抄録
In order to evaluate the performance of water jet, radial density distribution or liquid fraction distribution of jet is one of the most important parameters. However, no measurements have been carried out do for due to the very high speed (order of several hundred meters per sec) of water jet. The authors have developed newly measurement system of liquid fraction distribution of high speed water jet using Laser Schrielen method. Laser beam is expanded to parallel beam and crosses the water jet. Then the beam is collected by lens and expanded again through pin hole and recorded by digital camera. From the two-dimensional recorded image, liquid fraction distribution in radial direction of water jet is reconstructed by tomographic method. The experiments were carried out using high speed water jet of industrial use, the nozzle diameter is 1.7 mm, and pressure at outlet of nozzle is 0.1-20 MPa. Radial distributions of liquid fraction were successfully obtained at various positions form nozzle exit. Numerical simulation of water jet was also carried out using homogeneous droplet flow models. The predicted density distributions reasonably agree with experimental data.
