The importance of burner alignment on kiln operation has previously been discussed in FCT's regular news sheet "Burning Issues", noting there is no common, single optimum position for a burner. The prime location for the burner depends on secondary airflow patterns. These are influenced by hood design and the operation of the cooler.

Large hoods and well designed coolers on modern kilns give good airflow patterns, but many older kilns provide less than ideal airflow

It is not often easy (inexpensive) to correct airflow by modifying the hood or cooler, so that unless relatively simple changes can be made to the hood, the most cost effective method is to match the burner with existing aerodynamics. A suitably designed physical model is used to represent the precise aerodynamics of the kiln.

Water bead and acid-alkali are two modelling techniques used. The former is used too study flow patterns while acid-alkali modelling assists in the investigation of fuel-air mixing and determining flame shape.