Study on flow and heat transfer of small scale gas flow for air cooling system

The small scale pipe plays an important role in the heat and mass transfer of industrial application. For the study of the flow characteristics in small scale pipe, a modal mixed Discontinuous Galerkin (DG) method was proposed for solving axial-symmetrical Navier-Stokes (NS) equations with solid slip boundary conditions. A new limiter of modal DG was proposed. And, the special treatments of velocity slip and temperature jump in wall solid boundary were given in the numerical scheme. Extensive numerical studies for the flow characteristics of small scale pipe were conducted. For validation, the comparison between the present study and experiment data were performed. The heat transfer coefficients and frictional factor are found to be increased with the diameter decreasing. Furthermore, it is observed that the frictional factor of small scale pipe is larger than that of macro scale pipe. And, the proposed DG-NS method provides a new way for the investigation of the flow characteristics in small scale flow.