As shown in the illustration, what is the...

As shown in the illustration, what is the...

Question 1 of 2707066636eed28f7522a1c51e2b2

As shown in the illustration, what is the purpose of pressurizing the main bearing lube oil sumps on a typical marine gas turbine? Illustration GT-0023

Question 1 of 27070

Q

As shown in the illustration, what is the purpose of pressurizing the main bearing lube oil sumps on a typical marine gas turbine? Illustration GT-0023

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🔍 Key Concepts

• Notice the pressurizing port, sump vent, and how they relate to the air and oil seals in the illustration. • Think about pressure differences: if the sump is held at a certain pressure, in which direction will oil and air tend to move along the shaft? • Look at the paths labeled scavenge oil and cavity drain and ask what the designer is trying to keep OUT of the gas path and shaft area.

💭 Think About

• Which of the answer choices deals with controlling where the oil goes rather than changing how well it lubricates or cools the bearing? • If the sump were NOT pressurized, what unwanted flow or leakage might occur at the shaft and seals? • Does pressurizing the entire sump really change how evenly the oil is distributed around the bearing, or does it mainly affect leakage paths at the boundaries?

✅ Before You Answer

• Identify the main function of the air seal / oil seal / windback shown in the figure and match that function with the best choice. • Eliminate any options that describe effects that are already achieved by the oil jets or scavenge system, not by sump pressure itself. • Make sure the option you pick directly relates to controlling leakage at the shaft/seal interface, as suggested by the illustration.