Non-linear Taylor Instability Analysis for Elliptical and Elliptical Conical Liquid Hollow Jets and its Application for Non-Circular Fuel Injectors

Abstract

The main goal in the design of injectors is the finest-dispersed and uniform spraying of the liquid. In the case of engines, it gives a dual effect: Increased engine power, fuel economy, and reduction in the concentration of harmful impurities in the exhaust gases. For the processes of thin films spraying, this leads to the saving of expensive materials used for coatings and to obtain a better quality of a surface. A fundamentally this method based on the analysis of non-linear hydrodynamic instability is presented, which allows to determine the optimal shape and dimensions of an injector for a given aircraft/car engine or for deposition of protective shells on surfaces. The present study is a development of our research on the circular shape of a thin liquid film (the main ones are present in [1-4]). By varying the size of the slit for fluid injection and several standard shapes (circular, elliptical with the ratio apogee/perigee, etc.) it is possible to determine at what shape and size of the slit a minimum film breaking time is achieved. Exact hydrodynamic solutions, obtained by this method, may be tabulated to determine input parameters and modes of more optimal injectors, and, as the result, to increase the efficiency of injectors design. The method is based on our completely new physical model, explaining, predicting, and estimating sufficiently non-linear instability of interacting flows. In particular, the instability analysis results are obtained for the elliptically cylindrical and elliptically conical shapes of atomizers. It is shown that atomizers with elliptical nozzle shapes are more effective than atomizers with circular nozzle shapes; their times of the film destruction differ 18 times. The main goal in the construction and design of injectors is the finest-dispersed and uniform spraying of the liquid. In the case of engines, it has a dual effect: increasing of engine power, fuel economy, and decreasing the concentration of harmful impurities in exhaust gases. Software based on the developed theory, will eliminate some work of designers and provide better design of atomizers.