Discrete thermal element modelling of heat conduction in particle systems: Pipe-network model and transient analysis

In our recent work [Y.T. Feng, K. Han, C.F. Li, D.R.J. Owen. Discrete thermal element modelling of heat conduction in particle systems: basic formulations. Journal of Computational Physics. 227: 5072–5089, 2008], a novel numerical methodology, termed the discrete thermal element method (DTEM), is proposed for the modelling of heat conduction in systems involving a large number of circular particles in 2D cases. The method cannot be easily extended to transient analysis, which causes difficulties in combining the DTEM with the conventional discrete element method for modelling thermal/mechanical coupling problems in particle systems. This paper presents a simplified version of the DTEM, termed the pipe-network model, in which each particle is replaced by a simple thermal pipe-network connecting the particle centre with each contact zone associated with the particle. The model essentially neglects the direct heat transfer between the contact zones and thus significantly simplifies the solution procedure of the original DTEM. With this feature, transient heat conduction analysis can now be performed in a straightforward manner. In addition, the entire algorithmic structure of the pipe-network model is compatible with the discrete element method, leading to an effective scheme for simulating thermal–mechanical coupling problems. Numerical experiments are conducted to establish the solution accuracy of the proposed model.