Quantitative determination of engine water ingestionThis paper describes a novel non-intrusive optical technique for determination of liquid mass flux in a droplet laden airstream. The technique was developed for quantitative determination of engine water ingestion resulting from heavy rain or wheel spray. Independent measurements of the liquid water content (LWC) of the droplet laden aircraft and of the droplet velocities were made at the simulated nacelle inlet plane for the liquid mass flux determination. The liquid water content was measured by illuminating and photographing the droplets contained within a thin slice of the flow field by means of a sheet of light from a pulsed YAG laser. A fluorescent dye introduced in the water greatly improved the droplet image definition. The droplet velocities were determined from double exposed photographs of the moving droplet field. The technique was initially applied to a steady spray generated in a wind tunnel. It was found that although the spray was initially steady, the aerodynamic breakup process was inherently unsteady. This resulted in a wide variation of the instantaneous liquid water content of the droplet laden airstream. The standard deviation of ten separate LWC measurements was 31 percent of the average. However, the liquid mass flux calculated from the average LWC and droplet velocities came within 10 percent of the known water ingestion rate.
Document ID
19860037952
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Parikh, P. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Hernan, M. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Sarohia, V. (California Institute of Technology Jet Propulsion Laboratory, Pasadena, United States)