Table 2.

Thermophysical properties of air and liquid nitrogen (Anzaldua‐morales et al. 1999; Vasala 2004; Ban et al. 2007; Zachariah 2008; Usman et al. 2013)

	Air (T = 255 K)	Liquid nitrogen (T = 70 K)
Density, ρ (kg·m−3)	1.3835	840
Specific heat, Cp (J·kg−1·K−1)	1003	2024
Viscosity, μ (Pa·s)	1.650 × 10−5	2.20 × 10−4
Thermal conductivity, k (W·m−1·K−1)	0.0228	0.150
Prandtl number, Pr	0.715	2.97
Thermal expansion coefficient, β (K−1)	0.002	0.00504