Pressure drop Definition and 147 Threads

  1. T

    Pressure drop across an array of different nozzles?

    I have a question about calculating the pressure drop in a large flow meter across an array of nozzles. Basically its inside of a tunnel... air flows in this tunnel until it reaches a "gate" which is blocked off except for six nozzles of different size, which discharge back into an open...
  2. P

    Pressure drop for viscous fluid in conducts with an obstacle at the outlet

    Hello, I have the following system (see enclosed figure): A viscous (non Newtonian) fluid at high temperature is going trough a tube at a known mass flow, at the exit there is an inclined plane at a given angle (b). I would like to estimate in some way how the inclined plane at the exit...
  3. F

    Compressed Air System Dynamics: Calculating Pressure Drop & Cv

    I want to work out the dynamics of a compressed air system consisting of a filter/regulator unit some spool valves and a rotary actuator with all the associated fittings. Essentially I have a 2" nominal bore compressed air line at roughly 7.5 bar, I have a system which feeds off this air main...
  4. D

    Calculate the flow coefficient and pressure drop through valve?

    Hi I am wondering would ye be able to help me out? I am instructed with the task of calculating the pressure drop and flow coefficient for a valve. Please see basic diagram attached for layout of valve. I need to find the pressure drop and flow coefficient when the ram is closed at different...
  5. A

    Concentrated pressure drop in tube having 90 round bend

    Hi i want to calculate the concentrated pressure drop in a tube having 90 round bend and other one having 180 round bend. The equation that i know is: dP (concentrated) = 1/2 * b*r*v^2 where: b=specific coefficient for concentrated pressure drop r = liquid density (kg/m³) v = average...
  6. M

    Pressure drop across butterfly valves

    Hi, I'll make a valve open and close for some degrees that I have to calculate, the valve motion will produce a pressure wave in the pipeline. I have to know how many degraus I must open the valve to produce a pressure drop that I want. Someone know how I can calculate it? Is there an equation...
  7. A

    Pressure drop profile calculation

    I am so tired I tried many times to calculate the pressure drop profile. What is the right equation? Please help me
  8. T

    Pressure drop across a small section of pipe.

    Hello everyone. I have natural gas (methane) flowing through some piping, and the last little part of pipe is where I'm concerned. The gas goes through a drawn aluminum tube, about 5.08 mm ID (it's a very small tube). The tube has three 90 degree bends where it ejects out of an orifice. It...
  9. M

    Need help to find average velocity and pressure drop in duct

    Homework Statement 1. the average velocity of the air to meet the required volume flow rate, 2. the pressure a fan needs to produce to overcome the frictional losses in the duct, 2. Relevant Information Duct size - 600 mm x 600 mm which operates at 3 Pa/m. The air path is 87 meters from...
  10. N

    Question: Pressure Drop Across A Bed Of Stone

    Dears, I am going to find out the required pressure for the air to pass through a bed of stone in a cooling tower. I have read the book: Handbook of pneumatic conveying engineering (by David Mills) and it said that it can be determined by permeability of the stones (15-20mm size). The...
  11. M

    PWR Pressure Drop: Plenum to Plenum Pressure Drop

    For pressure drop of PWR, what is the plenum to plenum pressure drop?
  12. A

    Pressure drop in pipe due to bends and/or pressure reducing valves ?

    I am currently doing my final year project and have a few queries. I would be really grateful if someone could answer the following questions for me as soon as possible. • The requirement is to drop the pressure from 140-150 bars at the inlet of a pipe to 2 bars at the outlet of the pipe. •...
  13. Q

    Pressure drop in pipeline in a bend or elbow

    I wonder if there is no table or graph with which I can make a quick estimation of the pressure drop in relation with pipe diameter and flowrate ( for 90° bends only ) ... can anyone help me with that ?? Thanks !
  14. K

    Calculating Pressure Drop in Fuel Systems with Complex Geometry: A Case Study

    Hello. I have been asked to calculate the pressure drop across our fuel system. It is a large system with many fittings and bends. My numbers don't seem to make sense to me Please help... Before I begin, I use equation dp=(K*density*MeanVelocity^2)/(2*g) to calculate pressure drop. To...
  15. K

    A couple questions regarding pressure drop

    First, I am very confused as to the difference, if any, between head loss and pressure drop/loss. Can someone help me? Also, I know that the Darcy-Weisbach equation for head loss due to friction is hf=fL/D*V2/2g and you can plug that into get an equation for delta p that is dp=fL/D*pV2/2...
  16. A

    Understanding Pressure Drop in Parallel Piping Systems

    I have a question about network flow pressure drop. In a piping system with several identical components in parallel, is the pressure drop across the supply and return header equal to the pressure drop across one of the components? Or is it the inverse of the sum of the inverses? To use...
  17. T

    Pressure drop across orifice , calculation help

    Homework Statement A fluid of relative density 0.86 and viscosity 0.003 pa flows through a pipe of 12cm diameter. The flow rate is measured using an orifice plate with a 6cm diameter orifice, with pressure tapping connected to a differential U-tube manometer using mercury (density = 13600 kg...
  18. D

    Pressure drop in a water manifold

    Hi all, This is what I currently have. Water chiller with a flowrate of 2GPM (Choked to 2GPM) Ti= 50F H20 Pi=55-60psi It is a closed loop system. I am looking to split 1 line at 2 GPM (55-60psi) into 8 smaller lines that will run into my cooling jacket. All 8 lines are same length...
  19. S

    How can hydrostatic pressure drop to zero?

    Hello everyone, If this is a vessel the hydrostatic pressure would drop along the vessel due to resistance. My question is why does hydrostatic pressure drop if hydrostatic pressure is due to gravity. Gravity is always there, even if the molecules lose hydrostatic energy, they would gain it...
  20. Valour549

    How Long for Air Pressure to Drop 30% in Space Capsule with a Hole?

    Air pressure drop in Space (please help!) Homework Statement A space capsule, which may be treated as a sphere of radius 10 m, is hit by a micrometeorite which makes a hole of diameter 2mm in its skin. Estimate how long it will take for the air pressure to drop by 30%. (Answer should be...
  21. S

    Rate of air pressure drop in a reservoir with a hole to a vacuum

    Homework Statement A space capsule, which may be treated as a sphere of radius 10m, is hit by a micrometeorite which makes a hole of diameter 2mm in its skin. Estimate how long it will take for the air pressure to drop by 30%. Avogadro's number is about 6 \times 10^{23} Homework Equations...
  22. P

    Orifice design for pressure drop

    When designing an orifice plate to reduce the pressure of a constant flowing liquid, is it best to have one large hole in the center or multiple smaller holes? One example: Pipe diameter = 10 inches, Flow = 2800 gpm water, pressure drop = 150 psi, temperature = 115 F. The hole diameter...
  23. S

    Blood Pressure Drop: Understanding Mechanisms

    Hello! Ive been trying to understand mechanisms of blood pressure and so far the more I read the more confusing it gets. What I really don't understand is this - why does the pressure drop is largest in arterioles? The physiology book I use says that they constitute a high resistance and as...
  24. C

    Why Does Pressure Drop in Expansion Valves?

    I'm having trouble understanding expansion valves. Gas leaving a diffuser increases its pressure as the cross-section increases (i.e as the gas expands), like in a compressor. We convert kinetic energy in potential energy. That I understand. But in a expansion valve, pressure drops as the...
  25. A

    Calculate air-flow using pressure drop

    At what speed (flow/volume for that matter) does air leave an outlet when you know it holds x bars in the pipe? (It goes from x to zero (or athmospheric) -- you know the pressure difference) I assume you can neglect relative roughness, resistance, and so on as the pressure drop is over...
  26. A

    How to find the flow rate trough a pipe using pressure drop

    Hi, I want to know how high the flow rate trough a pipe is (outlet), but I only now the pressure difference (0.7MPa or 7 bar), and the diameter of the pipe. At what speed (or for that matter volume) does air leave a pipe when the pressure difference is 7 bar, and the diameter is 25.4mm...
  27. B

    What is the formula for finding pressure drop in pipe flow?

    Hi, Which equation should i be using to find the pressure drop across a channel. I know the length of the channel, the hydraulic diameter and the reynolds' number. Thank you
  28. A

    Why Is There a Pressure Drop Across Valves Despite Bernoulli's Equation?

    Hi guys, i want to ask why is there pressure drop across valves? Because if you look at bernoulli's equation, the head will be the same in 3 points, before the valve, at the valve and after the valve. The only thing changes when a fluid flow through a valve is its pressure and velocity at the...
  29. M

    Pressure Drop vs Velocity in a Rectangular Pipe

    Hi guys I am currently using Comsol to model a single rectangular channel, a typical one found in a fuel cell (with symmetry boundary). Dimension of the inlet and outlet area is of the order 10e-3 and the length of the pipe is 0.1 m. I am having difficulty getting the expected result. The...
  30. P

    Calculating Pressure Drop Across Valve in Horizontal Pipe

    Hi, 20m straight length horizontal pipe (60 mm internal diameter), steam flows at rate 0.5 kg/s, at midpoint there is a valve in the line. inlet pressure to this section of line is 5 bar (gauge), pressure at end of line is 3 bar (gauge). mass quality of steam is 0.8 and 2 phase flow occurs in...
  31. J

    Equation relating mass flow rate to pressure drop

    Hi I am designing a heat exchanger. I know the mass flow rate required for cooling. I have calculated the pressure drop for current design. How do I work out if the size if the heat exchanger can handle the flow rate ? Does the mass flow rate depend on the size of the heat exchanger tubes ...
  32. S

    Pressure drop across a packed bed

    I have a packed bed with an inlet pressure of 108psig and an outlet pressure of 88psig to give a total pressure drop of 20psi. The packing is becoming damaged due to the 20psi pressure drop. I have thought and looked for an answer for a long while, why does the packing only experience the...
  33. K

    Pressure Drop Across Radiator And Air Flow

    Hello all, I have some performance data on a particular radiator, and I want to model the system and see if I can't get a simple analytical model to match the data. The problem I'm having is with the air flow rate through the radiator. The only relevant data made available to me is the...
  34. Y

    How Does a 90-Degree Bend Affect Pressure Drop in Pipes?

    I have a centrifugal pump that gives flow of 56 lit/min at 50 psi. Media: clear water, Temp. ambt The discharge pipe size: 1 1/2", Material: SS Total pipe length: 14 feet At 3 feet from pump discharge there is 90 degree bend and again at 6feet there is 90 degree bend. My question is what...
  35. M

    Pressure Drop Due to Combining Flow in a Water Pipe System

    Hello, I am wondering how to determine the pressure drop due to fittings such as Tees and "Y's" when there are two flows coming in and one coming out. So for example there is a Tee where there are two flows coming in opposite directions (180 degrees from one another) and they combine and exit...
  36. M

    How to use flow rates (GPM) and pressure drop to determine if a valve is usefull

    I need to determine if a valve can handle a flow rate of 50 GPM, this valve being: 2/2 Way, Normally closed, w/ 2-pilot control, and coupled solenoid. I also need to determine pressure drop... it is a burkhert model - 457361D the valve specs indicate: Cv = 35.1 pressure...
  37. S

    Compressed Air Pressure Drop Across a Restriction

    I would like the formula that describes the reduction in pressure that results when a constant flow (cfm) of compressed air travels from a 3" diameter pipe through a bell reducer that provides a smooth transition to a 1.5" diameter pipe. Also, in the same piping configuration as described...
  38. K

    Calculating Pressure Drop with Displacement Thickness

    [FONT="Arial Black"][FONT="Arial"][SIZE="5"] Question In flow over a flat plate, how to calculate pressure drop by knowing displacement thickness values at 2 points. Free stream velocity is known.
  39. R

    Pressure drop in pipes and Velocity

    For pipes head loss causes pressure drop. If there is lower pressure at the end of the pipe, is the velocity lower? What I'm trying to figure out is if the average velocity in the pipe is constant. And how does it change if you place an object inside the pipe? Does velocity only change with a...
  40. W

    Pressure Drop & Flow Rate for Oxygen Delivery Tube

    I am on home oxygen and receive the gas through a 50feet long tube about .1" inside diameter.If the Machine delivers a flow rate of two liters per second, what is the pressure drop through the tubing; What is the flow rate at my end of the tubing?
  41. E

    Dynamic head, pressure drop formulas?

    My fluid dynamics is rather weak and i was wondering if someone could please tell me how to calculate dynamic head of the flow in the a tube and how to calculate pressure drop of a hole in a tube? Some formulas would be handy thanks engineering
  42. R

    Calculating Flow vs Pressure for PRV Valve | FORD 4" PRV Assistance

    I'm in need of some assistance in calculating some flow vs pressure specifications, in order to make some changes to the system. I have a PRV valve that has a preset setting of: PRV NO.1 & 2 SET PRESSURE = 1034 KPA (150 PSI) @ 0.63 L/S (10 USGPM) Meanwhile the design criteria states the...
  43. B

    Pressure drop in elbows & bends in a pipe

    hi! i want to calculate pressure drops in a pipe having various elbows ,bends & valves.whts equation should be used to calculate the pressure drop. thanks gaurav
  44. S

    Pressure drop along a tube of unkown length containing turbulent flow

    How do u calc pressure at each end of pipe if u know its turbulent and u don't know the length. Just got viscosity, density, temp diff at one end, D. Cheers.
  45. R

    Bernoulli's Pressure Drop Segregated from Friction Pressure Drop

    Hello Physics Masters! I would like to calculate pressure drop values caused by friction as water flows through a a smooth pipe at different velocities and different internal pipe diameters. I ONLY want the pressure drop values caused by friction, not the pressure drop values caused by...
  46. I

    Does Slower Flowing Fluid Experience Less Pressure Drop?

    Lets say water was rising vertically up a pipe at a lower pressure and lower velocity. Is the pressure drop the same in faster and slower moving fluids or does slower moving fluid lose less pressure from pressure drop.
  47. B

    Air Flow Crash Course: Pressure Drop V. Vol, Speed, Duct Size & Shape

    Can anyone suggest a site where I can get a crash course in air flow? What I am looking for is pressure drop verses various volumes, speed, duct size, shape, etc. I have spent over an hour searching the net, but haven't had any luck. Thanks.
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