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

    Mass Flow of Snow while Plowing?

    Homework Statement Let's say I am plowing snow in a straight line using a standard V-plow. The angle of the V between both blades is 130 degrees. The coefficient of kinetic friction between the blades and the snow is about .1. The speed of the plow is 5 mph or 2.2 meters per second. The...
  2. S

    Calculate Mass Flow rate of cooling water through condenser?

    I have a condenser with a mass flow rate of 60kg/s, an initial point 1: P=50kPa, Quality = 95% and a final point 2: P = 50kPa that is saturated liquid. cooling water flows through the condenser with a mass flow rate of m(dot) and has a delta temperature of 15 degrees Celsius. how do i...
  3. C

    Have You Calculated Mass Flow Rate Correctly in Fluid Dynamics?

    I've Attached the question and my answer to question 1 to task 3 and guidance if I've done it right? Or any guidance?
  4. S

    Tough Thermodynamics mass flow Problem Help

    Homework Statement [/B] Problem: In order to simplify your analysis, you will assume alcohol has the same properties of water so you can use the steam tables. You load the 30 gallon still 1/3 full with nearby water at 1 bar and 20°C and mash(assume the mash has negligible influence on...
  5. P

    Is the mass flow rate in a regenerative vapor power cycle constant?

    Does the mass flow rate differ depending on whether it's after the feedwater heaters or before the turbines or is it just constant throughout the entire system?
  6. C

    Repairing MKS 1179A Mass Flow Controllers: A Scientist's Journey

    Would love to talk to anyonw that is familiar with MKS instruments 1179A Mass Flow controllers. I have taken apart a MKS mass flow controller and am trying to fix it but I am not sure where to get replacement parts, or even what some of the parts do.Most specifically is a small block on top of...
  7. M

    Volume flow rate and mass flow rate

    Hello there, so I have answered my question from fluid systems but the answer doesn't look right ;/ and I have no idea what have I done wrong. Can you please check and correct where it's wrong ? ;) here is the question: A pipe contains a gradually tapering section in which its diameter decreases...
  8. L

    Mass flow rate for compressible flow

    I am confused about the relation of mass flow rate with different mach numbers in a compressible flow. In wikipedia (http://en.wikipedia.org/wiki/Choked_flow), I read the following: "Although the gas velocity reaches a maximum and becomes choked, the mass flow rate is not choked. The mass flow...
  9. elementHTTP

    Mass flow rate, conveyor screw calculations and books

    I am interested in mass flow rate in conveyor screw transportation http://www.colormaxsystems.com/wp-content/uploads/2013/11/5-screws-300x222.jpg any recommended book,engineering guides ?
  10. G

    Mass flow and rolling carts (Kleppner 3.11)

    Homework Statement Material is blown into cart A from cart B at a rate b kilograms per second. The material leaves the chute vertically down- ward, so that it has the same horizontal velocity u as cart B. At the moment of interest, cart A has mass M and velocity v. Find dv/dt, the instantaneous...
  11. B

    Volume flow through a one side closed capillary

    Hi everyone, I'm doing a simulation and need some help. A capillary which is closed on both ends with the length l (x=0 to x=l), with a radius R and the volume pi*R^2*l is dropped on a parachut at the time t=0 from a hight h above ground. At t=0 the pressure inside the capillary is p_i0 (this...
  12. N

    Solving Mass Flow Inlet Issues with Direction Vector

    Hi every one, I am a fluent user, & I need help to illustrate something concerning the mass flow inlet. when I want to inject a gas ''for example" I want then to change the parameters from normal on the shape into leaded by a 'direction vector', so I choose direction vector instead of...
  13. C

    How to calculate the power generated by a turbine (steam)?

    Firstly, let's assume the expansion is isentropic. An example I found: Mass flow = 0.5kg/s Pi = 6000 kPa Ti = 500 Celcius Pf = 30kPa From this, how do we find the power generated and final steam quality? Do we look at steam tables, W = m(flow) (h_1 - h_2) --- is that helpful?
  14. S

    Creating an Exponential decay equation for given parameters

    So, I am wanting to vary a parameter in an equation with respect to time. Vary mass flow [ m(t) ] for an exponential decay to half its original value in around 60 seconds. I know the regular decay equation where: m(t)=m0*exp(-At) but I want the value to approach a steady state at 60 seconds...
  15. S

    Temperature and Mass Flow effect on Pressure

    Hello, I am trying to create a theoretical model of pressurizing air in a constant volume tank to a pre-set pressure. We are increasing the pressure using a standard pressure regulator. From the equation PV=nRT I know that an increase in pressure at a constant volume can result from an...
  16. S

    Why increasing the mass flow of steam increases its temperature

    Maybe I'm over-analysing this but if we take a simple example of a tube within which steam is flowing. Why does the temperature (and pressure) of the steam increase as the mass flow rate is increased? Is it simply because as more mass is added in the flow, the pressure within the system...
  17. gfd43tg

    Vent line pressure and mass flow rate

    Homework Statement 1. An emergency vent line from a reactor is 55 feet long and has an inside diameter of 4.026 inches. The surface roughness of the pipe is 0.0012 inches. The line discharges hydrogen to the atmosphere (P = 14.7 psia) a) If the mass flow rate of hydrogen is 95 lb / minute...
  18. Q

    How do you calculate the mass flow rate, volume flow rate and velocity

    How do you calculate the mass flow rate, volume flow rate and velocity of a 6 bar compressed air supply through a 2mm tube? This is all the information I have been given. Is there any theory that could help me here? I can't seem to find much on the internet, so I have no clue where to begin...
  19. C

    Mass Flow at the Mid-Plane in a closed container

    Hi there. I am designing a type cilindrical can full of a fluid, with a temperature difference between the top and bottom. Now, after the simulation of the free convection phenomenom in COMSOL, I wanted to understand the effect of varying the temperatures, to the "fluid movement" (fluid...
  20. C

    Calculating Mass Flow Rate of Nitrogen at 0.3m^3/s

    Homework Statement Work out the mass flow rate of Nitrogen traveling through a at 0.3m^3/s if the pressure is 1 bar and the temperature is 18°C and the ideal gas constant is 8314 J/Kg K Homework Equations m=ρ*V*A m = mass flow rate ρ= density V = velocity A = flow area PV =...
  21. J

    Measuring mass flow rate into engine

    I have a motorcycle engine on a test stand and I need a way to measure the mass flow rate into the engine. It is currently carburated. I had two ideas off the top of my head. 1) build a venturi, and measure the pressure drop to figure out the velocity and therefore the mass flow rate...
  22. N

    Find the Mass Flow Rate Through the Nozzle

    Homework Statement Helium gas flows through a well-insulated nozzle at steady state. The temperature and the velocity at the inlet are 550°R and 150 ft/s, respectively. At the exit, the temperature is 400°R and the pressure is 40 lbf/in2. The area of the exit is 0.0085 ft2. Using the ideal gas...
  23. N

    Thermodynamics. Find the Mass Flow Rate of the Air and the Exit Area

    Homework Statement Air expands through a turbine from 8 bar, 960 K to 1 bar, 450 K. The inlet velocity is small compared to the exit velocity of 90 m/s, The turbine operates at a steady state and develops a power output of 2500 kW. Heat transfer between the turbine and it's surroundings and...
  24. N

    Find Mass Flow Rate and the Exit Flow Area

    Homework Statement Air enters aone-inlet, one-exit contreol volume at 6 bar, 500K and 30m/s through a flow area of 28cm3. At the exit the pressure is 3 bar, the temperature is 456.5 K and the velocity is 300 m/s. The air behaves as an ideal gas. For steady state operation determine a) the...
  25. P

    Mass flow rate using a pitot tube

    I am majorly stuck, we are doing a report in which we determine the flow rate using a venturi then compare values with the flow rate from a pitot tube. So basically we have recorded pressure values with a pitot tube, moving the tube 2mm from the centre of the venturi each time and re-recording...
  26. R

    Help with flow rates / mass flow rates.

    1. The problem statement, all variables and given/known A conical Nozzle has a diameter on one end of 0.5m and 2m on the other. The nozzle is 6m long. The flow rate is 10 m/s. or 10m^3/s We are assuming that the liquid is in compressible. 1. Calculate the flow rate at midpoint...
  27. B

    Conservation of momentum continous mass flow freight cart.

    Homework Statement I am having difficulty understanding why in 2.1 Worked Example Coal Car on page 3 One can use the initial time as time = 0, but 2.2 Worked example on page 4 they start the initial time at an arbitrary time t. Homework Equations The Attempt at a Solution
  28. C

    Help with finding mass flow rate

    1. Homework Statement A pump steadily delivers water through a hose terminated by a nozzle. The exit of the nozzle has a diameter of 0.6 cm and is located 10 m above the pump inlet pipe, which has a diameter of 1.2 cm. The pressure is equal to 1 bar at both the inlet and the exit, and the...
  29. C

    Calculating Mass Flow Rate: Pump Water Through Nozzle

    Homework Statement A pump steadily delivers water through a hose terminated by a nozzle. The exit of the nozzle has a diameter of 0.6 cm and is located 10 m above the pump inlet pipe, which has a diameter of 1.2 cm. The pressure is equal to 1 bar at both the inlet and the exit, and the...
  30. S

    Calculating Mass Flow Rate: Inlet & Outlet

    Homework Statement Inlet Average Velocity at Inlet = 2.50 m/s Pressure Abs. = 100 Kpa Elev = 2.00 m Inlet tube diameter 12.0 cm Water density 997 kg/m^3 Outlet Average velocity at outlet = 8.00 m/s Elevation = 2.00m a.) Calculate mass flow rate through the pump b.) w/ an outlet pressure of...
  31. O

    Mass Flow Rate Uncertainty: A simple problem gone horribly, horribly wrong

    The Mass Flow Rate in a water flow system determined by collecting the discharge over a timed interval is 0.2 kg/s. The scales used can be read to the nearest 0.05kg and stop watch is accurate to 0.2 s. Estimate the precision with which the flow rate can be calculated for time intervals of a.)...
  32. L

    Heat transfer coffefficient from mass flow

    If we have a pipe with dimensions D=0.006m L=0.01m and a mass flow of m' = 0.019 kg/s How can we determine the heat transfer coefficient of the pipe?
  33. S

    Does T and P effect the mass flow rate of air through a pipe?

    Hi all, I have a question regarding the mass flow rate of air through a pipe. On paper, it looks like temperature and pressure effect the mass flow rate but I can't rationalize it in my head. Here's what I got: Goal: Calculate the actual mass flow rate of let's say, CH4 through a...
  34. J

    Gas turbine brayton cycle thermodynamic mass flow rate of air

    Homework Statement a gas turbine is designed to produce 3000hp when using air at a maximum inlet temperature of 650k and assuming a heat loss of 70 kj/s. if the exhaust temperature is desired to be no greater than 200 degrees celsius, determine the mass flow rate of air required. Homework...
  35. M

    Find mass flow rate using heat differential

    Homework Statement An experimental power plant at the Natural Energy Laboratory of Hawaii generates electricity from the temperature gradient of the ocean. The surface and deep-water temperatures are 25°C and 7°C respectively. The cold water that enters the plant leaves it at a...
  36. B

    Find Diameter for Mass Flow, using gravity

    Homework Statement Height of water 19.9 inches, 1GPM flow rate min Gravity, Homework Equations The Attempt at a Solution Here is the run down first, I'm trying to find a min mass flow rate for my project which needs to be 1 GPM, and max 4 GPM. Now water is going out of a 5...
  37. B

    Water Flow, Mass Flow through 5 Gallon Jug

    Here is the run down first, I'm trying to find a min mass flow rate for my project which needs to be 1 GPM, and max 4 GPM. Now water is going out of a 5 gallon jug, that has the top cut off, and the water is flowing into a PVC pipe. The area is already set at 1.5 inches, which I know is to...
  38. X

    Calculating Mass Flow Rate of Nitrogen in a Circular Pipe at 100 psia and 300 F

    Homework Statement Nitrogen at a pressure of 100 psia and a temperature of 300 F flows through a circular pipe with a diameter of 6 inches. The velocity profile is parabolic with V= [1-(r/3)^2] where r is the local radius in inches and V is the velocity in ft/s. Determine the mass flow rate...
  39. F

    Calculating Mass Flow Rate of a Fluid in a Pipe

    Hi, how do i work this one out? The mass flow rate of a fluid flowing through a section of pipe with a diameter of 38mm at a flow velocity of 5ms-1 with a specific volume of 0.00109 m3/kg is? Thanks,
  40. D

    Mass flow rate through De Laval Nozzle

    Hey guys, Ive got a little stuck calculating the mass flow rate of a choked flow through a de laval nozzle. I have been given a formula to use for theoretical max and experimental but they seem to be SO far apart, I am sure I am missing something. Given data: Density of water 1000...
  41. E

    Thermodynamics. Turbine, hwo to use enthelpy to find mass flow?

    Homework Statement The problem (tried my best to translate it): A small high speed turbine is operating on compressed air. It deliveres dW/dT=100 W. At the inlet, the pressure is 400 kPa and the temperature 50*C. At the exit, the pressure is 150 kPa and the temperature -30*C. Neglect...
  42. E

    Thermodynamics: turbine, steady-state, how to find the necessary mass flow?

    The problem (tried my best to translate it): A small high speed turbine is operating on compressed air. It deliveres dW/dT=100 W. At the inlet, the pressure is 400 kPa and the temperature 50*C. At the exit, the pressure is 150 kPa and the temperature -30*C. Neglect the velocity and assume an...
  43. A

    Calculating Flow Rate & Pressure for Coriolis Mass Flow Meter

    Homework Statement I have a Coriolis mass flow meter and I'm supposed to run water through it at different flow rates. I have a motor / pump which is controlled by AC drive (which is controlled by potentiometer). Also, I have a pressure transducer mounted at the input side of Coriolis mass flow...
  44. B

    Mass flow in Vapor Compression Cylce HELP

    Hi guys, I'm doing some calculations on a vapor compression cycle system for my Master Thesis. My question is: Does the mass flow change when the refrigerant flows through the (electronic) expansion valve (assuming steady state flow)? I assume that it doesn't but I can't seem to get...
  45. B

    Liquids; volume and mass flow rates

    Suppose that two tanks, 1 and 2, each with a large opening at the top, contain different liquids. A small hole is made in the side of each tank at the same depth h below the liquid surface, but the hole in tank 1 has half the cross-sectional area of the hole in tank 2. (a) What is the ratio...
  46. O

    Why Do Sand Flow Rates Affect Freight Car Momentum Differently?

    Homework Statement Just have to ask one more question :redface:. I have two problems which I don't understand in Kleppner Kolenkow. They seem to contradict each other in my view. The first is 3.9 and the second is 3.10. 3.9 A freight car of mass M contains a mass of sand m. At t = 0 a...
  47. C

    Calculating Mass Flow Rate of Water in a Natural Draught Cooling Tower

    A natural draught cooling tower is designed to have a 3% loss of the mass of the water entering the tower by evaporation into the atmosphere. Atmospheric air enters the tower at a volume flow rate of 4 m^3/s a temp of 10C and a relative humidity of 50%. Air leaves the tower in a saturated...
  48. N

    Calculate Mass Flow Rate of Blood in Aorta

    Homework Statement Calculate the mass flow rate of blood (of den- sity 1 g/cm3) in an aorta with a cross-sectional area of 2 cm2 if the flow speed is 43 cm/s . Answer in units of g/s. Homework Equationsm=pAv The Attempt at a SolutionHey guys! I can tell that this is a very...
  49. U

    Understanding Momentum in Continuous Mass Flow Problems

    Homework Statement From 2.2 Worked Examplehttp://ocw.mit.edu/courses/physics/8-01sc-physics-i-classical-mechanics-fall-2010/continuous-mass-flow/MIT8_01SC_coursenotes19.pdf" Emptying a Freight Car - A freight car of mass mc contains a mass of sand ms At t = 0 a constant horizontal force of...
  50. 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)...
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