Numerical Study of Flow and Heat Transfer in a Cavity by Lattice Boltzmann Method

In this paper, the aircraft cabin is abstracted as a two-dimensional cavity. To save the energy and implement the green aviation, we simulate the flow and heat transfer in the cavity to ensure the arrangement of heating device in the aircraft cabin. Based on the lattice-Boltzmann method coupled the double distribution function model, the paper adopts D2Q9 velocity discrete model, which has nine different discrete velocity directions. And then calculates and analyzes the influence on the flow and heat transfer characteristic of different heater parameters and different Rayleigh numbers, so that we can obtain the optimal arrangement of heating device in the aircraft. The result show that heating parameters and Rayleigh numbers have great influence on the flow and heat transfer in the cavity. For example, with Rayleigh number increasing and heating position lower, the convective heat transfer intensity become greater. With the Rayleigh number decreasing, the convective intensity get the maximum value gradually when the heater located in the middle of the wall. When the Rayleigh number is fixed, the heat coverage area increases, the convective intensity decreases, the central axis velocity increase gradually, the velocity gradient increases and the flow change greatly. And the variation of flow function and isotherm are greatly affected by Rayleigh number, just like the classical natural convection in the cavity. Besides that, Rayleigh number has different effects on different heater parameters for the flow and heat transfer in cavity. The effect on the velocity distribution decrease gradually with the increase of Rayleigh number, while the effect of heating position on the flow and heat transfer increase with the increase of Rayleigh number.