High-Enthalpy Shock Tunnel Diagnostics Using Contact and Optical Sensing
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Solution Overview
Problem
Existing methods for diagnosing high-enthalpy shock tunnel parameters struggle to accurately measure and analyze the complex physical and chemical changes in high-enthalpy flows, such as gas molecule excitation, dissociation, and ionization, which are crucial for understanding re-entry phenomena of supersonic and hypersonic objects, due to the strong friction and energy conversion during re-entry.
Innovation Solution
A system and method utilizing contact measurement technology, laser schlieren technology, non-contact absorption and emission spectrum technologies, and multi-component, multi-temperature numerical simulation to diagnose high-enthalpy shock tunnel parameters, including piezoelectric sensors, total pressure sensors, absorption and emission spectrum systems, and data processing systems, to measure flow field parameters with high sensitivity and rapid time response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact measurement technology is used to measure flow field parameters, then measurement precision is improved, but the measurement system complexity increases due to multiple sensors and probes required
Solution Approach 1:
The measurement system is divided into multiple independent measurement modules (contact sensors, laser schlieren system, absorption spectrum system, emission spectrum system), each responsible for specific parameters. This segmentation allows parallel measurement of multiple parameters without interfering with each other, improving overall measurement precision while organizing system complexity into manageable modules.
Solution Approach 2:
Optical fibers serve as intermediaries to transmit measurement data from sensors and spectrum systems to processing systems, enabling non-contact data transmission and reducing electrical interference in the high-enthalpy flow environment. This intermediary approach simplifies the overall system architecture by separating measurement and processing functions.
2Loss of information
If multiple measurement systems are deployed to capture complex physical and chemical changes, then information completeness is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
Multiple measurement systems (contact sensors, laser schlieren, absorption spectrum, emission spectrum) are merged into a coordinated measurement platform that simultaneously captures thermodynamic parameters (temperature, pressure), component concentrations, and flow field structures. This merging approach ensures information completeness by capturing all relevant physical and chemical changes in the high-enthalpy flow.
Solution Approach 2:
The measurement approach transitions from single-point contact measurements to multi-dimensional measurement by incorporating optical methods (laser schlieren for density gradients, absorption/emission spectra for composition) that provide spatially distributed information. This dimensional expansion captures the complex three-dimensional structure of the flow field without increasing point-measurement complexity.
3Reliability
If non-contact spectrum technology is used for measurement, then the measurement system reliability is improved in high-temperature environments, but the device complexity increases due to specialized optical equipment
Solution Approach 1:
Traditional contact-based mechanical sensors are replaced with non-contact optical measurement systems (laser schlieren, absorption spectrum, emission spectrum) that measure flow field parameters through electromagnetic radiation interaction. This substitution eliminates physical contact with the high-temperature flow, improving measurement reliability in extreme thermal environments while using well-established optical techniques.
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
The method provides accurate measurements of flow field temperature, pressure, component concentrations, and non-equilibrium state information, as well as determining effective wind tunnel working time, enhancing the accuracy and efficiency of high-enthalpy shock tunnel testing.
Implementation Method 1
Multiple piezoelectric sensors are installed on a shock tube
Implementation Method 2
non-contact absorption spectrum technology
Implementation Method 3
non-contact emission spectrum technology
Implementation Method 4
laser schlieren technology
Data Source
AI summary
A method and a system for diagnosing high-enthalpy shock tunnel flow field parameters are provided. In the method, the parameters of the reservoir at the end of shock tunnel and nozzle free flow are measured by using a contact measurement technology and a non-contact spectrum measurement technology to diagnose the high-enthalpy shock tunnel flow field. With the method, not only flow field temperature, pressure, component category and component concentration, but also non-equilibrium state information of the flow field and the effective wind tunnel working time can be obtained.