Real-world calc ideas anybody?

  • Thread starter mechhie
  • Start date
  • Tags
    Ideas
In summary, the conversation discusses a problem posed by a friend from engineering school about finding the average pressure at a standard doorway with a known airflow rate and no leakage. The formula for solving this involves finding the velocity using the density and volumetric flow, and then using Bernoulli's equation. However, there may be discrepancies in the calculations if the door is considered an orifice. It is suggested to search for simplified methods for calculating flow through an orifice.
  • #1
mechhie
2
0
Hi all,
Here's a simple problem...

My friend from engineering school posed this seemingly simple situation and its been bothering me that I can't figure it out.

With a known airflow rate (cubic-m per hour, or cubic-feet per min) into a room, assuming no leakage. What would be the average pressure felt at a standard doorway (say A x B metres or feet in dimensions)?

Which formula would you use to arrive at real-world results? Any other parameters to be considered in coming up with the answer?

The desired result would be in Pa (pascals) but any input you have would be most appreciated!
:)
 
Engineering news on Phys.org
  • #2
I Assume the "no leaks" means he just meant that flow out of the door is equal to the fow in? It's air so you know density. You've got the capacity (the volumetric flow), so it is possible to find the velocity. Then with velocity you can solve for pressure.

Unless he really wants a solid answer and you have to account for the fact that the door is an oriface and flow through an oriface is different than flow through a straight plenum. That would get a little trickier but I doubt that is what you are looking for.

Do you see where you need to go with what you've got?
 
  • #3
hello TK.

yes. assuming all the airflow into the room goes out the door, we get the velocity.
with the few variables you listed, are you referring to Bernoulli's equation?

what formula would you use to solve it as an orifice?
and which one to solve as a plenum?

actually he was/is trying to arrive at a resultant pressure at the door, because the space immediately outside the room also has air pumped in at a different rate.
 
  • #4
the space immediately outside the room also has air pumped in at a different rate.
And again, that will alter your "real world" calcs.

Yup, I'm referring to bernoulli. Don't forget atmosphere.

Search the web for the oriface calcs. There are several simplified methods for calculating the flow through an oriface. By plenum I just meant a straight length of something, i.e. straight, relatively steady laminar flow as opposed to being channelled through a small rectangle like a nozzle.
 

1. What is the purpose of real-world calculus ideas?

The purpose of real-world calculus ideas is to apply mathematical concepts and techniques to solve problems and analyze real-world phenomena. This can range from calculating rates of change in the stock market to understanding the trajectory of a projectile.

2. How is calculus used in everyday life?

Calculus is used in everyday life in a variety of ways, such as in finance, engineering, and medicine. Some examples include determining interest rates on loans, designing structures like bridges and buildings, and analyzing the growth and spread of diseases.

3. What are some common applications of calculus?

Some common applications of calculus include optimization, finding areas and volumes of irregular shapes, and modeling and predicting real-world phenomena. It is also used in fields such as economics, physics, and biology.

4. How can calculus help us understand the world around us?

Calculus helps us understand the world around us by providing a framework for analyzing and solving problems that involve rates of change and accumulation. It allows us to make predictions and gain a deeper understanding of various natural and man-made phenomena.

5. What are some real-world examples of calculus in action?

Some real-world examples of calculus in action include predicting the path of a hurricane, determining the optimal shape for a spacecraft to re-enter Earth's atmosphere, and calculating the volume of a medication needed for a patient based on their weight and dosage requirements.

Similar threads

  • Thermodynamics
Replies
20
Views
1K
  • Sci-Fi Writing and World Building
Replies
2
Views
2K
  • Programming and Computer Science
Replies
29
Views
2K
  • Mechanical Engineering
Replies
1
Views
3K
  • Sci-Fi Writing and World Building
Replies
2
Views
2K
Writing: Input Wanted Great Lakes Earth Map
  • Sci-Fi Writing and World Building
Replies
6
Views
2K
  • Mechanical Engineering
Replies
2
Views
5K
Writing: Read Only Great Lakes Earth
  • Sci-Fi Writing and World Building
Replies
1
Views
3K
Replies
1
Views
3K
Replies
6
Views
909
Back
Top