How do I Define (time) Variable (HTC) Heat Transfer Coefficient?

  • In this example, we are going to change heat transfer coefficient (HTC) between pocket and die. Once you export solver deck, BC at pocket die will be similar to one shown below.
  • Here Heat transfer coefficient at wall is contact = 3000 W/m^2-deg C

SolidFluidInterface Pocket1_die {

HeatTransferCoeff = 3000

ContactBCName = "Die_Pocket1"

X_Velocity = 0

Y_Velocity = 0

Z_Velocity = 0

#Material = AA6060

}
  • Add function block to define variable HTC after MATASSIGN data block

BEGIN FUNCTION

EXPRESSION htcpocket "{x y z t} {htcpocketf $x $y $z $t}

END

htcpocket = name of expression

htcpocketf = name of TCL function. This is defined in separate TCL script file.
  • Use express name in BC packet as shown below

SolidFluidInterface Pocket1_Die {

HeatTransferCoeff = htcpocket

ContactBCName - "Die_Pocket1"

X_Velocity = 0

Y_Velocity = 0

Z_Velocity = 0

#Material = AA6060
  • Write TCL function to define HTC and save the fine with name VariableHeatTransfer.tcl

proc htcpocketf {x y z t } {

#default value of HTC

set convCoeffi 3000.0;

if { $t <= 0 } {

# HTC at 0th min

set convCoeffi 3000.0;

} elseif { $t >= 300 } {

#HTC after 5 mins

set convCoeffi 3000.0;

}

return $convCoeffi

}
  • Open.hx file and source TCL script file using following command

# Set environment variable for number of CPUs

set ::env(OMP_NUM_THREADS) 1

set ::env(MKL_NPROCS) 1

set ::env(MP_SET_NUMTHREADS) 1

set: ::env(P_NUMBER_OF_THREADS) 1

set :env(MLIB_NUMBER_OF_THREADS) 1

source VariableHeatTransfer.tcl