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[BeserkNINJA]

this problem is giving me a lot of trouble if anyone knows how to go about it please give me a hand.

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A pipe system has to be designed to have a input pipe diameter of 0.306m and a pumped mass flow rate of 294kg/s. the water is ejected through a larger diamter pipe at 1.5m/s. calculate the volume flow rate and outlet pipe diameter.
water density = 1000kg/m³

[MonkeyHead]

Volume flow rate should be trivial from the mass flow rate (d=m/v).

Outlet pipe diameter you can arrive at from knowing the volume flow rate and ejection velocity - work backwards from the volume and length of water body ejected per second to find the radius.

Unless I am radically simplyfying things of course.

[BeserkNINJA]

how would i go about getting the mass and volume of the water through the pipe?

[MonkeyHead]

Just use the values per second...

[BeserkNINJA]

sorry the last time we covered this in class was late 2011 and all of my notes are lost or useless.
Im unsure which values to use for volume would it be the size of the entrance hole times the amount of water passing it or or what?

and would the mass simply be 294kg? which we get from the amount of water entering the system

[MonkeyHead]

In one sec, 294kg of water pass in, and we know waters density. It follows then that v = (294/1000) cubic metres per second.

The same volume must leave the pipe per second, and we know the velocity at which it leaves: 1.5 m/s. So, in one second a cylinder of volume (294/1000) cubic metres of length 1.5m must be ejected. From that find the CSA of the cylinder, then radius with elementary geometry.

[BeserkNINJA]

thanks

[MonkeyHead]

No problem. I get enough of this in work so its second nature...