PET-CT and DAS Imaging for Fluid-Solid Coupling
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Solution Overview
Problem
Current experimental methods for studying fluid-solid coupling effects in materials lack accuracy and reliability due to indirect monitoring and high error rates in inversion algorithms, especially in simulating hydraulic fracturing and earthquake-induced processes.
Innovation Solution
A multi-physical field imaging method and system combining PET-CT technology with Distributed Acoustic Sensing (DAS) using phase-sensitive optical frequency domain reflectometers and a pressure device made of polyether ether ketone and carbon fiber, allowing for direct imaging of fluid-solid coupling processes by wrapping sensors on non-metallic samples and combining PET and CT images with acoustic emission data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional active source ultrasonic tomography or acoustic emission tomography monitoring is used, then the internal structure of opaque materials can be monitored, but the measurement precision and reliability are significantly affected by inversion calculation errors
Solution Approach 1:
The patent replaces traditional mechanical ultrasonic tomography and acoustic emission tomography systems with a PET-CT based imaging system. PET-CT uses radioactive positron nuclide tracers and coincidence detection of annihilation photons to directly image internal structures without requiring inversion calculations, thereby eliminating the measurement precision and reliability issues associated with traditional mechanical-based tomography inversion algorithms
Solution Approach 2:
The patent changes the physical parameters and detection principles from mechanical ultrasonic/acoustic methods to nuclear medicine PET-CT methods. By using radioactive tracers that emit positrons and detecting the coincident gamma rays from annihilation, the system achieves direct imaging with higher precision and reliability, avoiding the mathematical inversion errors inherent in traditional methods
2Ease of operation
If small-scale experimental samples are used, then the experiment can be conducted in laboratory conditions, but the calculation accuracy error significantly affects the reliability of results
Solution Approach 1:
The patent replaces small-scale laboratory mechanical testing with PET-CT based imaging that can handle larger samples. The PET-CT system's ability to penetrate and image large opaque materials directly eliminates the need for small samples and subsequent inversion calculations, thereby improving reliability while maintaining laboratory feasibility
Solution Approach 2:
The PET-CT system provides universal imaging capability that works for both small and large samples, eliminating the constraint of sample size. The system can image various sizes of opaque materials directly without requiring scale-specific inversion algorithms, thus improving reliability across different sample dimensions while maintaining ease of operation
3Difficulty of detecting and measuring
If indirect monitoring methods are used, then the internal structure can be observed, but the accuracy and reliability of fluid-solid coupling effect analysis is compromised
Solution Approach 1:
The patent replaces indirect mechanical monitoring methods with direct PET-CT imaging. The PET-CT system directly images the internal structure and fluid-solid coupling effects through coincidence detection of annihilation photons, eliminating the need for complex inversion calculations and significantly improving measurement precision while reducing the difficulty of detection
Solution Approach 2:
The patent uses radioactive positron nuclide tracers as intermediaries to visualize fluid-solid coupling effects. The tracers are introduced into the fluid phase, and their distribution is directly imaged by PET-CT through coincidence detection, providing accurate and reliable measurement of fluid-solid interactions without requiring indirect inference from surface measurements
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
This approach enables accurate and reliable direct imaging of fluid-solid coupling processes, providing comprehensive analysis of internal structural changes and perturbations, enhancing the understanding of fluid-solid interactions under various mechanical scenarios.
Implementation Method 1
utilize Rayleigh backward scattering (RBS) in an optical fiber to locate and recover the mechanical vibration information (amplitude, phase and frequency) anywhere on the optical fiber
Implementation Method 2
PET imaging adopts radioactive positron nuclide tracers to obtain internal molecular information of the sample to be tested
Implementation Method 3
PET technology combines positron emission tomography (PET) technology and CT imaging technology
Implementation Method 4
CT imaging directly images the internal structure of the material based on the difference in the X-ray absorption degree of various parts of the sample to be tested with different internal density
Data Source
AI summary
Embodiments of the present disclosure provide a multi-physical field imaging method based on PET-CT and DAS, comprising: wrapping distributed acoustic sensors on a surface of a non-metallic sample to be tested, and then placing them in a pressure device; loading triaxial pressures; preparing a tracer fluid; pumping the tracer fluid into the non-metallic sample; collecting PET images and CT images of internal structure of the non-metallic sample, meanwhile, monitoring internal acoustic emission events of the non-metallic sample in real time; combining the PET images with the CT images, to obtain PET/CT images; locating the acoustic emission events, and obtaining occurrence time and spatial location of internal structural perturbations; and analyzing a mechanism of fluid-solid coupling effect in the non-metallic sample under loaded stress. The imaging method and system of the present disclosure can accurately and reliably image the fluid-solid coupling process in the material.