Senin, 23 Mei 2011

Simulasi CFD Sof Orifice Plate R1


ORIFICE PLATE







CFD Model Assumptions
-          Natural gas was assumed to be 100% methane (CH4) at constant flow rate Q=37 MMSCFD (8.212kg/s)
-          Fluid flow was assumed to be incompressible and isothermal
·         low pressure drop compared to absolute pressure
·         Mach number is below 0.1
·         Heat transfer was neglected
-          Transport properties for CH4 computed at P=1590 psig (1604.7 psia) and T= 164oF=346.48 K
·         density =66.06 kg/m3                         (BWRS Lee-Starling equation of states)
·         viscosity = 0.015cP=0.000015kg/ms  (Cheng-Lee-Starling model)
-          Steady (time-averaged) simulations of turbulent flow field using realizable k-epsilon turbulence model
·         Re=1.25x106 (fully turbulent)
·         Turbulent boundary layer modeled using non-equilibrium wall function with a prescribed surface roughness of 100 microns


Prosedur CFD
  1. Atur domain
-                      Dim; p=25*0.5588=13.97m; t=0.5588m; l=bawaan
-                      Jumlah Cell (disesuaikan dengan perbandingan dimensi panjang dan tinggi (25:1); x=250 ;y=12 (10+2[dinding atas & bawah])

  1. Atur Cell (AC)
-          Inlet
x=1
    1
y=2
    11
-          Outlet
x=250
    250
y=2
    11

-          Orifice (ww1)
x=51
    51
y=8
    11

x=51
    51
y=2
   5

-          Dinding (ww1)
x=1
   250
y=1
    1

x=1
    250
y=12
   12






  1. Bangun Grid (bg) searah x karena perubahan dimensi searah x


 

 
Inisiasi segmen 3



 
  



 

Inisiasi segmen
Segmen 1
50
Segmen 2
(3.206/2.794)*50=57
Segmen 3
248-50-57=141
Modif segmen (ms) tujuan untuk memperapat grid pada segemen yang akan dianalisa
Segmen
2
Faktor pemberat awal
2.1
Faktor pemberat akhir
0
  1. Mahir
Gb
-9.81
Lainnya enter
Density acuan ditetapkan user
Y
Ref density
66.06

  1. Konstanta Fiskal (kf)
Density 66.06 kg/m3
Viscosity 1.5e-5
  1. Atur model (am)
PP
Y
Lainnya enter
Am
Tu
k-epsilon
Y
Lainnya enter
  1. Kondisi Sempadan
Inlet
Ku=0.57 m/s
Temp
346.483
Ww1
Temp
300
  1. Save
TFC
Mhscfds2-9/orifice
  1. Iter sampai konvergen
  2. Hasil CFD SOF













Berdasarkan analisa CFD SOF, ketika fluida masuk orrife, kecepatan tinggi sehingga pressure menjadi rendah.
Alhamdulillah-fin





























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