ρ	density, kg·m−3	v	velocity, ms−1
t	time, s	p	pressure, Pa
η	dynamic viscosity Pas	g	gravitational acceleration, m·s−2
cp	specific heat, Jkg−1·K−1	T	temperature K
∆T	temperature difference, K	λ	thermal conductivity, Wm−1·K−1
β	polymer expansivity, K−1	σ0	Stefan-Boltzmann constant, Wm−2·K−4
ε	emissivity, -	A	cross section, m2
δ	thickness, m	α	heat transfer coefficient, Wm−2·K−1