🔍 Key Concepts

• Cross-compounded steam turbine layout (one HP turbine on one shaft, one LP turbine on another) • How steam pressure and enthalpy drop are shared between HP and LP stages at full load • Typical energy distribution trends between HP and LP turbines in marine propulsion

💭 Think About

• Think about where the biggest enthalpy (energy) drop in the steam expansion usually occurs – in the higher or lower pressure stages? • If the LP turbine handles much larger volume flow but lower specific energy, how does that affect the fraction of total energy it receives compared with the HP turbine? • In a well-designed cross-compounded set, do designers aim for the HP and LP turbines to do almost the same work, or is one expected to take a clearly larger share?

✅ Before You Answer

• Recall that the ratio refers to energy share, not speed, pressure, or volume directly. • Mentally compare what would be a realistic engineering split (e.g., almost equal vs clearly dominant HP vs clearly dominant LP). • Eliminate any ratio that would imply the HP or LP turbine is doing almost none of the work, as that would be impractical in a full-load marine propulsion system.