Flow rate Definition and 496 Threads

In physics and engineering, in particular fluid dynamics, the volumetric flow rate (also known as volume flow rate, rate of fluid flow, or volume velocity) is the volume of fluid which passes per unit time; usually it is represented by the symbol Q (sometimes V̇). The SI unit is cubic metres per second (m3/s). Another unit used is standard cubic centimetres per minute (SCCM).
In hydrometry, it is known as discharge.
In US customary units and imperial units, volumetric flow rate is often expressed as cubic feet per second (ft3/s) or gallons per minute (either US or imperial definitions).
Volumetric flow rate should not be confused with volumetric flux, as defined by Darcy's law and represented by the symbol q, with units of m3/(m2·s), that is, m·s−1. The integration of a flux over an area gives the volumetric flow rate.

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  1. P

    Thermodynamics: Mass Flow Rate

    Homework Statement A cylindrical tank with a diameter, d, is being filled with a liquid having a density,p. There is an inlet at the top of the tank and an outlet at the bottom of the tank. The mass flowrate at the inlet is given by m(in) and the mass flowrate at the outlet is given by m(out)...
  2. J

    Thermodynamics (Mass flow rate & Volume flow rate)

    Homework Statement Steam at 400oC enters a nozzle with an average velocity of 20 m/s. If the specific volume and the flow area at the inlet are measured as 0.1 m^3/kg and 0.01 m^2 respectively, determine (a) the volume flow rate in m^3/s, and (b) the mass flow rate in kg/s Homework...
  3. T

    What is the Pressure Change in an Aortic Aneurysm?

    Homework Statement In an aortic aneurysm, a bulge forms where the walls of the aorta are weakened. If blood flowing through the aorta (radius 1.0 cm) enters an aneurysm with a radius of 2.5 cm, how much on average is the blood pressure higher inside the aneurysm than the pressure in the...
  4. R

    Flow Rate Calculation for Air Pressure in Cylinder

    Homework Statement Greetings! I am a student from Estonia and I have a little problem with my assignment. I have to make a simulator that controls air pressure in a cylinder. I need to calculate how much pressure flows into a cylinder each second. To do that I need to know the the flow rate...
  5. X

    Estimating Fan Flow Rate with Speed & Angle

    Is there an equation with which I can estimate the flow rate a fan will generate at a set diameter, speed and angle of the blades? Assume that this is a simple box fan that you would put in your window. I'm assuming that you would have to determine the axial speed of the air given the angle...
  6. A

    Calculating Flow Rate of 180°F and 3 GPM

    I'll elaborate a little. I trying to work out how to calculate and how to make at least 180 F (80 C) and 3 gallons per minute (11 liters/min)? Thanks in advance! Adam
  7. A

    Thermodynamics question about mass flow rate in an air conditioning unit?

    1. In an air conditioning unit fresh air at 10°C is mixed with warm air at 30°C. If the mass flowrate ratio of warm to fresh air is 1.6, estimate the temperature at which the mixed air leaves the air conditioner. State any assumptions made. and also do you always make the air standard...
  8. J

    The mass flow rate in a heat exchnager

    Refrigerant-134a is to be cooled by water in a condenser. The refrigerant enters the condenser with a mass flow rate of 6 kg/min at 1 MPa and 70oC and leaves at 35oC. The cooling water enters at 300 kPa and 15oC and leaves at 25oC. Neglecting any pressure drop, determine (a) the mass flow rate...
  9. C

    Determining Constant Mass Flow Rate in a Compressed Air System

    It's been a long time since I had to do any calculus and longer still since I had to deal with ideal gases but now I'm confronted with both. The problem setup is this: Air is coming into a compressor at a known mass rate, pressure and temp. It's being compressed to fill a known tank...
  10. M

    Calculating Flow Rate of a Fan Using Parameters

    I wonder if there is a mathematical formula to calculate the flow rate of a fan if following parameter are known Fan effective diameters Blade Angle ( Pitch ) Number of Blades Speed ( RPM ) Power Consumption Pressure at inlet of the fan Regards
  11. C

    Calc Volume Flow Rate of Water from Tap (45mm ht)

    [b]1. Homework Statement Tap water flowing has an cross section area of 1.2cm^2 near the tap. after a height, h=45mm the cross section becomes 0.35cm^2...find the volume flow rate of water from the tap Homework Equations g=9.8m/s^2 The Attempt at a Solution i think of using these...
  12. D

    Flow rate and velocity form a Conical tank.

    I am working on a Hydro project. Just can't get this right. I have a water tank (cone shaped) with Radius 60 Inches and height 120 Inches. The Tip of the cone has a nozzle with a 3 inch opening. If the Air pressure is ignored. What will be the flow rate of water and pressure. ?
  13. Z

    Solving For Mass Flow Rate of Two Water Jets

    Homework Statement I am supposed to find the mass flow rate for the two resulting water jets. Homework Equations Bernoulli's equation Mass Continuity equation Momentum equation The Attempt at a Solution I've assumed the two areas for jet A and B to be equal, and used mass...
  14. Z

    Finding mass flow rate and static pressure

    Homework Statement I was asked to find the mass flow rate and static pressure Homework Equations Bernoulli's equation The Attempt at a Solution I simply assumed that the area of the water jet hitting the vane is equals to the total area of water leaving the vane. I'm not sure if my...
  15. C

    Flow rate/ Bernoulli's equation

    ap physics student, on this for the first time The flow rate of water through a garden hose is 60 cm3/s, and the hose and nozzle have cross sectional areas of 5.1 cm2 and 1.6 cm2 respectively. (a) If the nozzle is held 11 cm above the spigot, what are the flow speeds through the spigot...
  16. W

    VFR= AxV ; VFR= 3.11ft^2(1.4578ft/sec)=4.51cfmAir Flow Rate: 4.51cfm

    Homework Statement (Static) Measure air flow in a duct 28"x16" w/ a Pitot tube is .4 inches w.c. What is air flow rate? Homework Equations P=dxh , VFR= AxV , P=(Hs1-Hs2)+(V2^2-V1^2/2g) + (He2-He1) + Hf or Hv=(V/4000)^2The Attempt at a Solution 28X16= 448in^2(1/144in^2)=3.11 ft^2...
  17. T

    Solve Flow Rate Problem: 9 kW Shower

    Homework Statement a) A student taking a shower notices that the power rating of the shower is 9 kW. Estimate the flowrate of the water. I think I have to use the equation Q = m c \delta T However I have not beeen given any temperature or anything, like that, or the mass? How would I do...
  18. C

    Flow rate problem (boat in water, with pic?)

    Homework Statement A yacht sitting in a harbor has a hole (area 8x10-3) in its hold and is located 2 meters below the surface of the water. The interior of the boat is at atmospheric pressure. If the hole went unnoticed for one hour, how much water has accumulated in the boat? Here's my...
  19. N

    Flow Rate for water not to freeze in pipe?

    I am a novice pipe designer and I have a project starting on Monday. I have to design a Filtered Water Supply system. The pipe is SS and the majority of the header is located outside. The engineer said no insulation is needed if we put a recirculation system in. He says by keeping the water...
  20. J

    Flow rate relation? (velocity distribution in pipe flow)

    i have this question which asks me to find the average flow velocity in a pipe, BUT based on flow rate relation and not statistical average what is the flowrate relation?
  21. C

    Thermodynamics - Mass Flow Rate

    Homework Statement Steam at 30 bar and 280C flowing steadily at 20,000 kg/hr is throttled to 20 bar. A separate stream of liquid water at 25 bar and 20C is throttled to 20 bar. Steam and liquid water are mixed in a mixing chamber so as to produce saturated steam at 20 bar. (a) What is the...
  22. B

    Flow rate depending on pressure with constant inlet rate.

    A 10 m high, 5 diameter cylindrical water tank has an inlet at the top and a drain at the bottom. The flow rate out of the tank depends on the pressure at the bottom of the tank via the following: dm/dt = (10^-4)*(P_bot) where P_bot is the absolute pressure in Pascal at the bottom of the tank...
  23. E

    Pump head and flow rate relation

    i need some help becoase i become confused according to pump characteristic curve if the flow rate increased the head will decreased the question is how i can increase the flow rate and what is the relation of RPM with head and flow rate
  24. P

    Calculate the flow rate of the etching solution

    Homework Statement In the semiconductor industry, integrated circuit (IC) production begins with the mechanical slicing of silicon rods into wafers. Once the wafers are sliced, the surfaces are lapped and polished to uniform flat surfaces. Contaminants and microscopic defects (work damage)...
  25. A

    A question about water flow rate

    Hi all, I'm doing a experiment at home I'm trying to know how the flow rate on the water height that tossed from a nozzle with 3mm of diameter. By an other word if there is a relationship between flow and the height please some one explain it to me. Also I wana to know if the head pressure...
  26. J

    Calculate Flow Rate Thru 3.175mm Nozzle Tip

    It's been a while since I've had to do these calculations.. I'm looking for the flow rate at the wall of a 3.175 mm nozzle tip. The diameter of the delivery leading up to it is 19 mm. This is a vertical assembly and the source of the air at 70 psi is a 1/4" outer diameter tube that is...
  27. C

    Calculation of tank height based on flow rate

    hi physics forum i am having a issue related to a tank size based on the flow rate and the diameter of the orifice. the dimensions would be the total height of the setup should be 1000mm the flow rate should be 525+/- 25ml/min the Internal diameter of the orifice is 4.3mm what would be...
  28. C

    Calculating Gas Flow Rate in a 180km Stainless Steel Natural Gas Pipeline

    1. The pressure at the start of a 180km stainless steel natural gas pipeline is 4Mpa and at the end is 2Mpa. If the diameter of the pipe is 0.4m, what will be the gas flow rate through the system? (ignore losses other than friciton) (for natural gas, \rho= 40kg/m3, \mu= 11x10-6 Pas2...
  29. C

    How Do You Calculate Gas Flow Rate in a Pipeline with Given Parameters?

    1. The pressure at the start of a 180km stainless steel natural gas pipeline is 4Mpa and at the end is 2Mpa. If the diameter of the pipe is 0.4m, what will be the gas flow rate through the system? (ignore losses other than friciton) (for natural gas, \rho= 40kg/m3, \mu= 11x10-6 Pas2...
  30. H

    Calculate Flow Rate using Pressure & Diameter

    I need to hook up an instrument that requires a source of compressed air at 47psi and 4cfm. I have a pressure gauge so I can measure the pressure at the source. It seems to me that I should be able to calculate the flow rate if I know the pressure and the diameter of the pipe. Can anyone help...
  31. S

    Flow rate calculation using pressure difference and time

    I am a second year engineering student out on my first co-op work term. My supervisor's first task for me was to calculate the flow rate of one of his parts that he will use on a system that he is designing. I hooked up the part to a compressed nitrogen tank initially at 6,000psi. I cracked open...
  32. A

    How to Convert Leak Rate to Flux for Permeability Coefficient Calculation?

    Hi, I am performing a helium leak experiment in which the detector outputs a number in mbar.L/s which is the amount of helium permeating through a specimen at a given pressure per unit of time. I am interested in obtaining a permeability coefficient (K) for this specimen for the given...
  33. C

    Steam quality, mass flow rate, temperature and pressure of the steam

    How should steam quality, mass flow rate, temperature and pressure of the steam be optimized in order to have the most out of turbine? I mean which ones have be to be higher? Also when they design turbine, do they design it based on the properties of the steam or they change the properties of...
  34. U

    Flow rate of a tank with RAMP at the bottom

    Flow rate of a tank with RAMP at the bottom** Homework Statement 50 m3 of water in a tank at a height of 11.5 metres. The water will be flowing out of the tank down a ramp of 30 metres. The angle of the ramp from the floor to the tank will be 22 degrees. Homework Equations v =...
  35. V

    Determining Flow Rate from a Closed Pipe

    im trying top find the flow rate of water from a closed pipe. one thing that i think i can work with is a hose. there is a hose branching of the main flow pipe, which can be used to clean floor etc. im thinking that i can not open the hose and thus measure the stagnatiob pressure at the...
  36. O

    Calculate Volume Flow Rate: Pressure & Speed

    Hi there, I have a lab project. Part of the project is to calculate the volume flow rate, I have 2 tubes,radius' are known , density of the fluid is known and pressure is known. How can i relate the pressure to speed?
  37. A

    Measuring Flow Rate in a Pipe with a Venturi Device

    Homework Statement Describe how a venturi device for measuring the flow of water in a pope works and estimate the slowest flow rate such a device could be expected to measure using 20% of cross sectional area constriction and a mercury manometer. Homework Equations A1V1=A2V2 I also know...
  38. C

    What is the average flow rate of water in an IC engine's water jackets?

    what is the average flow rate of water in the water jackets in an ic engine?
  39. russ_watters

    Gulf Oil Spill Velocimetry-Based Flow Rate Estimate

    In the thread in P&WA on the issue of the oil spill, I expressed my skepticism that the rate of the spill could be accurately measured via analysis of underwater video clips. That skepticism was strengthened by the recent statement by Prof Steven Wereley, the originator of the first such...
  40. S

    How to keep liquid flow rate constant

    How to keep liquid flow rate constant! hi, my grad. project is automated filling machine and am going to use a gravity liquid (water) filler tank ... my question is how to keep the flow rate from the tank nozzle constant while the liquid level in tank is changing as it fills every bottle ?
  41. D

    Fluid Dynamics Basics: Mass, Flow Rate & Density

    Trying to understand the basics of fluid dynamics after reading up on Bernoulli's principle. One thing I'm caught on. If I know the velocity of an incompressible fluid at a given point, and the force it exerts on a given mass at that point, can I then determine the density of the fluid, or would...
  42. A

    Calculate Time to Fill Bathtub with Volume Flow Rate

    Ok another stupid/smart question, I got a bath with x m^3 volume. And a water flow rate of a tap is y m/s. I also know pressure and velocity. How can I calculate time to fill up bathtub? I know it's simple but I can not figure it out!
  43. B

    Derive a flow rate equation that accounts for the fluid properties?

    :smile:Hi I have been wrestling with this situation for a while, trying to derive an equation for it...A sphere is placed in a fluid of viscosity n and density p, outside any gravity. The sphere is instantly beamed out (perhaps by Capt Kirk?). At what volume rate will the fluid rush into the...
  44. C

    Flow rate of water out of a pipe

    Hello, Am the owner of a 90 acre man made lake and am trying to calculate the flow out of 12 inch pipe at the bottom of the lake. The lake is approximately 10 feet deep. Can someone point me in the right direction on how to solve this question?
  45. M

    Flow Rate Problem: Solve for Time to Pour 6L SAE 10 Oil

    Flow Rate Problem - Please Help! 1. Homework Statement : SAE no. 10 oil has a viscosity of 0.2 Pa· s. How long (in sec) would it take to pour 6 liters of oil through a funnel with a neck 12 cm long and 2.6 cm in diameter. Assume that it is poured in such a way that the oil level is kept just...
  46. M

    How can i obtain the pump flow rate ?

    how can i obtain the pump flow rate ? is this done by filling a certin volume and measure time or there is another method ??
  47. J

    Fluid Mechanics - Estimating Reynolds number and flow rate.

    Homework Statement A pipe 0.15m in diameter has a roughness ratio (k/d) of 0.002 and carries water at a flow rate Q. Using the moody diagram, show that at high flow rates (where the friction factor is independent of reynolds number), the head loss per m length due to friction is approx...
  48. K

    Force to hold nozzle with given flow rate and velocity

    Homework Statement A fire hose discharges water at a rate of 16.0 kg/s with a speed of 20 m/s. What magnitude of force is needed to hold the nozzle stationary? Homework Equations Impulse= Change in Momentum, Momentum (p)= mv, velocity final=velocity inital + at The Attempt at a...
  49. C

    Flow rate, time, height in MATLAB?

    Flow rate, time, height in MATLAB? Homework Statement A tank vertical sides and a bottom area of 100ft^2 is used to store water. The tank is initially empty. To fill the tank, water is pumped into the top at a rate given in the following table. Determine the water height h(t) at t= 10 min...
  50. J

    COMSOL: Periodic inlet flow rate in a pipe

    Hi all - I would like to add a periodic inlet flow rate (Q(t) over an entire period T) as a BC in COMSOL. Does anyone know how to do this in 2D axisymmetric Transient Navier Stokes through COMSOL? I'm aware of the periodic boundary condition option available, but really just don't know how to...
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