Does the small size of a hole affect fluid flow rate?

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SUMMARY

The discussion focuses on calculating the fluid flow rate of oil through small orifices ranging from 0.0030 to 0.0760 inches in diameter. Key considerations include the Reynolds number, which determines whether the flow is laminar (Re < 2300) or turbulent (Re > 2300), and the need to establish the discharge coefficient (Cd) for accurate calculations. The ASME MFC-14 standard is referenced for flow through small orifices, although the sizes in question may require additional research. Experimental setups involving pressurized reservoirs and weighing scales are suggested for practical measurement of flow rates.

PREREQUISITES
  • Understanding of fluid dynamics principles, particularly the Reynolds number
  • Familiarity with orifice flow equations and discharge coefficients
  • Knowledge of ASME MFC-14 standards for flow measurement
  • Basic experimental design skills for setting up fluid flow experiments
NEXT STEPS
  • Research the calculation of discharge coefficients (Cd) for small orifices
  • Learn about the effects of viscosity on flow rates through small openings
  • Explore experimental methods for measuring fluid flow rates in controlled environments
  • Investigate automated dispensing systems for viscous fluids and their design considerations
USEFUL FOR

Engineers, fluid dynamics researchers, and anyone involved in the design or analysis of fluid transfer systems, particularly those working with small orifices and viscous substances.

pbiebach
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I would like to calculate the rate at which fluid(oil) is transferred from one chamber to the other.
Note the orifices is in the range of 0.0030 to 0.0760 in I'm wondering if the very small size of this hole requires any special consideration.

http://myimgs.net/images/oyfi.jpg

I realize more info such as oil density and dimensions are required for a exact solution, however I would like to determine a general solution into which I can substitute these values.
Any hints to get me on the correct path or even better a sample calculation would appreciated.

Note this is not a homework question.
 
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You might consider the type of flow to be expected for oil flowing through the small diameter hole using the definition of Reynolds number and the physical properties of the type of oil considered. If Re < 2300 flow is laminar, above it is expected to be turbulent.
Go on from this point.
 
ASME MFC-14 handles flow through small orifi but I am thinking that this is even too small for that. I have a copy at my desk which I don't have access to right now. That being said, the flow will still follow orifice equations. The tough part is to find out what the Cd of the small orifice is, especially with what will be pretty small Re.
 
I suppose a real experiment would not be difficult to set up: pressurized reservoir, small orifice and weighing scale (to measure output flow) On the other hand, there must have been done extensive research on flow of viscous substances through small holes if one considers automated dispensers for glues, hot melts etc
 
I'm confused about the setup. Is chamber #2 initially full of air? I would expect air bubbles to form at the orifice and rise to the top of chamber #1. Not a simple problem at all.
 
Both chambers are full of oil, single fluid problem, no air involved. also the spring is weak so we will assume the flow to be very slow.

happy new years everyone
 

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