Pressure drop Definition and 160 Threads

  1. sehrish shakir

    Neutron transport equation and pressure drop calculations in core ...

    i am a physicist now i am doing Ms in nuclear engineering ... i need to understand basic concepts ... neutron transport equation ? what is the transport phenomenon actually ? and pressure drop calculations in core ... please help thanks in advance
  2. Ravi Singh choudhary

    How water flows even after adverse pressure gradient?

    In nature, gradient is always required for flow; whether it is temperature gradient for heat transfer or pressure difference for fluid flow. There is a case of Venturimeter in which we have throat section. After throat there is a divergent section. How could flow even happen in that adverse...
  3. S

    Calculating pressure at pressure relief valve outlet

    I have a tank which has a Pressure Relief Valve (PRV) connected to the atmospheric vent (Carbon steel with friction coefficient of 0.14). The PRV is opened at Set pressure of 30 PSIG and has a capacity of 60,000 SATSTM (I assumed it to be in lb/hr). I am trying to calculate the discharge...
  4. P

    Calculate pressure drop in dense phase pneumatic conveying

    I've came across many references for pressure drop calculations for dilute phase pneumatic conveying, but I've yet to encounter any for dense phase. Anyone has any idea how do i calculate that? Thank you
  5. M

    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...
  6. F

    Calculate Pressure Drop of Air Across an Opening

    How do I determine the pressure drop of air across an opening? For example if I have 3,000 L/s (3 m3/s) and an opening of 8.4 m2 I know the velocity is 0.4 m/s. If the free area is 80%, the velocity increases to 0.45 m/s. What I'd like to cal is the pressure drop in each case. Cheers
  7. J

    Why do you get pressure drop in central circulation?

    What is the reason that the pressure drops in the central circulation?especially if you go from arteries to arterioles you get a huge pressure drop. If you look what is changing if you go from arteries to arterioles then it is that you get many many branches this leads to an increase of total...
  8. H

    Why Does the Laminar Flow Equation Use Different Coefficients?

    Homework Statement as we all know , D=4R , D=hydraulic diameter , in the equation of P= (8μLV_avg) / (R^2) , i would get (128μLV_avg)/ (D^2) , am i right ? why the author gave (32μLV_avg)/ (D^2) ? Homework EquationsThe Attempt at a Solution
  9. M

    Pressure drop across a valve in hydraulics

    Hello, I read something about the pressure drop across a valve and it was specified this is a singular pressure drop equivalent to K*U²/g (Borda formula). My question is, can we used the Bernouilli formula for a permanant incompressible flow to determine the flow rate function of the pressure...
  10. D

    Confusion about pressure drops and pressure regulators

    When designing the fuel plumbing for an efi system, do pressure drops in the fuel lines need to be considered when there is a pressure regulator? If so why? Been reading up a lot on plumbing design lately about how the goal is to minimize restrictions in the lines which ultimately cause...
  11. T

    Relationship between water flow and pressure drop

    A building has a water pipe inlet. I have found that at if I open the valve at this location fully, then I get 180 liters per minute at a residual pressure of 0,2 bars (static pressure is 5,4 bars). Is there a fixed relationship between the flow and pressure drop so that I can easily predict...
  12. T

    Thermodynamics: Pressure Drop over a Valve

    Hey Guys! Anyone able to help out here? I have already happily solved for T2 = 369.91K and m2 = 11.492kg However, for question 2.3, I'm terribly stuck. I'm not even sure what to make my control surface. How can I relate pressure outside the valve with the two thermodynamic states I have...
  13. S

    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...
  14. I

    Decrease in temperature and pressure of closed container

    Homework Statement Helium is stored in a tank initially at temperature To and pressure Po. It starts coming out through an opening (pipe outlet) at a constant mass flow rate of mdot. Calculate the decrease in temperature and pressure of the tank (assuming no heat loss to the surroundings) as a...
  15. Pumpquestions

    Will this pump work for my artificial irrigation system?

    Hi all, I am designing an artificial rain system and was thinking about using http://www.dannermfg.com/Store/Products/Danner/PID-02720.aspx to power it. The goal of the system is to deliver roughly 1 gallon of water per hour to each of the 8 exit points (I will measure this by using a bucket...
  16. P

    Why Does Inlet Pressure Decrease in a Constant RPM Gas Compressor?

    I would like to clear out my understanding of gas compressor. If it is moving at constant RPM, is it mean that it can only allow same volumetric flow rate all the time? So the power will remain constant too, (P=VI) then voltage and current will varies. My investigation is to find why there is...
  17. N

    Calculate power consumed by pressure drop

    Hello all! I am interested in how much energy a HVAC VAV box consumes. Can anyone help me come up with the following equation? I don't need to know the exact formula, and can assume an uncompressible fluid and/or ideal gas. Been about 20 years since I have done this and am a bit rusty...
  18. T

    Water pressure drop when 1 pipe splits into 3

    Hi, what happens when I have a single pipe with pressure 1bar. I split this pipe into 3 equal pipes with equal diameter. What will be my pressure at the ends of these 3 equal pipes ? From what I have been reading on the internet it seems that the pressure will be the same on the 3 equal...
  19. Merttt

    Calculating Pressure Drop w/ Oscillating Diaphragm

    Homework Statement During measurement of pressure differences by the using orifice and an electronic transducer, we can have some oscillation on diaphragm, I try to define this effect by the calculating pressure drop from vena contracta to transducer. I say that oscillation is 30 percent (maybe...
  20. A

    Calculating Pressure Difference w/ Bernoulli Law for Bay Inlet

    I have a container with one inlet and one outlet. I have the area of the inlet, Ai, velocity vi of the air coming in, and mass flow mi (assume a plane with an air inlet to a bay). I don't know anything about the outlet (just that there is one). What I need to do is calculate the size of an extra...
  21. moatilliatta

    Do Ocean Waves Experience Lower Downwards Air Pressure?

    Of the few occasions I've seen Airfoil Lift described to general audience (on documentaries), it has focused on the top-side curve of the Airfoil causing air on the topside to move faster than the bottom-side. This is said to reduce air pressure on the topside and result in lift. If a wave is...
  22. T

    Pressure drop analysis on water pipe system w/pump

    Hey everyone. Four days ago I didn't know anything about fluids but I started my internship and got assigned a project that is all about fluids! And I need some help, this topic can get really complicated but I'm trying to take it one step at a time. Problem Description: There is a pump...
  23. F

    Calculating pressure drop from a pressure vessel leak

    THIS PROBLEM WAS MOVED FROM GENERAL PHYSICS TO THIS FORUM BECAUSE OF ITS HOMEWORK-LIKE NATURE. SO THERE IS NO TEMPLATE. Pressure vessel has a electrical (coiled) furnace inside. A pressure vessel @ 550 bar @ 500 C containing argon has its gas inlet pipe (1 inch ext Diameter) that has come...
  24. T

    Spiral heat exchanger - pressure drop?

    Hi, I hope this is the right section. I'm trying to figure out a rough estimate of the pressure drop in a spiral heat exchanger. The fluids both being water. My guess it it would be in terms of the surface area of the inside of the heat exchanger, and the flow rate, but I can't seem to nail...
  25. U

    Pressure drop per unit length of the pipe

    MODERATOR NOTE: THERE IS NO TEMPLATE BECAUSE THIS THREAD WAS ORIGINALLY MISPLACED IN A NON-HOMEWORK FORUM Viscous liquid (ρ = 1460 kg/m3, μ = 5.2×10−1Ns/m2) is pumped through a smooth pipe with a 0.1 m diameter, at a rate of 5×10−2m3/s. Using your Fanning friction factor versus Reynolds Number...
  26. J

    What exactly does pressure drop tell you?

    Hello, I am currently a chemical engineering major and i have a question. What exactly does pressure drop tell you? i know the equations to solve for pressure drop for various situations (using ergon equation for a bed, or skin friction for pipes, using friction factor, etc etc ( is there...
  27. A

    Friction and pressure drop in a steam pipe

    Hi I am new to fluid mechanics and I wondering if anyone can explain to me in very simple terms why friction causes pressure loss when steam is moving through a pipe? I thought the friction would slow down the fluid which will lead to higher pressure but it seems its the opposite. I was trying...
  28. C

    Horizontal ring water main pressure drop

    Homework Statement The accompanying figure shows a horizontal ring main consisting of a single loop of pipe, as might be used for supplying water to various points on one floor of a building. Water enters the main at A at 50 psig and is discharged at B and C at rates of 20 gpm and 60 gpm...
  29. M

    How do I calculate pressure drop in a pipeline?

    Anybody can help me for calculating pressure drop in pipeline. I really appreciate the suggestions from your side. i have the values of dp for equipments and valves...i want to know how to interlink with these dp values for calculation...i want to know, how to calculate the dp of scrubber. i had...
  30. steves1080

    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...
  31. S

    Why does a pressure drop in a pipe cause a force on the pipe?

    Hi, I just started a course in drilling and the first chapter is about various situations where pressure drops in the drill string (pipe) causes forces on the pipe. I understand that a pressure drop due to friction causes a downward force on the pipe. The fluid is "pulling" the pipe down...
  32. Saladsamurai

    Pressure Drop due to Vortex Shedding

    Take a cylinder in cross flow. We know that for Reynolds number greater than 40, we will start to see vortex shedding occur. Using the Strouhal number, we can determine the frequency at which vortices will shed. Using the coefficients of drag and lift, we can determine the steady loadings on...
  33. L

    The physics of blood pressure drop

    Hello everybody. I have seen many people asking questions on this forum about the reason to why blood pressure drops as you get farther from the heart. But honestly, not a single answer satisfied me. My major is physiology, so it's quite funny that I still don't know this "trivial" detail. What...
  34. N

    Pressure Drop Testing - Too Many Unknowns?

    Hello there, I am having a discussion with a co-worker about a pressure drop test. I have two different 'boxes' for which I don't know the pressure drop. What I want to know is the difference in pressure drop between the two 'boxes'. Knowns 1) PA1 = PA2 = PA = Inlet Pressure for...
  35. K

    Understanding Pressure Drop Calculations in Fluid Mechanics

    Hello. I have had an attempt at solving this pressure drop problem, but I have been told it is incorrect. I am very much a beginner in the area of fluid mechanics, so if you could please define any terms that you are using, that would be so helpful! I thought using the Hagen-Poiseuille would...
  36. S

    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...
  37. S

    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 PaHomework 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 appreciated...
  38. gfd43tg

    Calculating Pressure Drop in a Fluidized Bed of Spheres Using the Ergun Equation

    Homework Statement Air at 100 F is flowing through a packed bed of spheres having a diameter of 0.5 inches. The void fraction (ε) of the bed is 0.38 and the bed diameter is 2 feet. The bed height is 8 feet. If the air enters at 16.2 psia at a rate of 47.5 lb / min calculate the pressure drop of...
  39. S

    Pressure drop across a filter medium vs. time modelling

    Hello guys, I am a computer science PhD student. But my project somehow requires some knowledge about computational fluid dynamic modelling (both discrete and continuous). nowadays I am abit stucked in an issue. I want to model pressure drop across a filter medium dynamically. i assume i have...
  40. M

    Gas Flow Rate Calculation using Pressure Drop

    Homework Statement Hi everyone, I'm trying to calculate the flow rate of air in straight tubing that is 30cm long and has a diameter of .1875 in and has an outlet into a 100 mL vial which is vented to the atmosphere. The starting of the system pressure is 20 psi and the ending psi is 14.6...
  41. gfd43tg

    Pressure drop at power station pumping power law fluid

    Homework Statement The Black Mesa pipeline transports 660 tons / hr of solid coal ground to 8 mesh (2.4 mm) as a 50 wt % slurry in water with an estimated sg of 1.26 for 273 miles across northern Arizona. The pipeline ID is 18 inches and the slurry flow rate (coal and water) is 4200 gal/min...
  42. P

    Calculating the pressure drop in a contraction?

    Homework Statement Water flows at room temperature in a horizontal pipe with mean velocity of 1 m/s. Then a sudden contraction of the pipe changes the diameter to half the upstreams diameter (##\frac{D_1}{D_2} = 2##). What is the pressure drop (##p_1 - p_2##) from a point (1) upstream of...
  43. S

    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...
  44. N

    How can i calculate pressure drop in air compressor?

    hi friends, I am confused with incompressible and compressible flow.Can i use moody diagram for air compressor.How can i calculate pressure drop in pipe.
  45. J

    Air Pressure Drop Problem: Solutions Explored

    I am having a problem with an air pressure drop. I have a supply of 100psi of around 4scfm. I have it regulated down to 90psi, but when I turn on an air turbine motor my regulated pressure drops momentarily (1-2sec) down to 80psi. This drop in pressure is unacceptable to other components in my...
  46. T

    Shear stress and pressure drop

    hello all... Please can i know physically why the pressure drop in a fluid when there's shear stress? what happens? thank you
  47. C

    How to Calculate Pressure Drop in Pipes with Variable Vents?

    I am calculating various pressure drops in a pipe and am and am having trouble calculating the pressure at a certain point, for a set case. This is the pipe... http://i50.tinypic.com/141mikg.jpg A and B are vents, through which air passes and travels on up the pipe, where is it discharged to...
  48. S

    Does a pressure regulator maintain constant pressure drop?

    I wanted to know the function of a pressure regulator.. Am using one to control liquid flow rate. Here is my understanding- A pressure regulator can be connected across a valve. The pressure regulator maintains a constant "pressure drop" across the valve so if i set it to give a drop...
  49. T

    Understanding Pressure Drop & Flow in Pipes

    Hello... I can't find the difference between the pressure drop in a pipe due to frictionnal loss and the Pressure difference that cause the flow like in Poiseuille Flow.. Thanks
  50. F

    Gravitational head against an adverse pressure drop

    Hey, Currently I have a system where I have a high pressure at the lowest point of a vertical pipe and a low pressure at the highest point of the pipe. I want the flow to travel down the pipe vertically under gravity but I am unsure of how gravitational head works in the mechanical energy...
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