Optical Diagnostics of the Dispersion Composition of Fuel-Air Flare
Authors: Oksana Isaeva, Marina Boronenko, Yura Boronenko
Abstract: One of the central problems of using heavy hydrocarbons as fuel for thermal burners and internal combustion engines is mixture formation. The purpose of this article is to present the results of optical diagnostics of the dispersion composition of a fuel-air torch according to the developed method. The technical means of the information acquisition and processing system can be a high-speed micropyrometric complex for measuring temperature and flame propagation velocity, the main elements of which are a personal computer and a VideoSprint high-speed video camera. The software includes the Origin data analysis package and ImageJ, a free image processing program. The peculiarity of the video camera is that it can detect low-intensity radiation due to amplification in microchannel plates, and the speed and multi-frame exposure is provided by an electronic shutter. To use video cameras as high-speed pyrometers, their preliminary calibration is necessary. During the calibration of the video camera, the non-linearity of the response of the measuring system depending on the exposure time was revealed. The study of the injection process in diesel mixture formation requires reliable information on the relationship between the speed characteristics of the fuel jet and the dynamics of the fuel supply cycle. Optical research methods do not destroy the structure of the fuel plume and allow obtaining information about the structure and dynamics of the flame development. The technique also makes it possible to obtain data on the root angles of fuel plumes and to estimate the distribution of aerosol particles along their length. For analysis, an experimental frame of the fuel atomization process was taken, made in the Videoscan VS-SST-285 system with an exposure of 39 µs, the delay time of the sync pulse from the pressure sensor was 300 µs. From the analysis of the fuel jet, it was found that the maximum fuel concentration is observed at the atomizer, in the initial zone of the jet and in the front (less than at the atomizer), and there is also a deviation of the torch core axis from the nozzle axis. As experiments show, a change in the angle of the spray cone by 10° and a deviation of the axis of the cone from the axis of the nozzle are permissible by 3-5°. Obtaining data for processing using a high-speed micropyrometric complex can greatly improve the quality of diagnostics. The result of experimental data processing according to the proposed method is consistent with the previously obtained results, which indicates great prospects for further development of this express diagnostic method to obtain numerical characteristics of fuel jet dispersity and improve the ecology of heavy hydrocarbon combustion processes.
Keywords: sputtering quality, optical non-uniformity, image processing
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