X-ray Tomography for Closed Metal Wall Flame Diagnostics
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Solution Overview
Problem
Current diagnostic techniques, such as acoustic pyrometers and optical spectroscopy, require optical access and are inadequate for measuring flame structure and particulate density within closed environments like internal combustion engines and drying towers, limiting the ability to ensure uniform coatings and diagnose high-pressure, high-temperature conditions in automotive engines and turbines.
Innovation Solution
The use of X-ray tomography systems positioned outside closed metal walls to detect variations in gas and particulate density, employing a source and detector array with a processor for data analysis and image reconstruction, capable of correcting for beam hardening and generating reconstructed images of gas density within the enclosed volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical diagnostic techniques (acoustic pyrometers, TDLAS, CARS, Heterodyne Interferometry) are used to measure flame structure and gas density, then measurement precision can be achieved, but optical access is required which is not available in closed metal wall environments
Solution Approach 1:
The patent introduces X-rays as an intermediary radiation type that can penetrate closed metal walls, serving as a mediator between the measurement system and the flame structure. Unlike optical radiation which requires direct line-of-sight access, X-rays can pass through the metal enclosure wall to interact with the flame and spray structures inside, enabling measurements without optical access.
Solution Approach 2:
The patent replaces optical measurement systems with an X-ray based tomography system. This substitution involves using X-ray sources and detectors instead of optical sensors, and employing computer tomographic reconstruction algorithms to process the data, thereby eliminating the need for optical access while maintaining measurement capability.
2Measurement precision
If conventional X-ray tomography is used for steady state or immobile objects, then imaging quality is improved, but it cannot capture dynamic flame and spray structures in turbulent flows
Solution Approach 1:
The patent employs rapid sequential acquisition of X-ray transmission data at multiple angular positions, creating a periodic sampling of the dynamic flame and spray structures. By capturing images at successive time intervals and angles, the system freezes the turbulent flow structures momentarily, allowing reconstruction of instantaneous density distributions that represent the dynamic state.
Solution Approach 2:
The patent performs preliminary alignment and positioning of the X-ray source and detector array around the combustion chamber before initiating measurements. The system pre-configures the geometric parameters and calibration data necessary for accurate tomographic reconstruction, enabling rapid processing of dynamic data once measurement begins.
3Ease of operation
If X-ray scanning tomography is used to diagnose flame structure under high pressure and temperature, then in situ measurement capability is achieved, but beam hardening effects degrade image quality
Solution Approach 1:
The patent varies the X-ray energy parameters and acquisition geometry to optimize penetration through the high-pressure, high-temperature environment. By adjusting the X-ray tube voltage and filtration, the system compensates for beam hardening effects caused by the dense combustion gases and metal chamber walls, maintaining image quality while enabling in situ measurements.
Solution Approach 2:
The patent implements iterative reconstruction algorithms that use feedback from the measured transmission data to correct for beam hardening artifacts. The system continuously refines the density distribution reconstruction by comparing predicted and actual measurements, adjusting the model to account for energy-dependent attenuation effects in the high-pressure flame environment.
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 in situ measurement of gas and particulate distribution within closed metal volumes, improving quality control, reducing pollution emissions, and enhancing the design and operation of turbine engines by providing detailed structural information under high-pressure and temperature conditions.
Implementation Method 1
X-rays can penetrate through very dense materials such as concrete and metal and still detect density measurements that are less than 0.1%
Implementation Method 2
X-Ray absorption has also been used in small laminar flames to obtain information on particulate formation
Data Source
AI summary
Method for detecting variations in gas density within a volume surrounded by a closed metal wall opaque to optical light includes a source of x-rays positioned at a selected location outside the closed metal wall. Positioning a detector outside the closed metal wall at a location suitable to detect x-rays from the source passing entirely through a portion of the volume surrounded by the closed metal wall. Providing the detector with a plurality of sensors arranged in at least one row to capture a dimensionally distributed view of detected x-rays. Coupling a processor to an output of the detector to analyze the data which can be displayed in a suitable graphical or pictorial presentation, including processing the data to correct for any beam hardening of the x-rays as they pass through the closed metal wall, to apply the Maximum Likelihood Estimation method to generate on the display a reconstructed image of the gas density, and to use Inverse Radon Transforms for deconvolution. A dopant can be added to enhance the interaction with the x-rays.