عنوان مقاله [English]
In a direct injection sprayer (DI), the delay time to change the concentration of chemicals in the spray tip can have a substantial effect on sprayer performance. Delay time is the most important variable in evaluating the performance of a DI system in real time herbicide application. The flow of solution from the injection point to the nozzles was mathematically modeled to quantitatively evaluate the effect of tube volume and carrier flow rate on dynamic specifications, such as delay time. Plug-Flow and Well-Mixed models were used to model solution flow in DI systems. A DI system was designed and built to allow comparison between the mathematical model and tests results. ANOVA (Duncan test) at a 5% confidence level was used to determine the effect of change of the parameters on the delay time. A factorial completely randomized block design and SPSS 15 software were used for statistical analysis of the data. Comparison of the mathematical model with the test results showed that, for time response, the Well-Mixed model had a more appropriate response time than did the Plug-Flow model. The Well-Mixed model is suggested for predicting the dynamic behavior of a DI system. Both models produced stable state values that were slightly different from test results.