Computational Design of Experiments for Compound Fuel Injector Nozzles

A computational design of experiments was constructed to analyze two basic nozzle designs. Several geometric features of the nozzles such as cavity height, exit orifice area, turbulence generator area and exit orifice position in addition to the pressure differential across the injector were used in a 2^k factorial design study. Performance characteristic which were analyzed in an analysis of variance study included the discharge coefficient. atomization efficiency and predicted spray pattern.

The computational design of experiments revealed which of the studied parameters had the greatest influence on a given nozzle performance characteristic. These results were compared to a similar investigation which was later performed experimentally from which similar conclusions were drawn. The computational study also produced the details of the fluid flow inside of the nozzle from which further information regarding the reasons for a particular correlation between a nozzle geometric feature and performance characteristic could be obtained. This information can effectively be used to design a nozzle which will contribute to an optimization of the combustion process.