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In this paper, a lattice Boltzmann (LB) model is established to simulate the gaseous fluid flow and heat transfer in the slip regime under the curved boundary condition. A novel curved boundary treatment is proposed for the LB modeling, which is a combination of the nonequilibrium extrapolation scheme for the curved boundary and the counter-extrapolation method for the macroscopic variables on the curved gas–solid interface. The established numerical model can accurately predict the velocity slip and temperature jump of the microscale gas flow on the curved surface, which agrees well with the analytical solution for the microcylindrical Couette flow and heat transfer. Then, the slip flow and the heat transfer over the single microcylinder are numerically studied in this work. It shows that the velocity slip and the temperature jump are obviously influenced by the Knudsen number and the Reynolds number, and the local Nusselt number depends on which gas rarefaction effect (velocity slip or temperature jump) is dominant. An increase in the Prandtl number leads to a decrease in the temperature jump, which enhances the heat transfer on the microcylinder surface. The numerical simulation of the flow and heat transfer over two microcylinders in tandem configuration are carried out to investigate the wake interference effect. The results show that the slip flow and heat transfer characteristics of the downstream microcylinder are influenced by the wake region behind the upstream cylinder as the spacing is small.

Understanding flow and heat transfer in porous media is a matter of prime concern for micro devices. In this work, slip flow and heat transfer of gaseous fluid through the confined porous media is numerically simulated using a multiple-relaxation-time lattice Boltzmann method. The method is employed using an effective curved boundary treatment based on non-equilibrium extrapolation and counter-extrapolation methods. Nusselt number prediction for varying porosity, Knudsen and Reynolds number are studied. Based on the obtained numerical results, it is proved that the current technique can be used to effectively model slip flow and heat transfer at pore-scale.

The unconventional gas reservoir has attracted more and more attention as the shale gas greatly expands worldwide energy supply, for which the gaseous fluid transport in complex porous domain is one important process as the shale gas is extracted. The apparent permeability of porous media is one important parameter in the related numerical model, however, its determination is still challenging. The apparent permeability varies with gas pressure, the porous media properties and gas–solid interactions based on the previous studies. For the slip gas flows, the velocity slip at the gas-solid interface in confined porous space is one significant difference compared with that on macro scale, which is caused by the gas rarefaction effect. In this work, a pore-scale LB model is established to simulate the gaseous fluid flow in the confined porous media. An effective curved boundary treatment is adopted for the porous surface and the validation test shows that the present model has superiority in capturing the slip phenomenon on the curved surfaces. Based on the numerical predictions, the different influential factors on the permeability of confined porous media are thoroughly studied, for which the gas rarefaction effect is considered.