Design of sprinkler-drip dual-purpose self-priming pump based on design of experiment

Abstract: Agricultural self-priming pump is widely used in sprinkler irrigation and drip irrigation system. But, the self-priming pump that could be used for sprinkler and drip dual-purpose irrigation system is lacking. Common centrifugal pump design method is used for a single point design only and not for multi-objective optimization design. At present，many design methods can be for multi-operation condition. These methods have made a certain progress in solving specific problems, but have some shortcomings such as causing big error between measured and real value. Design of experiment (DOE) is a statistic method for experiment arrangement and data analysis. It has been used for multi-objective optimization design in pump optimization design. The objective of this study was to design a self-priming pump that could be used for sprinkler and drip dual-purpose irrigation system based on DOE and numerical design. As such，the pump was expected to meet with the requirements of two operation conditions, the discharge 12 m3/h and the head 30 m for the sprinkler irrigation and the discharge 18 m3/h and the head 20 m for drip irrigation. The DOE design method was employed in the multi-point design of impeller for the self-priming pumps 50ZB-30C. Numerical simulation was conducted in the environment of computational fluid dynamics (CFX) with speed inlet and free flow outlet. The k-epsilon model was used as turbulence model and the calculation was based on the SIMPLEC algorithm. No slip wall boundary condition was used at the boundary layer. The boundary layer roughness was 25 μm and 0.02 s was chosen for physical time scale. The largest number of iterations was 1000. The influence of impeller geometric parameters on the head was analyzed so that the regression equations between them at different operation points were established. With proper variables in the regression equations, the geometric parameters of impeller could then be calculated for specific design requirements. The experiment on the newly designed self-priming pump showed that the discharge and the head was 12 m3/h and 30.3 m for the sprinkler irrigation, and 18 m3/h and 21 m for drip irrigation, meeting the design requirements. The results indicated that the mathematic models established by DOE could be used to describe the relationship between the head and corresponding impeller geometric parameters at different operation conditions. The head curve became steeper as the blade angle and the blade outlet angle decreased.