Shear heating, flow, and friction of confined molecular fluids at high pressure.

摘要: Understanding the molecular-scale behavior of fluids confined and sheared between solid surfaces is important for many applications, particularly tribology where this often governs macroscopic frictional response. In study, nonequilibrium molecular dynamics simulations are performed to investigate effects fluid surface properties on spatially resolved temperature flow profiles, as well friction. The severe pressure shear rate conditions studied representative elastohydrodynamic lubrication regime. agreement with experiments, flexible lubricant molecules give low friction, which increases linearly logarithmic rate, while bulky traction show higher but a weaker dependence. Compared lubricants, more significant heating stronger localization. Models developed systems can be used describe both profile shape mean film rise. thermal conductivity significantly lubricants compared fluids, in experimental results. subset simulations, efficiency thermostat one reduced represent lower conductivity. For these unsymmetrical systems, profiles become strongly asymmetric some slip occur at solid–fluid interface, despite absence velocity slip. larger rises steeper gradients cases lead large reductions high rate.