Calculating Drop Size, Number and Time for Water Flow Through Capillary

In summary, the problem involves finding the radius of water droplets flowing through a capillary, the number of drops in a given amount of water, and the time it takes for the water to exit the capillary. The solution involves using equations for surface tension, mass, and volume, as well as considering the period between drops. The proposed solution involves imagining the drop at the end of the tube before falling and using equations for mass and volume to calculate the number of drops and the time needed for the water to expire.
  • #1
10bunny10
6
0

Homework Statement


Trough a capillary with an inner radius r=1mm water flows in a form of small spherical droplets. What is the radius of the drops, the number of drops in m=10g water and the time needed the water to expire, if the surface tension of the water is =72x10^-3N/m, and the period between two drops is t=2s.


Homework Equations





The Attempt at a Solution


I need an idea how to imagine the situation and what to take into consideration? Help please :/
 
Physics news on Phys.org
  • #2
I tried something:
When the drop is at the end of the tube just before to fall
αl1+αl2=m0g
where m0 is the mass of one drop
2απr+2απR=m0g
R=m0g2απr/2απ
V0=4R3π/3
m0=ρV0
m0=4ρR3π/3
N=m/m0
N=3m/4ρR3π
τ=t3m/4ρR3π
t=2s
 
Last edited:
  • #3
Here is how I imagined it.
 

Attachments

  • kapka.png
    kapka.png
    562 bytes · Views: 404
  • #4
Can anybody tell me if it is correct please?
 
  • #5
You could've just used the edit button instead of posting 4 times on this thread that you pretty much just started.
 

1. How do you calculate the size of a water droplet from a capillary?

To calculate the size of a water droplet from a capillary, you will need to know the capillary diameter and the contact angle of the water on the capillary surface. Using the Young-Laplace equation, you can then calculate the droplet size using the following formula:

d = 2γcosθ/(ρg), where d is the droplet diameter, γ is the surface tension of the liquid, θ is the contact angle, ρ is the density of the liquid, and g is the acceleration due to gravity.

2. How do you determine the number of droplets in a given volume of water?

To determine the number of droplets in a given volume of water, you will need to know the volume of the water and the average size of the droplets. You can then use the following formula:

n = V/d, where n is the number of droplets, V is the volume of water, and d is the average size of the droplets.

3. What factors affect the time it takes for water to flow through a capillary?

The time it takes for water to flow through a capillary is affected by several factors, including the diameter and length of the capillary, the viscosity of the liquid, the pressure applied, and the surface tension of the liquid.

4. How do you calculate the flow rate of water through a capillary?

To calculate the flow rate of water through a capillary, you will need to know the pressure applied, the viscosity of the liquid, the capillary diameter and length, and the contact angle. Using the Hagen-Poiseuille equation, you can then calculate the flow rate using the following formula:

Q = πr4(P/8Lη), where Q is the flow rate, r is the capillary radius, P is the pressure applied, L is the capillary length, and η is the viscosity of the liquid.

5. Can the same calculations be applied to other liquids besides water?

Yes, the same calculations can be applied to other liquids besides water. However, the values for surface tension, viscosity, and density may vary depending on the liquid being used. It is important to use the correct values for each liquid in the calculations to ensure accurate results.

Similar threads

  • Introductory Physics Homework Help
Replies
1
Views
7K
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
6
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
951
Replies
3
Views
6K
  • Introductory Physics Homework Help
Replies
4
Views
2K
  • General Engineering
Replies
7
Views
2K
  • Introductory Physics Homework Help
Replies
4
Views
3K
Back
Top