Abstract:To characterize jet mixture profiles for inline injection of pesticides, twophase flow fields in conventional mixing chambers were investigated under various test conditions. The twophase flow was formed with water mixed with either a watersoluble liquid or a fatsoluble liquid (silicon oil). Test results illustrated that there were limitations for the conventional mixers to obtain uniform mixtures with the fatsoluble pesticide. To overcome these limitations, a new mixing device based on the swirling jet mechanism was conceived and developed to improve the mixture uniformity of water and the fatsoluble pesticide. The swirling jet mixer consisted of a spiral curved shrink tube, a diffuser and a guide vane to accelerate the twophase flow spiral movement and blend the two liquids. A computational fluid dynamics program (Fluent) was used to simulate the flow field inside the swirling jet mixer to optimize its design. The mixture uniformity was evaluated by introducing the uniformity index γa, representing that the two liquids were blended homogenously as γa was 1. Simulated results showed that the γa was 0.9989 across the entire cross sections inside the mixer, confirming uniform mixture profiles with the new mixer design. 〖JP3〗Therefore, the new swirling jet mixer would solve the nonuniform mixture problem associated with conventional mixers and could significantly improve the inline injection technology to reduce pesticide waste.