🔍 Key Concepts

• Location and purpose of a forward high-pressure turbine gland (prevents air leaking in or steam leaking out at the shaft penetration) • How pressure relationships change at minimum maneuvering speed (turbine internal pressure vs. atmospheric vs. sealing steam header) • Which side of the gland (spaces "E" and "F") is toward the turbine interior and which is toward the atmosphere/gland exhaust

💭 Think About

• First decide the direction of leakage at the forward end of the HP turbine when running at very low power: is the greater pressure inside the turbine or outside? • Based on that leakage direction, would sealing steam need to be admitted closer to the turbine side, the atmospheric side, or both, in order to form the correct pressure ‘barrier’? • Look at the labyrinth group arrangement: how would admitting steam at E versus F change which sets of teeth see sealing steam and which side would still be at vacuum/atmosphere?

✅ Before You Answer

• Confirm which cavity (E or F) is bounded by teeth facing the turbine internal pressure and which is bounded by teeth facing the atmosphere/gland exhauster • Verify how a HP forward gland behaves at full power versus minimum maneuvering (when does it become self-sealing, and when is auxiliary sealing steam required?) • Ensure your chosen option matches a realistic flow path: steam should move from higher pressure to lower pressure, forming a gradient from turbine → sealing steam space(s) → atmosphere/vacuum.