Leitschaufelwerk

Leitschaufelwerk is a component of turbomachinery consisting of an arrangement of adjustable guide vanes located upstream of the rotor to direct and shape the working fluid entering the runner. The set of Leitschaufeln defines the incidence angle and flow rate, enabling control of turbine output and efficiency across load ranges. It is typically part of the stator assembly and works in conjunction with gate mechanisms where applicable to regulate flow.

In hydroelectric turbines, particularly Francis and Kaplan, the Leitschaufelwerk forms a ring of adjustable vanes that can be opened or closed smoothly to control flow. In steam turbines, similar guide vane assemblies direct steam to the nozzle and rotor, contributing to starting and load regulation. Actuation is usually hydraulic, pneumatic, or electric, often with a feedback control loop to maintain the desired guide-vanes angle.

Design considerations include vane quality, sealing to minimize leakage, stiffness to withstand pressure loads, and corrosion resistance. Modern designs use servo-hydraulic or electro-hydraulic actuators, position and flow sensors, and protective controls to ensure rapid and accurate response. Maintenance focuses on wear of bearings, seals, and vane interfaces, as well as preventing cavitation and flow-induced vibrations.

Leitschaufelwerk contributes to efficiency, throttle response, and flow stability, reducing mechanical stress on the rest of the turbine and enabling efficient operation at part load or during transients. The term is used in German-speaking technical literature to describe this functional subsystem of the turbine's stator.