为什么空中单引气不能带双组件

理论上从系统工作角度是可以实现的。但是发动机引气的负荷不足以支撑这样实施。引气系统工作是一种动平衡,就是冷却气和热的引气的一个平衡,下游流量的增加就意味着热的气需求会更多,在冷却气量不变的情况下,然而为了防止引气过热跳开,450电门会不断的去关PRSOV,以减少流量,调节不足甚至会导致引气跳开。组件的正常工作,厂家一般认为在18PSI是一个最低可以正常工作的状态。

SR 1-103542877

1/ Operating two packs from one engine bleed is not recommended. It puts an increased load demand on the one remaining bleed, increasing the chance of an overheat. If the bleed air temperature rises too much, the valve will reduce the outflow to lower the temperature. A single pack is sufficient for providing adequate flow to pressurize the airplane, so that is our recommendation. Note also that dispatching under MMEL item 36-3 requires that altitude be limited to 25,000 feet. A single pack in high flow should provide proper pressurization.

2/ When a bleed trips during flight, the crew should follow the BLEED TRIP OFF NNC (see attached). This procedure instructs the crew to turn off the pack on the affected side. The rationale is the same as described above. One pack in high flow should maintain pressurization, and it is desirable not to put excessive load demand on the one remaining bleed.

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