Abstract
The aim of this paper is to clarify the effects of surface roughness and downstream pressure on the rarefied gas flow through passages. Surface roughness is modeled by two-dimensional triangular roughness. In the calculation, molecules are assumed to scatter from slope of triangular roughness according to the cosine law. Conductance of rarefied gas flows through passages is calculated using the Monte Carlo method. In the experiment, a flow measurement system for rarefied gas is manufactured to measure flow rate through passages. Experiments and calculations are conducted in the near free molecule flow region. Results of this study are as follows; The manufactured flow measurement system can measure flow rates below 1 × 10 -4 [Pa·m3/sec] accurately. The conductance of rarefied gas flows is affected by the downstream pressure even if pressure difference is equal in two flows. The effect of surface roughness does not change with the downstream pressure of passages.
