Steam Turbine Isentropic Efficiency & Willans Line Calculator
Calculate internal isentropic efficiency, actual vs theoretical steam rates (ASR/TSR), enthalpy drops, and Willans throttle curve per ASME PTC 6.
Steam Inlet Throttle Conditions
Load & Flow Parameters
Efficiency & Expansion Metrics
Recommended Tools & Equipment
Tested hardware and components for high reliability
Frequently Asked Questions
What is the Willans Line in steam turbine operation?
The Willans Line is a fundamental linear relationship between total steam mass flow rate (ton/hour) and electrical generator output (MW). The y-intercept represents the no-load steam flow required to overcome mechanical bearing friction, windage, and governor throttling at rated speed, while the slope represents the incremental steam rate.
What is the difference between TSR and ASR?
TSR (Theoretical Steam Rate) is the minimum quantity of steam required per kilowatt-hour under ideal 100% reversible isentropic expansion from inlet state to exhaust pressure (3600 / Δhs). ASR (Actual Steam Rate) is the measured steam flow divided by generator power output. Isentropic efficiency equals TSR / ASR multiplied by mechanical and electrical conversion efficiencies.
Why must exhaust steam moisture not exceed 12% (quality >= 88%)?
As steam expands into the two-phase dome, microscopic moisture droplets condense out of the vapor stream. At blade tip velocities exceeding 400 m/s (1300 ft/s), liquid water droplets impact the leading edges of low-pressure turbine rotating blades with bullet-like kinetic energy, causing severe erosion, pitting, and catastrophic blade notch failure.