Molecular Dynamics Studies for the Transport Properties of Bounded Repulsive Fluids: III. Thermal Conductivity

Molecular dynamics simulations for the penetrable-sphere model have been carried out over a wide range of the packing fraction phi and the repulsive energy parameter epsilon* to investigate the thermal conductivity properties of bounded repulsive fluids. The resulting thermal conductivity coefficients A, are compared with theoretical approximations including Boltzmann and Enskog predictions in the gas kinetic theory. We have also proposed the empirical Enskog-like approximation based on the Enskog theory in the hard-sphere model. In the lower repulsive energy systems of epsilon*=0.25 and 0.75, the kinetic-kinetic (kk) contributions are dominant over entire densities (lambda approximate to lambda(kk)), whereas the collision-collision (cc) contributions are gradually significant in the highly repulsive energy systems of epsilon*=4.0 with increasing the packing densities of phi >= 0.4 (lambda approximate to lambda(cc)). Based on the molecular scale, relevant transport properties of bounded repulsive fluids are discussed for self-diffusion, shear viscosity, and thermal conductivity reported in this series of molecular simulation studies.