3 replies to this topic

Dear Friends,
I am working on the vacuum system.
I am using Ludwig Vol. 1 as reference, but in attached graph I am facing problem.
Can any one explain why in section C & E velocity and pressure behaves opposite to bernollis equation.
As a example, In section C there is expansion of the mixture (motive+suction fluid), so pressure head should increase and velocity head should drop. But in the figure, we can see complete opposite.
Waiting for reply

Mahendra

Attached Files

•  Graph_from_Ludwig_Vol1.doc   56.5KB   67 downloads

[katmar]

Mahendra, I think you are simply misreading the diagram. In the diagram, section C refers to the motive steam. As the steam velocity increases, the pressure decreases - as per Bernoulli. In section E the velocity now DEcreases while the pressure INcreases - again as per Bernoulli. Perhaps I have misunderstood your question?

[Jiten_process]

hi

I think he is asking that though the sections A & C and E & G are opposite the effect is same?

In contraction velocity should increase (and pr. decrease) and in expansion velocity should decrease (pr. should increase), right?

if i am not mistaken his question!!!

Dear,
thanks for reply
Eductor is divided in one of chamber, and pressure and velocity graph is divided with resp to that sections, This is my understanding. In this if you compare the suction chamber © then you find velocity increses and pressure goes down from the graph but diagram shows expansion means velocity decreases and pressure increases. same case is in supersonic diffuser section.
I don't say its wrong but why it is like that

MK