Condensation of a hydrocarbon in the presence of a non-condensable gas: Heat and mass transfer

CFD Investigation of Non‐Condensable Gases in Vacuum and Non‐Vacuum Steam Sterilizers

“…Previous studies have shown that heat transfer decreases in the presence of NCGs [12,13]. The steam condenses partially on the chamber walls, partially on the trays, and, of course, on the medi-cal devices.…”

“…During the sterilization cycle, the NCGs are partially mixed with the incoming steam, partially not mixed with the incoming steam, and, finally, removed from the steam sterilizer. Previous studies have shown that heat transfer decreases in the presence of NCGs [12,13]. As a result of these studies, it is known that all NCGs should be reduced before the sterilization of the medical equipment takes place.…”

“…Studies in the past have shown [11,12] that an amount of 10 % of NCGs or higher, lead to a reduction of the heat transfer coefficient by half. In that case, the Nusselt numbers for all volume fractions of steam (j steam ) are set to the same Nusselt number as the ideal flow.…”

“…x ¼ m steam m steam þ m water (12) where m steam stands for mass of the steam and m water for the mass of the water. Outlets were set as pressure outlets during the times when the outlets were open.…”

“…In that case, the Nusselt number is set to the Nusselt number under ideal flow conditions multiplied with the CAF divided by two. Studies in the past have shown [11,12] that an amount of 10 % of NCGs or higher, lead to a reduction of the heat transfer coefficient by half. As a result, the authors used the half CAF to simulate the heat transfer under these conditions.…”