Condensation in the presence of a noncondensable gas in direct contact

This work analyses the effect of impurities of a noncondensable gas present in the bulk of a vapor in direct contact condensation. The physical model is a free laminar stream that is exposed to its own vapor atmosphere containing the inert gas. The solution is based on the boundary layer conservation equations and is obtained using an exact similarity solution and an approximate integral method. The analysis predicts reduction in the heat transfer rates near the "leading edge" (small x*), which may be significant depending on the concentration of the noncondensable gas and the temperature driving force. This effect is accentuated at lower pressures. Far downstream (x* > 1) the reverse effect is observed, namely, the local heat flux becomes much higher compared to the case without the presence of noncondensables.