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Steam engine valve losses: initial cylinder pressure vs. boiler pressure At the beginning of the piston stroke, how does the cylinder steam pressure compare with the boiler pressure (considering throttling and valve losses)? Choose the correct relation.

Difficulty: Easy

Equal to the boiler pressure
Less than the boiler pressure
Greater than the boiler pressure
Indeterminate/always variable

Correct Answer: Less than the boiler pressure

Explanation:

ConceptDue to throttling across ports/valves and pressure drops in the steam pipe, the initial admission pressure in the cylinder is lower than the boiler pressure in practical engines.

Final AnswerLess than the boiler pressure

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