Calculation of nitrogen flow in nickel micronozzle based on numerical approaches of gas and molecular dynamics

The work is devoted to the modeling of gas flows in micronozzles. The complexity of studying such processes is connected both with the small sizes of technical system that makes it difficult to carry out the natural experiments and with the violation of hypothesis of continuity of the considered gas medium. An additional factor of complexity is the lack of information on the real processes taking place at the gas-metal boundary. An attempt to consider the features of gas flow in a micronozzle using a multiscale approach is made. The multiscale approach has two computational levels and uses the calculations by macroscopic quasigasdynamic model and microscopic model of molecular dynamics. In this approach the macromodel is supplemented by parameters and boundary conditions from database made in micromodel calculations. The flow of nitrogen in the nickel micronozzle is considered as an example. Previously the parameters of interacting the nitrogen molecules and atoms of the nickel surface were calculated and saved in database. In this paper they were used to form the material coefficients in the quasigasdynamic equations. The performed preliminary modeling has shown that at low flow velocities in calculations it is possible to obtain a flow with a profile of longitudinal velocity close to the Poiseuille flow profile. It shows the adequacy of the developed numerical techniques