Creation of New Nasa 7 Polynomial
 

can we create nasa polynomial for new species .I am going to create a new vegetable oil for blending with the diesel but in order to add the new species i don't know how to add if there is any method.
I am having the data for specific heat , enthalpy and entropy with respect to temperature but i donot know how to create the 7 coefficient polynomial

It's nothing special. You just curve fit the properties to a fourth order polynomial in Temperature. There are 7 coefficients, but 1 is for the reference enthalpy and 1 is for the reference entropy. See Nasa Polynomials.


Note that NASA thermodynamic files (or chemkin thermo files) contain two sets of coefficients (more than 7 coefficients total), one set is for the low temperature range and one for the high temperature range.

TEMP ENTHALPY SPECIFIC HEAT ENTROPY
500 -105 30 60
750 -55 35 72
1000 -30 39 85
1250 -14 45 90
1500 -7 48 102
1750 1 50 112
2000 8 52 122
2250 15 55 125
2500 20 57 130
2750 24 59 135

the above table is our fuel property,
does we need to solve the three property equation simultaneously.
i donot know which software to use. could you please show us the right way?
Thanks in advance:)

What software do you have? Excel? Matlab? Other?

I am having Excel.

Sir i used python to solve each equation individually and i get 5+6+7 coefficient.
5 coefficient for specific heat and 6 coefficient for enthalpy and 7 coefficient for entropy but i don't know how to obtain overall 7 coefficient for low range and high range temperature.