Abstract
Many drop-size measuring method have been performed up to date. Illustrative explanations about them are made and the problems on each method are described.
The methods are divided into two kinds. In the first one, whole droplets of spray are sampled to get mean droplet diameter or size distribution. Sedimentation method, molten wax and freezing method, optical method and electrical method are included in this first kind. Measuring apparatuses of these methods become, in general, complex and large in scale.
Direct photography, inpression method and immersion liquid method are those in the second kind. In these method, sampled values have to be transformed into those of whole spray which requires some troublesome procedrures. As the immersion liquid method is relatively simple and easy, it is most popular now, but detailed considerations on it show us many difficulties and problems to get a correct droplet size.
It could be said that every method has its own problems to be solved and we have no method completely correct and reliable yet.
