摘要

The need for a reliable research method of the external flow field has increased with the more widespread use of intermediate pressure jets. The experimental method and numerical simulation method were investigated, using the particle image velocimetry (PIV) technique and the volume of fluid-level set (VOF-level set) method. Both methods performed well on nozzles with different geometric parameters at distances close to the nozzle and further away from it. With reference to the different measurement windows, the velocities in vertical profiles along the x-axis, the change of maximum jet velocities and the break-up length ranges of jet flows were obtained. The two methods authenticate each other, and the results indicate that the maximum velocities of jets decrease and the distribution widths of velocity field also increase with increase in distance away from the nozzles. The PIV and simulation gave similar results at different distances from the nozzle, and the experimental values were slightly higher than the simulation values due to the pressure fluctuation with an error of less than 8%. The break-up length of jets increases with pressures in situations where the experimental values were lower than the simulation values due to the effect of air. The experimental data from PIV agreed well with the simulation results. Therefore, the accuracy and reliability of the PIV experiment and the CFD (Computational Fluid Dynamics) result simulation were both validated.