ID 420

Assessment of Optimal Location for Water Injection in Intake Air of an Engine for Enhanced Spray Quality

 

Abstract:

Three-dimensional CFD study of diesel engine intake system was carried out for assessment of an optimal location to carry out water injection. Water injection in diesel engines has the potential to reduce Oxides of Nitrogen (NOx) if the spray quality is good. The current study includes assessment of two locations of placing the water injector in the intake duct with Exhaust Gas Re-circulation (EGR) in-order to take advantage of hot EGR stream. In the first part of the study, the CFD results were validated with test bench results of spray in quiescent condition as well as within an optical intake duct. Second part of the study involved assessment of suitable location by CFD analysis under boosted intake condition. Apart from spray length and droplet size, inertia of the water spray droplet and Weber number was calculated to make an assessment of the spray quality and atomization. CFD results show that a co-flow water injection spray into the intake air stream provides superior atomization. This was taken up for engine experimental studies as a next step which helped achieve NOx emission reduction to an extent of 20% without any penalty on soot emissions.