Typical overall compression ratio in simple gas-turbine cycles Select a representative simple-cycle gas turbine compressor pressure ratio used in basic textbook problems and older industrial sets. Choose the correct option.

Given data

• Context: simple (single-spool) gas turbines in classical MCQ settings.

Concept/Approach
Early and small industrial simple-cycle gas turbines commonly used modest compressor pressure ratios (≈ 3–6). Modern aero/industrial engines may be far higher, but the textbook representative choice in such MCQs is often about 4.

Elimination
A ratio of 1 implies no compression; 9 or 12 are possible in advanced designs but exceed the typical simple-cycle baseline emphasized in entry-level questions.

Final Answer
4