Steam Flow and Energy Conversion:
Large blades: Typically located in the high-pressure section of the steam turbine, where steam pressure and temperature are high, large blades can better capture and utilize the high-energy flow of steam, achieving efficient energy conversion.
Small blades: More commonly found in the low-pressure section of the steam turbine. As steam expands and performs work, its pressure and temperature gradually decrease. Small blades are better suited to operate under these low-energy flow conditions, reducing energy loss.
Adapting to Load Changes:
Steam turbines need to adapt to changes in external loads by adjusting the steam flow rate. The combination of large and small blades allows the steam turbine to maintain high operating efficiency under different loads. Under high loads, large blades can handle more steam flow; while under low loads, small blades can reduce the steam flow rate, maintaining stable turbine operation.
Reducing Energy Loss:
The size and shape design of the blades also considers reducing energy loss. Large blades can better guide steam flow and reduce flow resistance; while small blades can reduce steam leakage between blades, further improving turbine efficiency.
Intra-stage efficiency and overall performance:
Steam turbines typically consist of multiple stages, each with blades of varying sizes to accommodate the flow characteristics of steam at different pressures. This design helps improve the overall intra-stage efficiency and overall performance of the turbine.