Velocity Compounding:

Working Principle:

The high velocity steam jet then pass over the rings of moving blades and fixed blades alternatively. During which, a part of kinetic energy is absorbed in each ring of moving blades. The direction of steam is changed without altering much it's velocity in the rings of fixed.

The variation in pressure and velocity drop fully at the nozzle itself and the pressure is kept remains constant in moving blades and fixed blades. The velocity of the steam coming out of nozzle is very high and it is reduced in stage-by-stage of moving blades.

Hence, it is known as velocity Compounding.


Example of this type of turbine is Curtis turbine.


  1. It's initial cost is less because of few numbers of stages.

  2. Less space is required.

  3. The system is reliable and easy to start.

  4. There is a need of strong casing due to low pressure.


  1. Frictional losses are high due to high initial velocity.

  2. Efficiency is low.

  3. The ratio of blade velocity to steam velocity is not optimum for all wheels.

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