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pressure drop calculation :-

Pressure drop calculation in pipe is necessary for piping design. A piping design is incomplete without pressure drop calculation in pipe.First we need to understand exact reason behind the pressure drop.we can check the pump performance curves to check the pump discharge pressure and pump suction pressure as per our requirements which is also part of pressure drop calculation.

pressur drops in line is occurs due following reasons,

what are 4 reason for pressure drop in pipe ?

pressur drop due to friction

Pressure drop due to elevation
Pressure drop due to pipe fittings
Pressure drop due to valve

In today article we study only pressure drop due to friction.

pressure drop in pipe formula

pressur drop calculations are necessary to successful design of process. Due to pressure drop calculations we can design the required size of which is necessary as per process requirement.

what is formula for calculating pressure drop across the pipe?

Data required to calculate the pressure drop.

To do Pressure drop calculation in pipe line it is necessary to have some basic data which help us to calculate the pressure drop. First required data is flow. Yes we need exact flow to do pressure drop calculation across the pipe. Second most important data is lenth of pipe. Third required data is allowable pressure drop. Fourth required data is required pressure at the destination.

pressur drop calculations using Aspen hysis

we can calculate pressure drop in piping system by using aspen hysis software.

steps are as follows,

Open the Software
Click on new project in spending hysis
Salect components from component list

Add the required components as per process
Then we need to go in fluid package salection
Add suitable method in fluid package salection

After addition of method if we get green color then our method is correct.
Then click on simulation
Seach pipe

Drag the pipe segment in to the sheet
DOUBL click on pipe
Add inlet name and outlet name in design connection, also give any name in energy section

Pressure drop method method

we can use following formula to calculate the pressure drop across the pipe kine for liquid vapor and gas system.

Delta P = density x f x L x velocity^2 /(2 x g x D)

Schedule number can calculate using following formula,

Sch No = P max * 1000 / maximum allowable stress,

You can google Street value for different pipe MOC.

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where,

density is kg / M3

velocity is in My/Sec

diameter is in meter unit

g is 9.8 m/Sec

L is pipe length in meter.

f is friction factor which is need to calculate from Mody chart as per Re number

steps to calculate pressure difference in lines are,

Asume the velocity

Calculate diameter as per velocity

Calculate the Re number (Check the flow whether Turbulent or laminar)

Salect the pipe moc as per material property

Take pipe roughness (e)as per MOC in mm or inch or meter

Calculate e/D

With help of Re number and e/D check the value of f from Mody graph.

Importance of pressure drop calculation

Now question is why it is important to do pressure drop calculation. Pressure drop calculation is required to check and validate the required pressure at the end point. Also it is necessary do do pressure drop calculation to calculate required head for pump.

Conclusion

From above article we understand how to do pressure drop calculation in pipe. There two Methods available for calculation of it. There two calculation method where we can do calculation by using formula and second one is Aspen Hysis method where we can use Aspen hysis to do calculation.

Hope you like above article. I need your valuable comment on this, if you want excel file for to do pressure drop calculation with example please comment your email address below.

3.2 pressure drop calculation in pipe with example