ELECTROSTATICALLY PRODUCED FUEL SPRAYS FOR COMBUSTION APPLICATIONS

A charge injection nozzle suitable for package burner applications has been designed and tested, spraying insulating liquids such as kerosene, diesel or white spirit. The nozzle consists of a sharp pointed needle as a charge injector and a shaped nozzle body as an anode and extractor. A systematic experimental study together with numerical modelling has been carried out to optimise the nozzle and establish the basis for the theoretical study. The prediction of the atomization process is based on a better understanding of the charge injection mechanism. The charge injection from the needle tip is assumed to be not only by field emission but also by the creation of ions produced by dissociation of ion pairs from ionic compound or neutral molecules under a strong electric field. A description of the atomization characteristics using semi-empirical expressions which take account of the liquid volume flow rate and charge carrier mobility can give a prediction of the liquid breakup length which agrees well with the experimental results.