Identify compressor type from flow direction If the flow of air through a compressor is predominantly parallel to the machine axis throughout, the compressor is classified as which type?

Introduction / Context:
Compressor families are classified by the direction of the main flow path. Recognizing the flow orientation helps in quickly identifying machine types and their appropriate applications.

Given Data / Assumptions:

• Steady operation and conventional designs.
• “Parallel to the axis” refers to the absolute flow path through the rotor-stator stages.

Concept / Approach:
In axial-flow compressors, the air progresses along the machine axis through alternating rows of rotating and stationary blades, gradually building pressure over many stages. Centrifugal compressors turn the flow radially outward in the impeller; reciprocating compressors are positive-displacement piston machines without a continuous axial flow path.

Step-by-Step Solution:
Map flow direction to machine family: axial → axial-flow; radial → centrifugal; oscillatory piston → reciprocating.Since the flow is parallel to the axis, the correct classification is axial-flow compressor.

Verification / Alternative check:
Any schematic of gas-turbine cores shows multistage axial compressors with annular flow strictly along the axis.

Why Other Options Are Wrong:
(a) Reciprocating has no continuous axial flow corridor; (b) flow is primarily radial; (d) mixed-flow has combined radial and axial components; (e) Roots is a positive-displacement blower.

Common Pitfalls:
Confusing axial-flow compressors with axial turbines—direction is the same but function differs.

Final Answer:
Axial-flow compressor