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Cujo October 19, 2002 05:58

NASA format
 
Hi,

I want to use the coefficients that describe the specific heat capacity outside CFX5.5. These coefficients are given in the MATERIALS file (/cfx551/etc/). However, they are stated in the "NASA-format":

SPECIFIC HEAT CAPACITY:

Option = NASA Format

Temperature Limit List = 300 [K], 5000 [K], 1000 [K]

NASA Coefficient List = \

0.03697578E+02, 0.06135197E-02, -0.01258842E-05,\

0.01775281E-09, -0.01136435E-13, -0.01233930E+05,\

0.03189166E+02,\

0.03212936E+02, 0.01127486E-01, -0.05756150E-05,\

0.01313877E-07, -0.08768554E-11, -0.01005249E+05,\

0.06034738E+02

END #SPECIFIC HEAT CAPACITY

What exactly is this format. It isn't just a1+a2T+a3T^2+a4T^3+a5T^4+a6T^5+a7T^6, because this gives me a heat capacity of O2 of 6.11e+13 at 300K, which of course is not correct. Can anybody help me? Cujo

Cujo October 20, 2002 08:28

Re: NASA format
 
Hi, I found the answer myself: Only the first 5 coeffients are needed for the expression of the heat capacity. The first series of 5 coefficients in the CFX MATERIALS file are applicible for a temperature range of 300-1000[K]. The first 5 coefficients in the second block are for the range 1000-5000[K]. The heat capacity is obtained as: cp/Ru=a1+a2T+a3T^2+a4T^3+a5T^4 [J mol^-1 K^-1], with Ru the universal gas constant. Bye Cujo


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