Sensitivity testing apparatus and method for fiber-optic distributed temperature sensing in drainage pipeline

Abstract

A sensitivity testing apparatus and method for fiber-optic distributed temperature sensing in a drainage pipeline. A temperature-adjustable pipeline water supply tank (1) is provided with heating rods (11) and a water temperature sensor (12), which are electrically connected to a flow and water temperature control PLC system (4); the temperature-adjustable pipeline water supply tank (1) is connected to a water input end of a water pump (2), a water output end of the water pump (2) is in communication with a water input end of an experimental pipeline (3), and a water output end of the experimental pipeline (3) is in communication with the temperature-adjustable pipeline water supply tank (1); an inflow and infiltration water storage tank (61) of an external inflow and infiltration simulation system (6) injects a liquid into the experimental pipeline (3) by means of a water tank connection pipe (62) and a shunt pipe (63), so as to simulate an inflow and infiltration scenario in an operating state of the drainage pipeline; experimental pipeline water temperature sensors (31) perform spot-like temperature collection on the experimental pipeline (3); and a fiber-optic temperature sensing apparatus (5) performs linear temperature collection along the interior of the experimental pipeline (3), so as to detect and calibrate fiber-optic temperature sensing data, identify noise of a fiber-optic device in the drainage pipeline, and determine the detection sensitivity of the fiber-optic device.

Description

A sensitivity testing device and method for optical fiber distributed temperature measurement in drainage pipes Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and more particularly to a simulation device and a simulation method for optical fiber distributed temperature measurement in a drainage pipe. Technical Background

[0002] Drainage pipes are crucial urban infrastructure, playing a vital role in improving urban water quality. my country currently has over 870,000 km of urban drainage pipes, of which nearly 47.5% are over 10 years old. Due to lagging pipeline network construction, uneven ground subsidence, poor pipe material and joint construction, and internal pipe corrosion, damage, mixing, and misconnections in stormwater and sewage pipes are serious problems. Large amounts of external water, such as groundwater and rainwater, enter sewage pipes, resulting in low biodegradability of influent water for sewage treatment plants, high treatment costs, and inefficient utilization of sewage treatment capacity. Furthermore, some sewage mixes with stormwater pipes and ultimately discharges directly into rivers, leading to low sewage collection rates. Currently, the national average actual sewage collection rate is only around 66%, significantly lower than the nearly 90% rate in developed countries. Therefore, to improve the quality and efficiency of urban sewage treatment in my country, there is an urgent need to detect and locate problematic areas of damage, mixing, and misconnections in the drainage network, and to implement targeted pipeline repair and renovation measures.

[0003] As a real-time monitoring technology, fiber-optic distributed temperature measurement senses the temperature of the surrounding medium by laying optical cables longitudinally, determines temperature anomalies, and issues real-time warnings. In drainage pipe inspection, as a distributed real-time "stethoscope" technology for water temperature signals inside the pipe, it can accurately locate inflow and infiltration problems caused by damage, mixed connections, etc. by identifying abnormal water temperatures in the pipe. Compared with traditional closed-circuit television detection technology, fiber-optic distributed temperature measurement does not require plugging or precipitation operations, does not interfere with the operation of drainage pipes, and can be implemented under high water level conditions in the pipes. In addition, it has the advantage of all-weather high-frequency observation in time and space, which can further improve the reliability of pipeline problem point identification, especially the accurate identification of dynamic inflow and infiltration points of external water.

[0004] Because noise data caused by equipment operation is common in fiber-optic distributed temperature measurement, the quality of temperature data directly impacts the reliability of data analysis and result determination. This is especially true when the temperature difference between inflowing, infiltrating, and mixed sewage and the pipe water is small, inadequate noise level identification can lead to misdiagnosis. Therefore, it is essential to rationally determine the noise background value of fiber-optic temperature measurement data and the sensitivity of the fiber-optic temperature measurement system for detecting problematic points in drainage pipes.

[0005] Therefore, how to provide a sensitivity testing device and method and a simulation method for optical fiber distributed temperature measurement in drainage pipes to realize the noise identification of optical fiber equipment in drainage pipes and the determination of the detection sensitivity of optical fiber equipment is one of the technical problems that need to be solved urgently in this field.

[0006] Summary of the Invention

[0007] In view of this, the present invention provides a sensitivity testing device for optical fiber distributed temperature measurement in a drainage pipe, which is provided to address the above needs.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] A sensitivity test device for optical fiber distributed temperature measurement in a drainage pipe, the device comprising: a temperature-adjustable pipe water supply tank, a water pump, an experimental pipe, an external inflow and infiltration simulation system, a flow and water temperature control PLC system, and an optical fiber temperature measuring device; the temperature-adjustable pipe water supply tank is connected to the water inlet end of the water pump through a first connecting pipe, the water outlet end of the water pump is connected to the water inlet end of the experimental pipe through a second connecting pipe, and the water outlet end of the experimental pipe is connected to the temperature-adjustable pipe water supply tank through a third connecting pipe; the water outlet end of the temperature-adjustable inflow and infiltration storage tank in the external inflow and infiltration simulation system is connected to the water inlet end of its connecting pipe, and the water outlet end of its connecting pipe is connected to the top wall of the experimental pipe through its diverter pipe; a water temperature sensor is provided in the experimental pipe, The water temperature sensor of the experimental pipeline is electrically connected to the flow and water temperature control PLC system; the optical fiber temperature measuring device includes: an optical fiber temperature measuring host and an optical fiber, the optical fiber temperature measuring host includes: a pulsed laser source, a data acquisition card and a photoelectric converter, the first end of the optical fiber is connected to the pulsed laser source, and the second end of the optical fiber extends into the experimental pipeline, the pulsed laser source emits a detection laser to the optical fiber, the detection laser is transported along the optical fiber into the experimental pipeline, and scattered in the experimental pipeline, the scattered detection laser is returned to the optical fiber temperature measuring device through the optical fiber, the data acquisition card collects the returned scattered laser, and transmits the collected information to the photoelectric converter for data processing to obtain the temperature information in the experimental pipeline.

[0010] Preferably, the second end of the optical fiber passes through the side wall of the experimental channel.

[0011] Preferably, the water pump is provided with a speed converter, and the speed converter is electrically connected to the flow and water temperature control PLC system.

[0012] Preferably, an exhaust hole is provided on the top side of the experimental pipeline, and the exhaust hole is detachably connected to an air plug.

[0013] Preferably, an inlet and infiltration hole is provided on the top side of the experimental pipe, and the inlet and infiltration hole is detachably connected to a water plug.

[0014] Preferably, the first connecting pipe is provided with a first one-way electromagnetic control valve and a first electromagnetic flowmeter; the second connecting pipe is provided with a second one-way electromagnetic control valve and a second electromagnetic flowmeter; the third connecting pipe is provided with a third one-way electromagnetic control valve and a third electromagnetic flowmeter; the flow and water temperature control PLC system is electrically connected to the first one-way electromagnetic control valve, the first electromagnetic flowmeter, the second one-way electromagnetic control valve, the second electromagnetic flowmeter, the third one-way electromagnetic control valve and the third electromagnetic flowmeter, respectively.

[0015] Preferably, the temperature-adjustable pipe water supply tank is provided with a first heating rod and a water supply tank water temperature sensor, and the first heating rod and the water supply tank water temperature sensor are electrically connected to the flow and water temperature control PLC system respectively.

[0016] Preferably, it also includes: an external inflow and infiltration simulation system, which includes: an inflow and infiltration water storage tank with adjustable temperature, a water tank connecting pipe and a diversion pipe; the water outlet end of the inflow and infiltration water storage tank with adjustable temperature is connected to the water inlet end of the connecting pipe; the water outlet end of the connecting pipe is connected to the side wall of the experimental pipeline through the diversion pipe.

[0017] Preferably, the temperature-adjustable inflow seepage water storage tank is provided with a second heating rod and a seepage water storage tank water temperature sensor, and the second heating rod and the seepage water storage tank water temperature sensor are electrically connected to the flow and water temperature control PLC system respectively;

[0018] The connecting pipe is provided with an electric regulating valve and an electromagnetic flowmeter, and the electric regulating valve and the electromagnetic flowmeter are electrically connected to the flow and water temperature control PLC system respectively.

[0019] A simulation method for optical fiber distributed temperature measurement in a drainage pipe comprises the following steps:

[0020] S1, open the first one-way electromagnetic control valve, the second one-way electromagnetic control valve, and the third one-way electromagnetic control valve in sequence to start the water pump;

[0021] S2. Open the electric regulating valve on the connecting pipe to allow the temperature-adjustable liquid in the inflow and infiltration water storage tank to flow into the experimental pipe;

[0022] S3. The liquid in the thermostatic water supply tank flows into the experimental pipe. The experimental pipe water temperature sensor detects the temperature of the liquid and transmits the temperature information to the flow and water temperature control PLC system.

[0023] S4. The pulsed laser source emits a detection laser to the optical fiber, which is scattered in the experimental pipe. The scattered detection laser is transmitted back to the optical fiber temperature measurement device through the optical fiber. The data acquisition card collects the scattered laser light and transmits the collected information to the photoelectric converter for data processing to obtain the temperature information in the experimental pipe.

[0024] S5. Compare the temperature values ​​displayed by the flow and water temperature control PLC system with the water temperature data displayed by the fiber optic temperature measuring device to determine and analyze the noise and detection sensitivity of the fiber optic equipment operation.

[0025] Preferably, in step S1, the heating of the first heating rod is regulated, the heating of the second heating rod is regulated, the temperature of the pipeline liquid and the external inflow and infiltration liquid is controlled, and various pipeline water and inflow and infiltration water ratios and water temperature scenarios are simulated.

[0026] The present invention has achieved the following technical effects:

[0027] 1. An experimental pipeline water temperature sensor is provided in the experimental pipeline, and the experimental pipeline water temperature sensor is electrically connected to the flow and water temperature control PLC system to collect temperature at a specific point; a detection laser is transported into the experimental pipeline along the optical fiber and scattered in the experimental pipeline. The scattered detection laser is returned to the optical fiber temperature measuring device through the optical fiber. The data acquisition card collects the returned scattered laser and transmits the collected information to the photoelectric converter for data processing to obtain temperature information in the experimental pipeline. The temperature is collected, and double detection and calibration of the water temperature sensor and the optical fiber temperature measurement are achieved. Finally, the noise of the optical fiber equipment in the drainage pipeline is identified and the detection sensitivity of the optical fiber equipment is determined.

[0028] 2. The entire optical fiber can be further fixed by passing the second end of the optical fiber through the side wall of the experimental pipe;

[0029] 3. Control the operating frequency of the water pump through the speed converter, thereby controlling the water delivery speed;

[0030] 4. Exhaust the gas in the experimental pipeline through the exhaust hole to facilitate the experiment in a full pipe state;

[0031] 5. By heating the liquid through the first heating rod and the second heating rod, the drainage pipe damage scenario in each season can be simulated.

[0032] In summary, the overall structure of the present invention is compact and reasonably configured. The experimental pipeline, water supply tank system and external inflow and infiltration components simulate the scenario of inflow and infiltration in the operation state of the drainage pipeline. The experimental pipeline water temperature sensor is electrically connected to the PLC system to collect the water temperature of the pipeline at a specific location. The distributed optical fiber temperature measurement system performs linear temperature collection along the experimental pipeline to realize the detection and correction of the optical fiber temperature measurement data by the water temperature sensor, and finally identify the noise of the optical fiber equipment in the drainage pipeline and determine the detection sensitivity of the optical fiber equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a schematic diagram of the overall structure of the present invention;

[0034] FIG2 is a schematic structural diagram of an external inflow and infiltration simulation system according to the present invention;

[0035] FIG3 is a schematic diagram of the structure of a flow rate and water temperature control PLC system of the present invention;

[0036] FIG4 is a schematic diagram of the experimental pipeline structure of the present invention;

[0037] In the figure: 1 - Adjustable temperature pipe water supply tank; 11 - First heating rod; 12 - Water supply tank water temperature sensor; 2 - Water pump; 3 - Experimental pipeline; 31 - Experimental pipeline water temperature sensor; 32 - Vent; 33 - Inflow and infiltration holes; 4 - Flow and water temperature control PLC system; 41 - PLC programming module; 42 - Frequency conversion controller; 43 - Touch screen; 5 - Fiber optic temperature measurement device; 51 - Fiber optic temperature measurement host; 52 - Fiber optic; 6 - External inflow and infiltration simulation system; 61 - Adjustable temperature inflow and infiltration water tank; 611 - Second heating rod; 612 - Infiltration water tank water temperature sensor; 62 - Water tank connecting pipe; 63 - Diverter pipe; 7 - Support frame; DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] Example

[0040] Referring to Figures 1-4, a sensitivity testing device and method for optical fiber distributed temperature measurement in a drainage pipe is shown. The device includes: a temperature-adjustable pipe water supply tank 1, a water pump 2, an experimental pipe 3, a flow and water temperature control PLC system 4, an optical fiber temperature measuring device 5, and an external inflow and infiltration simulation system 6. The bottom end of the temperature-adjustable pipe water supply tank 1 is connected to the water inlet end of the water pump 2 through a first connecting pipe, the water outlet end of the water pump 2 is connected to the water inlet end of the experimental pipe 3 through a second connecting pipe, and the water outlet end of the experimental pipe 3 is connected to the top end of the temperature-adjustable pipe water supply tank 1 through a third connecting pipe, forming a closed loop for liquid circulation experiment.

[0041] A plurality of experimental pipeline water temperature sensors 31 are provided in the experimental pipeline 3, and the plurality of experimental pipeline water temperature sensors 31 are arranged along the extension direction of the experimental pipeline 3. Each experimental pipeline water temperature sensor 31 is electrically connected to the flow and water temperature control PLC system 4 respectively. The plurality of experimental pipeline water temperature sensors 31 independently detect the information of the liquid in each part, transmit it to the flow and water temperature control PLC system 4, and display the information.

[0042] The fiber optic temperature measurement device 5 includes a fiber optic temperature measurement host 51 and an optical fiber 52. The fiber optic temperature measurement host 51 includes a pulsed laser source, a data acquisition card, and a photoelectric converter. The first end of the optical fiber 52 is connected to the pulsed laser source, and the second end of the optical fiber 52 extends into the experimental pipe 3. The pulsed laser source emits a detection laser to the optical fiber 52. The detection laser is transmitted along the optical fiber 52 into the experimental pipe 3 and scattered within the experimental pipe 3. The scattered detection laser is then transmitted back to the fiber optic temperature measurement device 5 through the optical fiber 52. The data acquisition card collects the scattered laser light and transmits the collected information to the photoelectric converter for data processing to obtain temperature information within the experimental pipe 3. The second end of the optical fiber 52 extends from the side wall of the experimental pipe 3 and is away from the first end of the optical fiber 52, which facilitates the extension of the main body of the optical fiber 52 within the experimental pipe 3.

[0043] In this embodiment, the outer wall of the experimental pipe 3 is provided with scales to facilitate identification of changes in temperature information at different locations at different times.

[0044] The top side of the experimental pipe 3 is provided with an exhaust hole 32, and the exhaust hole can be detachably connected to a gas plug. The amount of gas in the experimental pipe 3 is controlled by the exhaust hole 32, and experiments in a partially full pipe and a full pipe state can be realized.

[0045] The top wall of the experimental pipe 3 is provided with an inlet and outlet hole 33 , and the inlet and outlet hole 33 is detachably connected to a water plug.

[0046] The flow and water temperature control PLC system 4 is provided with a PLC programming module 41, a frequency converter 42 and a touch screen 43. The touch screen 43 is electrically connected to the PLC programming module 41 for human-computer interaction and command input. The PLC programming module 41 is electrically connected to the frequency converter 42, and the PLC programming module 41 inputs frequency conversion instructions to the frequency converter 42.

[0047] The water pump 2 is electrically connected to the frequency converter 42 , and the frequency converter 42 controls the speed of the motor in the water pump 2 , thereby controlling the operation of the water pump 2 .

[0048] The first connecting pipe is provided with a first one-way electromagnetic control valve and a first electromagnetic flowmeter, the second connecting pipe is provided with a second one-way electromagnetic control valve and a second electromagnetic flowmeter, and the third connecting pipe is provided with a third one-way electromagnetic control valve and a third electromagnetic flowmeter. The PLC programming module 41 is electrically connected to the first one-way electromagnetic control valve, the first electromagnetic flowmeter, the second one-way electromagnetic control valve, the second electromagnetic flowmeter, the third one-way electromagnetic control valve and the third electromagnetic flowmeter, respectively, to monitor and control the liquid conditions in the first connecting pipe, the second connecting pipe and the third connecting pipe.

[0049] The thermostatically adjustable pipe water supply tank 1 is provided with a first heating rod 11 and a water tank water temperature sensor 12, and the first heating rod 11 and the water tank water temperature sensor 12 are electrically connected to the PLC programming module 41 respectively, so as to adjust the water temperature of the liquid in the water supply tank.

[0050] The external inflow and infiltration simulation system 6 includes a temperature-adjustable inflow and infiltration water tank 61, a water tank connecting pipe 62, and a diverter pipe 63. The outlet of the temperature-adjustable inflow and infiltration water tank 61 is connected to the inlet of the water tank connecting pipe 62, and the outlet of the water tank connecting pipe 62 is connected to the side wall of the experimental pipeline 3 through the diverter pipe 63. The inflow and infiltration water tank 61 injects liquid into the experimental pipeline 3 through the water tank connecting pipe 62 and the diverter pipe 63, simulating the inflow and infiltration scenario of the experimental pipeline 3.

[0051] In this embodiment, two inflow and infiltration holes 33 are provided on the side wall of the experimental pipe 3, and the two inflow and infiltration holes 33 are spaced a certain distance apart; the water tank connecting pipe 62 is connected to the two inflow and infiltration holes 33 through two branch pipes 63, respectively, to realize dynamic inflow and infiltration experiments.

[0052] A second heating rod 611 and a seepage water tank water temperature sensor 612 are inserted into the temperature-adjustable inflow seepage water tank 61, and the second heating rod 611 and the seepage water tank water temperature sensor 612 are electrically connected to the PLC programming module 41 respectively, so as to adjust the inflow seepage water temperature.

[0053] An electric regulating valve and an electromagnetic flowmeter are provided on the water tank connecting pipe 62 , and the electric regulating valve and the electromagnetic flowmeter are electrically connected to the PLC programming module 41 respectively, so as to adjust the outflow of water from the connecting pipe 62 .

[0054] In this embodiment, as shown in the figure, the experimental pipeline 3 is composed of multiple pipe segments, each of which is connected by flanges and is equipped with a support frame 7. The end of the pipe segment is equipped with a flange, and the flange of the end is connected to the end cap. The optical fiber 52 passes through the end cap and extends into the experimental pipeline 3.

[0055] In another embodiment, the exhaust hole 32 is an exhaust valve.

[0056] A sensitivity testing method for optical fiber distributed temperature measurement in a drainage pipeline comprises the following steps:

[0057] S1, open the first one-way electromagnetic control valve, the second one-way electromagnetic control valve, and the third one-way electromagnetic control valve in sequence to start water pump 2;

[0058] S2, open the electric regulating valve on the connecting pipe 62, and the liquid in the temperature-controlled inflow and infiltration water storage tank 61 flows into the experimental pipeline;

[0059] In steps S1 and S2, the first heating rod 11 is regulated to heat, the second heating rod 611 is regulated to heat, the temperature of the pipeline liquid and the external inflow and infiltration liquid is controlled, and various pipeline water and external inflow and infiltration water ratios and water temperature scenarios are simulated.

[0060] S3, the liquid in the thermostatic water supply tank 1 flows into the experimental pipe 3, the experimental pipe water temperature sensor 31 detects the temperature of the liquid and transmits the temperature information to the flow and water temperature control PLC system 4 for recording and storage;

[0061] S4: The pulsed laser source emits a detection laser to the optical fiber 52, which is scattered in the experimental pipe 3. The scattered detection laser is transmitted back to the optical fiber temperature measuring device 5 through the optical fiber 52. The data acquisition card collects the scattered laser light and transmits the collected information to the photoelectric converter for data processing to obtain the temperature information in the experimental pipe 3.

[0062] S5. Compare the water temperature value displayed by the flow and water temperature control PLC system 4 with the water temperature data displayed by the optical fiber temperature measuring device 5 to determine and analyze the noise and detection sensitivity of the optical fiber equipment operation.

Claims

1. A sensitivity test device for optical fiber distributed temperature measurement in drainage pipes, characterized in that: The device comprises: a temperature-adjustable pipe water supply tank (1), a water pump (2), an experimental pipe (3), a flow and water temperature control PLC system (4), an optical fiber temperature measuring device (5) and an external inflow and infiltration simulation system (6); The thermostatically adjustable pipe water supply tank (1) is connected to the water inlet of the water pump (2) via a first connecting pipe, the water outlet of the water pump (2) is connected to the water inlet of the experimental pipe (3) via a second connecting pipe, and the water outlet of the experimental pipe (3) is connected to the thermostatically adjustable pipe water supply tank (1) via a third connecting pipe; The experimental pipeline (3) is provided with an experimental pipeline water temperature sensor (31), and the experimental pipeline water temperature sensor (31) is electrically connected to the flow rate and water temperature control PLC system (4); The optical fiber temperature measurement device (5) comprises: an optical fiber temperature measurement host (51) and an optical fiber (52); the optical fiber temperature measurement host (51) comprises: a pulse laser source, a data acquisition card and a photoelectric converter; the first end of the optical fiber (52) is connected to the pulse laser source; the second end of the optical fiber (52) extends into the experimental pipeline (3); the pulse laser source emits a detection laser to the optical fiber (52); the detection laser is transported into the experimental pipeline (3) along the optical fiber (52) and scattered in the experimental pipeline (3); the scattered detection laser is transmitted back to the optical fiber temperature measurement device (5) through the optical fiber (52); the data acquisition card collects the scattered laser light transmitted back, and transmits the collected information to the photoelectric converter for data processing, thereby obtaining temperature information in the experimental pipeline (3); The external inflow and infiltration simulation system (6) comprises: an inflow and infiltration water storage tank (61) with adjustable temperature, a water tank connecting pipe (62), and a shunt pipe (63); the inflow and infiltration water storage tank (61) with adjustable temperature is provided with a second heating rod (611), a water temperature sensor (612) for the inflow and infiltration water storage tank, and an electric regulating valve, and is electrically connected to a flow and water temperature control PLC (4) system; the water outlet end of the inflow and infiltration water storage tank (61) is connected to the water inlet end of its water tank connecting pipe (62) through the electric regulating valve, and the water outlet end of its connecting pipe is connected to the top wall of the experimental pipeline (3) through its shunt pipe (63).

2. According to claim 1, a sensitivity test device for optical fiber distributed temperature measurement in drainage pipes is characterized in that: The second end of the optical fiber (52) passes through the side wall of the experimental pipe (3).

3. The sensitivity testing device for optical fiber distributed temperature measurement in drainage pipes according to claim 1 is characterized in that: The water pump (2) is provided with a speed converter, and the speed converter is electrically connected to the flow and water temperature control PLC system (4).

4. The sensitivity testing device for optical fiber distributed temperature measurement in drainage pipes according to claim 1 is characterized in that: An exhaust hole (32) is provided on the top side of the experimental pipeline (3), and the exhaust hole can be detachably connected to an air plug.

5. The sensitivity testing device for optical fiber distributed temperature measurement in drainage pipes according to claim 1 is characterized in that: An inlet and inflow hole (33) is provided on the top side of the experimental pipeline (3), and the inlet and inflow hole (33) is detachably connected to a water plug.

6. The sensitivity testing device for optical fiber distributed temperature measurement in drainage pipes according to claim 1 is characterized in that: The first connecting pipe is provided with a first one-way electromagnetic control valve and a first electromagnetic flowmeter; The second connecting pipe is provided with a second one-way electromagnetic control valve and a second electromagnetic flowmeter; The third connecting pipe is provided with a third one-way electromagnetic control valve and a third electromagnetic flowmeter; The flow and water temperature control PLC system (4) is electrically connected to the first one-way electromagnetic control valve, the first electromagnetic flowmeter, the second one-way electromagnetic control valve, the second electromagnetic flowmeter, the third one-way electromagnetic control valve, and the third electromagnetic flowmeter, respectively.

7. The sensitivity testing device for optical fiber distributed temperature measurement in drainage pipes according to claim 1 is characterized in that: The thermostatically adjustable pipe water supply tank (1) is provided with a first heating rod (11) and a water supply tank water temperature sensor (12), and the first heating rod (11) and the water supply tank water temperature sensor (12) are respectively electrically connected to the flow and water temperature control PLC system (4).

8. The sensitivity testing device for optical fiber distributed temperature measurement in drainage pipes according to claim 1 is characterized in that: The temperature-adjustable inflow infiltration water storage tank (61) is provided with a second heating rod (611) and a water temperature sensor (612) for the inflow infiltration water storage tank. The sensors (612) are electrically connected to the flow rate and water temperature control PLC systems (4) respectively; The water tank connecting pipe (62) is provided with an electric regulating valve and an electromagnetic flowmeter, and the electric regulating valve and the electromagnetic flowmeter are electrically connected to the flow and water temperature control PLC system (4) respectively.

9. A sensitivity test method for optical fiber distributed temperature measurement in drainage pipes, characterized in that: The method is implemented by using the sensitivity test device for optical fiber distributed temperature measurement in drainage pipes according to any one of claims 1 to 8, comprising the following steps: S1, opening the first one-way electromagnetic control valve, the second one-way electromagnetic control valve, and the third one-way electromagnetic control valve in sequence to start the water pump (2); S2, opening the electric regulating valve of the temperature-adjustable inflow infiltration water storage tank connecting pipe, so that the liquid in the temperature-adjustable inflow infiltration water storage tank (61) flows into the experimental pipeline (3); S3, the liquid in the thermostatic water supply tank (1) flows into the experimental pipe (3), the experimental pipe water temperature sensor (31) detects the temperature of the pipe liquid, and transmits the water temperature information to the flow and water temperature control PLC system (4) for continued recording and storage; S4, the pulse laser source emits a detection laser to the optical fiber (52), which is scattered in the experimental pipeline (3), and the scattered detection laser is transmitted back to the optical fiber temperature measuring device (5) through the optical fiber (52). The data acquisition card collects the scattered laser light and transmits the collected information to the photoelectric converter for data processing to obtain the temperature information in the experimental pipeline (3); S5. Compare the water temperature data displayed by the flow and water temperature control PLC system (4) with the water temperature data displayed by the optical fiber temperature measuring device (5), and judge and analyze the noise and detection sensitivity of the optical fiber equipment operation.

10. A sensitivity testing method for optical fiber distributed temperature measurement in drainage pipes according to claim 9, characterized in that: In steps S1 and S2, the first heating rod (11) is regulated to heat, and the second heating rod (611) is regulated to heat, so as to control the temperature of the pipeline liquid and the external inflow and infiltration liquid, and simulate various pipeline water and inflow and infiltration water ratios and water temperature scenarios.

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