Heat-Transport

Correction factor β_q for heat conduction to a sphere, valid across all Knudsen numbers from the continuum to the free-molecular regime. Exactly parallel to the Dahneke mass transport correction. Computes the heat transfer Knudsen number Kn_K = 2κ/(c̄'n'_gas m_gas c_v r) and the correction factor β_q = (Kn_K+1)/(2Kn_K(Kn_K+1)/α+1). Migrated from Aerosol.jl src/dahneke_brownian_diffusion.jl:93.