Implementation of Local Chemiluminescence Method on a Premixed Laminar Propane/Air Flame

In this work, the local chemiluminescent intensities ofOH* and CH* of a premixed laminar Propane/airbunsen burner flame have been measured. To achievehigh spatial resolution a multi-color integratedCassegrain receiving optics (MICRO) is developed. TheCassegrain-based optical system consists of two mirrorsso it is free of chromatic aberration. The design of theoptical system is optimized to minimize other kinds ofaberration, especially spherical aberration. Theoptimization process is done in Zemax program. Theeffective light collection volume of the MICRO systemis estimated to be a cylinder with ۵۸ micrometers indiameter and ۳.۴ millimeters in depth. To measurechemiluminescent emissions of OH* and CH* aphotodetection unit is developed. The photodetectionunit has the ability to separate CH* emission which itsmaximum is in wavelength of ۴۳۰.۵ nanometers andOH* emission which its maximum is in wavelength of۳۱۰.۴ nanometers through a dichroic filter.Photomultiplier tubes (PMTs) are used as light detectorsand the output voltage is measured through a dataacquisition system. The Temporal resolution of the dataacquisition system is ۲ microseconds. The effect of theequivalence ratio on the OH*/CH* signal is investigatedand the calibration curve is extracted between theequivalence ratio and the OH*/CH* signal in a certainrange of equivalence ratios for Propane/air combustion.The effort in this work is put into the design of theCassegrain-based optical system and the process of thedesign is discussed in detail.

کلیدواژه ها:

Chemiluminescence ، Cassegrain optics ، Combustion radicals ، Laminar flame ، Equivalence ratio