Method and system for synchronously measuring phase field and temperature field in thermal-state rod bundle channel

Abstract

The invention relates to the technical field of two-phase fluid measurement, and particularly discloses a method and system for synchronously measuring a phase field and a temperature field in a thermal-state rod bundle channel, and the method comprises the steps: constructing the rod bundle channel through a fuel rod simulation body in a flow channel, and directly heating fluid, a silk screen sensor is arranged to synchronously measure a phase field and a temperature field of a rod bundle channel, an optical fiber cladding on the silk screen sensor is excited through an alternating-current electric signal, the optical fiber cladding emits and receives the electric signal, and fluid void fraction distribution is measured after the electric signal is analyzed and processed; the optical fiber of the silk screen sensor is excited through an alternating current signal, optical signals are transmitted and converted, and fluid temperature distribution is measured. The method is realized through the system for synchronously measuring the phase field and the temperature field in the thermal-state rod bundle channel, and the method and the system for synchronously measuring the phase distribution and the temperature distribution in two-phase flow developed for the complex rod bundle channel in a high-temperature and high-pressure environment are provided.

Description

Technical Field

[0001] The invention relates to the technical field of two-phase fluid measurement, and in particular to a method and system for synchronously measuring a phase field and a temperature field in a hot rod bundle channel. Background Art

[0002] The phenomenon of two-phase boiling flow is widely present in industrial systems, such as bubblers, steam generators, nuclear reactors, etc. When the system boils, the complex gas-liquid coupled flow caused by the two-phase flow will affect the pressure drop, heat transfer, and energy and mass transfer properties of the system. In particular, for common pressurized water reactors, boiling may cause damage to fuel elements and safety accidents. Therefore, it is extremely important to clarify the phase state and temperature distribution characteristics in the rod bundle channel under high temperature and high pressure two-phase flow conditions. However, the rod bundle channel has a complex structure, and the high temperature and high pressure conditions of the reactor put forward strict requirements on the performance of the measuring instrument, which makes it difficult to measure the refined distribution of the phase field and temperature field in the rod bundle channel under full temperature and full pressure conditions.

[0003] At present, irradiation technology is usually used to measure the cavitation fraction distribution under high temperature and high pressure conditions based on the different attenuation of radiation when penetrating different materials. The temperature distribution of two-phase fluids is usually measured using thermocouples. However, the equipment of irradiation technology is complex and the resolution is low. The radiation will attenuate multiple times when passing through the rod bundle, making it difficult to capture the signal and the measurement accuracy is poor. It is difficult to apply to complex rod bundle channel structures. The volume of the thermocouple itself will cause a significant intrusion effect on the flow field, making it difficult to achieve high-resolution temperature field measurement.

[0004] Therefore, there is an urgent need to design a phase field and temperature field synchronous measurement system and method in a complex rod bundle channel under high temperature and high pressure environment. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the above-mentioned prior art and to provide a method and system for synchronously measuring the phase field and temperature field in a hot rod bundle channel, which is aimed at synchronously measuring the phase distribution and temperature distribution in two-phase flow developed in a complex rod bundle channel.

[0006] A method for synchronously measuring the phase field and temperature field in a hot rod bundle channel is provided, comprising: In the flow channel, a rod bundle channel is constructed through a fuel rod simulation body, the fluid is directly heated, and a wire mesh sensor is set to synchronously measure the phase field and temperature field of the rod bundle channel. The optical fiber cladding on the wire mesh sensor is stimulated by an alternating current signal, the optical fiber cladding transmits and receives the electrical signal, and the fluid cavitation fraction distribution is measured after analyzing and processing the electrical signal; The optical fiber of the wire mesh sensor is stimulated by an alternating current signal to transmit and convert the optical signal to measure the fluid temperature distribution.

[0007] Furthermore, directly heating the fluid further comprises: The effective heating section of the simulation body and the copper electrode thereon are isolated through an insulating ring, and the copper electrode is connected to a direct current power supply. The heating power of the simulation body is controlled by adjusting the current.

[0008] Furthermore, exciting the optical fiber cladding on the wire mesh sensor by an alternating current signal, wherein the optical fiber cladding transmits and receives the electrical signal further comprises: The alternating current is input to the emitter of the wire mesh sensor, and the optical fiber cladding of the emitter is excited by the alternating current signal. The receiving electrode receives the electrical signal and transmits it to the electrical signal acquisition card to measure the fluid phase field.

[0009] Preferably, measuring the fluid cavitation fraction distribution further comprises: S11: The electrical signal acquisition card accurately receives the electrical signal, and conditions and converts the received electrical signal, including amplifying weak electrical signals and removing noise and interference in the electrical signal; S12: Perform spectrum analysis on the AC signal to determine its frequency component and amplitude distribution, detect the phase difference between the received signal and the excitation signal through a phase detection algorithm, and extract characteristic parameters of the electrical signal; S13: establishing a phase field model by considering the material properties of the optical fiber cladding, the frequency and amplitude factors of the excitation signal, continuously collecting electrical signals, and calculating the phase field value in real time according to the established phase field model and the extracted characteristic parameters of the electrical signals; S14: Consider possible sources of error to conduct error analysis on the measurement results, evaluate the accuracy of the measurement, take appropriate measures to correct it, and output the measurement results in the form of a data file.

[0010] Furthermore, exciting the optical fiber of the wire mesh sensor by the alternating current signal to transmit and convert the optical signal further comprises: The optical signal emission model emits an optical signal to the wire mesh sensor, stimulates the optical fibers in the emitter and receiver of the wire mesh sensor through the optical signal, receives and reads the optical signal through the optical fiber modem, converts the optical signals of different wavelengths into temperature values, and realizes the measurement of the fluid temperature field.

[0011] Preferably, measuring the fluid temperature distribution further comprises: S21: The temperature of different positions of the fluid is measured by arranging a number of emitters and receivers in the fluid, the optical fiber path between each emitter and receiver covers a certain area, and a grating for measurement is engraved on the optical fiber to form a temperature measurement network; S22: construct a temperature field of the fluid according to the temperature measurement values ​​at each position, and generate a three-dimensional spatial function describing the temperature distribution in the fluid.

[0012] On the other hand, the present invention provides a synchronous measurement system of phase field and temperature field in a hot rod bundle channel, comprising a flow channel, a simulation body, and a wire mesh sensor: The simulation body and the wire mesh sensor are arranged in the flow channel, the flow channel wall and the simulation body are isolated by insulating material, the wire mesh sensor is perpendicular to the simulation body, and the wire mesh sensor and the simulation body are isolated by an isolation ring.

[0013] Furthermore, the simulation body includes an effective heating section and a copper electrode section, the effective heating section and the copper electrode section are internally wrapped with a heating tube, and the effective heating section and the copper electrode section are isolated by an insulating ring, wherein: In the effective heating section, the heating tube is covered with an insulating layer and a heating shell in sequence. In the copper electrode section, the heating tube is wrapped with a copper tube; The wire mesh sensor includes a plurality of emitters and receivers, and the emitters and receivers are perpendicular to each other but do not intersect.

[0014] Furthermore, the emitter and the receiver of the wire mesh sensor are rigidly connected to the fixed end, the fixed end comprises an optical fiber and an optical fiber cladding, the optical fiber cladding is coated on the optical fiber, and the optical fiber cladding is coated with an extremely thin insulating layer; The optical fiber needs to be engraved with a grating according to the measurement resolution; The optical fiber cladding is connected to the electrical signal acquisition card, one end of the optical fiber is connected to the optical signal transmitting module, and the other end is connected to the optical fiber regulator.

[0015] Furthermore, the fixed ends of the optical fiber pass through both sides of the flow channel, the simulation body passes through the upper and lower ends of the flow channel, and is sealed with an O-ring, and each part in the flow channel is connected to the flow channel through a flange.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses a fuel rod simulation body to construct a rod bundle channel, and sets a wire mesh sensor to synchronously measure the cavitation fraction distribution and temperature distribution of the fluid in the rod bundle channel, so as to achieve synchronous measurement of the phase field and temperature field of the rod bundle channel under high temperature and high pressure conditions in a complex rod bundle channel structure; The present invention avoids error interference in two-phase measurement of the rod bundle channel by arranging a high-temperature insulating layer between the heating tube and other components. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1This is a flow chart of a method for synchronously measuring the phase field and temperature field in a hot rod bundle channel of the present invention; Figure 2 This is a schematic diagram of the overall structure of a rod bundle channel of the present invention; Figure 3 This is a schematic diagram of the front structure of a fuel rod simulation body of the present invention; Figure 4 This is a schematic diagram of a top view cross-sectional structure of an effective heating section of a fuel rod simulation body of the present invention; Figure 5 This is a schematic diagram of the arrangement of a wire mesh sensor according to the present invention.

[0018] Reference numerals 1: flow channel; 2: simulation body; 3: screen sensor; 11: Insulation material; 12: Insulation ring-1; 13: O-ring; 14: Flange; 21: effective heating section; 22: copper electrode section; 23: heating tube; 24: insulation ring-2; 211: insulation layer-1; 212: heating shell; 221: copper tube; 31: emitter; 32: receiver; 33: optical fiber; 34: optical fiber cladding; 35: fixed end; 36: electrical signal acquisition card; 37: optical signal transmitting module; 38: insulation layer-2. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0020] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0021] like Figure 1 As shown, a method for synchronously measuring the phase field and temperature field in a hot rod bundle channel provided in this embodiment includes: In the flow channel, a rod bundle channel is constructed through a fuel rod simulation body, the fluid is directly heated, and a wire mesh sensor is set to synchronously measure the phase field and temperature field of the rod bundle channel. The optical fiber cladding on the wire mesh sensor is stimulated by an alternating current signal, the optical fiber cladding transmits and receives the electrical signal, and the fluid cavitation fraction distribution is measured after analyzing and processing the electrical signal; The optical fiber of the wire mesh sensor is stimulated by an alternating current signal to transmit and convert the optical signal to measure the fluid temperature distribution.

[0022] Wherein, directly heating the fluid further comprises: The effective heating section of the simulation body and the copper electrode thereon are isolated through an insulating ring, and the copper electrode is connected to a direct current power supply. The heating power of the simulation body is controlled by adjusting the current.

[0023] In this embodiment, exciting the optical fiber cladding on the wire mesh sensor by an alternating current signal, wherein the optical fiber cladding transmits and receives the electrical signal further comprises: The alternating current is input to the emitter of the wire mesh sensor, and the optical fiber cladding of the emitter is excited by a high-frequency alternating current signal. The receiving electrode receives the electrical signal and transmits it to the electrical signal acquisition card to measure the fluid phase field.

[0024] Specifically, measuring the fluid cavitation fraction distribution after analyzing and processing the electrical signal further includes: S11: The electrical signal acquisition card accurately receives the electrical signal, and conditions and converts the received electrical signal, including amplifying weak electrical signals and removing noise and interference in the electrical signal; S12: Perform spectrum analysis on the AC signal to determine its frequency component and amplitude distribution, detect the phase difference between the received signal and the excitation signal through a phase detection algorithm, and extract characteristic parameters of the electrical signal; S13: establishing a phase field model by considering the material properties of the optical fiber cladding, the frequency and amplitude factors of the excitation signal, continuously collecting electrical signals, and calculating the phase field value in real time according to the established phase field model and the extracted characteristic parameters of the electrical signals; S14: Consider possible sources of error to conduct error analysis on the measurement results, evaluate the accuracy of the measurement, take appropriate measures to correct it, and output the measurement results in the form of a data file.

[0025] Furthermore, the optical fiber of the wire mesh sensor is stimulated by an alternating current signal to transmit and convert the optical signal, including: The optical signal emission model emits an optical signal to the wire mesh sensor, stimulates the optical fibers in the emitter and receiver of the wire mesh sensor through the optical signal, receives and reads the optical signal through the optical fiber modem, converts the optical signals of different wavelengths into temperature values, and realizes the measurement of the fluid temperature field.

[0026] Measuring the fluid temperature distribution further comprises: S21: The temperature of different positions of the fluid is measured by arranging a number of emitters and receivers in the fluid, the optical fiber path between each emitter and receiver covers a certain area, and a grating for measurement is engraved on the optical fiber to form a temperature measurement network; S22: construct a temperature field of the fluid according to the temperature measurement values ​​at each position, and generate a three-dimensional spatial function describing the temperature distribution in the fluid.

[0027] This embodiment provides a synchronous measurement system for the phase field and temperature field in a hot rod bundle channel, which is used to implement the method described in Embodiment 1. Figure 2 As shown, it includes a flow channel 1, a simulation body 2, and a screen sensor 3: The simulation body 2 and the wire mesh sensor 3 are arranged in the flow channel 1, and are respectively used to generate heat to heat the fluid and measure fluid parameters. The wall of the flow channel 1 is isolated from the simulation body 2 by insulating material. The wire mesh sensor 3 is perpendicular to the simulation body 2. The wire mesh sensor 3 and the simulation body 2 are isolated by an isolation ring-1 12.

[0028] Specifically, Figure 2 and 3 As shown, the simulation body 2 includes an effective heating section 21 and a copper electrode section 22, wherein the effective heating section 21 and the copper electrode section 22 are internally wrapped with a heating tube 23, and the effective heating section 21 and the copper electrode section 22 are isolated by an insulating ring-2 24, wherein: In the effective heating section 21, the heating tube 23 is covered with an insulating layer 211 and a heating shell 212 in sequence. In the copper electrode segment 22, the heating tube 23 is wrapped with a copper tube 221; like Figure 4 As shown, the wire mesh sensor 3 includes a plurality of emitters 31 and receivers 32, which can be triggered by electrical signals and optical signals at the same time, and have a diameter of no more than 1 mm. The emitters 31 and receivers 32 are perpendicular to each other but do not intersect.

[0029] Specifically, the emitter 31 and the receiver 32 of the wire mesh sensor 3 are rigidly connected to the fixed end 35, and the fixed end 35 includes an optical fiber 33 and an optical fiber cladding 34, and the optical fiber cladding 34 is coated on the optical fiber 33, and the optical fiber cladding 34 is coated with an extremely thin high temperature resistant insulation layer-2 38; The optical fiber 33 is engraved with a grating according to the measurement resolution, and the grating spacing is not less than 5 mm; The optical fiber cladding 34 is connected to the electrical signal acquisition card 36 , one end of the optical fiber 33 is connected to the optical signal transmitting module 37 , and the other end is connected to the optical fiber regulator.

[0030] In addition, the fixed ends 35 of the optical fibers 33 pass through both sides of the flow channel, and the simulation body 2 passes through the upper and lower ends of the flow channel, and is sealed with O-rings 13 . Each part in the flow channel is connected to the flow channel through flanges 14 .

[0031] As can be seen from the above, in this embodiment, we use nickel-based alloy tubes as fuel rod simulation bodies to form rod bundle channels, and use direct heating by a DC power supply to heat the fluid to achieve simulation of two-phase working conditions.

[0032] The fuel rod dummy body is composed of an effective heating section 21 and a copper electrode section 22, which are connected and insulated by an insulating ring 24. The effective heating section is made of a heating tube 23, an insulating layer 211, and a heating cladding 212, and the copper electrode section 22 is made of a heating tube 23 and a copper tube 221, and the copper tube 221 is connected to a DC power supply.

[0033] The emitter 31 and the receiver 32 of the wire mesh sensor 3 are perpendicular to each other but do not intersect. From the inside to the outside, they are optical fiber 33, stainless steel cladding 34 and insulating coating 38, and both ends are rigidly connected to the fixed end 35. The emitter stainless steel cladding 34 is excited by an alternating current signal, and the receiver 32 receives the signal and transmits it to the acquisition card 36.

[0034] Optical signals are used to excite the optical fiber 33 in the emitter 31 and the receiver 32, and the optical signals are read in the regulator to convert the optical signals of different wavelengths into temperature values.

[0035] The fuel rod dummy 2 and the wire mesh sensor 3 are arranged in the stainless steel flow channel 1 and isolated by ceramic (insulating material 11). The fixed end 35 and the fuel rod dummy 2 pass through the ceramic (insulating material 11) and the stainless steel flow channel 1 and are sealed by an O-ring 13.

[0036] During the experiment, the heating power of the heating rod was controlled by adjusting the current to achieve different two-phase parameter conditions. After the operating parameters were kept stable for three minutes, the wire mesh sensor 3 was used to synchronously measure the distribution of the fluid temperature and the cavitation fraction.

[0037] Obviously, those skilled in the art can make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

[0038] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for synchronously measuring the phase field and temperature field in a hot rod bundle channel, characterized in that: include: In the flow channel, a rod bundle channel is constructed through a fuel rod simulation body, the fluid is directly heated, and a wire mesh sensor is set to synchronously measure the phase field and temperature field of the rod bundle channel. The optical fiber cladding on the wire mesh sensor is stimulated by an alternating current signal, the optical fiber cladding transmits and receives the electrical signal, and the fluid cavitation fraction distribution is measured after analyzing and processing the electrical signal; The optical fiber of the wire mesh sensor is stimulated by an alternating current signal to transmit and convert the optical signal to measure the fluid temperature distribution.

2. The method for synchronously measuring the phase field and temperature field in a hot rod bundle channel according to claim 1, characterized in that: Directly heating the fluid further comprises: The effective heating section of the simulation body and the copper electrode thereon are isolated through an insulating ring, and the copper electrode is connected to a direct current power supply. The heating power of the simulation body is controlled by adjusting the current.

3. The method for synchronously measuring the phase field and temperature field in a hot rod bundle channel according to claim 1, characterized in that: By exciting the optical fiber cladding on the wire mesh sensor by an alternating current signal, the optical fiber cladding transmitting and receiving the electrical signal further comprises: The alternating current is input to the emitter of the wire mesh sensor, and the optical fiber cladding of the emitter is excited by the alternating current signal. The receiving electrode receives the electrical signal and transmits it to the electrical signal acquisition card to measure the fluid phase field.

4. The method for synchronously measuring the phase field and temperature field in the hot rod bundle channel according to claim 3, characterized in that: Measuring the fluid cavitation fraction distribution after analyzing and processing the electrical signal further includes: S11: The electrical signal acquisition card accurately receives the electrical signal, and conditions and converts the received electrical signal, including amplifying weak electrical signals and removing noise and interference in the electrical signal; S12: Perform spectrum analysis on the AC signal to determine its frequency component and amplitude distribution, detect the phase difference between the received signal and the excitation signal through a phase detection algorithm, and extract characteristic parameters of the electrical signal; S13: establishing a phase field model by considering the material properties of the optical fiber cladding, the frequency and amplitude factors of the excitation signal, continuously collecting electrical signals, and calculating the phase field value in real time according to the established phase field model and the extracted characteristic parameters of the electrical signals; S14: Consider possible sources of error to conduct error analysis on the measurement results, evaluate the accuracy of the measurement, take appropriate measures to correct it, and output the measurement results in the form of a data file.

5. The method for synchronously measuring the phase field and temperature field in a hot rod bundle channel according to claim 1, characterized in that: Exciting the optical fiber of the wire mesh sensor by an alternating current signal, transmitting and converting the optical signal further comprises: The optical signal emission model emits an optical signal to the wire mesh sensor, stimulates the optical fibers in the emitter and receiver of the wire mesh sensor through the optical signal, receives and reads the optical signal through the optical fiber modem, converts the optical signals of different wavelengths into temperature values, and realizes the measurement of the fluid temperature field.

6. The method for synchronously measuring the phase field and temperature field in a hot rod bundle channel according to claim 6, characterized in that: Measuring the fluid temperature distribution further comprises: S21: The temperature of different positions of the fluid is measured by arranging a number of emitters and receivers in the fluid, the optical fiber path between each emitter and receiver covers a certain area, and a grating for measurement is engraved on the optical fiber to form a temperature measurement network; S22: construct a temperature field of the fluid according to the temperature measurement values ​​at each position, and generate a three-dimensional spatial function describing the temperature distribution in the fluid.

7. A synchronous measurement system for phase field and temperature field in a hot rod bundle channel, used to implement the method described in any one of claims 1 to 6, characterized in that: Including flow channel, simulation body, screen sensor: The simulation body and the wire mesh sensor are arranged in the flow channel, the flow channel wall and the simulation body are isolated by insulating material, the wire mesh sensor is perpendicular to the simulation body, and the wire mesh sensor and the simulation body are isolated by an isolation ring.

8. The phase field and temperature field synchronous measurement system in the hot rod bundle channel according to claim 7, characterized in that: The simulation body includes an effective heating section and a copper electrode section, wherein the effective heating section and the copper electrode section are internally wrapped with a heating tube, and the effective heating section and the copper electrode section are isolated by an insulating ring, wherein: In the effective heating section, the heating tube is covered with an insulating layer and a heating shell in sequence. In the copper electrode section, the heating tube is wrapped with a copper tube; The wire mesh sensor includes a plurality of emitters and receivers, and the emitters and receivers are perpendicular to each other but do not intersect.

9. The phase field and temperature field synchronous measurement system in the hot rod bundle channel according to claim 8, characterized in that: The emitter and the receiver of the wire mesh sensor are rigidly connected to the fixed end, and the fixed end includes an optical fiber and an optical fiber cladding, the optical fiber cladding is coated on the optical fiber, and the optical fiber cladding is coated with an extremely thin insulating layer; The optical fiber needs to be engraved with a grating according to the measurement resolution; The optical fiber cladding is connected to the electrical signal acquisition card, one end of the optical fiber is connected to the optical signal transmitting module, and the other end is connected to the optical fiber regulator.

10. The phase field and temperature field synchronous measurement system in the hot rod bundle channel according to claim 9, characterized in that: The fixed ends of the optical fiber pass through both sides of the flow channel, and the simulation body passes through the upper and lower ends of the flow channel. An O-ring is used for sealing, and each part in the flow channel is connected to the flow channel through a flange.

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