Mass flow Definition and 133 Threads

Mass flow, also known as “mass transfer” and “bulk flow”, is the movement of fluids down a pressure or temperature gradient, particularly in the life sciences. As such, mass flow is a subject of study in both fluid dynamics and biology. Examples of mass flow include blood circulation and transport of water in vascular plant tissues. Mass flow is not to be confused with diffusion which depends on concentration gradients within a medium rather than pressure gradients of the medium itself.

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  1. B

    Angular momentum with mass flow

    Homework Statement A drum of mass M_a and radius a rotates freely with initial angular velocity \omega_a(0). A second drum with mass M_b and radius b >a is mounted on the same axis and is at rest, although it is free to rotate. A thin layer of sand with mass M_s is distributed on the inner...
  2. 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...
  3. 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...
  4. 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...
  5. 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...
  6. 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...
  7. 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...
  8. 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...
  9. N

    Mass Flow through a 1.5 Pipe @ 300kpa

    Mass Flow through a 1.5" Pipe @ 300kpa Hi, I'm having some trouble with finding the "choke" point of a 1.5" diameter pipe. Conditions: 300 kPa 383 deg K 1.5 in D I've tried using this little guy, http://www.grc.nasa.gov/WWW/K-12/airplane/mflchk.html, with the Mach = 1, and only...
  10. edpell

    Mass Flow & Its Effect: Explained

    Ciufolini and Wheeler in their book "Gravitation and Inertia" talk about the effect of a flow of mass. Just as a flow of electric charge creates a magnetic field they say a flow of mass will create an effect. Can someone explain the nature of this effect to me? The author just fall back to...
  11. J

    Fluid dynamics - mass flow rate -dimensionless number

    (a) Is it true that if the mass flow rate of a gas is low, say 2g/s (grams per second), the friction losses and other losses in the piping will be negligible? (b) If it is true that losses in the piping are negligible, is it the Euler's dimensionless number that we can use to prove this...
  12. U

    What is the mass flow rate of the water?

    Hello, I have some physics homework and I'm not looking for the answers. Rather, the textbook I currently use does not seem to be doing a good job (in my opinion) in explaining the topics. If anyone has seen some of these questions before and know what textbook they are used in, please let me...
  13. M

    Mass flow rate of cooling water in Diffuser

    Hello Everyone, I am Mayur I am working on a system, in the system there is one diffuser through which exhaust gases at 3000K are flowing at a rate of 170Kg/s. The material of diffuser is Stainless Steel. The diffuser is double walled type with cooling water flowing between the walls. I need...
  14. D

    How can you determine the mass flow rate

    Homework Statement How can you determine the mass flow rate, given that net power output is 100 MW, of the cooling water if it enters the condenser at 20 C and leaves at 35 C. Homework Equations The Attempt at a Solution I thought that mass flow rate is the same all through...
  15. W

    Insane Jet Maneuvers, where do they get the mass flow?

    So I am doing a presentation on effects of inlet distortion on fan performance, I am trying to gauge it more towards the inlet aspect, diverting boundary layers, etc. So I am wondering, how do fighter jets pull such quick turns, and still maintain enough mass flow not to stall the compressors? I...
  16. 0

    How can I calculate the mass flow rate out of a PSV valve?

    Hi all, I am designing a pressure relief system for a high pressured gas (air) system. System consists of a highly pressurised gas receiver with PSV mounted driectly on it which vents via tailpipes to atmosphere. I know the max mass flow rate out of the container I know the back pressure...
  17. V

    Jet Engine Mass Flow Rate calculation

    hi how to find air mass flow rate in jet engine? we are using thrust/Isp equation to find the mass flow rate for rocket equation. is that any formula available for finding the mass flow rate in jet engine
  18. 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 ...
  19. A

    How Is Mass Flow Rate Calculated Through an Orifice?

    hi all, First all my disipline is not fluids so this is why asking for little help here on the following. Basically i have all the required information but i can't seem to figure out how the answer to the mass flow rate of an orifice is obatained, its doing my head in, if anyone could...
  20. A

    Effect of Downstream Pressure Fluctuations on Choked Mass Flow Rate

    What would be the effect on a choked mass flow rate if there were fluctuations in the downstream pressure? Thanks
  21. E

    Mass flow control and ideal gas calculation

    Homework Statement I have an experimental setup consisting of a 755ml stainless steel cylinder being fed with Hydrogen from atmospheric unitl 10 bar. I am using a Brooks Mass flow controller to measure and control the flow of Hydrogen into the cylinder while at the same time recording the flow...
  22. E

    Find Mass Flow Rate: Formula & Explanation from a Rocket

    I want to clarify this because I'm still not sure how to find the mass flow rate, for instance from a rocket. I still puzzled from the formula that describes the mass flow rate which is \frac{dv}{dt}. This the formula that I'm currently looking over but I'm not sure if its this formula to find...
  23. J

    Calculating the Mass Flow Rate for Point C

    Homework Statement see attachment Homework Equations Av=dV/dt mass flow rate =roe*dV/dt The Attempt at a Solution the velocity at point c is 50m/s and the area of the opening is 0.04m^2. (50m/s)(0.04m^2)(1000kg/m^3)=2000Kg/s
  24. W

    Question About Mass and Mass Flow Rate Relations

    Mass is the product of density and volume. Mass flow rate is the product density, velocity, and cross-sectional area. (It's the derivative of mass with respect to time.) Bare with the syntax please... Looking at a sphere within a larger sphere, the volume of the difference is...
  25. S

    Mass flow rate of cooling water in condenser needed

    Homework Statement Adiabatic Steam turbine produces 4000 kW Steam is fed at 21 bar/475 deg C Exhaust is saturated steam (P=0.1bar) Exhaust is fed into condenser where it is cooled to 30 deg C Problem asks for flow rate of cooling water supplied to condensener if water enters at 15 deg C...
  26. A

    Can a Wide Angle in a Diffuser Cause Total Pressure Loss and Affect Gas Flow?

    Change in gas velocity and pressure entering and exiting a duct or pipe expansion section (diffuser). Looking for a formula to determine velocity, pressure and density of a gas as it exits a duct or pipe diffuser section based on the entrance area to exit area ratio. Ambient temperature...
  27. C

    Continuity: Constant mass flow rate

    Homework Statement The aorta carries blood away from the heart at a speed of about 40 cm/s and has a radius of approx. 1.1cm. The aorta branches eventually into a large number of tiny capillaries that distribute the blood to the various body organs. In a capillary, the blood speed is approx...
  28. J

    Mass Flow Rate Through 40 cm Tube at 18 m/s

    If I know air is flowing through a tube with diameter of 40 cm at 18 m/s, with P=1 atm, T=32 C how do I find the mass flow rate..thank you
  29. S

    How Do You Calculate Mass Flow Rate in a Pressurized Tank?

    A pressurized cylindrical tank, 5.0 m in diameter, contains water which emerges from the pipe at point C, with velocity 29 m/s. Point A is 10 m above point B and point C is 3 m above point B. The area of the pipe at point B is 0.08 m^2 and the pipe narrows to an area of 0.04 m^2 at point C...
  30. J

    Calculating Mass Flow Rate of Steam Turbine

    Steam enters a turbine at 3 mpa and 450 c, expands in a reversible adaibatic process, (KE and PE are negligible) and exhausts at 10 kpa. The power output of the turbine is 800 kW. What is the mass flow rate? I did the problem but I don't know if the anwser is correct and wanted to check...
  31. J

    Calculating Exit Velocity & Mass Flow Rate of a Water Pump

    Consider a water pump that receives liquid water at 15C and 100kPa, and delevers it to a same diameter short pipe having a nozzle with exit diameter of .01m to the atmosphere at 100 kPa. Neglect KE in pipes and assume constant internal energy u for water. Find exit velocity and mass flow rate if...
  32. N

    Measuring Mass Flow Rate of AlO2 Particles in Real-Time

    Hi all, I've been asked to search for a way, cost isn't that big of an issue, to measure flow rate in real-time of small, fast, abrasive particles (AlO2). These particles are, on average, 50 microns in diameter, and are shot out of a nozzle, itself just a bit bigger than 50 microns...
  33. S

    Choked Flow in a Converging Duct: Volume vs. Mass Flow Rate

    If subsonic flow is accelerated in a converging duct to mach 1 and then the duct is further converged, choked flow will occur. Will flow at the exit of the duct be compressed as the volume flow rate is decreasing but the mass flow rate has to remain the same.
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