Spray cooling systems

The spraying of a fluid to cool gas, solids or even other fluids is a common industrial application.

Cooling is achieved by spraying a cooler liquid that absorbs and carries away heat.  Heat energy is transferred to the coolant either by warming it in its still liquid state or by evaporating/boiling the liquid into a gaseous state (phase change).  With water the latent heat capacity (energy to change water from liquid to gas) and the specific heat capacity (energy needed to warm the water in its still liquid phase) are both high compared to most other fluids.  These thermal properties of water make it a useful coolant.  However, there are some situations where water is not appropriate and so other coolants need to be sprayed.

Nozzle Selection

Depending on the specific cooling application a number of different nozzle designs may be appropriate.  In order to help selection the key engineering considerations are discussed in sub-sections of this page and can be accessed by the blue navigation box to the right of the page.  The different designs of nozzle that may be appropriate are accessed by the grey navigation box, also to the right.  The information presented on spray cooling nozzles of all designs is summarised in the 'cheat sheet' accessed via the orange box which, again, is found on the right-hand side of this page.

Sprial nozzles

Sprial nozzles can be configured to give very wide full cone spray patterns and so are excellent at distributing fluid over a large area. They also produce relatively fine droplets when compared to other hydraulic nozzles and so are suitable for some cooling applications. 

 

Misting nozzles
For evaporative cooling applications a small droplet is required so misting nozzles are a good choice.

  

Air atomising nozzles
Air atomisers use compressed air to help break the fluid into small droplets. The air also helps distribute the spray over a larger area. This makes them suitable for many cooling applications.