# Gas thermal conductivity¶

Thermal conductivity of gas as a function of temperature can be calculated from the following equation:

$k_{gas} = A + B\,T + C\,T^2 + D\,T^3$

where coefficients A, B, C, and D are obtained from tables in the Yaws’ Handbook for inorganic and organic compounds. The k_gas_inorganic function in the Chemics package supports 259 gas species while the k_gas_organic function supports 6,914 species. At a minimum, the functions require formula name and temperature as input parameters; however, the CAS number is also needed as an input if more than one form of a species exists.

## Nomenclature¶

$$k_{gas}$$ - Thermal conductivity of gas [W/(m K)]
$$A, B, C, D$$ - Coefficients from Yaws’ Handbook (-)
$$T$$ - Temperature (K)

## Source code¶

chemics.gas_thermal_conductivity.k_gas_inorganic(formula, temp, full=False)[source]

Thermal conductivity of gas as a function of temperature. Applicable to gas comprised of inorganic compounds. Results based on coefficients from Yaws’ Critical Property Data for Chemical Engineers and Chemists 1.

Parameters
• formula (string) – Molecular formula of the gas.

• temp (float) – Temperature of the gas [K]

• full (bool, optional) – When set to False (default) just thermal conductivity is returned. When set to True then return thermal conductivity and other information.

Returns

• k_gas (float) – Thermal conductivity of gas [W/(m K)]

• k_gas, cas, tmin, tmax, a, b, c, d (tuple) – Additional values are only returned when keyword full=True.

k_gas - Thermal conductivity of gas [W/(m K)]
cas - CAS number [-]
tmin, tmax - Temperature range at which results are applicable [K]
a, b, c, d - Values for regression coefficients [-]

Raises
• ValueError – If gas formula is not found in csv data file.

• ValueError – If gas temperature is not in range between tmin and tmax.

Examples

>>> k_gas_inorganic('N2', 773)
0.0535

>>> k_gas_inorganic('N2', 773, full=True)
(0.0535, '7727-37-9', 63.15, 1500.0, -0.0002267, 0.0001027, -6.0151e-08,
2.2331e-11)


References

1

Carl L. Yaws. Table 84. Thermal Conductivity of Gas – Inorganic Compounds in Yaws’ Critical Property Data for Chemical Engineers and Chemists. Published by Knovel, 2014.

chemics.gas_thermal_conductivity.k_gas_organic(formula, temp, cas=None, full=False)[source]

Thermal conductivity of gas as a function of temperature. Applicable to gas comprised of organic compounds. Results based on coefficients from Yaws’ Critical Property Data for Chemical Engineers and Chemists 2.

Parameters
• formula (string) – Molecular formula of the gas.

• temp (float) – Temperature of the gas [K]

• cas (string) – CAS number of the gas, required for some species [-]

• full (bool, optional) – When set to False (default) just thermal conductivity is returned. When set to True then return thermal conductivity and other information.

Returns

• k_gas (float) – Thermal conductivity of gas [W/(m K)]

• k_gas, cas, tmin, tmax, a, b, c, d (tuple) – Additional values are only returned when keyword full=True.

k_gas - Thermal conductivity of gas [W/(m K)]
cas - CAS number [-]
tmin, tmax - Temperature range at which results are applicable [K]
a, b, c, d - Values for regression coefficients [-]

Raises
• ValueError – If gas formula is not available in CSV data file.

• ValueError – If multiple substances have same formula. Require CAS number.

• ValueError – If gas temperature is not in range between Tmin and Tmax.

Examples

>>> k_gas_organic('CO', 801)
0.05722

>>> k_gas_organic('C18H38O', 920, cas='593-32-8')
0.04174


References

2

Carl L. Yaws. Table 85. Thermal Conductivity of Gas – Organic Compounds in Yaws’ Critical Property Data for Chemical Engineers and Chemists. Published by Knovel, 2014.