Joukowski formula in rubber hose (water hammer)

[jfaucher]

I would like to evaluate theoretically the pressure rise occuring during a water hammer effect in a piping circuit which includes high-pressure blended rubber hoses. Joukowski formula is based uppon Young modulus of the pipe material, but how to evaluate this variable with a composite "pipe"?

The hose is made of Vinyl/Buna-N mixture, and it is surrended by polyester and steel wire reinforcement... Moreover, rubber rigidity is normally dynamic dependent. How to evaluate water hammer effect in this condition?

Jean-Pierre Faucher, ing.

http://www.cel-aerospace.ca

 

[BigInch]

Use a Young's modulus based on the material composition, basically change the cross-sectional area of the wall to an equivalent area of one of the materials. To get an effective wall thickness, change the cross-sectional area of one material in relation to the other by the ratio of that material's Young's modulus to the Young's modulus of the other. Same principal used to design reinforced concrete by creating an effective all-concrete section by adding about 10 times the area of any steel reinforcement and then considering the whole x-section as concrete alone.

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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[stanier]

You will fond a more rigourous approach in ARD Thorley's Fluid Transients in Piping Systems