Saturated steam and pressure
Thread Content
There is a container with a constant volume and 100% thermal insulation (without considering heat loss), filled with dry saturated steam. Assumption 1: Release some of the steam to reduce the pressure inside the container. Question: Will the steam temperature change at this time? Is it rising or falling? At this point, is the steam saturated steam, superheated steam, or something else? Will water precipitate at this time? Assumption 2: Pour a certain amount of water into the container (the water temperature is lower than that of the steam inside the container). Question: How does the pressure inside the container change? Does it rise or fall, or does it first rise and then fall, or first fall and then rise? How does the temperature inside the container change? What kind of steam is it at this time?
The first vapor pressure decreases, and it becomes superheated steam.
If 1 is added, the temperature remains unchanged due to insulation; when it is released, the pressure drops but the temperature stays the same, and even in the case of superheated steam, no water will precipitate. In scenario 2, both the pressure and temperature decrease, but it remains saturated steam
The first vapor pressure decreases, water precipitates, and the temperature remains unchanged
Assumption 1: The temperature will not change; since the pressure decreases, the steam at this point is superheated steam, and superheated steam does not have water precipitate out of it. Hypothesis 2: The pressure will decrease because part of the steam is condensed into water; as a result, the pressure drops and the temperature drops as well. However, the steam remaining is still saturated steam – it is saturated steam at the reduced pressure.