Closed-cycle gas turbine layout: Identify the main components that a closed-cycle gas turbine must include for steady operation with a constant working fluid.

Introduction / Context:
Closed-cycle gas turbines circulate a fixed working fluid (often helium or nitrogen) through compression, external heating, and expansion. Recognizing the essential components clarifies how the cycle sustains itself.

Given Data / Assumptions:

• Closed loop with a constant mass of working fluid.
• External heat source adds energy; external cooler rejects heat.
• Compressor and turbine are connected by a shaft delivering net power.

Concept / Approach:
The compressor raises the pressure of the working fluid. The heating chamber (external heater) raises its temperature at essentially the same pressure. The turbine expands the hot fluid to produce work. The cooler then removes heat to return the fluid to a low temperature before recompression, completing the loop.

Step-by-Step Solution:

Verification / Alternative check:
On a T–s diagram, the closed Brayton cycle shows compression, constant-pressure heat addition, expansion, and constant-pressure heat rejection, consistent with the listed components.

Why Other Options Are Wrong:
Choosing only one or two components breaks the closed loop. Without a cooler, compressor inlet temperature rises and work skyrockets; without a heater, there is no useful expansion.

Common Pitfalls:
Confusing open and closed cycles; in an open cycle, combustion replaces the external heater and the working fluid is air that is exhausted to atmosphere.

Final Answer:
all of these