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

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.