Sharif Digital Repository

In this study, multi-component CFD and DSMC solvers are used to study the gas mixture flow through a separation micronozzle at different pressure ratios. The resulting velocity and mole fraction fields, which are predicted by these solvers, are compared with each other to examine the effects of flow rarefaction on the mixture flow and the species separation and to evaluate the validity of continuum flow theory provided by the CFD solver. The results indicate good agreement of the velocity and mole fraction fields in the regions in which the pressure is sufficiently high. A decrease in pressure value, which is the result of increasing the pressure ratio at a constant inlet pressure, and a... 

A gas sensor was developed to measure the concentration of binary gas mixtures. This sensor works based on the permeability change of different gas mixtures across the polymeric membranes. Although high values of permeability and selectivity are needed for an ideal separation, the performance of this sensor mainly depends on the permeability factor. Polysulfone and silicone rubber were applied as the membrane base and coat, respectively. Moreover, in contrast to existing polymeric sensors that use hollow fibers, the present sensor is made of flat membranes. This new design is cheaper, smaller, and easier to use in comparison to the hollow fiber polymeric sensors. In order to test the sensor...