ID 84

Evaluation of Different Methodologies used for Diesel Spray Angle Detection

 

Abstract:

The in-cylinder mixing, combustion and soot processes in diesel engines are strongly influenced by fuel injection and the spatio-temporal evolution of fuel sprays. Hence it is essential to experimentally characterise global spray parameters such as spray penetration and spray angle accurately to provide reliable experimental data for the validation of mathematical models. The accuracy of the experimentally obtained spray parameters is influenced by the algorithms used for image processing.

Many methods have been used in literature to detect spray angles from high pressure diesel spray images, with varying outcomes. To the authors understanding there is no systematic study that compares different spray angle detection methodologies for diesel sprays. For this purpose we have studied five different detection methods: (i) fitting the tangent lines to the spray edge to measure the angle as a function of spray penetration, (ii) fitting the tangent lines to the spray edge as a function of injector geometry, (iii) locally measured and averaged angles as a function of spatial location along the spray, (iv) triangular-based methods based on the spray area and (v) fitting tangent lines to the spray which coincide at an origin that can move freely with the spray. These methodologies were applied to spray images acquired using a high-speed camera and LED back-scatter illumination, in a constant volume chamber under high-pressure non-reactive environment.

In the paper we will present the spray angles obtained from each method, the sensitivity of each method and the level of variation for the full injection event