737,757左右发引气压力差（剪刀差）

shedengfeng · 发表于 2013-1-25 16:44:15

请教各位，737,757左右发引气压力差（剪刀差）值在多少范围内是正常的？手册中哪里有这方面的说明？

波音 · 发表于 2013-1-25 17:00:01

10到25？

ryn_82 · 发表于 2013-1-25 17:19:58

请参考B737NG FIM 36-10TASK 807. Duct pressure, L and R pointers not the same (split), the engine is the bleed source - Fault Isolation：
A. Description
(1) Split duct pressure is a condition in which the duct pressure on one side, as shown on the dual
duct pressure indicator, is either lower or higher than the duct pressure on the other side with
the engines as the bleed source. Duct pressure splits can occur during both normal and
abnormal operation of the engine bleed systems. The procedures in this task will enable you to
determine if a fault exists in either the left or right pneumatic system based on information from
the pilot report or knowledge of the pneumatic system pressure at specific engine N1 speeds
and aircraft altitudes.
There are no system controls to regulate both systems to a common pressure so an acceptable
split in duct pressure cannot be specified. Each system regulates duct pressure independent
from the other when the isolation valve is closed and should be evaluated based on the engine
N1, not compared to the other duct pressure. FIM 36–10 Task Support Figure 305 defines the 9th
stage regulated pressure as 32 ± 6 psig and 5th stage regulated presure as 42 ± 8 psig.
。。。
(4) If the pilot report does not contain all of the necessary information, the duct pressure split can be
greater than 15 psi but the pneumatic systems still may be operating within normal limits. In this
situation, a system test using the engines is necessary to determine if either system has faults
because the systems may have been operating in different modes of pressure regulation and a
duct pressure comparison under those conditions would be invalid.
(5) In summary, duct pressure splits do not always indicate a fault condition. As long as the
pressures are within system tolerances for the pneumatic system 9th and 5th stage operation,
fault isolation is not required.
只要试车在各种N1下各自的引气压力在正常范围内就行。
+-6是相差12,+-8相差16，系统正常的情况下，在使用9级引气时可能相差12，在使用5级引气时可能相差16。当然相差不超过12和16也不一定就正常，主要是看试车时引气压力得在正常范围。但是如果超过16肯定就不正常了。
未命名1.jpg

君心可晴 · 发表于 2013-1-25 21:31:58

2楼解释的很详细，呵呵！

shedengfeng · 发表于 2013-1-28 10:31:23

谢谢各位了哈。但是在我们公司的试飞工作单上(737-300)，在发动机引气压力检查中，要求左右发引气压力不超过6PSIG.这个我就不明白了。

005315 · 发表于 2013-1-28 10:32:39

楼主：不好意思哦，我不知道哦。

ryn_82 · 发表于 2013-1-29 09:37:11

shedengfeng:谢谢各位了哈。但是在我们公司的试飞工作单上(737-300)，在发动机引气压力检查中，要求左右发引气压力不超过6PSIG.这个我就不明白了。 (2013-01-28 10:31)

B737-300我就不知道了，我发的是B737NG的。

reamon · 发表于 2013-1-29 19:18:55

NG的还是比较熟悉的，CL干的少啊

747-400 · 发表于 2013-7-23 12:58:23

不太明白，有点难

lefoly · 发表于 2014-3-14 10:20:43

机务人才多

888888888 · 发表于 2014-4-11 15:22:07

今天遇到这个问题尴尬

于 2014-08-11 19:53:14 连续回帖自动追加:
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[GE] 737,757左右发引气压力差（剪刀差）

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