An analytical investigation of the dynamic performance of a centrifugal lift fan was conducted to provide an explanation for the behavior which occurred when the fan was subjected to a varying backpressure. Analysis of test data shows that the fan response delta Q/delta P can be represented by a first-order lag system. An in-depth analysis of the various elements of the lift fan system revealed that the inertia of the air within the fan was the primary contributor to the observed fan behavior. The analysis further showed that variations in fan speed would not produce the behavior measured in the test and that the response due to the compliant properties of air within the fan occurs at a frequency that is much higher than the frequency range of the test. A time-domain digital computer program has been developed which integrates the rate of change of fan flow with a varying backpressure. Good correlation is exhibited between test data and the computer predictions at all frequencies. (Kursetz)
Dynamic response of lift fans subject to varying backpressure
Das dynamische Verhalten des Triebwerkgeblaeses bei einer Beanspruchung von unterschiedlich hohem Gegendruck
AIAA-Papers ; 1-11
1978
11 Seiten, 19 Bilder, 4 Quellen
Conference paper
English
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