A guide to spray properties

It could be said that the spray nozzle business is “just flinging water about”.  Whilst that description is certainly factually correct, there is a little more to “just flinging water about” than one might first suspect.  In fact, there are numerous ways in which water can be flung.  How it is flung will greatly affect the properties of the spray produced and this can have a dramatic impact on the effectiveness of the spray.

In this guide we explore some of the basic characteristics of sprays and how nozzle selection affects them.  This is not an extensive guide to spray dynamics, as that would fill several large volumes, but simply an introduction to allow a non-specialist to engage in a meaningful conversation with an expert manufacturer of spray systems.  

The guide is broken down into 8 parts

Part 1: This introduction 
Part 2: Basic spray patterns. Here the basic spray pattern types are explained

In the next four sections important spray characteristics are discussed as follows

Part 3: Droplet size. This is the first of the 4 critical characteristics of a spray which are discussed.  Details are given on what factors affect droplet size and why droplet size can be important. 
Part 4: Spray reach and impact. A discussion of why this is important and what factors can affect it.
Part 5: Actual vs theoretical coverage. A discussion of how the theoretical, idealised geometric shapes of spray patterns may vary in the real world and what factors will cause such variations.
Part 6: Fluid distribution. A discussion on how fluids are distributed within a given spray pattern and how nozzle design and other factors affect how evenly distibuted fluid is

The preceding sections have discussed only hydraulic nozzles and so the next section discusses the effects of air atomising nozzles

Part 7: Air atomising nozzles. This section illustrates how the introduction of air as an atomising medium changes the rules outlined above.

Part 8: Conclusions and recommendations.

This entire article can be accessed as a single PDF if preferred. 

Next: Part 2 -The basic spray patterns