The development of planar imaging technique for spray characterization

Abstract

The symmetry of spray patterns produced by an atomizer is an important variable in most practical applications. Patternation is a measure of the uniformity of the circumferential or radial distribution of liquid in a conical spray. Unless spray asymmetry is severe, it may not be detected by visual inspection. Hence, quantitative determination of is desirable not only in nozzle design and development but also for quality control in specific applications. For decades, in order to obtain a spray pattern, mechanical patternators have been used. However, mechanical patternators require a careful control to minimize perturbation in the two-phase flow field due to the collectors and provide a limited spatial resolution. To overcome these disadvantages of mechanical patternators, the method using planar imaging which is non-intrusive, has been developed. This optical patternation provides a non-intrusive, high-resolution and quantitative measuring of spray distribution. The fluorescence signal is proportional to the mass of fuel, and thus it is advantageous for quantitative imaging of fuel distribution in sprays. Moreover, the SMD distribution can be obtained from the ratio of fluorescence signal and scattering signal. However, there are several problems in obtaining quantitative spray patternation. The objective of the paper is to describe the method to obtain the quantitative imaging of mass distribution and measure the semi-quantitative SMD distribution.