Why axial-flow compressors are used in aircraft gas turbines In aircraft gas-turbine engines, which primary advantage makes axial-flow compressors preferable over centrifugal compressors for high mass-flow propulsion applications?

Introduction / Context:
Compressor selection in aircraft propulsion is driven by aerodynamic packaging, efficiency, and achievable pressure ratios for the required mass flow. Axial-flow compressors dominate modern turbojets and turbofans because they can process very large airflows while keeping the engine diameter small, reducing drag and easing nacelle integration.

Given Data / Assumptions:

• High mass-flow requirements typical of flight propulsion.
• Constraints on engine nacelle diameter (frontal area) due to drag and installation.
• Comparable technology levels and good design practice.

Concept / Approach:
For the same mass flow, a centrifugal stage tends to require a larger diameter (due to radial flow path and diffuser volute), increasing frontal area. Axial compressors build pressure gradually over many stages while maintaining a slender annulus, resulting in a small frontal area and favorable installation aerodynamics.

Step-by-Step Solution:
Identify the key aircraft need: high mass flow with minimal drag.Recognize axial-flow architecture allows compact diameter by stacking multiple stages axially.Conclude that low frontal area is the decisive advantage in aircraft gas turbines.

Verification / Alternative check:
Modern turbofan cores universally employ multistage axial compressors, validating the dominance of low frontal area for large mass flows.

Why Other Options Are Wrong:
“Higher thrust” is not an intrinsic compressor property; thrust depends on overall cycle and nozzle. Single-stage pressure rise is actually higher for centrifugal than for a single axial stage.

Common Pitfalls:
Confusing stage pressure rise with overall engine performance; an axial machine attains high overall pressure via many stages, not a single stage.

Final Answer:
Low frontal area for a given mass flow rate