Computations of Drop Sizes in Pulsating Sprays and of Liquid-Core Length in Vaporizing Sprays

820133

02/01/1982

Event
SAE International Congress and Exposition
Authors Abstract
Content
Computations are reported of transient axisymmetric pulsating and evaporating sprays that account also for drop collisions and coalescence. It is found that, for the same upstream and gas conditions, pulsating injections result in smaller drops than continuous injections. The difference is particularly marked at high gas densities and is due to the inhibition of collisions and coalesce of drops generated by the gas gap in between the pulses. However, the tip penetration rates are not markedly different for continuous and pulsating injections. For transient evaporating sprays it is found that all drops except the largest evaporate within a well defined distance from the injector. Beyond this distance only vaporized liquid and entrained gas continue the penetration. For engine applications the length of the liquid core is found to be of the order of centimeters and sensitive to conditions. In particular it decreases with increasing injection pressure, gas temperature, and gas density. The sensitivity of the liquid core length to conditions may explain the different importance attached by different authors to the liquid phase in direct injection stratified-charge and Diesel engines.
Meta TagsDetails
DOI
https://doi.org/10.4271/820133
Pages
23
Citation
Kuo, T., and Bracco, F., "Computations of Drop Sizes in Pulsating Sprays and of Liquid-Core Length in Vaporizing Sprays," SAE Technical Paper 820133, 1982, https://doi.org/10.4271/820133.
Additional Details
Publisher
Published
Feb 1, 1982
Product Code
820133
Content Type
Technical Paper
Language
English