Pipe Flow Calculations Forum

Hi
I want to pump air through buried corrugated drainage pipe in order to cool the air. I am looking at the costs of the air pump for using 50m of 160mm pipe or 100m of 100mm pipe so trying to get an idea of the pressure required for 300m3/hr. Found your fantastic calculator but can't find a k value for the pipe. I found a Mannings Roughness Coefficient of 0.018 - 0.025 but dont know if it is possible to relate this?

Thanks for your help!

Roghness really depends on the level of surface treatment for new pipes and corrosion level for old ones. It can be anything up to 1 mm depending on the pipe itself.

Thanks for the response, but I am looking at using plastic corugated pipe like this http://www.jdpipes.co.uk/shop/uploads/p ... 240214.jpg I want turbulent flow so there is more heat exchange.

Do I gather that I can measure the amplitude of the corrugations to get k?