Flow measurements in water turbines

Many of our hydropower plants were built decades ago and are now in need of modernisation. A key part of this work is measuring and verifying turbine efficiency – both before and after an upgrade. This requires reliable methods for determining the flow rate in the system.

This project focuses on further developing the pressure-time method, an established and cost-effective method for measuring the flow rate. The method is based on calculating the flow rate by integrating the measured differential pressure between two cross-sections in the water system during the time when the flow is slowed down.

However, the pressure-time method has certain limitations according to the IEC-60041 standard, this is especially true for low head where the waterways are short and the flow field does not have time to develop fully.

The aim of the project is to improve the accuracy of the pressure-time method and expand its scope of application so that it can also be used on turbines with low head. Numerical simulations and experimental measurements are combined to evaluate the flow rate to adapte to modern plants with alternative intake geometries that do not comply with current standard recommendations.