Turbine exhaust temperature

What is the relationship between the turbine exhaust temperature and what? During the warm-up phase of the turbine rotor after it has been started but before any load is applied, the steam that enters is subjected to throttling. At this point, the steam pressure behind the main steam valve or the throttle valve is very low; the enthalpy of the steam increases significantly as a result of throttling, which means that the entropy drop is small. As a consequence, the temperature of the steam after it has done work is very high (in a superheated state), and this affects the increase in temperature of the exhaust cylinder. When the turbine reaches its rated speed (under no-load conditions), the amount of steam entering the turbine is very small. This small amount of steam results in a vacuum condition downstream of the regulating stages. At this point, most of the turbine’s work is generated by these regulating stages. In the passages leading to the exhaust cylinder, the flow cross-section is large, the flow rate is low, and the flow velocity is slow; this leads to significant draught effects, thereby increasing the draught losses. Furthermore, as the rotor rotates, friction occurs between the impeller and the steam, resulting in frictional losses. All these cause the steam to be reheated or superheated, thereby contributing to an increase in the temperature of the exhaust chamber.

As a supplementary point, a high exhaust temperature is also related to the vacuum level.

Thank you very much. I also want to ask whether it is related to the exhaust temperature

During normal operation, the exhaust steam is wet steam, and the exhaust temperature corresponds one-to-one with the exhaust pressure. As for the factors affecting the exhaust pressure, these include load, cooling water volume, water temperature, heat exchange area, and thermal resistance.

Thank you very much. I also want to ask whether there is a relationship between exhaust temperature and oil temperature

It’s okay. For condensing steam turbines, in actual production the exhaust temperature is mainly related to the vacuum level

I’ve learned it; it seems that technical forums are really different – you just need to do a search and it appears right away.

The exhaust temperature of a turbine is related to the exhaust pressure; the greater the vacuum level of the exhaust pressure, the lower the temperature. The higher the efficiency of the turbine.