Experimental Investigation of Mixture Formation and Flame Development Using the Basics Technique of Schlieren Optical Visualization Principle

Abstract

The Schlieren technique remains to be one of the most powerful technique to visualize the flow and it is relatively easy to implement, high and variable sensitivity, low cost and its used conventional of light. This technique allows us to see the invisible of the optical inhomogeneities in transparent media like air, water and glass that otherwise cause only ghostly distortions of our normal vision. This research investigates the mixture formation and flame development of biodiesel fuel using the Schlieren optical visualization principle. This method can capture spray evaporation, spray interference, mixture formation and flame pattern clearly with real images. During the experiment, the camera lens was used with telephoto lenses (Nikon 70-300mm f/4-5.6G) in order to capture a large amount of light especially the low flame intensity during the initial flame development. The flame development was captured with color images from a color digital video camera. This method can capture the flow of fluids of varying density, such as spray evaporation, spray interference and mixture formation clearly with real images. The result shows that the mechanism of fuel-air mixing and a better comprehension of combustible mixture that can give valuable information to improve and optimize the combustion process. IntroductionThe Schlieren photography technique is a visualization that used to capture the flow. The Schlieren technique remains to be one of the most powerful technique to visualize the flow and it is relatively easy to implement, high and variable sensitivity, low cost and its used conventional of light. Schlieren imaging system has been used since early 1800's to visualize fluxions optical density [1][2]. Schlieren optical visualization technique system [1] is the unique technique because it produce a neutral image easily-interpretable image of refractive-index-gradient fields [3]. The Schlieren technique remains to be one of the most powerful technique to visualize the flow and it is relatively easy to implement, high and variable sensitivity, low cost and its used conventional of light. Schlieren technique also based on the light reflection and in this technique the light reflect by using concave mirror. It is more sensitive than its companion the shadowgraph, and better suited to the qualitative visualization than its cousin the interferometer [1][2][3]. The Schlieren optical system delivers the ability to view the phase of the object that cannot be seen normally by a human eye [4]. Most of the Schlieren technique is utilizing the toopler technique as the benchmark for the most Schlieren systems.However, the traditional instrument of Schlieren have a limitation in the field of view by the cost for the lagers diameter of Schlieren mirror also got the high quality optics. The method of slain