JP5101012B2 - Gas-liquid two-phase flow simulation test apparatus and gas-liquid two-phase flow simulation test method - Google Patents

Description

  The present invention relates to a gas-liquid two-phase flow simulation test apparatus and a gas-liquid two-phase flow simulation test method for simulating, for example, the boiling state of water.

For example, in a steam generator used in a pressurized water reactor (PWR) and an integrated modular light water reactor (hereinafter referred to as “IMR”; Integrated Modular Reactor), boiling heat transfer is performed under high-temperature and high-pressure conditions. This phenomenon shows a complicated flow state of a gas-liquid two-phase flow composed of water and water vapor, and it is generally difficult to grasp the flow characteristics due to the condition of high temperature and high pressure.
In order to overcome this, there is known a test apparatus capable of performing a test at a laboratory level using alcohol and sulfur hexafluoride gas having physical property values equivalent to water and water vapor under high temperature and high pressure conditions at room temperature and low pressure ( Patent Document 1).

JP 2002-189096 A (paragraph [0026])

  However, the test apparatus described in Patent Document 1 merely simulates the flow phenomenon of two-phase flow during boiling heat transfer. It is not configured to simulate the process of natural circulation of water. Therefore, it is impossible to grasp the flow process of the steam generator and the IMR that is realistic.

  The present invention has been made in view of such circumstances, and is a gas-liquid two-phase flow simulation test that can grasp the flow process of a steam generator and IMR in which water circulates naturally by buoyancy caused by generated steam bubbles. An object is to provide an apparatus and a gas-liquid two-phase flow simulation test method.

In order to solve the above problems, the gas-liquid two-phase flow simulation test apparatus and the gas-liquid two-phase flow simulation test method of the present invention employ the following means.
That is, the gas-liquid two-phase flow simulation test apparatus according to the present invention includes a container in which a simulated liquid whose physical property value governing the boiling phenomenon approximates at a low temperature and a low pressure is stored inside the container, and the container And a simulated gas supply means for supplying a simulated gas having a physical property equivalent to a high temperature and high pressure gas at a low temperature and a low pressure to the inside of the cylindrical body. And a first void ratio acquisition means for obtaining a void ratio of a two-phase fluid formed above the cylinder by the simulation gas leaked from the side wall of the cylinder rising in the simulation liquid; Based on the void ratio obtained from the first void ratio acquisition means, an ascending amount calculating means for calculating an ascending amount by which the simulated liquid positioned above the cylindrical body moves upward from below the container ; It is characterized by having.

A simulation test at a low temperature and a low pressure is made possible by using a simulated liquid and a simulated gas whose physical property values approximate at low temperatures and low pressures to the physical properties of liquids (such as water) and gases (such as water vapor) under high temperature and high pressure conditions. Examples of the simulated liquid include alcohols such as ethanol and methanol. An example of the simulated gas is sulfur hexafluoride gas.
Here, high temperature means a temperature of 100 ° C. or higher. Moreover, high pressure means the pressure of 1 MPa or more in absolute pressure. The low temperature means a temperature lower than the high temperature, and is a temperature that can be withstood by equipment having materials and dimensions that can be employed in a laboratory, for example, 0 to less than 100 ° C. The low pressure means a pressure lower than the high pressure, and is a pressure that can be withstood by equipment having materials and dimensions that can be employed in a laboratory. For example, the absolute pressure is less than 1 MPa.
The approximation of the physical property values of the high-temperature and high-pressure fluid and the simulated fluid means that the physical property values governing the boiling phenomenon are approximated. For example, density (kg / m ³ ), viscosity coefficient (Pa · s), surface tension It means that a physical property value such as (N / m) is approximate.
In the present invention, the simulated gas is supplied into the cylinder by the simulated gas supply means, and the simulated gas leaks from the side wall of the cylinder. The leaked simulation gas ascends in the simulation liquid located on the outer peripheral side of the cylindrical body and moves upward of the cylindrical body. Above the cylinder, due to a decrease in the buoyancy and pressure of the simulated gas, a rising driving force is given to the simulated liquid at this position (so-called gas lift pump phenomenon or flushing phenomenon). The rising amount of the simulated liquid is obtained by the raising amount calculating unit based on the void rate at the upper position of the cylinder obtained by the first void rate acquiring unit.
In addition to the void ratio, the bubble diameter may be further obtained by the bubble diameter acquisition means. Thereby, the rising amount of the simulated liquid can be obtained more accurately. From the measurement results of the void ratio and the bubble diameter, it is possible to predict the growth of bubbles in a field accompanied by a phase change, and to determine the ascending flow rate of the liquid by using a two-phase flow model (such as a drift flux model).
In this way, the amount of increase in the simulated liquid can be obtained under low temperature and low pressure conditions. For example, natural circulation of water in a steam generator used in an IMR (integrated modular light water reactor) or a pressurized water light water reactor (PWR). Can be simulated.
As the first void ratio acquisition unit and the bubble diameter acquisition unit, it is preferable to use a void meter (for example, a two-needle optical fiber type void sensor) that directly measures the upper part of the cylinder, but is not limited thereto. It is good also as a structure which estimates the void ratio of an upper position with the void meter provided in the intermediate | middle height position of the body.

  Furthermore, the gas-liquid two-phase flow simulation test apparatus of the present invention further includes a simulation liquid supply means for supplying the simulation liquid to the outside of the cylinder from below the cylinder, and the simulation liquid supply means The simulated liquid is supplied based on the calculation result of the amount calculation means.

  By supplying the simulated liquid corresponding to the rising amount from below the cylinder, the natural circulation of the liquid can be simulated. Thereby, for example, natural circulation of water of IMR and steam generator can be simulated.

Furthermore, the gas-liquid two-phase flow simulation test apparatus of the present invention is based on the second void ratio acquisition means for acquiring the void ratio of the outer periphery of the cylindrical body, and the void ratio obtained from the second void ratio acquisition means. The simulated steam generation amount is calculated, the simulated calorific value corresponding to the simulated steam generation amount is calculated, and the simulated gas amount corresponding to the simulated steam generation amount generated at the next time is calculated based on the simulated calorific value. A heat calculation unit and the simulated gas amount calculated by the heat transfer calculation unit are supplied by the simulated gas supply unit.

  Dynamic nuclear reaction operation can be simulated by calculating the amount of simulated gas at each time and supplying it to the inside of the cylinder.

Further, the gas-liquid two-phase flow simulation test method of the present invention includes a container in which a simulated liquid whose physical property value governing boiling phenomenon approximates at a low temperature and low pressure is stored inside a high-temperature high-pressure liquid ; And a simulated gas supply means for supplying a simulated gas having a physical property equivalent to a high temperature and high pressure gas at a low temperature and a low pressure to the inside of the cylindrical body. The simulated gas leaked from the side wall portion of the cylindrical body rises in the simulated liquid and obtains a void ratio of a two-phase fluid formed above the cylindrical body. Based on the above, an amount of increase in which the simulated liquid positioned above the cylinder moves from the lower side to the upper side of the container is calculated.

A simulation test at a low temperature and a low pressure is made possible by using a simulated liquid and a simulated gas whose physical property values approximate at low temperatures and low pressures to the physical properties of liquids (such as water) and gases (such as water vapor) under high temperature and high pressure conditions. Examples of the simulated liquid include alcohols such as ethanol and methanol. An example of the simulated gas is sulfur hexafluoride gas.
Here, high temperature means a temperature of 100 ° C. or higher. Moreover, high pressure means the pressure of 1 MPa or more in absolute pressure. Further, the low temperature means a temperature lower than the high temperature, and is a temperature that can be withstood by equipment having materials and dimensions that can be employed in a laboratory, for example, less than 100 ° C. The low pressure means a pressure lower than the high pressure, and is a pressure that can be withstood by equipment having materials and dimensions that can be employed in a laboratory. For example, the absolute pressure is less than 1 MPa.
The approximation of the physical property values of the high-temperature and high-pressure fluid and the simulated fluid means that the physical property values governing the boiling phenomenon are approximated. For example, density (kg / m ³ ), viscosity coefficient (Pa · s), surface tension It means that a physical property value such as (N / m) is approximate.
In the present invention, the simulated gas is supplied into the cylinder by the simulated gas supply means, and the simulated gas leaks from the side wall of the cylinder. The leaked simulation gas ascends in the simulation liquid located on the outer peripheral side of the cylindrical body and moves upward of the cylindrical body. Above the cylinder, due to a decrease in the buoyancy and pressure of the simulated gas, a rising driving force is given to the simulated liquid at this position (so-called gas lift pump phenomenon). The amount of increase in the simulated liquid is obtained based on the void ratio at the upper position of the cylinder.
In addition to the void ratio, the bubble diameter may be further obtained by the bubble diameter acquisition means. Thereby, the rising amount of the simulated liquid can be obtained more accurately. From the measurement results of the void ratio and the bubble diameter, it is possible to predict the growth of bubbles in a field accompanied by a phase change, and to determine the ascending flow rate of the liquid by using a two-phase flow model (such as a drift flux model).
In this way, the amount of increase in the simulated liquid can be obtained under low temperature and low pressure conditions. For example, natural circulation of water in a steam generator used in an IMR (integrated modular light water reactor) or a pressurized water light water reactor (PWR). Can be simulated.

  Since the amount of increase of the simulated liquid is calculated based on the void ratio, it is possible to grasp the flow process of the steam generator and IMR in which water naturally circulates by the buoyancy caused by the generated steam.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
FIG. 1 shows a gas-liquid two-phase flow simulation test apparatus (hereinafter simply referred to as “test apparatus”) 1 according to the present embodiment. This test apparatus 1 simulates an integrated modular light water reactor (IMR), and simulates a boiling phenomenon under high temperature and high pressure conditions under low temperature and low pressure conditions.

The test apparatus 1 includes a container 3 in which ethanol (simulated liquid) L is stored, and a cylindrical body 5 disposed in the container 3.
The container 3 is made of a transparent material such as acrylic or glass so that it can be observed from the outside. Ethanol stored in the container 3 is equivalent to physical properties (density, viscosity) at a low temperature of about 30 to 60 ° C. and a low pressure of about 0.5 to 1 MPa for high temperature water of about 300 ° C. and high pressure of about 6 MPa. Coefficient, surface tension). In place of ethanol, other alcohols such as methanol can also be used.
A liquid phase supply means (simulated liquid supply means) 7 is connected below the container 3. Ethanol L is supplied into the container 3 from the liquid phase supply means 7. The liquid phase supply means 7 includes a liquid phase flow rate control valve 9, and the flow rate is controlled by the liquid phase flow rate control valve 9. The opening degree of the liquid phase flow control valve 9 is controlled based on the output result of the increase amount calculation means 11.
The rising amount calculation means 11 calculates the amount by which alcohol rises due to the buoyancy of bubbles (sulfur hexafluoride gas) B rising from below. The rising amount calculation means 11 includes a first void meter (first void ratio acquisition means) 13 that measures the void ratio of the two-phase flow at a position above the cylinder 5. As the first void meter 13, for example, a two-needle optical fiber type void sensor is used. This two-needle optical fiber type void sensor can obtain not only the void ratio but also the bubble diameter.
Further, although not shown, a flushing calculation means for calculating the flushing at a position above the cylinder 5 based on the void ratio obtained from the first void meter 13 is provided separately from the rising amount calculation means 11.

The cylindrical body 5 has a space inside, and the side wall portion is composed of a porous body such as sintered metal or ceramics. This cylinder 5 simulates the core fuel. The cylinder 5 corresponds to a heat transfer tube through which the primary coolant flows when simulating a steam generator.
Inside the cylinder 5, sulfur hexafluoride gas (simulated gas) is supplied from a vapor phase supply means (simulated gas supply means) 15 connected to the lower part of the cylinder 5. Sulfur hexafluoride gas has the same physical properties (density, viscosity coefficient, surface tension) at a low temperature of about 30-60 ° C. and a low pressure of about 1 MPa with respect to high temperature steam of about 300 ° C. and high pressure of about 6 MPa. It is what you have.
The sulfur hexafluoride gas supplied to the inside of the cylindrical body 5 leaks outward from the porous side wall, becomes a bubble B, and rises upward. This leakage amount of sulfur hexafluoride gas corresponds to the amount of steam generated to be simulated. The amount of bubbles B generated is measured by a second void meter (second void ratio acquisition means) 19 provided at a substantially intermediate position of the cylinder 5. For example, a two-needle optical fiber type void sensor is used as the second void meter 19. This two-needle optical fiber type void sensor can obtain not only the void ratio but also the bubble diameter.

The gas phase supply means 15 includes a gas phase flow rate control valve 17, and the flow rate is controlled by the gas phase flow rate control valve 17. The opening degree of the gas phase flow control valve 17 is controlled based on the calculation result of the nuclear heat reaction program (heat transfer calculation unit) 21.
The nuclear thermal reaction program 21 obtains a steam generation amount simulated from the void ratio obtained from the second void meter 19, and calculates the reactivity of the core fuel (cylinder 5) simulated from this steam generation amount. Next, a calorific value is calculated from the obtained reactivity, and a steam generation amount corresponding to the calorific value is calculated. Then, a command is sent to the gas phase flow rate control valve 17 so that sulfur hexafluoride gas having a flow rate corresponding to the amount of generated steam flows.

  A plurality of video cameras 23 are arranged outside the container 3 so that the simulated boiling state can be visualized.

The test apparatus 1 having the above configuration is operated as follows.
As shown in step S1 of FIG. 2, sulfur hexafluoride gas is supplied from the vapor phase supply means 15, and sulfur hexafluoride gas is leaked from the side wall portion of the cylinder 5 which is a simulated core fuel.
Next, as shown in step S2, the void ratio on the outer periphery of the cylindrical body 5 is measured by the second void meter 19, the nuclear reaction corresponding to the void ratio is calculated, and the reactivity is calculated. Then, the flow rate of sulfur hexafluoride gas corresponding to the calorific value of the reactivity is calculated, and the valve opening degree of the gas phase flow rate control valve 17 is controlled. Thereby, the bubble generation amount at the next time is determined.
Next, as shown in step S <b> 3, the increase amount of the ethanol (liquid) L is calculated by the increase amount calculation means 11 based on the void ratio above the cylinder 5 measured by the first void meter 13. Then, the valve opening degree corresponding to the obtained increase amount is instructed to the liquid phase flow rate control valve 9, and ethanol L is supplied from below the cylinder 5 by the liquid phase supply means 7.
The above steps S1 to S3 are repeated to simulate steam generation and natural water circulation at each time.
In parallel with the above steps, the video camera 23 acquires an image.

According to this embodiment, there exist the following effects.
Based on the void ratio of the upper position of the cylinder 5 obtained by the first void meter 13, the amount of increase in the amount of increase in ethanol, which is a simulated liquid, that rises due to the buoyancy of sulfur hexafluoride gas, which is a simulated gas, is calculated. 11 can be obtained. In addition, a flow rate corresponding to the rising amount is supplied from below the cylindrical body 5 by the liquid phase supply means 7. Therefore, it is possible to simulate liquid phase circulation in a boiling state under high temperature and high pressure conditions, and to simulate natural circulation of water in an integrated modular light water reactor (IMR). In addition to the void ratio, the bubble diameter may be obtained by the first void meter 13. Thereby, the increase amount of a liquid phase can be obtained more correctly. Specifically, bubble growth in a field accompanied by a phase change is predicted from the measurement results of the void ratio and the bubble diameter, and the rising flow rate of the liquid is obtained using a two-phase flow model (such as a drift flux model).

  In addition, by performing a nuclear reaction calculation using the void ratio obtained by the second void meter, sulfur hexafluoride gas corresponding to the amount of steam generated at the next time is supplied into the cylinder 5. Thereby, a dynamic nuclear reaction operation can be simulated.

  In the present embodiment, the first void meter 13 is used to directly measure the void ratio above the cylinder. However, the second void meter 19 provided at the middle height position of the cylinder is used to measure the upper void ratio. It is good also as a structure which estimates a void ratio.

  Further, the present embodiment may be modified as shown in FIG. That is, as shown in the figure, a liquid-phase circulation passage 25 is provided on the side of the container 3. The circulation channel 25 connects the space above the cylinder 5 and the space below the cylinder. With such a configuration, it is possible to simulate a carry-under in which bubbles in the upper space flow downward along with the liquid phase.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
In this embodiment, a test apparatus 30 simulating a steam generator used in a pressurized water reactor (PWR) is shown.
The test apparatus 30 includes in a container 32 a cylindrical body 34 that simulates a heat transfer tube group bent in an inverted U shape, and an inner cylinder 36 that is disposed so as to cover the cylindrical body 34 from the outside. ing. A simulated air / water separator 38 and a simulated moisture separator 40 are provided above the inner cylinder 36.

A void meter 42 and a video camera 23 are provided at various locations of the test apparatus 30. The void meter 42 located above the cylinder 34 corresponds to the first void ratio acquisition means used when calculating the amount of increase in ethanol, and the void meter 42 located on the side of the cylinder 34 calculates the simulated steam generation amount. This corresponds to second void ratio acquisition means used for calculation.
In addition, a differential pressure gauge 44 for measuring the upper and lower differential pressures in the inner cylinder 36 is provided. The differential pressure gauge 44 determines the resistance (pressure loss) in the heat transfer tube group.
A gas phase supply means (simulated gas supply means) 46 is provided below the cylindrical body 34, and thereby sulfur hexafluoride gas is supplied.
The container 32 is filled with ethyl alcohol L, which is a simulated liquid, and the symbol L0 indicates the liquid level of this liquid phase.

A steam generator simulation test is performed by the test apparatus 30 configured as described above. That is, sulfur hexafluoride gas is supplied from the gas phase supply means 46 and leaks from the side wall portion of the cylindrical body 34. The leaked sulfur hexafluoride gas simulates a boiling state in a high temperature and high pressure state, and this is photographed by the video camera 23. At the same time, the void ratio is measured by the void meter 42 to grasp the flow state.
The sulfur hexafluoride gas leaked from the cylindrical body 34 rises as bubbles and pushes out ethyl alcohol, which is a simulated liquid above the cylindrical body 34, by its buoyancy (see arrow U). The increase amount of the ethyl alcohol can be obtained by an increase amount calculation unit (not shown) as in the first embodiment.
In a heat transfer calculation unit (not shown), a void ratio is obtained from a void meter 42 located on the side of the cylindrical body 34, a bubble generation amount is calculated from the void ratio, and a heat generation amount corresponding to the bubble generation amount is calculated. . Then, the vapor phase supply means 46 supplies the vapor phase flow rate at the next time according to the calorific value.

According to the test apparatus 30 of the present embodiment, the boiling state of the steam generator under actual high temperature and high pressure conditions can be simulated under low temperature and low pressure conditions.
Moreover, since the amount of increase in the liquid phase above the cylindrical body 34 can be calculated based on the void ratio obtained from the void meter 42 installed as appropriate, the actual flow state can be simulated.
In addition, since the calorific value is calculated from the amount of bubbles generated from the cylinder 34 and the gas phase flow rate at the next time is controlled based on the calorific value, the actual flow state can be simulated.

It is the schematic diagram which showed the test device concerning 1st Embodiment of this invention. It is the flowchart which showed the test procedure. It is the figure which showed the modification of FIG. It is the schematic diagram which showed the testing apparatus concerning 2nd Embodiment of this invention.

Explanation of symbols

1 Test equipment (gas-liquid two-phase fluid simulation test equipment)
3 Container 5 Tube 7 Liquid phase supply means (simulated liquid supply means)
11 Increase amount calculation means 13 First void meter (first void ratio acquisition means)
15 Gas phase supply means (simulated gas supply means)
19 Second void meter (second void ratio acquisition means)
30 test equipment (gas-liquid two-phase fluid simulation test equipment)
32 container 34 cylinder

Claims (4)

For a high-temperature high-pressure liquid , a container in which a simulated liquid whose physical property values governing boiling phenomenon approximate at low temperature and low pressure is stored,
A cylinder having a side wall portion disposed in the container and having a porous body;
Simulated gas supply means for supplying a simulated gas having the same physical property value at a low temperature and low pressure to a high temperature and high pressure gas into the cylindrical body,
A first void ratio acquisition means for obtaining a void ratio of a two-phase fluid formed above the cylinder by the simulation gas leaked from the side wall of the cylinder rising in the simulation liquid;
Based on the void ratio obtained from the first void ratio acquisition means, an ascending amount calculating means for calculating an ascending amount by which the simulated liquid positioned above the cylindrical body moves upward from below the container ;
A gas-liquid two-phase flow simulation test apparatus characterized by comprising: A simulated liquid supply means for supplying the simulated liquid to the outside of the cylindrical body from below the cylindrical body,
The gas-liquid two-phase flow simulation test apparatus according to claim 1, wherein the simulated liquid supply means supplies the simulated liquid based on a calculation result of the rising amount calculation means. Second void ratio acquisition means for acquiring a void ratio of the outer periphery of the cylindrical body;
A simulated steam generation amount is calculated based on the void ratio obtained from the second void rate acquisition means, a simulated heat generation amount corresponding to the simulated steam generation amount is calculated, and generated at the next time based on the simulated heat generation amount A heat transfer calculation unit that calculates a simulated gas amount corresponding to the simulated steam generation amount,
The gas-liquid two-phase flow simulation test apparatus according to claim 1 or 2, wherein the simulated gas amount calculated by the heat transfer calculation unit is supplied by the simulated gas supply means. For a high-temperature high-pressure liquid , a container in which a simulated liquid whose physical property values governing boiling phenomenon approximate at low temperature and low pressure is stored,
A cylinder having a side wall portion disposed in the container and having a porous body;
A simulated gas supply means for supplying a simulated gas having the same physical property value at a low temperature and low pressure to a high temperature and high pressure gas into the cylindrical body,
The simulated gas leaked from the side wall portion of the cylindrical body rises in the simulated liquid to obtain a void fraction of a two-phase fluid formed above the cylindrical body,
A gas-liquid two-phase flow simulation test method characterized in that, based on the void ratio, an amount of increase in which the simulated liquid located above the cylinder moves from below to above the container is calculated.

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