[Sam0508]

Hi,
Let me Explain the conditions of problem.

Pipe Ø4mm, Air velocity 50m/s, Turbulent flow, Dy viscosity 1.79E-5 N.S/m2, Density of Air 1.23kg/m3.Need of finding the Pressure Drop for 0.1m length.

The Calculation value is 1.076kPa,but in STAR CCM+ got value as 1.255kPa.In software i specified the B.C as Inlet-Velocity inlet 50m/s and outlet-massflow outlet -7.539E-9 kg/s and mentioned Roughness Height also for account of friction factor.

In physics continuum..Constant density/Segregated flow/Steady state/K-Epsilon Turbulence.

Can u tell me what i did wrong in software?



Thankyou,
Sam0508

[ryancoe]

What is your 'calculation' value (is it from an empirical experiment)? If so, the CFD and empirical calculation should not necessarily be expected to match exactly.

[Sam0508]

Originally Posted by ryancoe

What is your 'calculation' value (is it from an empirical experiment)? If so, the CFD and empirical calculation should not necessarily be expected to match exactly.

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Hi Ryan Coe,
It's not a experimental value, found by normal Dp(Pressure drop) Derived equation.i.e

Dp=(f*L*rho*V2)/(2*D) Dp units Pa
[f= friction factor(beased on Reynolds No and Relative Roughness), L=Pipe lenght 0.1m, rho=Density of Air, V= velocity of air 50m/s and D=Pipe diameter]

Why this values is not match with Theoritical data/Derived one.the difference(STAR CCM+ result Dp-Theoritical Dp result) is 170Pa,how we can accept? or What i did mistakes in this. Plz give ur feedback.Thankyou