Is the heat exchange in the air-steam preheater equivalent to the adiabatic exchange in the turbine?
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As the title suggests, I’m not quite understanding the concept of adiabatic exchange. I don’t see why the same steam entering a preheater is generally not considered to cause a pressure drop, while in a turbine it results in negative pressure
1. Typically, a preheater is not in a truly closed vacuum state, whereas a condensing steam turbine is considered to be in such a vacuum state. 2. The calculated pressure for a steam preheater is not very important, while for a steam turbine, the impact of back pressure on its operation must be taken into account.
I thought about it – for creating a vacuum seal, is it because the steam turbine has a vacuum pump to generate the vacuum? What impact does the turbine back pressure have on pressure?