Convective Heat Transfer Discrete Modeling

Abstract

The article presents the investigation results of the heat transfer process in a moving continuous medium. The lattice Boltzmann model (LBM) was used. This model is based on the principles of the cellular automata system. For the study, an orthogonal spatial lattice with diagonal constraints was adopted, by means of which the particle distribution functions were introduced from a discrete set of allowed velocities. These distribution functions were described by a discrete analogue of the Boltzmann kinetic equation. This approach made it possible to study the evolution of the distribution functions of particles in a continuous medium as a fuction of discrete-time steps. The model used made it possible to describe both mechanisms of thermal energy transfer in a moving medium – macroscopic and microscopic. In this case, the macroscopic transfer due to the motion of a continuous medium was determined by a change in the density of the particle distribution, and the microscopic (molecular) transport was determined by the relaxation heat exchange operator. This operator of the mathematical model characterized the redistribution of heat in a discrete region due to the collision of particles, that is, it takes into account the thermal conductivity of the medium. Since not only the moving continuous medium but also the boundary surfaces (walls, obstacles) participate in the heat exchange process, the elements taking into account this fact were included in the model. To test an adequacy of the approach used a software application was developed. It was used to simulate and visualize the process of heat transfer by a moving continuous medium. The application also allowed setting confining surfaces of various forms. An analysis of the computer experiment results allows us to state that the obtained data do not contradict to the real concepts of the processes of heat transfer in a moving fluid. The advantage of the proposed discrete approach is the possibility of describing hydrodynamic and thermal processes within the framework of a single model, which makes it quite convenient to use. In addition, this method makes it possible to solve heat transfer problems for objects that have a complex geometric configuration of the interfaces. Forcitation:Chernyavskaya A.S., Bobkov S.P. Convective heat transfer discrete modeling. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 2. P. 86-90