Computer Simulation of Positional Beaming Effect of Molecular Flow in Straight Cylindrical Pipeline by Monte Carlo Method

The existence of positional beaming effect of gas molecular flow in straight cylindrical pipeline is proved by the Monte Carlo Simulation method in this paper. The positional beaming effect is defined as the passing density difference of the molecules in pipeline. The inlet molecule uniformity distributes, but outlet molecular do not uniformity distribute that it increases in the center area of the pipeline and decreases at the edge area of pipeline. In order to evaluate the positional beaming effect, a criterion gamma is defined as the ratio of molecule density passing a given circular area to the total molecule density passing the whole cross-sectional area. The simulated results show that the averaged gammaap1.11 around the pipe axis and the averaged gammaap0.91 near the pipe wall.