Measurement of mixture homogeneity in direct injection systems.

摘要

Direct injection systems have been developed in recent years to enhance the feasibility of this technology for site-specific on-field pesticide application, to reduce environmental pollution, and to ensure operator's safety and comfort. The injection of concentrated pesticides downstream of the water tank demands additional features for mixture homogenization. To evaluate the system's mixing properties, a decolorization method and a new sensor for mixture quality measurement at the nozzle were developed and tested. Results showed that the sensor and the method described in this work were adequate for determining the homogeneity of the mixture during injection. Different mixing chamber settings were tested with and without a KMS static mixer. The results indicated the necessity of a mixing device for direct injection systems with short lag times. For a static mixer, the impacts of the mixer position, mixer length, additive viscosity, and mixing ratio were tested. The 12 L/D KMS static mixer was found to be an optimal device for the mixing process in the nozzle with additive concentrations of up to 0.3%. The mixing time can be reduced to 40.2 ms in this case. In the case of non-optimal positioning of the mixer or mixing at lower concentrations, the mixer length should be extended to achieve the same mixing result.