Can someone help me to calculate the velocity at Stack Tip?

  • #1
3
0

Homework Statement


How can we calculate the velocity at stack tip if the distance of larger diameter is 2.5 m?
I think i cannot use the equation of V1A1 = V2A2 because they may have some effect from 2.5 m of distance.
Thank you very much.

Homework Equations


Q1=Q2

The Attempt at a Solution


V1A1 = V2A2
45.74*2.4 = V2*6.16
V2 = 17.82 m/s
 

Attachments

Answers and Replies

  • #2
rude man
Homework Helper
Insights Author
Gold Member
7,864
792

Homework Statement


How can we calculate the velocity at stack tip if the distance of larger diameter is 2.5 m?
I think i cannot use the equation of V1A1 = V2A2 because they may have some effect from 2.5 m of distance.
I think you're right. That formula applies to incompressible fluids like water. The flue gases are of course compressible.

I'm afraid I must leave this one to other helpers.
 
  • Like
Likes Suradanai
  • #3
haruspex
Science Advisor
Homework Helper
Insights Author
Gold Member
2020 Award
35,509
6,421
There seems to be some confusion in the diagram. It shows a "velocity" in m3/s, asks about another such in the same units, but also quotes a "flow rate" in those units at the "exhaust temperature". How does that relate to the two velocities?
I have a suspicion the two "velocities" are supposed to be m/s. Given the diameter, that would seem to be consistent with the volumetric flow rate. If so, it makes the question much easier; you can ignore most of the information.
 
  • Like
Likes Suradanai
  • #4
3
0
I think you're right. That formula applies to incompressible fluids like water. The flue gases are of course compressible.

I'm afraid I must leave this one to other helpers.
Thank you very much, now I am looking the gas equation also that can apply this issue.
 
  • #5
3
0
There seems to be some confusion in the diagram. It shows a "velocity" in m3/s, asks about another such in the same units, but also quotes a "flow rate" in those units at the "exhaust temperature". How does that relate to the two velocities?
I have a suspicion the two "velocities" are supposed to be m/s. Given the diameter, that would seem to be consistent with the volumetric flow rate. If so, it makes the question much easier; you can ignore most of the information.
Oh!, that's my mistake, the right should be (m/s) as you said.
Thank you very much
 
  • #6
haruspex
Science Advisor
Homework Helper
Insights Author
Gold Member
2020 Award
35,509
6,421
Oh!, that's my mistake, the right should be (m/s) as you said.
Thank you very much
"The right"? Do you mean the "flow rate"? I would have thought that was m3/s, and the two "velocities" should be m/s.
 

Related Threads on Can someone help me to calculate the velocity at Stack Tip?

  • Last Post
Replies
4
Views
1K
Replies
15
Views
859
Replies
6
Views
3K
Replies
13
Views
6K
  • Last Post
Replies
5
Views
1K
  • Last Post
Replies
5
Views
2K
Replies
4
Views
877
  • Last Post
Replies
1
Views
3K
  • Last Post
Replies
3
Views
1K
  • Last Post
Replies
1
Views
1K
Top