Pressure Loss in Transmission Line: Analyzing Reducing Union, Filter & L Pipe

[can12345]

Homework Statement

I would like to define pressure loses through transmission line to the transducer. In transmission line I have a reducing union, filter and L pipe. How I can find this differences?

In case of frequency my reducing union reduce pipe diameter 6 mm to 3 mm how i can determine my frequency by these two diameter value?

Homework Equations

The Attempt at a Solution

 

[billy_joule]

Can you give more information?
What frequency are you reffering to?

Pressure loss in pipe work due to friction ('major losses') is generally found via:
http://en.wikipedia.org/wiki/Darcy–Weisbach_equation

Pressure loss due to fittings are 'minor losses', the coefficicnt for your fittings may be found in their datasheets or from general tables:
http://www.engineeringtoolbox.com/minor-pressure-loss-ducts-pipes-d_624.html
http://www.engineeringtoolbox.com/minor-loss-coefficients-pipes-d_626.html

If this is just a dead end line to a pressure gauge then there is no flow and the pressure loss is zero.

 

[can12345]

I actually try to define the pressure loss through diaphragm. When turbulent flow is acting to pressure diaphragm, there is two situation. First of all the diaphragm is always under oscillation. This is the reason why I want to separate the problem into 2 section. First of all when fluid is coming and crushing with diaphragm and extending it, the deflection rate is so small but when it goes back it makes back flow. and velocities are really small I guess, but my advisor wants me to know it. If its negligible still he wants me to find why it is negligible. Boundary conditions are min deflection and maximum deflection.

 

[can12345]

The exactly question is actually to check whether pressure loses are negligible in unsteady (turbulent, oscilation) conditions.

 

[billy_joule]

First of all when fluid is coming and crushing with diaphragm and extending it, the deflection rate is so small but when it goes back it makes back flow. and velocities are really small I guess, but my advisor wants me to know it.

Why not calculate the velocities rather than guessing? A raw feed from the transducer should show the oscillation frequency.
What literature have you found on the topic? This is an old problem, it's why gauges are liquid filled, probably since their invention. I'm sure research has been done in the area.

 

[can12345]

How I can determine this velocity? Can you give equation or help please?

 

[billy_joule]

calculate a flow rate from swept volume & frequency.

What literature have you found on the topic?

 

[can12345]

http://ocw.metu.edu.tr/pluginfile.php/1869/mod_resource/content/0/AE547/AE547_7_unsteadypressure.pdf

Here you can see they also say as '' The rate at which this will occur will also depend on the pressure loss characteristics of the connecting connecting line, wall pressure pressure tapping tapping, or type of pressure pressure probe used (static (static, total, multiple multipleholes).''