MAXIMUM GAS-FLOW IN CIRCULAR DUCTS AT VARIOUS PRESSURES - AN APPROXIMATE APPROACH

An approximate solution is given for the prediction of the gas flow ra te depending on the pressure drop for compressible laminar flow in cir cular ducts. The pressure and pressure drop range from high to low val ues, i.e. both Newtonian flow and Knudsen flow as well as the transiti on regime have to be modelled. The resulting equations are easy to han dle and may be sufficient to serve engineering purposes. A numerical e xample displaying how fast a vessel can be evacuated is also included in the paper.