The geometric parameters of the heat pipe include the effective total length of the heat pipe (L_tot), the length of the evaporation section (L_e), length of the condensation section (L_c), the inner diameter of the heat pipe (R_HP.i), the outer diameter of the heat pipe (R_HP.O), the thickness of capillary wick structure (δ_wick), etc.;

Wick structure parameters include porosity (ε), porous radius (r_w), and permeability (K_w). The purpose of this simulation is to focus on the change of Q_{max(calculate)} when the heat pipe geometry parameter is changed.

The friction process coefficient f', an indicator of the quality of the user's manufacturing process technology for heat pipes. If the user already knows the experimental value Q_max(exp), then Q_max(exp) can be the same as Q_{max(calculate)} by adjusting f'. One thing should be notice that once f' is adjusted, then f' is fixed until the manufacture process is changed. f' is a parameter that cannot be changed in the same manufacturing process. If you don't know the Q_max(exp), then f'=800 will be used as the default value for the general heat pipe.

Operating condition includes the operating temperature (T_op) and its corresponding working fluid thermodynamic properties, which have the density, viscosity, specific volume, specific heat, and enthalpy.