Performance of an Opposed-Jet Molecular Impactor with W(CO)₆ Molecules Suspended in a H₂ Carrier Gas

Abstract

An opposed-jet impactor is operated at low pressures with H₂ as the carrier gas and W(CO)₆ molecules playing the role of the suspended particles. The compositions of the two streams leaving the device are determined with two thermal conductivity detectors operating at the same reduced pressure as the impactor. In order to compensate for the effect of diffusion, which leads to a nonzero crossing efficiency even at negligible values of the Stokes numbers, the impactor is operated in an unbalanced condition. As a result, a negligible crossing efficiency is observed below a threshold value of the Stokes number, similar to the critical Stokes number of particle impactors. Such a behavior can have important practical implications for the aerodynamic separation and purification of heavy gases.