Sensitivity testing device and method to calibrate the distributed optic-fiber temperature sensing system for inflows and infiltrations identification in drainage pipeline

1 . A sensitivity testing device to calibrate a distributed optic-fiber temperature sensing (DOFTS) for inflow and infiltration (I/I) identification in a drainage pipeline, wherein the device comprises:

a temperature-adjustable water supply tank,

a water pump,

an experimental pipeline,

a centralized programmable logic controller (PLC) system,

a DOFTS for I/I identification, and

a unit of simulating external water I/I into experimental pipeline;

the temperature-adjustable water supply tank is communicated with a water inlet of the water pump through a first connecting pipe; a water outlet of the water pump is communicated with a water inlet of the experimental pipeline through a second connecting pipe; a water outlet of the experimental pipeline is communicated with the temperature-adjustable water supply tank through a third connecting pipe;

a high-accuracy physical water temperature sensor is arranged in the experimental pipeline, and the high-accuracy physical water temperature sensor is electrically connected to the centralized PLC system;

the DOFTS for I/I identification comprises a data acquisition and transmission system of distributed optical fiber and an optical fiber; the data acquisition and transmission system of distributed optical fiber comprises: a pulse laser source, a data acquisition card, and a photoelectric converter; a first end of the optical fiber is connected to the pulse laser source; a second end of the optical fiber is laid within the experimental pipeline; the pulse laser source emits laser to the optical fiber; the laser is transmitted into the experimental pipeline along the optical fiber and is scattered in the experimental pipeline; the scattered laser is transmitted back to the DOFTS for I/I identification through the optical fiber; the data acquisition card acquires the scattered laser and de-codes the acquired information through the photoelectric converter, and temperature information inside the experimental pipeline is obtained; and

the unit of simulating external water I/I into experimental pipeline comprises: a temperature-adjustable water storage tank for simulating external water I/I into experimental pipeline, a water tank connecting pipe, and a water distribution pipe; the temperature-adjustable water storage tank for simulating external water I/I into experimental pipeline is provided with a second heating rod, a high-accuracy physical water temperature sensor in I/I water storage tank, and an electric regulating valve and is electrically connected to the centralized PLC system; a water outlet of the temperature-adjustable water storage tank for simulating external water I/I into experimental pipeline is communicated with a water inlet of the water tank connecting pipe through an electric regulating valve; a water outlet of the connecting pipe is communicated with a top wall of the experimental pipeline through the water distribution pipe.

2 . The sensitivity testing device to calibrate the DOFTS for I/I identification in drainage pipeline according to claim 1 , wherein the second end of the optical fiber is threaded out of a side wall of the experimental pipeline.

3 . A sensitivity testing method to calibrate the DOFTS for I/I identification in a drainage pipeline performed by the device according to claim 2 , wherein the method comprises:

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, and turning on the water pump;

S2, opening the electric regulating valve on a connecting pipe of the temperature-adjustable water storage tank for simulating external water I/I into experimental pipeline, and enabling water in the temperature-adjustable water storage tank to flow into the experimental pipeline;

S3, enabling water in the temperature-adjustable water supply tank flow into the experimental pipeline, detecting water temperature of the experimental pipeline by the high-accuracy physical water temperature sensor at designated stations, and transmitting water temperature information to the centralized PLC system for continuous recording and data information storage;

S4, transmitting the laser emitted by the pulse laser source into the experimental pipeline along the optical fiber, scattering the transmitted laser back to the DOFTS for I/I identification through the optical fiber, acquiring, by the data acquisition card, and decoding the acquired information through the photoelectric converter to obtain spatial-temporal continuous temperature information in the experimental pipeline; and

S5, comparing water temperature data displayed in the centralized PLC system with water temperature data measured by the DOFTS for I/I identification, and determining noises and the detection sensitivity of the optical fiber sensing system.

4 . The sensitivity testing device to calibrate the DOFTS for I/I identification in drainage pipeline according to claim 1 , wherein a frequency converter is arranged on the water pump, and the frequency converter is electrically connected to the centralized PLC system.

5 . A sensitivity testing method to calibrate the DOFTS for I/I identification in a drainage pipeline performed by the device according to claim 4 , wherein the method comprises:

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, and turning on the water pump;

S2, opening the electric regulating valve on a connecting pipe of the temperature-adjustable water storage tank for simulating external water I/I into experimental pipeline, and enabling water in the temperature-adjustable water storage tank to flow into the experimental pipeline;

S3, enabling water in the temperature-adjustable water supply tank flow into the experimental pipeline, detecting water temperature of the experimental pipeline by the high-accuracy physical water temperature sensor at designated stations, and transmitting water temperature information to the centralized PLC system for continuous recording and data information storage;

S4, transmitting the laser emitted by the pulse laser source into the experimental pipeline along the optical fiber, scattering the transmitted laser back to the DOFTS for I/I identification through the optical fiber, acquiring, by the data acquisition card, and decoding the acquired information through the photoelectric converter to obtain spatial-temporal continuous temperature information in the experimental pipeline; and

S5, comparing water temperature data displayed in the centralized PLC system with water temperature data measured by the DOFTS for I/I identification, and determining noises and the detection sensitivity of the optical fiber sensing system.

6 . The sensitivity testing device to calibrate the DOFTS for I/I identification in drainage pipeline according to claim 1 , wherein a gas release hole is set up in a top side of the experimental pipeline, and the gas release hole is equipped with a detachable plug.

7 . A sensitivity testing method to calibrate the DOFTS for I/I identification in a drainage pipeline performed by the device according to claim 6 , wherein the method comprises:

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, and turning on the water pump;

S2, opening the electric regulating valve on a connecting pipe of the temperature-adjustable water storage tank for simulating external water I/I into experimental pipeline, and enabling water in the temperature-adjustable water storage tank to flow into the experimental pipeline;

S3, enabling water in the temperature-adjustable water supply tank flow into the experimental pipeline, detecting water temperature of the experimental pipeline by the high-accuracy physical water temperature sensor at designated stations, and transmitting water temperature information to the centralized PLC system for continuous recording and data information storage;

S4, transmitting the laser emitted by the pulse laser source into the experimental pipeline along the optical fiber, scattering the transmitted laser back to the DOFTS for I/I identification through the optical fiber, acquiring, by the data acquisition card, and decoding the acquired information through the photoelectric converter to obtain spatial-temporal continuous temperature information in the experimental pipeline; and

S5, comparing water temperature data displayed in the centralized PLC system with water temperature data measured by the DOFTS for I/I identification, and determining noises and the detection sensitivity of the optical fiber sensing system.

8 . The sensitivity testing device to calibrate the DOFTS for I/I identification in drainage pipeline according to claim 1 , wherein an I/I hole is set up in a top side of the experimental pipeline, and the I/I hole is equipped with a detachable plug.

9 . A sensitivity testing method to calibrate the DOFTS for I/I identification in a drainage pipeline performed by the device according to claim 8 , wherein the method comprises:

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, and turning on the water pump;

S2, opening the electric regulating valve on a connecting pipe of the temperature-adjustable water storage tank for simulating external water I/I into experimental pipeline, and enabling water in the temperature-adjustable water storage tank to flow into the experimental pipeline;

S3, enabling water in the temperature-adjustable water supply tank flow into the experimental pipeline, detecting water temperature of the experimental pipeline by the high-accuracy physical water temperature sensor at designated stations, and transmitting water temperature information to the centralized PLC system for continuous recording and data information storage;

S4, transmitting the laser emitted by the pulse laser source into the experimental pipeline along the optical fiber, scattering the transmitted laser back to the DOFTS for I/I identification through the optical fiber, acquiring, by the data acquisition card, and decoding the acquired information through the photoelectric converter to obtain spatial-temporal continuous temperature information in the experimental pipeline; and

S5, comparing water temperature data displayed in the centralized PLC system with water temperature data measured by the DOFTS for I/I identification, and determining noises and the detection sensitivity of the optical fiber sensing system.

10 . The sensitivity testing device to calibrate the DOFTS for I/I identification in drainage pipeline according to claim 1 , wherein

a first one-way electromagnetic control valve and a first electromagnetic flow meter are arranged on the first connecting pipe;

a second one-way electromagnetic control valve and a second electromagnetic flow meter are arranged on the second connecting pipe;

a third one-way electromagnetic control valve and a third electromagnetic flow meter are arranged on the third connecting pipe;

the centralized PLC system is electrically connected to the first one-way electromagnetic control valve, the first electromagnetic flow meter, the second one-way electromagnetic control valve, the second electromagnetic flow meter, the third one-way electromagnetic control valve, and the third electromagnetic flow meter respectively.

11 . A sensitivity testing method to calibrate the DOFTS for I/I identification in a drainage pipeline performed by the device according to claim 10 , wherein the method comprises:

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, and turning on the water pump;

S2, opening the electric regulating valve on a connecting pipe of the temperature-adjustable water storage tank for simulating external water I/I into experimental pipeline, and enabling water in the temperature-adjustable water storage tank to flow into the experimental pipeline;

S3, enabling water in the temperature-adjustable water supply tank flow into the experimental pipeline, detecting water temperature of the experimental pipeline by the high-accuracy physical water temperature sensor at designated stations, and transmitting water temperature information to the centralized PLC system for continuous recording and data information storage;

S4, transmitting the laser emitted by the pulse laser source into the experimental pipeline along the optical fiber, scattering the transmitted laser back to the DOFTS for I/I identification through the optical fiber, acquiring, by the data acquisition card, and decoding the acquired information through the photoelectric converter to obtain spatial-temporal continuous temperature information in the experimental pipeline; and

S5, comparing water temperature data displayed in the centralized PLC system with water temperature data measured by the DOFTS for I/I identification, and determining noises and the detection sensitivity of the optical fiber sensing system.

12 . The sensitivity testing device to calibrate the DOFTS for I/I identification in drainage pipeline according to claim 1 , wherein a first heating rod and a high-accuracy physical water temperature sensor in water supply tank are inserted into the temperature-adjustable water supply tank, and the first heating rod and the high-accuracy physical water temperature sensor in water supply tank are electrically connected to the centralized PLC system respectively.

13 . A sensitivity testing method to calibrate the DOFTS for I/I identification in a drainage pipeline performed by the device according to claim 12 , wherein the method comprises:

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, and turning on the water pump;

S2, opening the electric regulating valve on a connecting pipe of the temperature-adjustable water storage tank for simulating external water I/I into experimental pipeline, and enabling water in the temperature-adjustable water storage tank to flow into the experimental pipeline;

S3, enabling water in the temperature-adjustable water supply tank flow into the experimental pipeline, detecting water temperature of the experimental pipeline by the high-accuracy physical water temperature sensor at designated stations, and transmitting water temperature information to the centralized PLC system for continuous recording and data information storage;

S4, transmitting the laser emitted by the pulse laser source into the experimental pipeline along the optical fiber, scattering the transmitted laser back to the DOFTS for I/I identification through the optical fiber, acquiring, by the data acquisition card, and decoding the acquired information through the photoelectric converter to obtain spatial-temporal continuous temperature information in the experimental pipeline; and

S5, comparing water temperature data displayed in the centralized PLC system with water temperature data measured by the DOFTS for I/I identification, and determining noises and the detection sensitivity of the optical fiber sensing system.

14 . The sensitivity testing device to calibrate the DOFTS for I/I identification in drainage pipeline according to claim 1 , wherein

the second heating rod and the high-accuracy physical water temperature sensor in (I/I) water storage tank are inserted into the temperature-adjustable water storage tank for simulating external water I/I into experimental pipeline, and the second heating rod and the high-accuracy physical water temperature sensor in (I/I) water storage tank are electrically connected to the centralized PLC system respectively; and

an electric regulating valve and an electromagnetic flow meter are arranged on the water tank connecting pipe; the electric regulating valve and the electromagnetic flow meter are electrically connected to the centralized PLC system respectively.

15 . A sensitivity testing method to calibrate the DOFTS for I/I identification in a drainage pipeline performed by the device according to claim 14 , wherein the method comprises:

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, and turning on the water pump;

S2, opening the electric regulating valve on a connecting pipe of the temperature-adjustable water storage tank for simulating external water I/I into experimental pipeline, and enabling water in the temperature-adjustable water storage tank to flow into the experimental pipeline;

S3, enabling water in the temperature-adjustable water supply tank flow into the experimental pipeline, detecting water temperature of the experimental pipeline by the high-accuracy physical water temperature sensor at designated stations, and transmitting water temperature information to the centralized PLC system for continuous recording and data information storage;

S4, transmitting the laser emitted by the pulse laser source into the experimental pipeline along the optical fiber, scattering the transmitted laser back to the DOFTS for I/I identification through the optical fiber, acquiring, by the data acquisition card, and decoding the acquired information through the photoelectric converter to obtain spatial-temporal continuous temperature information in the experimental pipeline; and

S5, comparing water temperature data displayed in the centralized PLC system with water temperature data measured by the DOFTS for I/I identification, and determining noises and the detection sensitivity of the optical fiber sensing system.

16 . A sensitivity testing method to calibrate the DOFTS for I/I identification in a drainage pipeline performed by the device according to claim 1 , wherein the method comprises:

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, and turning on the water pump;

S2, opening the electric regulating valve on a connecting pipe of the temperature-adjustable water storage tank for simulating external water I/I into experimental pipeline, and enabling water in the temperature-adjustable water storage tank to flow into the experimental pipeline;

S3, enabling water in the temperature-adjustable water supply tank flow into the experimental pipeline, detecting water temperature of the experimental pipeline by the high-accuracy physical water temperature sensor at designated stations, and transmitting water temperature information to the centralized PLC system for continuous recording and data information storage;

S4, transmitting the laser emitted by the pulse laser source into the experimental pipeline along the optical fiber, scattering the transmitted laser back to the DOFTS for I/I identification through the optical fiber, acquiring, by the data acquisition card, and decoding the acquired information through the photoelectric converter to obtain spatial-temporal continuous temperature information in the experimental pipeline; and

S5, comparing water temperature data displayed in the centralized PLC system with water temperature data measured by the DOFTS for I/I identification, and determining noises and the detection sensitivity of the optical fiber sensing system.

17 . The sensitivity testing method to calibrate the DOFTS for I/I identification in drainage pipeline according to claim 16 , wherein

in steps S1 and S2, heating of the first heating rod is regulated; heating of the second heating rod is regulated; temperatures of in-pipe water and external I/I water are controlled; and various combination scenarios of inflow rate, water temperature of experimental pipeline and those of I/I water are tested.