The superheated spray has attracted attention due to its enhanced atomization in gasoline direct injection (GDI) engines. Even though spray characteristics of multicomponent fuels under superheated conditions have been studied before, the connection between plume-to-plume interaction and spray cyclic variation (SCV) has not been adequately addressed. Moreover, the lack of physical understanding of SCV for multicomponent fuels hampers effort to reduce GDI engine cyclic variations. Thus, this work investigates the SCV of binary and ternary multicomponent fuel blends under superheated conditions. Three pure components of n-pentane, isooctane, and n-decane were analyzed and compared to their twelve binary and ternary blends. The experiments were conducted using the laser Mie-scattering technique in a spray chamber at a fuel temperature of 70 • C and ambient pressure of 50 kPa. This test condition facilitated the occurrence of subcooled, transitional, and superheated sprays for all 15 fuel blends. Five spray plume-to-plume interaction levels are defined to reveal the relationship between the SCV and plume-to-plume interaction. The results show that the spray structure is constrained by the blending ratio of n-pentane (high volatility component). The transitional spray exhibited higher plume-to-plume interaction with larger SCV on the variations of partially connected plumes. Both the non-collapsed spray (no plumes interaction) and totally collapsed spray (wholly merged plumes) showed less SCV. However, the total collapsed spray showed higher SCV compared to non-collapsed spray. |
