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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Calculate heart valve flow rates over time. What formulas are involed?
I'm trying to program a simulation of a human heart which I want to produce results close to the following:
(Source: https://en.wikipedia.org/wiki/Cardiac_cycle#/media/File:Wiggers_Diagram_2.svg)
For ...
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Measuring Pressure of a Press Machine
I am designing a heat press and need pressure feedback of the force or pressure being applied to the product.
I need to measure the pressure between to press plates on a hydraulic press.
I would like ...
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Darcy-Weisbach: Static or Total Pressure?
Does the Darcy-Weisbach equation give the change in static pressure or does it give the change in total pressure (static plus dynamic)?
I’m assuming here that the static pressure includes the ...
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How to design a pressure regulator test?
We're designing a pressure regulator test. It is taking an input from an N2 tank at 300 bars, output pressure should be around 70 bars. We are thinking of using 2 pressure transducers, a solenoid to ...
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Calculating Pressure Loss (K Value) of Pipe Bends at varying Angles
I am analyzing the total pressure loss of a run of pipe that has several pipe bends at varying angles (30, 60, 45, 90, etc. degrees). Reading through CRANE: Flow of Fluids Through Valves, Fittings, ...
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Hertz contact pressure formula for cone on a plane
Can anyone please point me to some literature that contains formula for Hertz contact pressure for conical body on a plane? I know that there are general solutions that probably cover also this, but I'...
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Backpressure vs Pressure Drop
We were asked by a customer to calculate the backpressure of an exhaust system we were supplying a muffler for. The system includes piping from the engine to our muffler, then from the muffler to the ...
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Do I need a pressure relief/safety valve if my pump can't exceed the rated system pressure?
I am designing a resin dosing & mixing room for a production plant. This will use pneumatic diaphragm pumps to pump the resin & additives, flow meters to measure the dose, and pneumatic ball ...
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Cuboid pressured container - will the pressure reach the shear pressure of the material?
I'm having a go at designing a water electrolyser for producing hydrogen. I would like to store the hydrogen with minimal compression effort. Up until the past week I have been thinking about using a ...
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How can I determine the size of holes along a pipe so that the flow rate is equal out of each hole?
Suppose I have a pipe with holes on its top (kind of like a flute, but with different sized holes). One end of the pipe is open and the other is closed. The pipe is submerged in water horizontally, ...
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Piston Compressed Pneumatic Cannon
During an discussion with friends regarding pneumatic cannons, I came up with this gem :). Piston power pneumatic cannon. My friends however, didn't share my excitement regarding this revolution in ...
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How to get a wire from the inside to the outside of a pressure vessel?
Imagine you have a pressure vessel, e.g., the hull of a deep sea submersible. A good one would be a sphere of inches thick metal. But how could I wire the inside to a component on the outside? If I ...
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Calculate Air Conditioning Duct Pressure from Sources and Users
I am currently modeling a high fidelity simulation of Boeing 747-200 for a flight simulator, and I am now at the stage of programming what is essentially the HVAC system for the aircraft.
I will try ...
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What is the optimum layout for a hydrogen compressor, that would have least wear and tear on the compressor?
I have been investing time in understanding the layout/schematic of a compressor that would be used for compressing hydrogen to high pressure ratings.
It's not clear to me what is the best design - ...
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Effect of pump suction lift on pump vibrations and motor current
Consider the case of an electric motor driving a centrifugal pump.
The pump is installed above the tank.
In Case-I, the tank is completely filled with water.
In Case-II, the tank is emptied and thus ...
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Pressure scanner for multi-hole Pitot-static probe going to 100km altitude and M3.5
I am wondering if anyone has experience in looking for multi-channel differential pressure scanners for use with pitot static probes in aerospace? What companies/manufacturers/product familes would ...
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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.
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What happens when running a piston pump below minimum air drive?
My question is what happens when you give an air driven liquid piston pump less air drive pressure then the minimum recommended. I have a pump that says its minimum drive pressure is 25psi. What would ...
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Can a fluid have more or less static pressure than atmospheric pressure in atmosphere?
We assume static pressure of a fluid coming out of a pipe or nozzle of gas turbine with high temperature and velocity is equal to atmospheric pressure, which confuses me for some point.
Does it mean ...
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Value of the manometric pressure
I need to know the pressure acting on the left side of the surface in this picture.
And the answer is that $p_{M0} = \rho*g*h$ and the $\rho$ in that equation is equal to the $\rho$ of the fluid on ...
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Why are the water tank walls made of stretch film warping a lot whereas theoretically they shouldn't that much?
I am building a water tank of custom dimensions (1.5 m x 0.72 m x 0.86 m) out of stretch film. The stretch film is wrapped around a steel frame (see here for more info on this open source project).
I ...
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Pressure drop across orifice plate
I have been trying to estimate pressure loss caused by an orifice plate. The fluid flowing through it would be water.
I found equations for discharge efficient and pressure loss coefficient K from ISO ...
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Why did pressure decrease above the piston?
I can understand the pressure increase below,but why did pressure decrease above as more bricks were added?
Image source: https://www.youtube.com/watch?v=4REdJIW6-Kg
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What pressure do objects at exhaust of pipes feel from flowing fluid? Dynamic or Total?
Let's imagine that we have one fluid source separated somewhere in two pipes of R1 and R2, and we put one object at exhaust of R1 pipe and one more object at exhaust of R2 pipe (R1 > R2). Let's ...
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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 ...
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Steel expanding in a tight space
Hypothetical question: What would happen if I were to cool down a steel cylinder to make it contract, and then slide it all the way into a cylindrical hole in a room-temperature solid steel box? The ...
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Determining bearing pressure between mating convex and concave conical surfaces?
(In the illustration above, the "Collet" piece in the middle is a bushing)
I'm designing an axial linkage of sorts, and I'm having trouble finding resources, theorems, or guidelines for ...
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What is the most appropriate set-up to pressurize air in a closed, confined space?
Assume that we have hot air in a confined closed space of 36 m^3. This hot air will be distributed trough a piping network of 500 m to be blown on trees. What is the most appropriate set-up to ...
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Design a manifold block and calculation of pressure drop
How to calculate pressure drop inside a manifold block with different pipe sizes for one connection to another. Overall the manifold block maximum working pressure is 10 bar. Can anyone send me basic ...
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Pumping machine (Centrifugal ) fails to pump
I have a centrifugal pumping machine that fails to pump up consistently. When powdered on, it spills up water, then stops and continues intermittently like that without a consistent flow of water out. ...
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How to calculate the required power to pump out (to vacuum) a container?
Consider I have a cubic container with its volume is 1m cubic as in the simple picture above. It is sealed nicely, it is air proof, no air leaking. I would like to pump out (to vacuum) the container ...
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Why would the compressor provide more pressure than necessary? Isn't the pressure determined by the resistance?
I clearly misunderstood something
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If a piston has a larger upper surface area than lower surface area experience a force downwards even if that piston is ventilated?
Here I have a system where there is 18 bar of Nitrogen in a valve with a piston. The pressurized nitrogen is below the piston, above the piston, and also in the ventilation bore in the piston. ...
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How to build a hydraulic standing desk?
I am trying to build a standing desk but I want it to be wireless (aka - no electricity needed).
My idea is:
have 4 hydraulic pistons that extend (from 60 cm (25in) to 120 cm (50in)).
They will be ...
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Saturation of penetration length using Lucas-Washburn equation
The Washburn equation for capillary flow provides the following expression for the calculation of the penetration depth (or capillary rise):
$L \propto \sqrt(t)$
My question is when t goes to infinity,...
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Calculating strength of Vacuum from Boil->Seal->Cool type Methods
I'd like to be able to boil water within a container, remove heat and seal the container, then cool in order to produce a vacuum within the container of a target strength (~5 mbar).
I don't know the ...
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Preventing u- tube effect on a fluid
Say you have two cylinders, one fixed bigger outer cylinder and the other is free (lets say a straw with a tapered end 1/3 from the bottom. As you push the straw into the medium (fairly dense viscous ...
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How to quantify a misty-ness of a spray?
Picture1 source:
Picture2 source:
Picture3 source:
The above are three spray models. The latter one is fuel injector spray. Consider I have a closed container which I can increase its pressure by any ...
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Pitot and static port placement - How to choose the ideal location
Forgive the this topic placement as it might be similar to other older ones (Although I a bit sure that the main contents might be different than other older ones).
In the upcoming days I will have a ...
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How does high inlet head affect outlet head on a fixed speed centrifugal water pump
I am curious to know what happens to a fix speed centrifugal water pump's outlet head if the inlet head is already relatively high.
For example, say a pump is said to have a max head of 10m. If it is ...
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What is the behaviour of water at a pressure reducing valve (PRV)?
Suppose I pass water through a pressure reducing valve, which can lower the pressure enough for the water to boil, will the water fully boil? If so, what would happen if that vapour passed to a tube, ...
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How this centrifugal pump works in creating a vacuum?
Stumbled upon this video (vacuum fryer commercial)
It obviously using 2 centrifugal pump (large ones, most likely above 700 litres/min) to circulate the water inside condenser
But then, these pumps ...
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Calculating how many bolts are needed to hold parts
Suppose we have a stack of thin metal sheets, layered on top of each other. Let's say 20 sheets, 0.2mm thick, and each sheet is 70mm by 70mm.
Let's also say that the sheets are not totally flat, so ...
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What does pressure rating of pumps mean?
So I am thinking of purchasing a double motor pump for higher flow rates. This pump is available in two pressure ratings, 150PSI and 220PSI. What does it mean? I read that it means how much resistance ...
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How to 'normalise' the effect of temperature on pressure to determine an accurate leak rate
I want to determine the leak rate of a container. I pumped it with air and measured the temperature and pressure within the container. What I observed is that, due to fluctuations of temperature in ...
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Minor loss coefficient for pipe end
I want to estimate the head loss in a piping system. However, I don't know how to find or determine the loss coefficient for a connection point within the system.
At one point the pipe ends in a ...
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Pneumatic pressure sensing in a moving air compressor line
I am building an automatic control system for an compressor that stops at a designated pressure. Here's a rough sketch of the system:
The compressor should receive the on signal from the ...
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What are possible applications for room temperature superconductor requiring extreme presssure?
At standard room pressure, the highest temperature superconductor is "the cuprate of mercury, barium, and calcium, at around 133 K" (-140 °C).
If pressure can be increased, however, the ...
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Debunk closed Boyle flask for perpetual energy
Somebody is insisting on this design to me, and while I cant put my finger on what exactly makes this impossible, I know it is. I need your help.
I believe it's to do with the pressure of the ...
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Do axial displacement experiments under hydrostatic load scale linearly to any size?
In J. D. Stachiw's book Acrylic plastic viewports for ocean engineering applications [PDF] on page 337 it includes a Figure 7.12 [2] showing the results of applying hydrostatic loads to an acrylic ...
