What is Pressure drop: Definition and 160 Discussions
Pressure drop is defined as the difference in total pressure between two points of a fluid carrying network. A pressure drop occurs when frictional forces, caused by the resistance to flow, act on a fluid as it flows through the tube. Pressure drop increases proportionally to the frictional shear forces within the piping network.
There are a number of factors that impact on the degree to which pressure drop occurs in a piping system, including the following:
The nature of the product being pumped, including its density, heat capacity, temperature, viscosity, and the velocity at which it is moving.
Mechanical components in the piping system, including valves, flow meters, adaptors, and couplings. All of these remove energy from the piping system, contributing to pressure drop.
Changes in the elevation of the piping. If the starting elevation of a pipe is lower than its end elevation, the rise in elevation will cause pressure drop as the fluid moves through the pipe. Conversely, if the starting elevation is higher than the end elevation, there will be a pressure gain as the fluid moves through the pipe.
Pump is supply fluid to the 35 nozzles through 3 inch pipe and manifold.At nozzle the pressure is 32 m and pressure at pump outlet is 30 m .The flow rate required at nozzles is 500 lpm. Pump can deliver 860 lpm at 24 m head.pump size 100x100 mm
1)how delivary pipe size affects the pressure head...
Hello everyone,
I have been trying to find a relatively accurate pressure drop correlation for horizontal flow of air-oil mixture. I have been testing 7 correlation in my test points however I am still hesitated to select the appropriate one based on the results.
System Props:
* D_pipe: 17.63...
Hi togehter,
this may be an easy one for most, but I'm really struggling with imagining the process.
Suppose we have a compressed air vessel that is half filled with water. The pressure in the vessel drops from 10 bar to atmospheric pressure within a few seconds. How does the water surface...
I am currently working on a project trying to calculate leak rate and fluid loss from pressurised vessels filled with water over a time period of 30 minutes. So far I have used the Boyles Law which assumes that PV/T = constant which gets us P1 * V1 = P2 * V2 and PdV+VdP = 0 I formed this over to...
Thanks for your response.
I'm trying to estimate the pressure in the cavity, i.e. P2. I know the areas, A1 which in practicality is an annulus and A2 which is a 600m pipe with i/d 8mm.
I would like to initially understand how to calculate the pressure drop across the annulus.
At the moment I'm...
When calculating water pressure drop in chilled water pipisystem (closed circuit) we always use Hazen Williams equation as follow:-
but in case of calculating water pressure drop in cooling tower piping system (open circuit), shall we modify something in Hazen Williams equation or shall we use...
Hi,
I have some measurements for pressure drop of Helium at room temperature and I would like to scale it to other temperatures. Taking into account that, i) the flow is turbulent, ii) the pressure drop, ##\Delta p##, happens always in the same piping and iii) there is only variation on the...
Hi all, I'm a tinkerer with no formal engineering background, but enjoy read about physics and engineering in general.
I'm reading up on fluid flow and I'm a bit grasping at the concepts. As far as I understand it, flow rate, pressure drop and pipe size are all interrelated, where one affects...
Hallo. Since I'm new in this field, I hope someone can help me.
I have a laminar, steady state, incompressible flow in a channel (a fully developed).
Geometry of the channel is on the photo.
How should I calculate the drop of static pressure across the channel?
Since I have Re, I did calculate...
Hello everyone,
I would appreciate any help with my task I am struggling to resolve. I need to calculate or simulate pressure drop when got the following parameters:
1. Supply pressure: 45barg.
2. Pipe Length: 80 meters
3. Pipe diameter: OD - 10mm, ID - 8mm.
4. Pipe material: stainless steel...
I am trying to understand how birds fly. If you consider a plane, using it's engine & streamline shape of the wings, it can create a low pressure region above the wings and high pressure region below and this makes it fly and the upward force is proportional to the speed.
Birds seem to flap its...
We have a project that relating with pipeline system and pressure control, the project is actually having goal to knowing how much pressure drop will occurs in pipe line system that in initial condition the pressure inside the pipeline staying at steady or constant in particular psi and at the...
Good day I'm trying to calculate the pressure drop in each branch of the following loop ring system
I used the following formula to find the pressure drop
but i seems that it worked only for the ring, and the branch #2 ( the branch in the middle), the solution given by the professor show...
Hi All,
Recently, I have been struggling to seek a solution for a seemingly simple flow question and try to rationalize my thoughts with mechanical engineering knowledge I have acquired from school but none of them can make me feel comfortable about answering the phenomenon I encountered in...
I am trying to calculate pressure losses. I've attached an image to show what I mean. Starting out tank 1 is 92.8 litres at 155 psi and when the shutoff valve is open the volume goes from 92.8 to 192.8 and so I thought the pressure would drop by the same factor that the volume increased by so...
Assuming laminar viscous (meaning not frictionless) flow.
Here is what I know about fluids flowing: You have a pressure difference between the two ends of the pipe. This causes a net force acting on the left side of the fluid in the pipe. Therefore, this incompressible fluid flows from left to...
Hello Everyone,
I've been trying to find an answer to this but am not getting anywhere. Any help would be greatly appreciated!
I need to be able to calculate (or more likely estimate) the pressure drop I can expect when putting water under pressure if I know there is air in the system.
For...
Hello,
I'm a chemist and I'm currently working on my PhD on materials science.
I'm trying to determine the pressure difference necessary to achieve the desired gas flow inside a chamber. The scheme of the chamber is the following:
I have a big chamber which is evacuated to 0.2 bar, and another...
Hello everybody,
I'm designing a gas pressure feed system for a hydrogen peroxide - ethanol rocket engine, and after analyzing the devised injection plate, I noticed it is very sensitive to the propellants' pressure drops and discharge coefficients. Once the plate is manufactured, the only...
Hello everybody,
I hope you are doing fine. I'm currently designing an injector for a hydrogen peroxide - ethanol engine, and the following formula is confusing me:
Q = Cd * A * sqrt( 2 * dP / rho); where Cd is the discharge coefficient, A the total area, dP the pressure drop, and rho the...
A large tank filled with air is compressed to 49 PSI. A valve is open and air escapes through the hole (d = 0.04 ft) to the atmosphere. How long will it take for the compressed air to reach 29 PSI.
Assume constant temperature.
Not exactly sure how to approach this problem since the flow rate...
Hi,
I'm trying to determine if a compressed air system has sufficient system to feed a new load
The minimum pressure required for existing loads and the current load is 7 bar.
In order to determine the pressure at E i did a pressure loss calculation for the following
A to B - △P start of pipe...
Greetings,
I am trying to understand how to setup/solve for the pressure drop across an orifice L=3.5in
The pipe diameter starts at 1in, then abruptly decreases to 0.5in for the length of the orifice, and abruptly transitions to 1in diameter. (See the attached file for an illustration.)...
Greetings,
I have very little experience with fluid dynamics and I was wondering how I can calculate a pressure drop across an abrupt change in diameter of the piping used for water.
Any help is appreciated!
Thanks!
Hi There,
I have constantly come across the fact that as fluid (hydraulic oil say) travels along a pipe you will see a continual drop in pressure the further you travel down the pipe. Am I right in saying that the pressure at any point is simply the result of the resistances (friction with pipe...
Hello Everyone,
Can someone please explain to me how I would go about verifying the External Static Pressure of a pump that feeds a pressurized fire fighting network with loops in it. An image of the network is attached. I'm not being able to grasp the concept of pressure drop in a pressurized...
I have a system where pipes run 24l L/min of water @60 degrees through 3 manifolds and those manifolds distribute the water over 8 heat exchangers. Every heat exchanger requires 1 L/min, and has a resistance of about 1.333 KPa per heat exchanger at that flow (2 meter @ 9mm diameter + 2...
Hey
I've gotten some good answers here before, so I'm giving it another try:
Recently I attended a building-engineering meeting, and trying to learn something new (or refresh old knowledge in some cases..) I had a hydrodynamic question/case. My firm is engineering a concrete tank for a water...
Something that routinely comes up as a problem at work is when we size flow projects for piping systems. We calculate pressure drop across a length of fixed diameter for compressible gasses, but we do not calculate pressure changes through an expansion or contraction with gas (for example...
Hi guys,
I know the difference between these two things but I'm struggling with something that I hope someone could help me with.
What dictates the water pressure needed for a "system" to work? I would imagine that if you've calculated your system to have a pressure drop of 1 bar (for...
Hello,
I am calculating pressure drop through a pipe using CFD, which will be validated with hand calculations and experiments for a project. When I take results from my software, I can either take the pressure at a specific point (assume the centreline of the pipe) or I can take an average...
I am a non technical innovator trying to develop a new product. Can someone help me calculate pressure drop and flowrate across a cylinder packed with uniform spheres of 10mm diameter.
I found this online but unable to calculate...
As a follow-on to this thread, which in turn followed this closed thread, I'm starting a new thread on a related real-world problem.
Say I have a 2-liter plastic soda bottle filled partway with water, and pressurized. It has been sitting inverted (with the opening pointed down, and sealed) for...
I have a pump running at 400rpm with 8" inlet and outlet with head 30 ft 500 gpm. Now I am planning to reduce the discharge line to 6" . Assuming the flow rate and speed constant the velocity in the pipe will increase. How do I calculate the change in head?
I'm an engineering student, one of my task is to search the best orifice type for pressure drop. I have no idea which one would it be since I believe that the beta ratio is the one that would determine the best orifice for pressure drop.
Homework Statement
Hi, Iv got to find the minimum diameter of a pipe if the pressure drops in a system is to be limited to 0.3bar. when delivered through a pipe of equivalent length 160m
I have to use the formula
Pressure Drop = 800lQ^2/Rd^5.31
I believe I have to transpose this to find...
So, a coworker approached me today with a 'simple problem' to solve, looking to sanity-check a design choice.
Much to my dismay, I had no idea how to approach it. Worse, google had no straight-forward answers either, and any formulae I did find seemed circular.
This seems too simple to...
I'm trying to optimize a system involving one or more propellers / fans driving air through a packed bed for scrubbing (compressed then expanded) and out the other side to achieve propulsive thrust. So there's going to be a pressure drop in the slipstream. I've already set up a system to do the...
Hi all,
I'm having a Kaiser compressor producing compressed air for my garage. I've installed a FRL unit at point of use. I understand that the filter medium adsorbs atmospheric dust, moisture and oil particles in compressed air. Gradually the pressure drop across the filter builds up and I need...
Homework Statement
[/B]
Q = A / V
Bernollis therom → γH = P+γZ+ρ.v2 /2
Air Flow Speed = 0.058 m3/s
A = Section Area of the tube = π.r2
r = 19.65 mm
ρ =1000 kg/m3
g =9.8 m/s2
P=pressure energy of water = 2.338
Homework Equations
Find :
V= Fluid Velocity = ?
H=Energy Denisty = ?
Z= Geodesic...
Hi folks,
I have a pressure sensor working with arduino to measure depth. I want to calculate what I should see as a change in pressure if I move the tube horizontally under the surface of the water, keeping the tube opening parallel to the flow.
I have calculated the dynamic pressure but...
Good evening everyone,
I have a pressure meter from where we determined a pressure drop of 5.5 psi (Initial pressure 45.5 psi, final pressure 40 psi). The working fluid is air. The diameter of one of the hoses that is connected to the pressure meter is 1/4". I wasn't able to take a picture of...
Homework Statement
The pressure in a bulb dropped from 2000 to 1500 mm of mercury in 50 minutes when the contained oxygen leaked through a small hole. The bulb was then evacuated. A mixture of oxygen and another gas of molecular weight 72 in the molar ratio of 1 : 1 at a total pressure of 6000...
why does the pressure drop equation derived for the laminar flow has no parameter to indicate the surface roughness of the material of the pipe,unlike the turbulent flow !
I've modeled a U-Pipe with laminar flow. The pressure drop from Fluent is about 3 kpa , but by theory it should be about 6 kpa (checked several times and I'm sure)
My mesh is very fine and boundary conditions are vel-inlet and pre-outlet and wall. Would you please help me with the problem?
Hello!
I am studying the mentioned topic I am confused in calculating the average value of friction factor in sub channels ... please help ??
thank you in advance
Hello!
I am studying the mentioned topic I am confused in calculating the average value of friction factor in sub channels ... please help ??
thank you in advance