Abstract
A new approach to model heat transfer between two bodies in mechanical contact is presented. The proposed method is inspired on the “mortar method”, more frequently used for mechanical contact, and its development was triggered by the necessity of correctly modelling the heat transfer between glass and moulds in glass forming processes due to the large dependence of glass viscosity on temperature. Typically, when modelling these processes with the finite element method a moving mesh, attached to the deforming glass, deals with the mechanical and thermal problems in the glass. In the moulds due to the low pressures involved only the heat transfer problem is usually addressed and consequently the same mesh is kept throughout the modelling process. In the proposed method a virtual interface, the “mortar”, is established between the two bodies to deal with the heat transfer between them. A master/slave strategy, combined with a penalty formulation, is used. Interface elements are established in the discretisation of the “mortar” surface, in which the nodes are projection of the interface nodes of the two bodies. The heat flux between the two bodies is obtained from theinterpolation of the temperatures of the two bodies at the interface and the heat transfer coefficient may be evaluated from the contact pressure and viscosity on the slave body. As a result a more effective thermal contact solution is obtained and dependence on the chosen meshes and spurious oscillations, which are typical in standard penalty formulations, are avoided