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evaporation of R134a in a channel3 Attachment(s)
Hi
I am doing simulation of evaporation of R134a in a channel and I did not observed phase change from R 134a to R134a gas. Does anyone can help me ? FLUENT Version: 3d, dp, pbns, vof, lam, transient (3d, double precision, pressure-based, VOF, laminar, transient) Release: 12.1.4 Models ------ Model Settings --------------------------------------------------------- Space 3D Time Unsteady, 1st-Order Implicit Viscous Laminar Heat Transfer Enabled Material Properties ------------------- Material: r134a-gas (fluid) Property Units Method Value(s) ---------------------------------------------------------------- Density kg/m3 constant 32.203999 Cp (Specific Heat) j/kg-k constant 1030.98 Thermal Conductivity w/m-k constant 0.01381 Viscosity kg/m-s constant 1.1687e-05 Molecular Weight kg/kgmol constant 102.03 Standard State Enthalpy j/kgmol constant 42063000 Reference Temperature k constant 298.14999 Material: r134a-liquid (fluid) Property Units Method Value(s) ----------------------------------------------------------------- Density kg/m3 constant 1207.3 Cp (Specific Heat) j/kg-k constant 1424.41 Thermal Conductivity w/m-k constant 0.081198998 Viscosity kg/m-s constant 0.00019525 Molecular Weight kg/kgmol constant 102.03 Standard State Enthalpy j/kgmol constant 23909000 Reference Temperature k constant 298.14999 Thermal Expansion Coefficient 1/k constant 0 Speed of Sound m/s none #f Boundary Conditions ------------------- Zones name id type ------------------------------------ wall-solid 10009 wall inlet 6 velocity-inlet outlet 7 pressure-outlet wall-solid Condition Value ------------------------------------------------------------- Thermal BC Type 1 Temperature (k) 300 Heat Flux (w/m2) 15000 Convective Heat Transfer Coefficient (w/m2-k) 0 Free Stream Temperature (k) 300 inlet Condition Value -------------------------------------------- Velocity Magnitude (m/s) 0.2 Coordinate System 0 Temperature (k) 295.15 Solver Settings --------------- --------------------------------------------- Time Step (s) 0.00050000002 Max. Iterations Per Time Step 100 Relaxation Variable Relaxation Factor ----------------------------------- Pressure 0.3 Density 1 Body Forces 1 Momentum 0.7 Volume Fraction 0.5 Energy 1 Pressure-Velocity Coupling Parameter Value ------------------ Type SIMPLE Discretization Scheme Variable Scheme ------------------------------------ Pressure PRESTO! Momentum First Order Upwind Volume Fraction First Order Upwind Energy First Order Upwind |

Forgot to mentioned the UDF, I setted the saturated temperature to 298.15K for R 134a in 5.6bar pressure.
/* UDF to define a simple mass transfer based on Saturation Temperature. The "from" phase is the gas and the "to" phase is the liquid phase */ #include "udf.h" DEFINE_MASS_TRANSFER(liq_gas_source, cell, thread, from_index, from_species_index, to_index, to_species_index) { real m_lg; real T_SAT = 298.15; Thread *gas = THREAD_SUB_THREAD(thread, from_index); Thread *liq = THREAD_SUB_THREAD(thread, to_index); m_lg = 0.; if (C_T(cell, liq) >= T_SAT) { m_lg = -0.1*C_VOF(cell,liq)*C_R(cell,liq)* fabs(C_T(cell,liq)-T_SAT)/T_SAT; } if ((m_lg == 0. ) && (C_T(cell, gas) <= T_SAT)) { m_lg = 0.1*C_VOF(cell,gas)*C_R(cell,gas)* fabs(T_SAT-C_T(cell,gas))/T_SAT; } return (m_lg); } |

evaporation of R134a in a channelHi,
I'm having similar kind of problem. That's unable to observe the phase change. Did you found any solution on this? Please do let me know. Regards, Vinod |

hi
i want the standard state enthalpy of r404a(liquid and gas) for evaporation modeling. |

UdfHi all
after compiling UDF with FLUENT , how can i hook it with FLUENT? Many Thanks |

R134aHi all
Please, i did not find R134a in list of fluid how can i find it? |

Enable the appropriate NIST real gas model by typing the following text command at the ANSYS Fluent console prompt：
> define/user-defined/real-gas-models/nist-real-gas-model |

Enable the appropriate NIST real gas model by typing the following text command at the ANSYS Fluent console prompt：
> define/user-defined/real-gas-models/nist-real-gas-model |

1 Attachment(s)
Quote:
thank you so much i went to define<<user-define and i did not find the real-gas and<<, why?? |

hello peterliu,
would u plz tell me how you get standard state enthalpy of r134a? i want standard state enthalpy of r1234ze and i have searched internet, research papers, softwares but unable to find it. i would be very thankful to you |

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