Effect of Straightening Vane on Hydraulic Performances of Sprinkler by CFD Analysis

Abstract

A typical internal flow passage of sprinkler is composed of bearing nipple, bend, tube and nozzle. For a medium or large size sprinkler, a unique straightening vane is often installed inside tube in attempts to minimize internal turbulence and to increase radius of sprinkler. To investigate the effect of different structural parameters and installed positions of straightening vane on the hydraulic performances of sprinkler becomes more and more important. The computational fluid dynamics (CFD) approach can be successfully used to simulate the flow characteristics in internal flow passage. In this study, several turbulence models and different mesh types were utilized for different structural characteristics of straightening vanes in search of optimal CFD methods for sprinkler. The distributions of velocity, pressure and turbulence kinetic energy for different straightening vanes at inlet pressures ranging 250-500kPa were obtained. The calculated results revealed that turbulence kinetic energy is reduced significantly at nozzle outlet for sprinkler with straightening vane and the flow rate increases by 8.5% compared with sprinkler without straightening vane. In addition, the relationship between inlet pressure and flow rate for different nozzles were also predicted. Comparisons of CFD predictions with experimental data were presented for a typical PY₁40 impact sprinkler. The results of the simulated and experimental data were in good agreement. Finally optimized geometrical parameters of straightening vanes were brought forward.