Questions tagged [pressure]

Questions pertaining to pressurized systems and their applications, from containment to system losses to using as a benchmark for measurement.

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15 votes
3 answers
266k views

How to calculate flow rate of water through a pipe?

If a water pipe is 15 mm diameter and the water pressure is 3 bar, assuming the pipe is open ended, is it possible to calculate the flow rate or water velocity in the pipe? Most of the calculations I ...
Richard's user avatar
  • 331
4 votes
3 answers
3k views

How an airfoil works

I have read on many sites that for lift to occur, the pressure below a wing must be higher than the pressure above it. This happens by somehow moving air faster over the top of the air foil so the ...
Fady basem's user avatar
3 votes
3 answers
614 views

Would a structurally sound pressure cooker be able to withstand an internal vacuum?

Would the body of a normal round pot shaped pressure cooker (built to cook foods at 15 psi) be able to withstand being evacuated down to high-vacuum pressures? Apparently it has been done before: i.e....
norlesh's user avatar
  • 275
1 vote
2 answers
608 views

Calculating Minimum Pipe Pressure Requirement for an Irrigation System

I am setting up an irrigation system for my ranch and I have a hard time calculating the minimum pipe pressure requirements to reduce cost. I need to know the maximum pressure the pipe has to cope ...
Ehsan Darrudi's user avatar
5 votes
2 answers
1k views

Gigapascal pressures in a small package

How small/compact can a pump or other mechanism be, that would allow compressing gas (or liquid) to pressures of excess of 10GPa, continuously? Throughput may be minuscule, of order of milligrams per ...
SF.'s user avatar
  • 6,135
4 votes
0 answers
2k views

Estimating Maximum Speed for a Pneumatic Cylinder

I am designing an machine that is going to use a pneumatic cylinder to accelerate a projectile. I have a tentative cylinder specified, and am working on the control and supply side. I have verified ...
Ethan48's user avatar
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4 votes
4 answers
3k views

Calculating maximum internal pressure from maximum rated external pressure?

Is there a calculation / rule of thumb that can determine a containers rough maximum negative pressure (vacuum) from it's rated internal pressure (assuming a single layer construction so there is no ...
norlesh's user avatar
  • 275
3 votes
3 answers
11k views

CFM in relation to Static Pressure

My background is more Chemistry and Biology, not Physics, or specifically engineering with fluid dynamics, so bear with me! Also, this is a little long, so I will do my best to make it easy to follow. ...
ItsScience's user avatar
2 votes
2 answers
216 views

Why textbooks use geometric center/centerline of the pipe when calculating/measuring pressure?

Studying Fluid Mechanics, I started to notice that almost every textbook/website uses a specific point to make calculations about the pressure in a liquid at a given depth (hydrostatic pressure): the ...
Vinicius ACP's user avatar
2 votes
2 answers
2k views

Whistle Design - Optimizing sound initiation pressure and volume

Assume you can use any whistle type, is there a way to choose the pressure point at which a whistle makes noise? For example I have a whistle that starts making noise at 2 psi but I would like to ...
Exclusiveicon's user avatar
1 vote
2 answers
198 views

How does steam in almost vacuum condense at 35 Celsius?

I read about absorption chillers and found out that the water is evaporated/boiled off at the generator. Water boils over at about 3.7 Celsius in the near-vacuum conditions in the generator. Now the ...
El Flea's user avatar
  • 98
1 vote
2 answers
162 views

Where is the contact point between screw spindle teeth and nut teeth?

So this is a screw press used to hmm disconnect the clamp connection (sorry if these are not the correct terms I really don't know how to translate it properly). Anyway, I think it's obvious what this ...
M. Wother's user avatar
  • 361
0 votes
1 answer
75 views

Does a disk placed in a pipe perpendicular to flow direction of fluid feel dynamic pressure or total pressure?

There are two discs in the pipe but not at the same time. You can consider conditions with X but without Y, then with Y and without X. I am pretty sure that disc X will feel less force from fluid than ...
Jawel7's user avatar
  • 125
0 votes
2 answers
102 views

Fluid Mechanics about Hydrostatic Pressure

The rectangular gate will open authomatically, when the depth of water becomes very large. What is the minimum value of d that will cause the gate to just open? The width of the gate is 2 m.
Ayça Arırt's user avatar
-1 votes
3 answers
3k views

Is it safe to use a 125PSI rated auxiliary air tank with a 150PSI air compressor?

I have a small, 5 gallon, pancake compressor which has a maximum 150PSI rating. Unfortunately, it doesn't have the air capacity to power the demands of an HVLP paint sprayer or a die grinder without ...
user148298's user avatar
-2 votes
1 answer
371 views

Why using average pressure in calculations gives the most accurate results?

In the saga of trying to answer the question that came into my mind while studying the basic concepts of Fluid Mechanics, "Why textbooks use geometric center to calculate hydrostatic pressure when ...
Vinicius ACP's user avatar