Index

Thermal conductivity

Ver: 1
 

DESCRIPTION

Modifies the thermal conductivity k(T) used in the energy equation for non-isothermal flow problems (also for gas flow problems).
The thermal conductivity k(T) is given as :

for all problems except the gas flow problems, a third order polynomial function of the temperature T :
k(T) = a + b * T + c * T**2 + d * T**3
where a, b, c and d are material parameters.
Default values : a = 1, b = c = d = 0.
all zero.

for gas flow problems, a power function of the temperature T :
k(T) = fact * (T/Tref)**expo
where fact, Tref and expo are parameters.
Default values : fact = 1, expo = 0, Tref = 300.

  OPTIONS
 
-1  Upper level menu
The current values are accepted

For all problems except the gas flow problem:
1  Modification of a
2  Modification of b
3  Modification of c
4  Modification of d 

For the gas flow problem only,
1  Modification of fact
The current value of fact is modified
2  Modification of expo
The current value of the power is modified
3  Modification of Tref
The current value of the reference temperature is modified

NOTES While selecting values for the coefficients of the polynomial expression, the user should verify that the sign of the thermal conductivity must remain positive within the temperature range of in the problem.

Values of fact and Tref must be strictly positive.

The units for k(t) and the four parameters a, b, c and d are :
 
Parameter
Mass
Length
Time
Temperature
    k(T)
    a
    b
    c
    d
    fac
    expo
    Tref
1
1
1
1
1
-
-
-
1
1
1
1
1
1
-
-
-3
-3
-3
-3
-3
-3
-
-
-1
-1
-2
-3
-4
-1
-
Kelvin

SEE ALSO