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

In summary, the small diameter hole in a chamber may require special consideration when calculating the rate of transfer of oil because the flow may be turbulent.
  • #1
pbiebach
5
0
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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  • #2
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.
 
  • #3
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.
 
  • #4
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
 
  • #5
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.
 
  • #6
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
 

1. What is fluid flow through a tiny hole?

Fluid flow through a tiny hole refers to the movement of a fluid (liquid or gas) through a small opening or orifice. This phenomenon is also known as a "pressure drop" or "pressure loss" and can occur in various systems such as pipes, nozzles, and valves.

2. What causes fluid flow through a tiny hole?

The flow of fluid through a tiny hole is caused by a difference in pressure between the two sides of the opening. This pressure difference creates a force that pushes the fluid through the hole. The amount of flow is also influenced by the properties of the fluid, such as viscosity and density.

3. How is the flow rate through a tiny hole calculated?

The flow rate through a tiny hole can be calculated using Bernoulli's equation, which considers the pressure, velocity, and density of the fluid. Other factors such as the size and shape of the hole, as well as the fluid's viscosity, also play a role in determining the flow rate.

4. What are the applications of studying fluid flow through tiny holes?

Studying fluid flow through tiny holes is important in various fields, such as engineering, physics, and biology. It can help in understanding and designing systems that involve fluid flow, such as fuel injectors, inkjet printers, and blood vessels. It can also aid in optimizing processes and improving efficiency.

5. How does the size of the hole affect fluid flow?

The size of the hole has a significant impact on fluid flow. Generally, a smaller hole will result in higher flow velocity and a larger pressure drop. This is because a smaller hole creates more resistance to the flow of fluid, causing it to accelerate and increase the pressure difference. However, the exact relationship between the size of the hole and the flow rate depends on various factors and can be complex to predict.

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