Oilers/Plant Tenders (HHC) Civil Service Practice Exam

In normal operation, how does the lubricating oil in a steam turbine affect the leaving steam?

1. Affects its temperature

2. Affects its pressure

3. Affects its quality

4. Does NOT affect it

The correct answer is: Does NOT affect it

In the context of a steam turbine's operation, the lubricating oil typically serves to reduce friction within the turbine's moving parts. Its primary function is mechanical rather than thermodynamic or fluid dynamic regarding the steam being produced. As such, the presence of lubricating oil does not directly influence the characteristics of the steam that exits the turbine. The leaving steam's temperature, pressure, and quality are primarily determined by the thermodynamic processes occurring within the steam generation and turbine systems, including heat transfer, phase changes, and the pressures and temperatures at which the steam operates. Since the lubricating oil operates within a separate lubrication system, its impact on the steam's properties is minimal or non-existent. Therefore, it is accurate to say that in normal operation, the lubricating oil does not affect the characteristics of the leaving steam. This understanding is crucial in maintaining turbine efficiency and performance, as well as ensuring that steam quality remains appropriate for downstream processes.