Helical Optical Fiber Monitoring of Polyurethane Diffusion in Porous Media
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Solution Overview
Problem
Current monitoring techniques for polyurethane diffusion in porous media are costly and prone to missed detection, lacking comprehensive coverage and accuracy due to reliance on point-based methods, making it difficult to intuitively capture the diffusion process in underground engineering.
Innovation Solution
A method and apparatus using distributed optical fiber technology to monitor polyurethane diffusion by analyzing thermal conductivity changes during curing, involving a helical structure deployment of optical fibers, spatial coordinate mapping, and real-time temperature fluctuations to determine moisture field changes and polyurethane distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If point-based monitoring techniques are used, then monitoring cost is reduced, but monitoring coverage and detection accuracy deteriorate
Solution Approach 1:
The patent replaces traditional mechanical point-based monitoring systems with distributed optical fiber sensing technology. The optical fiber acts as a continuous sensing medium that can detect temperature changes along its entire length, transforming discrete point measurements into continuous distributed measurements. This substitution enables comprehensive monitoring coverage without proportionally increasing system complexity, as the optical fiber inherently provides distributed sensing capability along its deployment path.
Solution Approach 2:
The patent utilizes temperature as a proxy parameter to indirectly measure polyurethane diffusion. By monitoring temperature changes in the porous medium during polyurethane injection and curing, the system infers diffusion patterns without directly measuring the chemical substance. This parameter transformation allows comprehensive spatial monitoring using established thermal sensing technology rather than requiring complex direct chemical sensing at multiple points.
2Loss of information
If traditional grout volume or pressure control methods are used, then control simplicity is maintained, but direct acquisition of grout diffusion information deteriorates
Solution Approach 1:
The patent introduces temperature as an intermediary parameter to capture grout diffusion information. The optical fiber sensing system measures temperature fields in the porous medium, which change in response to polyurethane diffusion and curing processes. This intermediary measurement approach provides direct diffusion information without requiring complex direct chemical sensing, maintaining operational simplicity while eliminating information loss.
3Measurement precision
If distributed optical fiber temperature sensing technology is applied, then monitoring precision and coverage are improved, but system complexity increases
Solution Approach 1:
The patent applies distributed optical fiber temperature sensing technology, which is a mature multi-functional system capable of providing continuous spatial temperature measurements along the entire fiber length. This universal technology serves multiple functions: monitoring polyurethane diffusion, detecting curing progression, and mapping moisture distribution. By leveraging an existing multi-functional system rather than developing specialized sensors, the patent achieves high measurement precision without proportionally increasing system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise, comprehensive, and cost-effective monitoring of polyurethane diffusion in porous media, improving accuracy and coverage by correlating thermal conductivity changes with moisture content, thereby enhancing the monitoring process.
Implementation Method 1
the thermal conductivity of the grout during the phase transition process is different from the thermal conductivity of the grout after curing. This phenomenon leads to changes in the heat transfer properties of the cured porous medium.
Implementation Method 2
by utilizing heatable sensor cables (AHFO), a moisture inversion function is established based on the difference in the rate at which heat diffuses to the surroundings under varying moisture contents and infiltration speeds
Data Source
AI summary
Provided are a monitoring method and apparatus, a device, and a medium. The method includes selecting a diffusion model according to a diffusion characteristic of polyurethane in the porous medium and winding a distributed optical fiber around at least one sensing cage to form a helical structure; mapping coordinates of each temperature measurement point on the helical structure to a spatial Cartesian coordinate system of the porous medium; measuring an initial moisture field of the porous medium before polyurethane infiltration; monitoring a post-infiltration moisture field in the stabilized state of temperature transmission fluctuations during the polyurethane diffusion that occurs in the polyurethane infiltration in the porous medium; and analyzing a change in water content based on the initial moisture field and the post-infiltration moisture field and identifying a polyurethane diffusion distribution field in the porous medium in conjunction with the diffusion model.