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.
Friendly argument at work (both non physics majors) with what tube would fill up faster with a flow rate (siphon like) that remains the same through two different diameter tubes. The dialysate jug is open to atm pressure. One tube is about .5 inches in diameter and the other is .25. We were...
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Summary: Calculate the air change rate required to keep a certain temperature
In question d above, you were asked to calculate how long the air flow in the system would be active in a day. Now factor in...
A valve is installed between the throttle body and intake manifold and decrease its area to restrict the flow. How do I analyze the mass flow rate of air in the decreasing area to know the engine working condition at a minimum valve area?
a) so Q=V/t = Av
Q is constant ( same At A0 and A). That means I have to find the velocity of the water either at A0 or at A. But how can I find it? I thought there must be a reason that h is given but the only way I can use it is to assume the velocity is 0m/s at A0 but actually it is not...
Lets say if I have a pipe with one end closed, and drill a small hole on the side of the pipe near the closed end. Then I use vacuum at the open end to create mass flow exiting the pipe. Where is the opposite force on the pipe?
[crackpot youtube video deleted by moderator @russ_watters ]
Some thoughts that I've had on the question are saying the volume flow rate (##Q##) in, must equal the volume flow rate out. If that's the case, then:
##Q_{in} = Q_{out}##
##A_1V_1=A_2V_2##
But... no areas have been given. And height doesn't enter this equation at all.
Then I thought it...
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I'm try to calculate the pressure (in bar) needed for a certain flow rate 3 L/min of Argon gas given the following setup:
- I have a tank of Argon gas and the line pressure can be between 0 bar to 5 bar.
- The gas will flow out to the open air in the end.
- My pipe has an internal radius...
Homework Statement
Fire hose has diameter of 4.0 cm and flow rate of 10 L/s. There is pressure of 2.2 bar inside the hose. How high the water can go at best? Water density is 1.00E3 kg/m^3 and air pressure outside the hose is 1.0 bar.
Homework Equations
Flow rate
$$ Q = Av $$
Newtons...
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I hope you are all doing well! I've been always intrigued by fluid mechanics and decided to try out a quick experiment with my water faucet. After using some equations I found online [1] [2], I plugged a hose to the faucet and let the water run. I filled a 1 quart bowl and recorded the...
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I need help with the following question:
Please have a look at the question and my attempt at the solution.
Alternative cooling systems are considered for a large computing centre requiring 1 MW of cooling...
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Can the mass flow rate of air by a propeller connected to an engine through a small tube change if the rpm of the propeller is increased?
Homework Statement
Find the flow rate of water. The fluid in the manometer is mercury. ##d_{1},d_{2}## are the diameters in the figure
Homework Equations
Bernoulli, continuity equations
The Attempt at a Solution
We know that
##p_{1}=p_{1Top}+\rho_{water}gh_{2}##...
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1. Homework Statement
Symbols and variables:
##\dot{V}## : flow rate
##H## : Hydraulic head
##g = 9.81 \frac{N}{kg}##
##P_{atmosphere} = 101325Pa##
##\rho = 1000\frac{kg}{m^3}##
I am given a piping system, with serie and parallel pipes, they start from one point and go back into one...
My issue is related to the actual flow-rate I obtain when sampling air across a filtering membrane.
Each pump reports a nominal amount of air that it can draw in a certain amount of time (i.e.: flow-rate, like 10 liters per minute), but this is generally reported assuming normal temperature and...
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If I have the following known variables:
- P1, Pressure of fluid entering the pipe = 50 psi
- L, Length of pipe = 10 in
- D, Diameter of pipe = 0.5 in
I want to learn how to calculate:
- P2, Pressure of fluid at the end of pipe.
- Q1, Volumetric flow rate of fluid entering pipe.
- Q2...
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Can you tell me please the mass flow rate of hydrogen and oxygen per unit of area of electrodes in fuel cells? Or if you have information on the mass flow rate of hydrogen and air per volume of fuel cell stack?
I understand this may vary, but I am looking for publications or other...
Hey, I'm a student who has to complete a written assignment for physics. I chose to launch water rockets and investigate the effect of volume on the range. I am trying to also come up with a mathematical model however I am struggling to understand an equation
I found the following equation to...
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...
The main aim of my question is to find time taken by gas filled tank while emptying (from full to zero) it into atmosphere?
I require a set of equations which might be used in the calculation of such a situation.
Known parameters are:
1. Pressure inside the gas tank.
2. Dimension and shape of...
Hello everybody,
This is my first post. I've been working on a liquid rocket engine for a while, but I have never gotten to work on its feed system (fluid mechanics), until recently. We are using a very simple pressure fed system, and its main goal is to deliver the propellants at a specific...
Hi. Just looking for an average answer to a practical scenario. At work we use a liquid O2 cylinder which includes an outer jacket that houses a regulated gas pressure of 24 bar. I need to calculate the flow rate in l/min when the supply tap (15mm diameter) is open fully?
This is essentially...
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 a mechanical engineer, but working as Safety Engineer. I have a question how to calculate the flow rate of hydrogen gas before a flow controller in case of leak through a 4.5 mm line at 35 bar pressure. Thanks in advance.
Using a pump we are cycling water through a capsule with filter media inside; while measuring the flow rate (l/min) and the pressure (psi) going in and the pressure going out. The water is cycled back into the same storage tank. As the flow rate increases the differential pressure should change...
Hello all,
I'm trying to calculate the pressures exerted back on a piston by a working hydraulic fluid in a damper system. I've attached a drawing of the system and the equations I'm using. Essentially the piston motion is restricted by flow through an orifice. I have data for the flow rates...
I'm having a brain storm, If I have an 8 cylinder 4 stroke engine running at 4000 rpm over a 10 minute test and it consumes 4.4 Kg of fuel, then is the fuel mass flow rate as simple as the 4.4 Kg divided by the time to give me an answer on Kg/sec ? Thanks,
I have a 5/8" tube that air is blown through. I want to subdivide the center section using .1" tubes so that the same volume of air can be blown through it. It will start as 5/8", but immediately be divided into the separate .1" tubes, then end as a single 5/8" tube. How many .1" tubes would I...
A building has a water inlet and outlet. The static water pressure at the buildings water intake is 5 bar. I'm trying to determine how much water this outlet will deliver when its valve is fully open. In that state, the pipe size and length will result in a certain head loss that I can calculate...
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I have a reaction ## aA → bB ## in a PFR reactor. The simplest equation to write is:
## \frac {dF_A} {dV} = -R ## where ##F## is the Molar flow rate. ##F = C_A*Q## where ##Q## is the volumetric flow rate and ##C_A## is the molar concentration of A.
My textbooks says that if ##a=b##...
Consider an underfloor heating system in an apartment building. Each apartment has its own distribution box with a number of loops and a thermostatic mixing valve set to 35°C. The loops are intended to work with a ΔT of 5°C (35-30), and the riser pipe supply temperature is 75°C. Say there are...
Homework Statement
A 40cm well was drilled penetrating straight into unconfined aquifier at depth of 90m . The other wells were drilled at a distance of 20m and 100m from initial well have decrease in water level of 12m and 8m from groundwater level . If the aquifier has a permeability value...
Most engine specifications I have found only provide the engine mass flow rate for take-off setting. For example, the V2500 has a mass flow rate of 354.25 kg/s.
How does the flow rate vary through different power settings? For example, if the engine is on idle, will the mass flow rate be 0...
Hi everyone. Let me give a little bit of background on the problem I need help understanding.
I want to plumb an aquarium that has a sump and move the water from the sump to the main aquarium using a pump and 1" PVC pipe. The total system pipe length is going to be roughly 10 feet total with...
Hi, wondered if anyone can give me a pointer on this problem I am working on.
6 Diesel engines each with power 55kW running, given output cooling water temperature of 80°C, and required return temp of 60°C. The coolant is to be fed through a heat exchanger, with the heat exchanger outlet to be...
Hello all,
Looking for ideas on how to calculate mass flow rate from a velocity contour plot. The cross-sectional area is circular. An example of the velocity contour plot is shown in the figure below:
In most of the cases (as exemplified above) the flow is non-axisymmetric. Any suggestions...
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I have an in-house designed flow meter with roughly the configuration in the figure. In the setup, a restriction is placed in the flow stream (the rows of horizontal lines in the figure). Pressure measurements upstream and downstream of the restriction, P1 and P2, respectively are...
It seems there must be a way, but I cannot seem to wrap my head around it. Here's the scenario...
I have a 24" line flowing with a wet gas (combustion flue gas) into a dryer. It comes in at 90 degrees F, at a rate of 180 SCF/M. It leaves the dryer at 73 degrees F at a rate of 124...
I have a work related question. Although it seems like a relatively simple question, I am having difficulties finding the correct equation(s) to calculate the answer.
Question: Given a fixed volume air tank filled with pressurized air, how does one calculate the flow rate over time through...
I'm trying to learn more about how air compressors work (not how they mechanically function - how they're input/out pressures and flow rates work) and I'm having a lot of trouble getting a specific questioned answered even after a lot of google searching.
Suppose I have a compressor that the...
Can adding a nacelle in front or behind a standard pedestal fan affect the speed of the air coming in and out? If so, which is more beneficial: an intake nacelle or a nacelle in the front?
Using Q=AV, with Q being constant because of the fan blade's max speed, can affecting the area (A) create...
I have a diesel pump doing 900 lpm with a hose reel 30 meters long, the inside diameter of the hose is 32mm. The frictional loss for 30 meters of hose is 461.04 kPa. The Viscosity of Diesel is 4.5 mPas. I would like to know the final flow rate.
thanks in advance
Hey guys. I could use some explanation since I am new to FM: So my problem is the following one: Fluid flows with an average velocity 8 m/s in a pipe with diameter 3m. What is the volume flow rate?
Now, I think the formula I got to use is Q= v.A Yet, I found my solution from a formula I found on...
Homework Statement
More a report question but unsure where to put it.
Take a 5mL syringe and a 10mL syringe (both filled to 5mL) with the plungers removed.
Time how long it take to full drain each syringe
Make a statement regarding your results.
Homework Equations
Fluid flow rate = volume /...
Homework Statement
A fireman's hose acting as a water cannon, directs 100 litres/s (100 kg/s) of water horizontally at your chest at speed 5 ms-1. Assuming water essentially falls to the ground after hitting your chest (rather than say reflecting horizontally backwards), what horizontal force...
Hi
When I was writting my thesis I found in an article, published in International Journal of Heat and Mass Transfer, an unit of mass flow rate G - kg/(m^2*s). Isn´t it wrong? I think that the unit of mass flow rate is kg/s. Would you mind helping me to figure it out? Thanks.
In the case of a kidney vessel from point a to point b(a-------------b), say we constrict point b and increase resistance. Would the flow rate be decreased before the constriction at b, or would the flow rate only be changed after the constriction.
Thank you Physicsforums!
Hi Friends,
I am Milind Nachane, New member of PF.
We have to buy a Water Treatment Device which eliminates the scaling and rusting Hazard.
To decide model of device we need to know Flow rate of Pump.
I know that Pump is Mono-block (Non-submersible) of 7.5 Hp and has 2 Inches Diameter...