Terminology: A machine specifically designed to raise the pressure of air is called a compressor.

Introduction / Context:
Correct terminology helps avoid confusion among related machines in fluid and thermal engineering. This question asks for the proper name of a device that raises air pressure.

Given Data / Assumptions:

• Working fluid is air.
• Device function is to increase pressure from an inlet level to a higher discharge level.
• Steady operation is assumed.

Concept / Approach:
A compressor absorbs shaft power to elevate the total pressure of a gas. Types include reciprocating, rotary screw, centrifugal, and axial compressors. Gas turbines, in contrast, produce net power by expanding hot gas, while internal combustion engines produce mechanical power by combusting fuel with air. An air motor converts compressed air energy back into shaft work.

Step-by-Step Solution:

Verification / Alternative check:
Manufacturer datasheets and engineering texts classify machines that increase gas pressure under the category of compressors, distinct from turbines and motors.

Why Other Options Are Wrong:

• Gas turbine: expands gas to create work, not primarily to compress air.
• I.C engine: produces mechanical work from combustion, not a pressure-raising device for air alone.
• Air motor: consumes compressed air to deliver shaft work, the reverse of a compressor.

Common Pitfalls:
Confusing the compressor inside a gas turbine engine with the entire engine. The compressor is a component, not the whole machine.

Final Answer:
compressor