关键词: 相分离, 流型调控, 分层流, 冷凝传热

Abstract:   Condensation heat transfer is widely applied in various condensers.The thick liquid film separates the vapor from the cold wall surface, which causes worsening condensation heat transfer.The passive phase separation concept which inserts a mess cylinder to the condenser tube was proposed, the insert mesh cylinder divide condenser tube into a centre region to flow liquid and an annular region to flow gas to modulate the flow pattern for the first time.In order to verify the novel concept, the air-water two-phase flow experiment was performed, and the experimental results on the stratified flow pattern modulation by the phase separation concept was reported.It was found that all the liquid could be captured into a mesh cylinder (MC)installed in the condenser tube when the liquid level was relatively higher in the horizontal tube, forming the “gas-floating-liquid” mode.When the liquid height was small in the horizontal tube, partial liquid could be sucked by the MC, and the contact area between gas and tube wall was increased.According to the result of the adiabatic two-phase flow pattern modulation, it was expected that the contact area between vapor and cold tube wall was increased, yielding the super-enhanced condensation heat transfer when condensation heat transfer occurred.

Key words: phase separation concept, flow pattern modulation, stratified flow, condensation heat transfer