Creation of New Nasa 7 Polynomial

arunmass · March 1, 2019, 02:26

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

LuckyTran · March 1, 2019, 14:51

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.

arunmass · March 5, 2019, 02:53

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

LuckyTran · March 5, 2019, 08:45

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

Arun Mass · March 5, 2019, 11:49

I am having Excel.

arunmass · March 6, 2019, 02:35

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.

March 1, 2019, 02:26	Creation of New Nasa 7 Polynomial	#1
arunmass New Member Arun Join Date: Mar 2019 Posts: 3 Rep Power: 7	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

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March 1, 2019, 14:51		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,675 Rep Power: 66	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.

March 5, 2019, 02:53		#3
arunmass New Member Arun Join Date: Mar 2019 Posts: 3 Rep Power: 7	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

March 5, 2019, 08:45		#4
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,675 Rep Power: 66	What software do you have? Excel? Matlab? Other?

March 5, 2019, 11:49		#5
Arun Mass New Member batman Join Date: Nov 2017 Posts: 1 Rep Power: 0	I am having Excel.

March 6, 2019, 02:35		#6
arunmass New Member Arun Join Date: Mar 2019 Posts: 3 Rep Power: 7	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.