CN113921153A - System and method for measuring flow field in rod bundle channel under unsteady state flow condition - Google Patents
System and method for measuring flow field in rod bundle channel under unsteady state flow condition Download PDFInfo
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- CN113921153A CN113921153A CN202111343050.6A CN202111343050A CN113921153A CN 113921153 A CN113921153 A CN 113921153A CN 202111343050 A CN202111343050 A CN 202111343050A CN 113921153 A CN113921153 A CN 113921153A
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C17/00—Monitoring; Testing ; Maintaining
- G21C17/017—Inspection or maintenance of pipe-lines or tubes in nuclear installations
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/18—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the time taken to traverse a fixed distance
- G01P5/20—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the time taken to traverse a fixed distance using particles entrained by a fluid stream
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C17/00—Monitoring; Testing ; Maintaining
- G21C17/02—Devices or arrangements for monitoring coolant or moderator
- G21C17/022—Devices or arrangements for monitoring coolant or moderator for monitoring liquid coolants or moderators
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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Abstract
The invention discloses a system and a method for measuring a flow field in a rod beam channel under an unsteady state flow condition, wherein the system comprises a control system, a circuit converter, a function generator, a diode pumped continuous laser and a CCD high-speed camera, the output end of the control system is connected with the control end of the CCD high-speed camera through the circuit converter and the function generator, the diode pumped continuous laser and the CCD high-speed camera are right opposite to a channel to be measured, laser emitted by the diode pumped continuous laser enters the CCD high-speed camera after passing through the channel to be measured, the channel to be measured is of a transparent structure, and liquid in the channel to be measured contains tracer particles.
Description
Technical Field
The invention belongs to the field of fluid mechanics, and relates to a system and a method for measuring a flow field in a rod bundle channel under an unsteady state flow condition.
Background
Unsteady flow can be summarized as the corresponding problem of viscous fluid under the condition of external disturbance, such as the change of the structure relative to the attitude of the incoming flow with time, the periodic change of a driving pressure head with time, and the like. This type of unsteady flow is characterized by unsteady flow caused by changes in external boundary conditions. When a land-based reactor is under accident conditions or a sea-based pressurized water reactor is influenced by the marine environment, the flow of the coolant in the reactor core is in an unsteady flow state, and the damage threshold of a fuel assembly is determined by the capacity of the coolant for taking away the heat of the fuel, so that the safe operation of the reactor is directly influenced. When the coolant is insufficient to remove the heat inside the core, the core may be melted excessively, resulting in a serious core damage accident. Therefore, the research on the hydraulic characteristics of the thermal power in the reactor core under the condition of flow fluctuation has important significance for ensuring the safe operation of the reactor.
The basic principle of the PIV technology is as follows: the PIV measurement technology adopts the principle that tracer particles with the density similar to that of water are dispersed in a flow field, the whole measurement area is illuminated by using sheet laser, the relative movement distance of the particles at continuous moments is recorded by a camera, and the velocity field distribution of different areas of two frames of images can be calculated based on displacement and interval time through an autocorrelation and cross-correlation algorithm.
The pulsating flow can be regarded as the superposition of unsteady reciprocating flow and steady flow, and compared with the steady flow, the pulsating flow is influenced by the pulsation frequency, the amplitude and the time-average Reynolds number, so that the research difficulty of the pulsating flow is increased. A flow field obtained by using the traditional PIV measurement not only contains ordered fluctuation caused by pulsating flow and irregular fluctuation caused by turbulent flow, but also cannot be separated by processing during passing, and great difficulty is caused to the research of the internal flow field of the fuel assembly under the unsteady state condition. Therefore, an experimental device needs to be designed to perform repeated measurement at the fixed phase position of the pulsating flow for many times to strip the influence of ordered fluctuation of the pulsating flow. Therefore, irregular fluctuation measurement of the turbulence of the fuel assembly under the condition of pulsating flow is realized, and experimental data are provided for verification of CFD calculation analysis. And the understanding of the hydraulic characteristics of the heat engineering in the fuel assembly under the unsteady state condition is improved, and the safety and the economical efficiency of the reactor are improved.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a system and a method for measuring the flow field in a rod bundle channel under the unsteady flow condition, and the system and the method can accurately measure the flow field in the channel.
In order to achieve the above purpose, the system for measuring the flow field in the rod bundle channel under the unsteady state flow condition comprises a control system, a circuit converter, a function generator, a diode pumped continuous laser and a CCD high-speed camera, wherein the output end of the control system is connected with the control end of the CCD high-speed camera through the circuit converter and the function generator, the diode pumped continuous laser and the CCD high-speed camera are right opposite to the channel to be measured, laser emitted by the diode pumped continuous laser enters the CCD high-speed camera after passing through the channel to be measured, the channel to be measured is of a transparent structure, and liquid in the channel to be measured contains tracer particles.
The device also comprises a centrifugal pump and a frequency converter, wherein the control system is connected with the centrifugal pump through the frequency converter, and the centrifugal pump is communicated with the pipeline to be measured.
The output end of the control system is connected with the frequency converter and the circuit converter through the digital-to-analog converter.
The method for measuring the flow field in the rod bundle channel under the unsteady state flow condition comprises the following steps:
sinusoidal signals output by the control system are converted into square wave signals through the circuit converter, then are converted into TTL signals with adjustable phases through the function generator, and then are input into the CCD high-speed camera to trigger the CCD high-speed camera to shoot an original flow field diagram under the current phase.
Further comprising:
before measurement, a sinusoidal signal output by a control system is converted into a square wave signal through a circuit converter, then the square wave signal is converted into a TTL signal with adjustable phase through a function generator and then is input into a CCD high-speed camera, and an original flow velocity field diagram under the current phase is obtained through the CCD high-speed camera; and simultaneously, sending a sinusoidal signal output by the control system into a frequency converter, and controlling the centrifugal pump to work by the frequency converter according to the sinusoidal signal so as to determine the corresponding relation between the original flow field diagram and the flow velocity field at different phases.
Further comprising:
in a measuring period, the CCD high-speed camera is arranged every noThe phase shooting acquires an original flow field diagram once, and the velocity fields under 360/n different phases are obtained according to the original flow field diagram, so that the average velocity under any phase is obtained by averaging the velocity fields under the phase in a plurality of periods.
The invention has the following beneficial effects:
when the system and the method for measuring the flow field in the rod bundle channel under the unsteady state flow condition are operated specifically, the phase of the TTL signal can be adjusted, so that the measurement of the flow field under any phase of pulsating flow can be realized; in addition, the invention utilizes the diode pumping continuous laser to emit continuous laser to irradiate the pipeline to be measured so as to ensure that the flow field is always illuminated, and reduce the error caused by controlling laser triggering by the synchronizer; in addition, the flow field measurement is carried out based on the tracer particles, and the calculation according to the relaxation time of the particles in the fluid shows that the phase lag of the particles in the pulsating flow can be almost ignored, so that the distribution characteristics of the pulsating flow field can be well reflected, and the flow field measurement device is simple in structure, low in price, accurate and convenient in data acquisition and accurate in control.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a flow chart of pulse stream generation in the present invention;
fig. 3 is a schematic diagram of different phase divisions of a pulse stream.
Wherein, 1 is a control system 1, 2 is a frequency converter 2, 3 is a centrifugal pump 3, 4 is a circuit converter 4, 5 is a CCD high-speed camera 5, 6 is a function generator 6.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
There is shown in the drawings a schematic block diagram of a disclosed embodiment in accordance with the invention. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, according to actual needs.
Referring to fig. 1, the system for measuring the flow field in a rod beam channel under an unsteady state flow condition includes a control system 1, a circuit converter 4, a function generator 6, a diode pumped continuous laser and a CCD high-speed camera 5, wherein an output end of the control system 1 is connected with a control end of the CCD high-speed camera 5 through the circuit converter 4 and the function generator 6, the diode pumped continuous laser and the CCD high-speed camera 5 face a channel to be measured, and laser emitted from the diode pumped continuous laser enters the CCD high-speed camera 5 after passing through the channel to be measured, wherein the channel to be measured is of a transparent structure, and liquid in the channel to be measured contains trace particles.
The invention also comprises a centrifugal pump 3 and a frequency converter 2, wherein the control system 1 is connected with the centrifugal pump 3 through the frequency converter 2, the centrifugal pump 3 is communicated with a pipeline to be measured, and the output end of the control system 1 is connected with the frequency converter 2 and a circuit converter 4 through a digital-to-analog converter.
Referring to fig. 2 and 3, the method for measuring the flow field in the rod bundle channel under the unsteady flow condition according to the present invention includes the following steps:
through a D/A port of a printed circuit, a digital signal generated by the control system 1 is converted into an analog signal with the voltage of 0-10V through a digital-to-analog converter, and then the analog signal is sent into the frequency converter 2, the flow of the centrifugal pump is adjusted by adjusting the rotating speed of the centrifugal pump 9, the output flow of the centrifugal pump is influenced by the driving force and the loop resistance, and the driving force and the pump speed are in a nonlinear relation, so that the frequency of the frequency converter and the loop flow rate are required to be in one-to-one correspondence in the test process, and the pulsating flow experimental condition with required parameters is obtained.
A sinusoidal signal output by the control system 1 is converted into a square wave signal through a circuit converter 4, then is converted into a TTL signal with adjustable phase through a function generator 6, and then is input into a CCD high-speed camera 5, and an original flow velocity field diagram under the current phase is obtained through the CCD high-speed camera 5; and simultaneously, a sinusoidal signal output by the control system 1 is sent to the frequency converter 2, the frequency converter 2 controls the centrifugal pump 3 to work according to the sinusoidal signal, and the corresponding relation between the original flow field diagram and the flow velocity field at different phases is determined according to the sinusoidal signal.
During measurement, a sinusoidal signal output by the control system 1 is converted into a square wave signal through the circuit converter 4, then is converted into a TTL signal with adjustable phase through the function generator 6, and then is input into the CCD high-speed camera 5 to trigger the CCD high-speed camera 5 to shoot an original flow field diagram under the current phase.
In addition, the CCD high-speed camera 5 is arranged every n within one measurement periodoThe phase shooting acquires an original flow field diagram once, and the velocity fields under 360/n different phases are obtained according to the original flow field diagram, so that the average velocity under any phase is obtained by averaging the velocity fields under the phase in a plurality of periods.
Within a period, every noThe phase position obtains a velocity field, obtains 360/n velocity fields with different phases phi1And phi360/2n+1Respectively the phase position phi of the maximum positive acceleration and the maximum negative acceleration measured by the test360/4n+1And phi3×360/4n+1The phases with the maximum speed and the minimum speed respectively, the average speed in any phase is obtained by averaging the speed fields in the phase in a plurality of periods.
For statistical averages of pulsating flows with externally applied periodic excitation, the instantaneous velocity components in each direction are decomposed into long-term average velocities
Periodic sequential oscillation f' (x)iT) and turbulence-induced velocity pulsations f "(x)iT) is
By the formula of phase averaging
The instantaneous velocity field of the mth phase of the n cycles is averaged,obtaining the average speed field of the mth phase, wherein the average speed field can also be periodic ordered oscillation f' (x)iT) and long-term average velocity<F(xi,φ)>And thus pass through
Calculating turbulent pulsating velocity component f' (x) of each phaseiPhi), where phi is the phase and n is the number of repetition periods.
The phase-locked PIV technique used in pulsating flow ideally uses enough periods of velocity field to perform phase averaging, so as to obtain statistically significant turbulence results, and a frame velocity field of a certain phase of pulsating flow needs to go through a complete period, and the time T is n × T, where n is the number of samples and T is the period of pulsating flow.
Finally, the invention realizes the fine measurement of the flow field and the turbulent flow field in the fuel assembly under the condition of pulsating flow, and solves the problem of the separation of ordered fluctuation and turbulent flow irregular pulsation caused by unsteady state in the traditional PIV measurement method, thereby developing the research on the thermodynamic and hydraulic characteristics in the unsteady state fuel assembly; the invention has simple structure, low price, accurate and convenient data acquisition and accurate control, and can be popularized and applied to other unsteady flow field measurement.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
Claims (6)
1. The system is characterized by comprising a control system (1), a circuit converter (4), a function generator (6), a diode pumped continuous laser and a CCD high-speed camera (5), wherein the output end of the control system (1) is connected with the control end of the CCD high-speed camera (5) through the circuit converter (4) and the function generator (6), the diode pumped continuous laser and the CCD high-speed camera (5) are right opposite to a channel to be measured, laser emitted by the diode pumped continuous laser enters the CCD high-speed camera (5) after passing through the channel to be measured, the channel to be measured is of a transparent structure, and tracing particles are contained in liquid in the channel to be measured.
2. The system for measuring the flow field in the rod bundle channel under the unsteady state flow condition according to the claim 1, further comprising a centrifugal pump (3) and a frequency converter (2), wherein the control system (1) is connected with the centrifugal pump (3) through the frequency converter (2), and the centrifugal pump (3) is communicated with a pipeline to be measured.
3. The system for measuring the flow field in a rod bundle channel under unsteady state flow conditions according to claim 1, characterized in that the output of the control system (1) is connected with the frequency converter (2) and the circuit converter (4) via a digital-to-analog converter.
4. A method for measuring a flow field in a bundle channel under an unsteady flow condition, based on the system for measuring a flow field in a bundle channel under an unsteady flow condition of claim 2, comprising the steps of:
sinusoidal signals output by the control system (1) are converted into square wave signals through the circuit converter (4), then are converted into TTL signals with adjustable phases through the function generator (6), and then are input into the CCD high-speed camera (5) to trigger the CCD high-speed camera (5) to shoot an original flow field diagram under the current phase.
5. The method of measuring a flow field in a bundle channel under unsteady flow conditions according to claim 4, further comprising:
before measurement, a sinusoidal signal output by the control system (1) is converted into a square wave signal through the circuit converter (4), then is converted into a TTL signal with adjustable phase through the function generator (6) and then is input into the CCD high-speed camera (5), and an original flow velocity field diagram under the current phase is obtained through the CCD high-speed camera (5); and simultaneously, sinusoidal signals output by the control system (1) are sent to the frequency converter (2), and the frequency converter (2) controls the centrifugal pump (3) to work according to the sinusoidal signals, so that the corresponding relation between the original flow field diagram and the flow velocity field at different phases is determined.
6. The method of measuring a flow field in a bundle channel under unsteady flow conditions according to claim 5, further comprising:
in a measuring period, a CCD high-speed camera (5) shoots every n degrees of phases to obtain an original flow field diagram, and therefore speed fields under 360/n different phases are obtained, and the average speed under any phase is obtained by averaging the speed fields under the phase in a plurality of periods.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111343050.6A CN113921153A (en) | 2021-11-12 | 2021-11-12 | System and method for measuring flow field in rod bundle channel under unsteady state flow condition |
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| CN202111343050.6A CN113921153A (en) | 2021-11-12 | 2021-11-12 | System and method for measuring flow field in rod bundle channel under unsteady state flow condition |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115659875A (en) * | 2022-12-26 | 2023-01-31 | 成都航空职业技术学院 | Rod bundle fuel assembly testing device and testing parameter obtaining method thereof |
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- 2021-11-12 CN CN202111343050.6A patent/CN113921153A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115659875A (en) * | 2022-12-26 | 2023-01-31 | 成都航空职业技术学院 | Rod bundle fuel assembly testing device and testing parameter obtaining method thereof |
| CN115659875B (en) * | 2022-12-26 | 2023-10-17 | 成都航空职业技术学院 | Rod bundle fuel assembly test device and test parameter acquisition method thereof |
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