Characterization of n-butanol and gasoline spray from a multihole injector using phase doppler anemometry

This work reports results of an experimental investigation carried out on a multihole injector for direct injection spark ignition engines by using phase Doppler anemometry (PDA). Results of droplet size and velocity were compared testing n-butanol and gasoline injected at 5 and 10 MPa in a vessel at atmospheric pressure and ambient temperature. Experiments were focused on the characterization of the dynamic behavior of droplet size and velocity acquired on the axis and the edge of one of the jets at different distances from the nozzle hole. The effect of the injection interval and the photomultiplier voltage on the sample distribution was investigated. It was found that these parameters have a strong influence on data validation and their fine tuning can avoid the occurrence of time intervals with lack of validated data. Different post-processing filtering methods were applied in order to evaluate differences linked to the data statistical distributions. Results have highlighted that the different fuel properties have an influence on the droplet size and velocity and affect the jet dynamic behavior.