A thermal modeling approach for the piston/cylinder interface of an axial piston machine under asperity contact

This paper makes a contribution to the field of positive displacement piston machines by presenting an approach that models the piston/cylinder interface, taking into account thermal effects and surface asperity contact. The pressure distribution in the interface is evaluated using the universal mixed thermal Reynolds equation, while the temperature distribution is determined using a simplified formulation of the conservation of energy. The rigid body motion and elasto-hydrodynamic effects of the piston and block bodies are described by Newton’s second law and an influence matrix method, respectively. A coupled formulation for the heat transfer problem is used to describe the temperature distribution in the piston and block bodies. The effect of heat dissipation due to asperity contact is considered by incorporating an experimentally determined asperity friction coefficient. The proposed modeling approach is then validated by comparing it with experimentally measured temperature distribution in the block, and the error between the simulation and experiments is found to be less than 6%. The paper emphasizes the importance of considering thermal effects in such an interface and highlights the potential applications of the model.