Infrared CO2 State Monitoring for Brayton Compressor Inlet Control
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Solution Overview
Problem
Current methods for monitoring the state of supercritical carbon dioxide at the inlet of a compressor in Brayton cycle systems are inaccurate due to limitations in temperature measurement and sensor placement, leading to deviations in flow and heat transfer characteristics, which affect the system's efficiency and stability.
Innovation Solution
A supercritical carbon dioxide state monitoring and control system based on infrared spectrum characteristic analysis, which includes a test section, an infrared light source, an infrared spectrometer, a pressure control module, and a temperature control module, stabilizes the pressure and temperature of carbon dioxide at the inlet of the compressor to match critical state conditions, using transmittance analysis to adjust and control the state effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are arranged to measure the temperature of supercritical carbon dioxide at the inlet of the compressor, then the temperature can be monitored, but the sensors disturb the flow field distribution of the carbon dioxide in the pipeline, making the actual state deviate from the monitoring result
Solution Approach 1:
The patent introduces an intermediary measurement approach by using infrared spectral absorption characteristics to indirectly determine the state of supercritical carbon dioxide. Instead of placing physical temperature sensors that disturb the flow field, the system uses infrared light passing through the pipeline to measure absorption at specific wavelengths (particularly around 4.26 μm for the asymmetric stretching vibration mode of CO2). This intermediary optical measurement method allows temperature and pressure state determination without physical contact with the flowing supercritical fluid, thus avoiding flow field disturbance while maintaining measurement accuracy.
2Device complexity
If indirect temperature and pressure measurement methods are used to determine the state of supercritical carbon dioxide, then the system structure is simple, but the measurement precision is insufficient due to limitations in temperature test accuracy and complicated state change around the critical point
Solution Approach 1:
The patent transforms the measurement approach by changing from direct temperature and pressure sensing to optical absorption parameter measurement. The system measures the infrared absorption coefficient at specific wavelengths, which is highly sensitive to the state of supercritical carbon dioxide near the critical point. By monitoring changes in absorption parameters (particularly the ratio of absorption at different wavelengths), the system can accurately determine temperature and pressure states without the limitations of conventional temperature sensors. This parameter transformation enables high-precision state monitoring while maintaining relatively simple system structure.
Solution Approach 2:
The patent replaces mechanical/physical temperature sensors with an optical measurement system. Instead of using contact式 temperature sensors that have accuracy limitations and disturb the flow field, the system uses infrared spectroscopy to optically determine the state of supercritical carbon dioxide. The infrared light interacts with the molecular vibrations of CO2, and the absorption characteristics provide information about temperature and pressure without mechanical contact. This substitution of mechanical measurement with optical measurement resolves the contradiction between device simplicity and measurement precision.
3Ease of operation
If the state of supercritical carbon dioxide is not accurately controlled, then the system operation is simpler, but the compressor power consumption increases and cycle efficiency decreases
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the infrared absorption characteristics of supercritical carbon dioxide and adjusts the compressor operation accordingly. The system measures the absorption coefficient at specific wavelengths, compares it with reference values for optimal critical state conditions, and provides feedback control signals to adjust temperature and pressure control mechanisms. This feedback loop ensures that the supercritical carbon dioxide maintains optimal state parameters (temperature and pressure near the critical point) throughout operation, minimizing compressor power consumption and maximizing cycle efficiency while maintaining relatively simple operation through automated control.
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 system accurately monitors and controls the state of supercritical carbon dioxide, reducing compressor power consumption, stabilizing phase states, and improving the overall efficiency of the Brayton cycle system by ensuring the carbon dioxide remains around the critical point, thus enhancing the system's performance and longevity.
Implementation Method 1
an infrared light source emitting a detection beam to the carbon dioxide passing through the test section; an infrared spectrometer receiving and analyzing the detection beam passing through the test section
Implementation Method 2
an infrared light source emitting a detection beam to the carbon dioxide passing through the test section
Data Source
AI summary
A supercritical carbon dioxide state monitoring and control system based on infrared spectrum characteristic analysis. The system includes: a test section for carbon dioxide to pass through; an infrared light source emitting a detection beam to the carbon dioxide passing through the test section; an infrared spectrometer receiving and analyzing the detection beam passing through the carbon dioxide; and a pressure control module controlling pressure of the carbon dioxide at a set value. In addition, the system also includes a temperature control module capable of monitoring and adjusting temperature of the supercritical carbon dioxide. The supercritical carbon dioxide state monitoring and control system may monitor and control a state of the carbon dioxide at an inlet of an apparatus under an actual operation condition in a Brayton cycle system, which improves working performance of the apparatus in the Brayton cycle system, thereby improving overall efficiency of the Brayton cycle system.