Register to reply

Longer conduit... Impedes flow? What?

by bobrsanchez
Tags: conduit, flow, impedes
Share this thread:
Aug30-14, 01:54 PM
P: 4
Hi all,

I am studying for the MCAT and a section in the book lists the equations

dT= IR

For thermal, fluid, and electricity flow respectively. It then goes to state that a thicker conduit allows for greater flow. That part makes sense to me because a larger diameter pipe has relatively more volume compared to its surface area, which gives it relatively less resistance compared to a pipe that has a smaller diameter.

However, it then goes to say that a "LONGER conduit impedes flow". This part I don't get because I can't see how a longer pipe would in any way increase resistance or slow down the flow rate. For example, wouldn't a 1m pipe of 5m diameter have the same flow rate as a 100m pipe with a diameter of 5 if the pressure difference between two openings of both pipes were equal?

Is my book BSing me right now??
Phys.Org News Partner Physics news on
'Squid skin' metamaterials project yields vivid color display
Team finds elusive quantum transformations near absolute zero
Scientists control surface tension to manipulate liquid metals (w/ Video)
Aug30-14, 02:28 PM
P: 663
Quote Quote by bobrsanchez View Post
Is my book BSing me right now??
I don't think so as there is flow resistance/friction in any real piping system that increases with length so you can't expect the pressure to be the same at both ends for all flow rates just like you can't expect the voltage to be the same on both ends of a resistive electrical transmission line under load as the length increases.

We normally use piping tables to calculate pressure losses with cooling systems on the job.
Aug30-14, 02:41 PM
P: 4
I see.

Edit: nvm you are correct. I had forgotten that length of resistors are a factor in determining resistance. Oops

Register to reply

Related Discussions
How does voltage in wires affect conduit and nearby materials? Electrical Engineering 4
What is a valvular conduit General Physics 5
Conduit Bending Question General Engineering 7
Temperature Profile measurement within a conduit Mechanical Engineering 0
Microsoft assimilates the human body as a conduit for consumer electronics Computing & Technology 2