Molecular dynamics simulation of argon flow in large scale within different microchannels under phase change condition

摘要

In this research, the molecular dynamics simulation method is employed to simulate the boiling flow of argon flow inside the microchannels with different surfaces of ideal and roughened with cone barriers, cubic barriers, and spherical barriers respectively. For all simulations, boundary walls of all microchannels are set at a temperature of 98 K to prepare the required thermal energy for boiling argon fluid flow within channels. Also, to enforce argon fluid to flow along the mentioned microchannels, a unique external driving force is prepared at the entry region of all microchannels. Afterward, the evolution of boiling flow is reported in four-time steps of 250,000, 500,000, 750,000, and 1,000,000, respectively. Then, velocity and temperature profiles of argon flow are reported after completion of the boiling process at 1000000-time steps. Investigations in the progress of boiling flow until 7,500,000-time steps show different behavior between rough microchannel with cubic barriers and behaviors of fluid flow within other channels in the distribution of argon particles in middle regions of channels. But, it is reported that with completion of the boiling process at 1000000-time steps, consequences of cubic geometry of barriers on the normal distribution of fluid atoms in a different region of the microchannel are removed. Also, it is reported that differences between maximums and minimums of flow temperatures are around 150 K for ideal channel and rough channels with cone and spherical barriers, while it is about 300 K for the rough channel with cubic barriers. Moreover, the temperature of argon flow in the center of the channel with cubic barriers can be reached even to 410 K which needs to be controlled by polishing the internal surfaces in some of the practical applications such as microprobes in medical cryosurgeries.