liquid film L in two positions spaced by a predetermined dimension S in the direction of the flow of the liquid film L By doing so, the gas-liquid interface speed U can be obtained.
In this manner, the steam generator 1 can measure the thickness t _f of the liquid film L of the heat transfer tube 3 and the gas-liquid interface speed U in real time, so that the control of the steam generator 1 can be further improved. It is possible to carry out finely.
Further, in the above-described sensor 10, the detection range of the sensor units 13A and 13B is very small with respect to the size (area) of the detection surface 10a. Therefore, it is possible to measure the thickness t _f of the locally liquid film L, can be performed delicate measurement.
[0015]
[Second embodiment]
Next, a second embodiment of the present invention will be described.
Here, in the above-described first embodiment, the sensor 10 is provided with the two pairs of sensor units 13A and 13B to measure the flow in one direction of the liquid film L. In the embodiment, the sensor 10 'is provided with a total of four pairs of sensor units 13A, 13B, 13C, and 13D, and is configured to measure a flow in two directions. Therefore, in the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0016]
As shown in FIG. 5, the sensor 10 ′ has a detection surface 10 a on all or some of the heat transfer tubes 3 constituting the tube group 4 (see FIG. 1) of the steam generator 1. It is mounted so as to be substantially flush with the outer peripheral surface 3b.
The sensor 10 ′ includes a total of four pairs of sensor units 13A, 13B, 13C, and 13D including electrodes 15a and 15b between the casing 11 and the shaft 12.
Here, the sensor units 13A and 13B are arranged along a predetermined direction passing through the central axis of the shaft 12, and the sensor units 13C and 13D are arranged along a direction orthogonal to the one direction. That is, two pairs of the sensor units 13A and 13B and the sensor units 13C and 13D are provided along different directions. At this time, it is preferable to use platinum (Pt) as the conductive material constituting the electrodes 15a, 15b of the sensor units 13A, 13B, 13C, 13D, as in the first embodiment.
[0017]
A power supply 20 is connected to the shaft 12, and a predetermined potential difference V ₀ is applied between the shaft 12 and the casing 11. The electrodes 15a and 15b constituting the sensor units 13A, 13B, 13C and 13D are connected to the electrometers 21A, 21B, 21C and 21D so that the potential difference V generated between the electrodes 15a and 15b can be detected. It has become.
The voltage values detected by the electrometers 21A, 21B, 21C, and 21D are transmitted to the controller 30, and the controller 30 controls the steam generator 1 based on the voltage values.
[0018]
In such a sensor 10 ', the potential difference between the electrodes 15a and 15b is detected by the electrometers 21A, 21B, 21C and 21D in each of the sensor sections 13A, 13B, 13C and 13D. Thus, it is possible to measure the sensor unit 13A, 13B, @ 13 C, the thickness _{t f} of the liquid film L at the position of 13D.
[0019]
As shown in FIG. 5A, in the sensor 10 ', the sensor units 13A and 13B located along the same direction (this is defined as the X direction) are the same as in the first embodiment. can be obtained from the phase difference [delta] _t of the waveform indicating the thickness t _f of the liquid film L, measures the X-direction of the gas-liquid interfacial velocity U _X. Similarly, the phase difference δ _{t of the} waveform indicating the thickness t _f of the liquid film L in the sensor units 13C and 13D located along the direction orthogonal to the X direction (this is defined as the Y direction). from, it is possible to measure the Y-direction of the gas-liquid interface velocity U _Y.
A gas-liquid interface velocity U _X of the measured X-direction, and a Y-direction of the gas-liquid interfacial velocity U _Y, can be calculated liquid film L gas-liquid flow direction and the gas-liquid interface velocity U at the interface.
U = (U _X ² + U _Y ² ) ^1/2
θ = tan ⁻¹ (U _Y / U _X )
Where θ is the angle of the flow direction of the liquid film L with respect to the X direction.
[0020]
According to the sensor 10 'as described above, a total of four pairs of the sensor unit 13A provided along the two directions, 13B, @ 13 C, the 13D, not only the thickness _{t f} of the liquid film L, of the liquid film L The flow direction of the gas-liquid interface and the gas-liquid interface speed U can be obtained.
Accordingly, in addition to the same effects as those of the first embodiment, it is possible to perform measurement with higher flexibility and higher accuracy.
[0021]
In the first and second embodiments, the sensors 10 and 10 'are configured to measure the liquid film L along the outer peripheral surface 3b of the heat transfer tube 3, but as shown in FIG. The sensors 10 and 10 ′ (the sensor 10 is illustrated in the drawing) are provided such that the detection surface 10 a thereof is located on substantially the same plane as the inner peripheral surface (wall surface, flow path) 40 a of the tube 40. It is also possible to adopt a configuration in which measurement is performed on the liquid film L flowing inside the tube 40.
Further, such sensors 10, 10 'are provided not only for the steam generator 1, but also for other pipes and devices such as endothermic refrigerators, boilers and air conditioner pipes through which a gas-liquid two-phase flow flows. Is also possible.
Further, such sensors 10, 10 'are not necessarily used for controlling a device such as the steam generator 1 as shown in the embodiment, but can be used only for evaluating the functions of various devices. It is. In such a case, the controller 30 does not control the steam generator 1 as described in the above embodiment, and measures only the flow of the liquid film L. Thus, such a sensor 10 can be configured as a liquid film measurement device.
In addition, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate without departing from the gist of the present invention.
[0022]
【The invention's effect】
As described above, according to the present invention, the thickness of the liquid film of the gas-liquid two-phase flow and the gas-liquid interface velocity can be measured in real time.
Further, by disposing the sensors along two directions, it is possible to detect the gas-liquid interface velocity in any direction and the direction of the flow.
Further, according to the present invention, by providing such a sensor, it is possible to grasp in detail the state of the flow of the gas-liquid two-phase flow inside or outside the pipe of the equipment, and to make the operation of the equipment more detailed. Control becomes possible.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a steam generator according to the present embodiment.
FIG. 2 is a perspective cross-sectional view showing how a sensor is installed on a heat transfer tube.
3A and 3B are diagrams illustrating a configuration of a sensor according to the first embodiment, wherein FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view along a direction in which electrodes of a sensor unit are arranged.
FIG. 4 is a diagram for explaining a detection principle in a sensor.
5A and 5B are diagrams illustrating a configuration of a sensor according to a second embodiment, in which FIG. 5A is a plan view, and FIG. 5B is a cross-sectional view along each direction in which electrodes of a sensor unit are arranged.
FIG. 6 is a perspective view showing an installation state of a sensor for performing measurement on a liquid film on an inner peripheral surface side of a tubular body.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Steam generator (equipment), 3 ... Heat transfer tube, 3b ... Outer peripheral surface (wall surface, flow path), 4 ... Tube group, 10 and 10 '... Sensor, 10a ... Detection surface, 11 ... Casing (ground-side electrode) , 12 ... shaft (power supply side electrode, center member), 13A, 13B, 13C, 13D ... sensor part, 14 ... filler (insulating part), 15a, 15b ... electrode (detection electrode), 20 ... power supply, 21A, 21B , 21C, 21D: electrometer, 30: controller, 40: pipe, 40a: inner peripheral surface (wall surface, flow path), L: liquid film

Claims (9)

A power supply side electrode and a ground side electrode which are arranged at intervals and to which a predetermined voltage is applied,
The power supply-side electrode and the ground-side electrode comprise a pair of two detection electrodes arranged at a predetermined interval from each other, and the power-supply-side electrode, the ground-side electrode, and the two pair of detection electrodes are in contact with each other. A sensor unit for detecting a potential difference generated in the target,
The power supply side electrode, the ground side electrode, an insulating portion filled between the pair of two detection electrodes,
A sensor comprising: 2. The sensor according to claim 1, wherein two pairs of the sensor units are provided, and each of the sensor units includes two pairs of the detection electrodes arranged along one predetermined direction. 3. The two pairs of the sensor units are provided in two sets, and the two pairs of the detection electrodes are arranged along directions different from each other in one set and the other set. Sensor. The sensor according to claim 1, wherein the detection electrode is formed of platinum. The sensor according to claim 1, wherein the insulating portion is formed of a glass-based material or a belometal material. A liquid film measurement device for performing measurement on a liquid film,
A cylindrical casing,
A center member disposed at the center of the casing,
A sensor unit that is disposed between the casing and the center member and includes a pair of two detection electrodes that are disposed at a predetermined interval.
An insulating layer formed between the casing, the center member, and the sensor unit;
A power supply for applying a predetermined voltage between the casing and the center member;
An electrometer for detecting a potential difference generated between the pair of two detection electrodes of the sensor unit,
The liquid film measurement device, wherein the casing, the center member, and the pair of two detection electrodes are arranged so that their respective tips face the flow path of the liquid film to be detected. A flow path having a wall surface through which the liquid flows in contact with the gas,
A sensor for detecting a flow of the liquid on the wall surface of the flow path,
A controller that controls the flow of the liquid to the flow path based on the detection result of the sensor,
The sensor is
A power supply side electrode and a ground side electrode which are arranged at intervals and to which a predetermined voltage is applied,
It is arranged at a predetermined interval between the power supply side electrode and the ground side electrode, from a pair of two detection electrodes for measuring the liquid film thickness of the liquid flowing on the wall surface by detecting the voltage A sensor unit,
The power supply side electrode, the ground side electrode, an insulating portion filled between the pair of two detection electrodes,
A facility through which a liquid flows, comprising: The sensor unit is provided at a plurality of locations on the wall surface,
The equipment according to claim 7, wherein the controller detects a flow velocity of the liquid on the wall surface based on a change in a liquid film thickness detected by each of the sensor units at a plurality of locations. . 9. The equipment according to claim 8, wherein the controller detects the flow direction of the liquid on the wall by detecting the flow velocity of the liquid on the wall in at least two directions. 10.

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