X-ray high speed visualization and measurement of cavitation flow in a nozzle under transient injection condition

초록

A number of studies on cavitation flow in the nozzle of fuel injectors have been carried out. However, quantitative measurement of local liquid velocity and liquid volume fraction in cavitation region has not been conducted yet due to the inaccessibility of the visible light, which prevents the verification and modification of numerical cavitation model. In this study, we develop a new high-speed measurement method to measure the spatial distributions of local liquid velocity and local liquid volume fraction using X-ray at SPring-8 (Super Photon ring-8 GeV). We mixed tiny hollow glass particles in liquid, which can be visualized by X-ray phase contrast imaging method. By Particle Image Velocimetry (PIV) analysis of the glass particle images, we measured instantaneous liquid velocity distribution in the cavitation region within a two-dimensional nozzle with 1.00 mm in nozzle width W and 4.0 mm in length L (L / W = 4.0). We simultaneously measured the local liquid volume fraction αL based on the local particle number n of the glass particles. As a result, we obtained the spatial distribution of liquid velocity and liquid volume fraction in a cavitating flow within a nozzle. © 2018 Solar Turbines Incorporated.

키워드