I have also tried using various hypothetical low values of specific heat but no success.
This hydrocarbon is not available in the FLUENT database (thermodb file) therefore I am defining the fuel empirically by MANUALLY defining these values. (Note: I am dealing with a fuel hydrocarbon named JP-8 chemical formula C31H48 molecular weight 420 KJ/kgmol: specific heat value 2200 J/KgK. While I enable the compressibility effects in non premixed combustion window followed by recalculating the pdf table, the solution does not proceed beyond 05 iterations with error 'INCORRECT SPECIFIC HEAT VALUE' displaying for almost 100 times followed by divergence in AMG solver. when I run the simulation for ADIABATIC CASE in non premixed combustion (energy eqn 'OFF', compressibility effects disabled) the solution is easily converged and reasonable results are obtained. I am working on simulation of non premixed combustion of a gas turbine engine afterburner in FLUENT. How to distinguish the maximum turbulent viscosity? dont forget about lowering under-relaxation of turbulent variables to sth like(0.6,0.6,0.5)in solve-control-solution in first timestep/iteration of solution. then simply initialise domain with inlet and solve. if you have an internal flow problem choose intensity=5 and hydrolic diameter of your case and if you have external flow, choose intensity=5 and viscosity ratio=5. in inlet and outlet you should specify turbulent variables of inlet flow and backflow. (high turbulent flow usually occurs in very high speed flows around bodies, like supersonic flow around high angle of attack airfoil)īut if your case must not have high turbulent flow, check boundary conditions as mentioned in case check. if your case has a complicated flow with high turbulent flow, changing limit of turbulent viscosity limit in solve-control-limit can help. Turbulent viscosity limit occurs when the ratio of turbulent viscosity to dynamic viscosity is upper than the specified limit in fluent. Turbulent viscosity limited to viscosity ratio of 1.000000e+05 in 511831 cells - CFD Online Discussion Forums
0 kommentar(er)
