Abstract
A fibre-optic heterodyne interferometry system wasdeveloped to obtain the temperature histories of an unburnedmixture with high temporal resolution non-intrusively. In laserinterferometry, the effective optical path length of the testbeam changes with the gas density and corresponding changes of the refractive index. Therefore, the temperature history of anunburned gas can be determined from the pressure and phaseshift of the heterodyne signal. A polarization-preserving fibreis used to deliver the test beam to and from the test section,to improve the feasibility of the system as a sensor probe. Thetemperature of the unburned mixture in the end-gas region of aconstant-volume combustion chamber and in an engine cylinder wasmeasured during flame propagation. The accuracy of themeasurements and the feasibility of this system are discussed.The measurement accuracy of our system was sufficient to beapplied to temperature history measurement of an unburned gascompressed by flame propagation in a constant-volume combustion chamber. The uncertainty of this method is within ±10 K.The resolution of the temperature measurement is approximately0.5 K, and is dependent on both the sampling clock speed of theA/D converter and the length of the test section. Thisfibre-optic heterodyne interferometry system can also be usedfor other applications that require a transient temperature witha fast response time.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
