[manoj7782]

How will you find out the Optimum velocity for liquid line by comparing Pressure drop and Line cost.
My quistion is If I have two different line carring same liquid at same vol flowrate
 and same Diameter but at different pressure ,Which line have the higher velocity.
Either line having higher pressure or lower pressure.

[eugenedakin]

Hello manoj7782,

One of the main aspects to consider is the flow type: is it laminar or turbulent. Determine a reynolds number which is just below turbulent (<2100).

I hope this helps,

Sincerely,

Eugene

[technologist]

HI Manoj
The velocity in the pipe which is having higher pressure will be more as DP will increase due to fixed pressure of downstream section. However U want ot do something different.

So consider the following steps

1. Assume pipe size say 1"
2. Your flow requirement is fixed i.e. Kg/Hr or M3/hr is also almost fixed if it is liquid
3. Calculate velocity & find out pressure drop
4. consider downstream pressure
5. U need total pressure at pipe inlet as downstream system pr + frictional drop
6. consider suction condition & accordingly U need pumping power
7. So calculate required pump head
8. then calculate pump power
9. Now consider pipe cost & pumping cost and TOTAl cost.
10. Repeat it for several pipes & plot
11. Find out minimum so that U can select the optimum pipe size

12. Do all this in excel with nicely formatted conditions so that U can use it later.