Abstract
Making quantitative measurements of the vapor distribution in a cavitating nozzle is difficult, owing to the scattering of light at the phase interfaces and walls, as well as the small scales involved. In this paper, we present the results of
new x-ray radiography experiments performed at the 7-BM beamline of the Advanced Photon Source at Argonne National Laboratory. X-ray radiography enables quantitative measurement of the fluid density in multi-phase flows
that are optically opaque. Cavitation in a submerged beryllium nozzle 500 microns in diameter with L/D ratio of 6 was studied. Beryllium was used as it is highly transparent to x-rays. It can withstand higher pressures than plastic
models and has a surface roughness similar to a metal fuel injector. We present quantitative, time-resolved measurements of cavitation vapor distribution with a spatial resolution of 5um and a temporal bandwidth of 6.5MHz. The measurements are compared to RANS and LES predictions of the flow made using a homogeneous relaxation model. The properties of the gasoline surrogate used in the experiments have been replicated in a pressure-enthalpy lookup table that avoids the need for a simplified equation of state. Comparisons are made at cavitation and Reynolds numbers typical of diesel injectors, and variations between the quantitative experimental vapor fraction data and the simulations are discussed. In addition to quantitative comparisons of the time-average vapor fraction distribution in the nozzle, the time-resolved radiography data enable quantitative comparison of the power spectrum of the vapor volume fraction between experiments and simulations. The data highlight the need for validation of both time-average and transient phenomena in cavitation simulations.
new x-ray radiography experiments performed at the 7-BM beamline of the Advanced Photon Source at Argonne National Laboratory. X-ray radiography enables quantitative measurement of the fluid density in multi-phase flows
that are optically opaque. Cavitation in a submerged beryllium nozzle 500 microns in diameter with L/D ratio of 6 was studied. Beryllium was used as it is highly transparent to x-rays. It can withstand higher pressures than plastic
models and has a surface roughness similar to a metal fuel injector. We present quantitative, time-resolved measurements of cavitation vapor distribution with a spatial resolution of 5um and a temporal bandwidth of 6.5MHz. The measurements are compared to RANS and LES predictions of the flow made using a homogeneous relaxation model. The properties of the gasoline surrogate used in the experiments have been replicated in a pressure-enthalpy lookup table that avoids the need for a simplified equation of state. Comparisons are made at cavitation and Reynolds numbers typical of diesel injectors, and variations between the quantitative experimental vapor fraction data and the simulations are discussed. In addition to quantitative comparisons of the time-average vapor fraction distribution in the nozzle, the time-resolved radiography data enable quantitative comparison of the power spectrum of the vapor volume fraction between experiments and simulations. The data highlight the need for validation of both time-average and transient phenomena in cavitation simulations.
| Original language | English |
|---|---|
| Title of host publication | ILASS-Americas 2016, 28th Annual Conference on Liquid Atomization and Spray Systems |
| Place of Publication | Irvine California USA |
| Publisher | Institute for Liquid Atomization and Spray Systems |
| Number of pages | 12 |
| Publication status | Published - 2016 |
| Externally published | Yes |
| Event | International Conference on Liquid Atomization and Spray Systems 2016: ILASS-Americas - The Henry Hotel, Dearborn , United States of America Duration: 15 May 2016 → 18 May 2016 |
Conference
| Conference | International Conference on Liquid Atomization and Spray Systems 2016 |
|---|---|
| Country/Territory | United States of America |
| City | Dearborn |
| Period | 15/05/16 → 18/05/16 |