中文摘要：

本文提出一种考虑流体热物性变化的格子-玻尔兹曼通量求解器。该求解器能够捕捉流体物性参数的变化对流动和传热的影响,在保留了传统格子-玻尔兹曼方法固有优势的同时,克服了在网格划分、边界条件处理等方面的缺陷。本文采用该求解器模拟了同心环型腔内由温差驱动的自然对流,讨论了不同温差条件下的流动和传热特性,分析了物性变化的影响。结果表明：常物性解低估了换热设备的传热性能,而且Ra数越大,偏差越显著。

英文摘要：

A variable property-based lattice Boltzmann flux solver is proposed in the present paper.This solver is capable of capturing the effects of the variation in fluid properties on flow and heat transfer characteristics. It retains inherent advantages of conventional lattice Boltzmann method and overcomes many drawbacks such as the difficulty in using non-uniform meshes, the inconvenience of dealing with boundary conditions, etc. In the present paper, the natural convection induced by a radial temperature difference in a horizontal concentric annulus is simulated by the solver, the flow and heat transfer characteristics obtained under different temperature difference conditions are studied, and variable property effects are discussed. It is found that the commonly-concerned constant property solution（CPS） underestimates the heat transfer performance of heat exchangers, and the deviation of the CPS from the variable property solution becomes more and more notable with the increase of the Rayleigh number Ra.