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August 2, 2016, 11:55 |
CEL and variable
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#1 |
New Member
Casper
Join Date: Nov 2015
Posts: 14
Rep Power: 10 |
Hi All!
How to define density or thermal conductivity variables? When I defined value in CEL expression, it doesn't change like a constant. How Can I define it? |
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August 2, 2016, 16:27 |
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#2 |
Senior Member
Erik
Join Date: Feb 2011
Location: Earth (Land portion)
Posts: 1,167
Rep Power: 23 |
....I'm confused, can you explain a little more what you are trying to do exactly?
Are you trying to make it a variable of temperature or something? You have to make an expression in the format: 0.2 [W/m/K^3]*T^2+ 0.2 [W/m/K^2]*T + 0.5[W/m/K] Last edited by evcelica; August 3, 2016 at 13:43. |
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August 2, 2016, 21:38 |
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#3 |
New Member
Casper
Join Date: Nov 2015
Posts: 14
Rep Power: 10 |
is it polynomial function? which you described it . I am going to define two points. And then it should be found variables.
For instance, T= 300[K] , rho=1.17[kg/m^3], cp=1005.7[J/kg/K], thermal conductivity 0.02624[W/(m/K)] dynamic viscosity 18.46x10^-6 T= 1500[K] , rho=0.235[kg/m^3], cp=1230[J/kg/K], thermal conductivity 0.094[W/(m/K)] dynamic viscosity 54.46x10^-6[Pa/S] How to create like variables? |
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August 2, 2016, 22:46 |
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#4 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
You can define functions for all these properties (CEL expressions, interpolation functions, user fortran etc) and then you make them define the material properties in the materials tab.
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August 3, 2016, 13:43 |
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#5 |
Senior Member
Erik
Join Date: Feb 2011
Location: Earth (Land portion)
Posts: 1,167
Rep Power: 23 |
Be careful using functions for both density and specific heat, it can lead to thermodynamic inconsistencies. Use ideal gas instead to avoid this. (Or Constant Specific Heat, which you probably don't want to do)
For your conductivity, if using linear curve fit, it would be: (5.64667*10^-5)[W/m/K^2]*T + 0.0093[W/m/K] |
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