Improvement of Measurement Accuracy of Laser Diffraction Method in Sizing Spray Particles

Drop size measurement is an important part in studying atomization characteristics and spray behavior. Recently, the laser diffraction method that does not interrupt the spray flow is being widely used. In the present study, a set of reticles (reference particles) with known size distributions, based on the Rosin-Rammler distribution function, were used to evaluate the measurement accuracy of the laser diffraction method. Experimental results showed that Sauter mean diameters (SMD) measured with a laser diffraction particle analyzer were in good agreement with the true values for the entire range of the Rosin-Rammler distribution parameters tested. However, the dispersion parameters in the Rosin-Rammler function were measured to be considerably different from the actual ones, as the particle distribution became monodispersed. Thus, functional expression for the parameter representing the dispersion was proposed in terms of the peak height ratio obtained directly from the light energy distribution information.