In a gas channel, water vapor in th

In a gas channel, water vapor in the flow condenses to form a heat source, while liquid water in the channel evaporates (in the form of thin films or droplets) to form a heat sink. Evaporation occurs when both of the following given conditions are met：a）Liquid water exists in the flow of gas；b）Gas unsaturated (if the pressure drops or the temperature rises, the saturated gas may become unsaturated). Conversely, condensation occurs when the gas is fully saturated or its temperature drops. Also, condensation occurs when the reaction gas or other components "disappear" in the electrochemical reaction, although this phenomenon does not occur in the channel instead of at the catalyst layer.