turbinkanal

A turbinkanal, also known as a turbine channel or draft tube, is a crucial component in many types of hydraulic turbines, particularly reaction turbines like Francis and Kaplan turbines. Its primary function is to efficiently recover the kinetic energy of the water leaving the turbine runner and convert it into pressure energy before it is discharged into the tailrace. This process increases the overall efficiency of the hydroelectric power plant.

The design of a turbinkanal is typically a diverging passage, meaning its cross-sectional area gradually increases downstream. This expansion causes the water velocity to decrease, and according to Bernoulli's principle, this reduction in kinetic energy is converted into an increase in static pressure. This pressure recovery is essential for maximizing the work extracted from the water by the turbine. Without an effective turbinkanal, a significant portion of the water's energy would be lost as turbulence and high velocity in the discharge.

The shape and dimensions of a turbinkanal are carefully engineered based on the specific turbine design, flow rates, and head conditions. Common shapes include conical, elbow, or Boston-type draft tubes. The efficiency of a turbinkanal directly impacts the net head available to the turbine and, consequently, the power output of the hydroelectric generator. Proper design and maintenance of the turbinkanal are therefore vital for optimal performance and longevity of the hydroelectric installation.