Two dimensional laser doppler anemometry velocity measurement of a swirling jet flow

Ali R Yilmaztuerk, Purdue University

Abstract

The initial motivation for this work was to supplement the study by Crook (2009) who, amongst other things, designed an axial-plus-tangential swirl injector, performed 1D velocity measurements and calculated normal stresses for supercritical carbon dioxide jets. Therefore, measurements were planned using a 2D LDA operated in coincidence mode to simultaneously acquire both axial and radial velocities, which yield Reynolds stresses. Unfortunately, this objective was not achieved. Investigations were conducted and causes identified which might have been responsible for discrepancies between the two sets of results. Causes include the focal length of the transmitter lens, operating in coincidence versus non-coincidence mode, and the large density gradient near the critical point leading to temperature-driven refractive index changes that masked velocity induced ones. Based on the lessons learned, a set of free jet experiments with similar jet Reynolds number were conducted. Two-dimensional LDA were acquired. Those results are presented herein. The axial and radial velocity data are overall in excellent agreement with the reported values in the literature and with Crook's values (after normalization). The calculated axial normal stresses are in excellent agreement with the literature and in good agreement with Crook's data, as were the radial normal stress results. Finally, cross stress results were in excellent agreement with literature values.

Degree

M.S.M.E.

Advisors

Sojka, Purdue University.

Subject Area

Mechanical engineering

COinS