Instrumentation for Non-Intrusive Water Droplet Size and Mass Flux Measurements Utilizing the Phase Doppler Method

There is a need for non-intrusive instrumentation to characterize the drop size distribution and volume flux in support of on-line engine/inlet icing tests. The ducts may vary from three to twelve feet in diameter with flow field speeds from Mach 0.2 to 0.5. The Phase Doppler technique offers the best potential for making these measurements non-intrusively and with sufficient accuracy to meet the size distribution and volume flux accuracy requirement. Large optical systems that utilize Cassegrain mirrors will be considered. These systems have the aperature size that will ensure accurate size measurements and acceptable SNR. To process the signals reliably and at a very high data rate, the further development of the advanced Real-Time Signal Analyzer (RSA) using Fourier analysis will be part of the program. This new method for signal processing will be fully automated to minimize the need for user intervention. It also has excellent accuracy even at low SNR so it will meet the present requirements of accuracy in large scale facility operations. Software will be developed to expedite the measurements. A prototype system will be used to evaluate the potential of using this method for routine testing.