17 - Steam valves and turbine inlet flow path design

Abstract

A steam turbine design that minimizes losses along the whole steam flow path is essential to achieve further performance increases and, particularly, turbine valves and turbine inlets play a significant role regarding the achievable overall performance level in addition to the turbine blade path. Steam turbine valves control the operation of the steam turbine by adapting the steam mass flow and the way the steam is guided to the different turbine inlet sections. Valves are also fundamental to instigate a turbine trip in case of any unforeseen events. With that, valves are an essential part to enable safe turbine operation while achieving high reliability. Likewise, the steam turbine inlet design plays an important role by combining aerodynamically ideal geometries with other design requirements like manufacturability or mechanical integrity. To reach maximum efficiency in the different expansion sections of the steam turbine, a homogenous flow especially into the first blade stages is important. The article gives an overview about the state of the art of steam valves and inlet designs as part of the steam flow path with examples from the Siemens Energy portfolio.