TWO PHASE FLOW DOWNSTREAM OF A MULTIPOINT LEAN DIRECT INJECTION LOW NO_x NOZZLE

摘要

This work examines the flow downstream of a Parker Hannifin low NO_x LDI nozzle. The nozzle is a square matrix of 3x3 airblast simplex fuel ports. The air pressure drop was set to 5%, for a Reynolds number of 40,000. Liquid injection pressure was 2.28kPa. The nozzle is tested at atmospheric conditions without combustion. The objective of this work is twofold: first characterize the spray and the turbulent flow fields; and second examine the effect of the interaction between jets on turbulence and spray profiles. Jet-jet lateral impingement starts within ～ 1 ― 2 nozzle diameters downstream. The comparison of a single jet and the 3x3 matrix spray profiles shows some degree of coalescence due to the interaction between jets. Despite this, the Sauter mean diameter of the resulting spray field is in the 25 ― 35 μm range. In the first few air swirl cup diameters downstream of the nozzle exit plane (down to z/D=3), the droplets are still accelerating to the air velocity and turbulence is anisotropic. No-slip and turbulence isotropy assumption are accurate only well downstream of the exit plane (z/D=7.5).