Non-Intrusive, Reliable, and Portable Laser Induced Breakdown Spectroscopy for Instantaneous Gas Composition and Density Measurements in High-Speed Flows
Abstract
The original design of the gas property monitoring system is illustrated in Fig. 1. There are two separate measurement domains considered for the design; (1) Cold (unburned) Flow Region and (2) Hot (burned) Flow Region. In the Region (1), ps-LIBS or chopped ns-LIBS is proposed for measuring the gas density, species concentration, and velocity in the intake and isolator area since there is no photon source (within UV, VIS, and NIR for easy detection) in cold flows. For improving the accuracy and extending the possible measurement conditions of the ns-LIBS, the ns laser pulses are modulated, and data-driven machine learning techniques are employed. However, the LIBS measurement inherently requires relatively high laser pulse energy for inducing the breakdown. In addition, a diode laser with a set of guide optics is essential for the velocity measurement using LIBS as tested in the first project year. Interestingly, particularly in the supersonic flows, the SRBS signal is found to be sensitive to the flow speed, therefore, the SRBS signal can also be used for estimating the flow velocity although the LIP-induced shockwave velocimetry (LIPSV) developed in the first project year is more accurate velocity measurement method. We will continue to improve the SRBS velocimetry in a future work.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 25, 2024
- Accession Number
- AD1230661
Entities
People
- Hyungrok Do
Organizations
- Seoul National University