Magnetic Resonance Flow Profiling With a Static Field Gradient
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Solution Overview
Problem
Existing MR-based methods for characterizing fluid flow primarily focus on average velocity, which is insufficient for studying fluid rheology, particularly under laminar conditions, and require expensive superconducting equipment and high-performance gradient systems, limiting their industrial application.
Innovation Solution
A magnetic resonance method using a portable sensor with a constant magnetic field gradient, employing Carr-Purcell-Meiboom-Gill (CPMG) measurements and phase-based, magnitude-based, and velocity spectrum methods to determine flow behavior index and velocity profile, enabling characterization of fluid rheology in conduits like pipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If MRI-based methods with superconducting equipment and high-performance gradient systems are used, then measurement precision of flow velocity profiles is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent replaces expensive, complex superconducting MRI equipment with a simple permanent magnet system that generates a static magnetic field gradient. This permanent magnet system is cost-effective, portable, and eliminates the need for sophisticated gradient coils and superconducting infrastructure, making flow measurement accessible for industrial applications.
Solution Approach 2:
The patent substitutes the complex electromagnetic gradient systems of MRI with a static magnetic field gradient generated by a permanent magnet. Instead of using time-varying gradient fields requiring high-performance electronics, the invention uses a fixed spatial gradient that simplifies the hardware while maintaining measurement capability through MR signal phase encoding.
2Loss of information
If conventional MRI-based methods are used, then flow velocity information is obtained, but the ability to characterize fluid rheology under laminar conditions is insufficient
Solution Approach 1:
The patent applies a static magnetic field gradient along the flow direction before the flow enters the measurement region. This preliminary application of the gradient ensures that spins at different radial positions accumulate different phases during their transit, encoding the velocity profile information into the MR signal phase. This enables subsequent extraction of both average velocity and flow behavior index that characterizes rheological properties.
Solution Approach 2:
The patent uses the phase of the MR signal as an intermediary to convey velocity profile information. By encoding velocity distribution into phase differences caused by the static magnetic field gradient, the system can retrieve detailed flow characteristics including flow behavior index, which serves as a mediator between the physical flow field and the measurable MR signal.
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 characterization of fluid rheology by determining flow behavior index and velocity profile in conduits, using a low-cost, portable sensor that does not require expensive superconducting equipment, thus expanding industrial applicability.
Implementation Method 1
subjecting the flowing fluid in the measurement volume to a magnetic field gradient generally in the direction of flow of the fluid
Implementation Method 2
The phase shift of the signal detected occurs due to flows with a flow-oriented gradient, which is proportional to the average velocity
Implementation Method 3
radio frequency excitation pulses, generating a signal in the form of a series of echoes
Implementation Method 4
Arnold and Burkhart (1965) employed a spin echo to study the influence of flow on MR signal under laminar flow conditions
Data Source
AI summary
A magnetic resonance method and device for characterizing the pattern of flow of a flowing fluid including the steps of flowing the fluid through a conduit, wherein a segment of the conduit defines a measurement volume, subjecting the flowing fluid in the measurement volume to a magnetic field gradient generally in the direction of flow of the fluid, wherein the magnetic field gradient in the direction of flow comprises a generally fixed value in the measurement volume, and a magnetic resonance pulse, acquiring at least one odd echo from the magnetic resonance pulse, wherein the echo comprises signals from streamlines in the flowing fluid in the measurement volume, processing the signals to determine a flow behaviour index for the flowing fluid, determining an average velocity of the flowing fluid, and calculating velocity as a function of the radius of the conduit using the flow behaviour index and the average velocity and relating the function to a pattern of flow to characterize the pattern of flow exhibited by the flowing fluid.