# Pressure Drop

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 March 27, 2019, 05:29 Pressure Drop #1 New Member   cerez Join Date: Mar 2019 Posts: 6 Rep Power: 7 Hi everyone i have a question with hose pressure drop analysis. I am doing try to find rubber hose pressure drop on intake system. Material:Air flow:turbulance Pressure based inlet boundary condition mass flow:0.1kg/s Temperature of fluid:200C pressure 165kPa I dont know what should i write on outlet boundary condition. Please if u know the answer help me. Sorry for bad english

March 27, 2019, 10:54
#2
Senior Member

Lane Carasik
Join Date: Aug 2014
Posts: 692
Rep Power: 14
Quote:
 Originally Posted by cerez Hi everyone i have a question with hose pressure drop analysis. I am doing try to find rubber hose pressure drop on intake system. Material:Air flow:turbulance Pressure based inlet boundary condition mass flow:0.1kg/s Temperature of fluid:200C pressure 165kPa I dont know what should i write on outlet boundary condition. Please if u know the answer help me. Sorry for bad english
Use a mass flow rate inlet and a pressure outlet. Why aren't you just doing this with a hand calculation?

 March 27, 2019, 11:06 #3 Senior Member   Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,683 Rep Power: 66 Two ways. 1) Mass-flow inlet and a pressure outlet, with the outlet pressure of 165 kPa. This is the most robust way. 2) Other way is to do a pressure inlet with inlet pressure of 165 kPa. Use a presssure outlet with the targeted massflow rate outlet. This is slightly less numerically robust but should also work. It's just a question of whether you want to fix the inlet pressure or outlet pressure to 165 kPa. Also keep in mind that at inlets you're specifying the total/stagnation pressure (not the static pressure).

March 28, 2019, 03:13
#4
New Member

cerez
Join Date: Mar 2019
Posts: 6
Rep Power: 7
Quote:
 Originally Posted by lcarasik Use a mass flow rate inlet and a pressure outlet. Why aren't you just doing this with a hand calculation?
Because geometry is comleks for me

March 28, 2019, 03:24
#5
New Member

cerez
Join Date: Mar 2019
Posts: 6
Rep Power: 7
Quote:
 Originally Posted by LuckyTran Two ways. 1) Mass-flow inlet and a pressure outlet, with the outlet pressure of 165 kPa. This is the most robust way. 2) Other way is to do a pressure inlet with inlet pressure of 165 kPa. Use a presssure outlet with the targeted massflow rate outlet. This is slightly less numerically robust but should also work. It's just a question of whether you want to fix the inlet pressure or outlet pressure to 165 kPa. Also keep in mind that at inlets you're specifying the total/stagnation pressure (not the static pressure).
Thank you for your answer. I am try to execute old analysis with same geometry and same inlet boundary condition but i dont have outlet condition.
i try almost every outlet boundary condition with the program that i use with.
i use scflow14. i will add a picture on the below that i can not fine pressure distribution on the hose. inlet.PNG

Pressure.png

Outlet boundary condition.PNG
by the way i am using air(incompressible) as a fluid.

Last edited by cerez; March 29, 2019 at 06:23.

 March 29, 2019, 07:53 Found the solution #6 New Member   cerez Join Date: Mar 2019 Posts: 6 Rep Power: 7 I found the solution i should have write outflow B.C to -0.1kg/s mass flow and inlet to 165kPa. After i analysis i found the almost close result. like 2kpa pressure drop

 Tags pressure based, pressure drop