Describe the diffuser in an annular diffuser design.

Describe the diffuser in an annular diffuser design.

• A. The diffuser is an annular chamber provided with a number of vanes forming a series of divergent passages into the manifold
• B. The diffuser is a straight pipe with no vanes
• C. The diffuser is a cone with convergent passages
• D. The diffuser is a rectangular duct with parallel walls

Answer: (A)

In an annular diffuser design, the goal is to decelerate the fast, incoming flow and convert its kinetic energy into static pressure as it enters the manifold. This is achieved with a circular (annular) chamber that uses vanes to create several divergent passages feeding into the manifold. The vanes guide the flow and shape multiple wedge-shaped channels that expand toward the manifold, evenly distributing the flow around the circumference and reducing flow separation. This arrangement provides better pressure recovery and a more uniform inlet to the compressor, which is crucial for stable operation. A straight pipe with no vanes wouldn’t diffuse the flow or raise pressure. A cone with convergent passages would accelerate the flow instead of decelerating it. A rectangular duct with parallel walls isn’t annular and doesn’t create the circular, vaned divergent paths needed for uniform annular diffusion.

In an annular diffuser design, the goal is to decelerate the fast, incoming flow and convert its kinetic energy into static pressure as it enters the manifold. This is achieved with a circular (annular) chamber that uses vanes to create several divergent passages feeding into the manifold. The vanes guide the flow and shape multiple wedge-shaped channels that expand toward the manifold, evenly distributing the flow around the circumference and reducing flow separation. This arrangement provides better pressure recovery and a more uniform inlet to the compressor, which is crucial for stable operation.

A straight pipe with no vanes wouldn’t diffuse the flow or raise pressure. A cone with convergent passages would accelerate the flow instead of decelerating it. A rectangular duct with parallel walls isn’t annular and doesn’t create the circular, vaned divergent paths needed for uniform annular diffusion.