Ma=1的气流流进一个渐缩喷管会怎么样?若是被减速,则一旦Ma1,渐缩喷管立刻会使气流减速直到Ma=1.难道是一直保持Ma=1?我可以证明不会一直保持Ma=1,如下理想气体绝热流动假设保持Ma = 1,则u = a =
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![Ma=1的气流流进一个渐缩喷管会怎么样?若是被减速,则一旦Ma1,渐缩喷管立刻会使气流减速直到Ma=1.难道是一直保持Ma=1?我可以证明不会一直保持Ma=1,如下理想气体绝热流动假设保持Ma = 1,则u = a =](/uploads/image/z/4767624-0-4.jpg?t=Ma%3D1%E7%9A%84%E6%B0%94%E6%B5%81%E6%B5%81%E8%BF%9B%E4%B8%80%E4%B8%AA%E6%B8%90%E7%BC%A9%E5%96%B7%E7%AE%A1%E4%BC%9A%E6%80%8E%E4%B9%88%E6%A0%B7%3F%E8%8B%A5%E6%98%AF%E8%A2%AB%E5%87%8F%E9%80%9F%2C%E5%88%99%E4%B8%80%E6%97%A6Ma1%2C%E6%B8%90%E7%BC%A9%E5%96%B7%E7%AE%A1%E7%AB%8B%E5%88%BB%E4%BC%9A%E4%BD%BF%E6%B0%94%E6%B5%81%E5%87%8F%E9%80%9F%E7%9B%B4%E5%88%B0Ma%3D1.%E9%9A%BE%E9%81%93%E6%98%AF%E4%B8%80%E7%9B%B4%E4%BF%9D%E6%8C%81Ma%3D1%3F%E6%88%91%E5%8F%AF%E4%BB%A5%E8%AF%81%E6%98%8E%E4%B8%8D%E4%BC%9A%E4%B8%80%E7%9B%B4%E4%BF%9D%E6%8C%81Ma%3D1%2C%E5%A6%82%E4%B8%8B%E7%90%86%E6%83%B3%E6%B0%94%E4%BD%93%E7%BB%9D%E7%83%AD%E6%B5%81%E5%8A%A8%E5%81%87%E8%AE%BE%E4%BF%9D%E6%8C%81Ma+%3D+1%2C%E5%88%99u+%3D+a+%3D)
Ma=1的气流流进一个渐缩喷管会怎么样?若是被减速,则一旦Ma1,渐缩喷管立刻会使气流减速直到Ma=1.难道是一直保持Ma=1?我可以证明不会一直保持Ma=1,如下理想气体绝热流动假设保持Ma = 1,则u = a =
Ma=1的气流流进一个渐缩喷管会怎么样?
若是被减速,则一旦Ma<1,渐缩喷管立刻会使气流加速直到Ma=1.
若是被加速,则一旦Ma>1,渐缩喷管立刻会使气流减速直到Ma=1.
难道是一直保持Ma=1?我可以证明不会一直保持Ma=1,如下
理想气体绝热流动
假设保持Ma = 1,则u = a = sqrt(γRT)
质量守恒:ρu A = constant
因为渐缩喷管A↓,所以(ρu)↑
因为ρ= P/RT,u = sqrt(γRT),所以(P/RT)×sqrt(γRT)↑
为使流动方向向前,必有P↓,所以只能(sqrt(T)/T)↑
等价于(1/sqrt(T))↑,sqrt(T)↓,T↓
然而对于绝热流,h = Cp×T + 1/2×u^2 = constant
现在T↓,则必须u↑
但是前述u = sqrt(γRT),当T↓时,u↓
故矛盾.这是质量守恒和能量守恒之间产生的矛盾.
Ma=1的气流流进一个渐缩喷管会怎么样?若是被减速,则一旦Ma1,渐缩喷管立刻会使气流减速直到Ma=1.难道是一直保持Ma=1?我可以证明不会一直保持Ma=1,如下理想气体绝热流动假设保持Ma = 1,则u = a =
你的推导都是正确的,所以就是说,你说的情况不存在.
也就是不存在Ma=1的气流流进收缩管道的情况.
因为:如果是从开放的自由流动冲入收缩管道的情况,这时在管口会产生弓形激波,导致一部分气流溢流.
如果是封闭的情况,那么在收缩管道前部是不会出现Ma=1的情况的,因为如果是从低速加速上来的话,后部的喉道处Ma达到1就堵塞了,前部的气流就保持亚音的,如果是从高速减速下来的话,前部就保持超音的.
你可以问,那么从超音速的状态一直减小来流压力,总有一个时刻在收缩管道的进口是音速的吧?嗯,可能有,不过不是个稳定状态,是非定常的,你用的定常公式就不对了.
has a month to get married and be happy happy. .
finally into the real men from the boys, and very much looking forward to ah!
Although I used to lazy to death, even the brain do not want ...
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has a month to get married and be happy happy. .
finally into the real men from the boys, and very much looking forward to ah!
Although I used to lazy to death, even the brain do not want to use what. But I am serious guarantees:
\
also please bless us all right.
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