| Abstract | A series of transient tests was conducted to establish the effects of P3 Dump Bleed and of Anti-Icing Bleed on J85-CAN-15 compressor performance, under Sea Level Static operating conditions. Bleeding compressor air through either the P3 Dump System or the Anti-Icing System reduced the peak transient pressure ratio by 0.15 to 0.30, or 2.4 to 4.8%. However, in throttle bursts from 20% NPI, 40% THRUST, and IDLE to MAX A/B, compressor bleed resulted in increased rollback, typically between 0.4 and 1.6% compressor speed over the no bleed conditions. The combined effect of drop in pressure ratio and greater compressor rollback was an increased stall margin of between 15% and 35% for all types of transient accelerations investigated. Within test tolerances, no difference in compressor operating behaviour could be established between P3 Dump or Anti-Icing Bleeds. Both bleed systems were equally effective at reducing the stall propensity of the test engine. |
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