Spatial, Temporal, and Thermal Analysis of a Cavitating High-Pressure Water-Jet

Abstract

A cavitating high-pressure water-jet (as used for testing the erosion resistance of pipelines) was examined using high-speed photography, thermography, and image analysis to describe the relationships between spatial and temporal fluctuations observed in the flow and the temperature fields at pressures reaching 69 MPa. Frictional heating of the jet, as it left the nozzle, increased as the pressure increased. The increase from 13.8 MPa to 69.0 MPa was 2.9 K (70.7%) on the minimum, and 2.6 K (29.9%) on the maximum, temperatures measured. Good correlation was seen between the upper and lower jet-edge frequencies which ranged from 4.5 Hz to 6.8 Hz. Correlation coefficients were 0.85 and 0.97 respectively. The jet’s lower edge was influenced by temperature at lower x/dn values (x/dn≤ 2), with correlation coefficients at x/dn = 1 and 2 of 0.80 and 0.87, respectively. This experimental characterisation of a high-pressure water-jet is offered as a baseline case suitable for benchmarking against any of the packages (or models developed on an ad hoc basis) used for the numerical analysis and simulation of multiphase fluid flows.