| 摘要 |
<p>A multi-spool turbofan engine (6) has a high pressure spool (26) that operates at high idle RPM so as to power accessories and minimize acceleration time from idle to full rated RPM without producing high idle thrust which compromises the landing maneuver and ground operation. Gas flow from a combustor (40) is split immediately aft of a high pressure turbine (36) so that only a portion thereof passes through intermediate and low pressure turbine blades (22 and 24) on a low pressure spool (12), thereby reducing significantly the power developed by the low pressure spool (12). Accordingly, the RPM of the fan (18) is significantly reduced thereby reducing the thrust of the engine (6) at idle conditions. Moreover, the relatively high idle RPM of the high pressure spool (26) is maintained due to bleed off of combustion gas immediately aft of the high pressure turbine (36). The relatively high idle RPM for the high pressure spool (26) results in adequate power being delivered to an alternator (56).</p> |
