Visualization of Internal Flow and Spray Combustion with Real Size Diesel Nozzle

Abstract

The internal flow in a diesel nozzle affects generation of cavitation and spray formation. The internal flow of a mini-sac type nozzle and its spray combustion have analyzed with optically visible real-size nozzle. The mechanism of cavitation formation in the nozzle hole is investigated by the study of internal flow in the nozzle sac with micro PIV method and CFD. String-type cavitation in the nozzle hole as well as film-type cavitation at the hole inlet can be observed including its generation place and frequency. The spray cone angle close to the hole outlet and spray flame are greatly influenced by string-type cavitation.