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GATE 2019 AE – Question 22

Propulsion · Turbomachinery: Axial compressors, work and compression, degree of reaction, multi-staging · 1 mark · Multiple choice

For single-stage subsonic compressors, compare the highest obtainable pressure ratios of axial and centrifugal types.

  1. Axial is greater than centrifugal.
  2. Axial is less than centrifugal.
  3. They are equal.
  4. Any of the above is possible.

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Show answer and explanation

Correct answer: (B) Axial is less than centrifugal.

Explanation

A centrifugal stage combines substantial impeller energy input with diffusion and commonly achieves a larger pressure rise per stage. A subsonic axial stage is more restricted by blade loading and diffusion. Thus the highest single-stage axial pressure ratio is lower, B; multistaging is how axial compressors achieve large overall ratios.

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