How many Curtis stages are contained in the...

🔍 Key Concepts

• Curtis stage in an impulse turbine is defined by a single large pressure drop across a set of nozzles, followed by one or more rows of moving blades with constant pressure through those blade rows. • On the diagram, the steam absolute pressure curve shows where pressure actually drops, while the steam absolute velocity curve shows how the velocity is divided among the blade rows. • The illustration also labels nozzles, fixed blades, and moving blades; how these are grouped tells you how many Curtis stages are present.

💭 Think About

• Look at the steam absolute pressure graph at the top: how many distinct pressure drops do you see between the inlet and outlet of the turbine shown? • Each Curtis stage begins with a nozzle set where pressure falls sharply; after that, pressure should be nearly constant while steam passes through multiple moving and fixed blade rows. How many such nozzle-and-pressure-drop groups are in this cutaway? • Ask yourself: is a Curtis stage counted by the number of moving-blade rows, or by the number of times the steam has a major pressure drop across nozzles? How does that affect your choice among the options?

✅ Before You Answer

• Before choosing, count the separate nozzle groups actually shown in the lower turbine section, not just the number of blade rows. • Verify on the pressure diagram how many major pressure drops occur that line up with those nozzle groups. • Confirm that a Curtis (velocity-compounded) stage is identified by one pressure drop in nozzles with velocity compounding in subsequent blades, not by the total number of rows of moving blades alone.

How many Curtis stages are contained in the turbine shown in the illustration? Illustration SE-0003

only a reaction turbine stage is shown

🔍 Key Concepts

💭 Think About

✅ Before You Answer