# What is Orifice: Definition and 71 Discussions

An orifice plate is a device used for measuring flow rate, for reducing pressure or for restricting flow (in the latter two cases it is often called a restriction plate).

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1. ### Software advice on fitting an orifice within a cylinder

I have a stp file (PF does not support it so I cannot upload it here. If there is a way I can share it please let me know) of an orifice and I want to create a new file where the orifice is fit inside a cylinder. What software do you recommend me to use? Thank you! :)
2. ### Gas flow through orifice

Summary:: How to find gas flow through an orifice that links two vessels at different pressures. Two vessels containing the same gas are linked through an orifice with diameter ##d##. The pressure inside vessel 1 is ##P_1## and the pressure inside vessel 2 is ##P_2##, and let's have...
3. ### I Compressible choked gas flow through an orifice -- Excel formula

Hello, I normally get these things working but I am a bit stuck as i don't feel I am getting sensible answers... The problem is simple (!): Q: Model the flow through an orifice with an upstream/supply pressure of 301BarA where the downstream pressure is in the range 1BarA to 301BarA. The...
4. ### Designing an orifice plate to increase the pressure in a pipe

say for 3.013bar absolute pressure pressure ratio : P/Po = 14.7psi/43.707psi = 0.33 which means its chocked flow now i want to find diameter or area of orifice : so could anyone help me
5. ### Pressure profile of a gas flow through an orifice

Hello, The question will probably be related to mechanical engineering / chemical engineering / aeronautics. I come from the field of optics and have no background at all on fluid dynamics. I'm trying to calculate the dependence of pressure on distance, i.e. P(x) in a gas flow problem: I...
6. ### Volume of air flow through an orifice at speed

Trying to figure out how much air can (or would) flow through an air intake on a vehicle. I have a rectangular intake opening that is 13.52 square inches, the vehicle is traveling at 60 MPH for 1 hour. Obviously more air is being forced into the intake due to the speed but I can't sort out...
7. ### Flow of Water into a Bowl with Holes

I'm facing a problem with that rhyming title up there. The design is thus: a downward-facing, vertical pipe with known constant flow and diameter has water flowing out of it, into a short (15cm-91cm) free fall. At the end of that fall is a bowl of indeterminate depth made of steel with holes...
8. ### How can I calculate the drop in pressure across an orifice?

I know the inlet pressure, temperature and density along with the massflow rate across the orifice and the orifice cross section. Is there a way for me to calculate the drop in pressure across the orifice?
9. ### Pressure drop across a thick orifice

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.)...
10. P

### The formula for Thick-Edge Orifice

Hi all, I have some problem in my research about the thick-edge orifice formula. I can't find the influence of orifice length to the discharge. I have found an online calculator for it but I can't find the formula derivation. Anybody can help me? Anybody have recommended literature? The...
11. ### Calculation of Pressure in a Cylinder with an orifice on its surface

I want to calculate the pressure profile inside a cylinder whose initial pressure is less than the outside pressure and has a orifice on its surface to flow air through it. Air is a considered as compressible ideal gas and mass flow rate across a orifice is assumed isentropic. Also the...
12. ### Propelling force due to an orifice

Homework Statement A tank 1.5m high stands on a trolley and is full of water .it has an orifice of diameter 0.1m at 0.3m from the bottom of the tank.if the orifice is suddenly opened coefficient of discharge of the orifice is 0.60, then find propelling force on the trolley. Ans: 67.39N Homework...
13. ### The Best Orifice Type for highest pressure drop

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.
14. ### Flow rate through a submerged orifice

Homework Statement Homework Equations Bernoulli: p1+½ρU12+ρgz1=p2+½ρU22+ρgz2 Continuity: Q=U1A1=U2A2 Area=CC*(¼πd2) The Attempt at a Solution [/B] I attempted to apply the Bernoulli equation, making point 1 the top surface of the left hand side and point 2 the instant at the sharp edge...
15. ### Calculating velocity of steam through orifice

Hi all, First time poster here and I'm stuck with what for me seems to be a simple problem. The situation is this: I have a 100mm diameter pipe connected to a steam kettle, which produces steam at a constant 0.3barG. This pipe is split up into 4 50mm pipes, each pipe has a valve at the end...
16. ### Pressure differential through orifice plate

Hi, This is probably an easy answer but I can't get my head round it! If I have a test rig that measures pressure differential in a test chamber at a set flow rate, how do I calculate what the pressure differential should be if I put an orfice plate in with a certain size diameter hole in the...
17. ### Pressure -- non-compressed gas through an orifice

I have 1/4" diameter tubing (tightest point prior to valve) leading to a solenoid valve with a 2.5 mm orifice. I am trying to compute how much pressure it would take to move 1 and 2 CFM of 190C air through the valve (to atmosphere). I am using blowers and I don't know if they will be able to...
18. ### How to find Orifice Plate Area

I have a diameter of orifice is 1.025 inches and it says the Plate Area is 0.0058ft ^2 how is this answer received? Ill be using it to find orifice coefficient I don't understand why its 0.0058
19. ### Accurately calculating the pressure drop through an orifice

I have a scenario where a specific nozzle is defined to have a flow of 900cc/min. The flow co-efficient for this nozle is defined @9.8 MPa -> flow co-efficient= 0.85. If I then run fluid through this nozzle at say 200 MPa and I would like to calculate the pressure drop. My understanding is taht...
20. ### Calculate the pressure drop of air across an orifice?

Hi guys, I don't know if you can help me, or if I am asking my question correctly but your feedback will be greatly appreciated. I have a 2" piping system that connects a scrubber that is rated for 675 psi (36" OD x 7'-4") to another scrubber rated for 75 psi (84"ID X 24'- 0") ; there is a...
21. ### Venturi, Orifice and Nozzle

Hello everyone. When I try to do mass flow systematic uncertainty estimation for venturi nozzle and orifice, I am getting the biggest error from venturi nozzle. What is the reason for it? ( Why coefficient of velocity of venturi nozzle is too big compared to orifice and nozzle.)
22. ### Formulas for flow rate through orifice

I am in need of a formula to calculate mass flow rate of liquids through a known orifice size and known pressure/secondary pressure. I need to do this for multiple liquids and I know the specific gravity for each liquid. can anyone help with this formula.
23. ### Force on an orifice plate

<<Moderator note: Missing template due to move from technical forum.>> I am having difficultly with a problem in my fluid mechanics course and I'm hoping someone could help me out. Here is a screenshot of the question I'm stuck on: So far I have been using Bernoulli equation to find the...
24. ### Flow Through Orifice Homework: Bernoulli's & Motion Eqs

Homework Statement Please see attached. Homework Equations [/B] v = u + at s = ut + ½ at² v² = u² + 2as The Attempt at a Solution I've managed to get the first part of the question applying Bernoulli's principle and then the equations of motion above by considering separately the...
25. ### How to size an orifice on a vent line

I would like to install a vent stone on a 3/4" vent line. The line vents upwards of 1500 psig of stored gasous nitrogen in under 1 second. The vent stones are only rated for 300 psig, so I'd like to add an orifice just upstream to limit the exit flow rate to a point where it can handle the...
26. ### Orifice Pressure and Flow drop

0http://math.stackexchange.com/questions/946493/solve-for-pressure-drop-across-and-orifice# [Broken] I'm running 1/2" pipe but the only way to connect a 9/16" flow switch is with a 1/4" adapter. I'd have to go from 1/2" down to 1/4" to the 9/16" flow switch down to 1/4" back to 1/2". I was...
27. ### How do I calculate the pressure drop of air across an orifice?

I am trying to size an orifice to place on an outlet of an air vent line. The reason for this is that I am installing a noise suppressing muffler, but it is only rated for 300 psig. Since I am venting a line that will be pressurized to 1600 psig, I'd like an orifice restrictor in order to...
28. ### Designing Nut and Orifice fittings (brass)

Hi, I get parts made in China, and I need to make a full CNC drawing. It is a modified 1/4" BSP nut and orifice fitting. I cannot find anywhere how to draw the nut and orifice so they work correctly. This is the part they make the most mistakes with, as the tolerances are small. It is not...
29. ### Pressure drop across an orifice (Orifice pressure drop in meters?)

Homework Statement ΔP = 1000 x 9.81 x (Orifice pressure drop in m) Pressure drop across orifice = 470.72 Pa 2. Homework Equations 3. The Attempt at a Solution I am not sure how this works. How can pressure be converted to meters? It does not make sense to me. Any...
30. ### Pressure drop across an orifice (orific drop in meters?)

Homework Statement ΔP = 1000 x 9.81 x (Orifice pressure drop in m) Pressure drop across orifice = 470.72 Pa Homework Equations The Attempt at a Solution I am not sure how this works. How can pressure be converted to meters? It does not make sense to me. Any help would be much...
31. ### How to purge a panel with orifice and vent

Hi, I have a stainless steel panel that I would like to purge with GN2. The panel is roughly 5' x 4' x 2'. Nearby, I have a 1/4" steel line that contains 90 psig of GN2 that I can use. My thought was to run a small line (1/4" or 1/8") to the panel, and insert a small orifice to restrict the...
32. ### Pressure reducing orifice plates

Hi, I would like to know how would i be able to solve a problem involving two (2) pressure reducing orifice plates in series with seawater as medium. I know the orifice diameters, the supply pressure, but i don't know the overall flowrate, and pressure after the orifice plates. The...
33. ### Finding the velocity of fluid through orifice

Homework Statement A horizontally oriented tube AB of length ##l## rotate with a constant angular velocity ##\omega## about a stationary axis OO' passing through the end A. The tube is filled with an ideal fluid. The end A of the tube is open, the closed end B has a very small orifice. Find the...
34. ### Fluid Mechanics problem - cylinder over a orifice

Homework Statement The horizontal bottom of a wide vessel with an ideal fluid has a round orifice of radius ##R_1## over which a round closed cylinder is mounted, whose radius ##R_2>R_1##. The clearance between the cylinder and the bottom of vessel is very small, the fluid density is ##\rho##...
35. ### Reduction Orifice sizing for desired pressure drop

Good afternoon, I am trying to size a reduction orifice for a desired pressure drop. I do not need the drop to be specific, since this is just for valve protection and not for metering. D1 (Pipe) = 2.5" P1 = 125 PSI P2 Required = 75-85 PSI Q = 1020 gal/hr Fluid = Water, 90 Deg F...
36. ### Orifice place to limit pressure after regulator

Hello, I am working on a project and having an issue that I just ran into. I want the user to be able to regulate pressure from 0-60 psig max. When I start specifying the pressure regulators, found that they're sold with maximum outlet range either 0-50 psig and 0-100 psig. so I figured to...
37. ### Converting CFM on an Anemometer help? 4.5 inch orifice on vacuum

I have an anemometer that I bought that does not have the ability to put in the ID of the orifice I am trying to measure. In this case it is a 4.5 inch orifice-stays the same for me 95 percent of the time. Does anyone know how I convert the reading manually so that I can get an accurate...
38. ### Calculating Jet Pressure at Nozzle orifice

Hello, So i am using this 3HP pump for which the head ranges from 6 meters to 14 meters. Discharge being 19.1 LPS to 10.4 LPS respectively. I am using a 2" pipe to carry the water upto a height of approx. 3 meters, which is then routed into a jet manifold containing number of jet nozzles...
39. ### Pressure drop through an orifice in a pipe

Hey all, I'd need help with determining the pressure loss over an orifice in a pipe. I have an equation for the friction factor so no problem there, and I know the Reynold's number as well. What confuses me is choosing the suitable velocity for the pressure drop equation; \frac{Δp}{ΔL} =...
40. ### Flow of gas into a vacuum system through an orifice

Hello, I'm sorry if this is in the wrong section but I recently took real interest in physics, particularly fluid mechanics, so this is my first post. Consider the following: A glass system has a pump pulling gas out of the system, which has an orifice to the atmosphere at the opposite end...
41. ### Pressure drop w.r.to time through a orifice dia(D) in a container of volume (V)

Let initial preasure (P) = 10 bar,volume of container (V)=100000 cubic cm. At what time period pressure will become 5 bar.
42. ### Orifice Diameter Impact on Vortex Formation

can anyone tell me how the orifice diameter can affect the vortex forming ? no much info from internet , thanks for help~:smile:
43. ### Flow through orifice?

Hallo, How to calculate the air flow (volume flow in m3/s) through an orifice of diameter ∅ 1mm, 1.2 mm and 1.5 and length 1mm? The air at room temperature is sampled through the orifice from atmosphere at pressure 1013 mbar. The pressure behind the orifice is regulated at 100 mbar or 200 mbar...
44. ### Orifice plate effect on impeller flow rate

Hi everyone, Hoping someone can point me in the right direction. I'm trying to find (a theoretical approximation of) the flow rate through a pipe where the pressure is provided by an axial flow impeller, but restricted by an orifice plate. I have (or can get hold of) all the physical...

Orifice problem I've been given a list of quantities Pipe before orifice head = 255mm Diameter = 31.75mm Pipe after orifice head = 230mm Diameter= 20mm Time for 10litres to fill in collection tank 67.09seconds Assuming g= 9.81 and density = 1000 from the experiment difference in...
46. ### Flow rate measurement: Venturi vs Sharp edged circular orifice. Help

Flow rate measurement: Venturi vs Sharp edged circular orifice. Help! :) Homework Statement Hello guys, I am having trouble answering these questions. I know the the discharge coefficient for a venturi is always higher than that of the sharp edge orifice. Can you guys help me out with the...
47. ### Flow Rate & Velocity of Air Through Orifice @ 130 psi

I have been searching for formulas to determine the flow rate and velocity of air through an orifice at a given pressure differential. I need to know the flow rate to determine the CFM requirements of the compressor. And I need to determine the velocity to be able to accurately size the orifice...
48. ### I need two simple formulas to figure flow rate and velocity of air through an orifice

I have been searching for formulas to determine the flow rate and velocity of air through an orifice at a given pressure differential. I need to know the flow rate to determine the CFM requirements of the compressor. And I need to determine the velocity to be able to accurately size the...
49. ### Pneumatic Valve and Orifice Issues

I am working on a problem trying to find out why a 0.010” orifice can be used to open a pilot actuated, spring return pneumatic 5/2 directional control (spool) valve, but a 0.0045” orifice only seems to work intermittently. The air system that I am working with is 100 psig. The air enters...
50. ### Vena contracta in orifice plates

Hi, does anybody know how to find the diameter of the vena contracta in gas/vapour flows in orifice plates?