The use of modern production techniques such as 3D printing brings new requirements for shaping machine parts. In the case of the production of the runner blades of Kaplan micro-turbine using 3D printing technology from plastic, the emphasis is on the mechanical properties of the blade and hydraulic properties of the entire turbine. Achieving the required parameters is conditioned by finding a suitable shape of the runner. Therefore the design, virtual testing, optimization and evaluation process is automated. The paper describes the whole process where virtual testing of hydraulic parameters is performed by CFD simulations, and the methods of genetic algorithms are used for optimization. Selected final geometrical shapes of the blade are subjected to a more detailed analysis of hydraulic parameters in the wider operating range and also to the strength analysis.

Standard technical solutions are not cost-effective for many small hydropower sites. This study aims to demonstrate the workflow for the tailor-made variable-speed axial propeller turbine and provide proof of this concept. The turbine is designed to meet the site’s specific space limitations and operating range needs. The runner shape is adjusted to the variable-speed operation and defined hydraulic profile using a parametric geometry model and CFD-based optimization. The variable-speed propeller turbine shows excellent flow control while keeping the mechanical design simple. The tailor-made approach minimizes construction costs using existing structures and is highly suitable for mini-hydropower applications. The prototype—an atypical turbine designed for highly restricted space and installed on-site—serves as proof of the concept. The findings on the design of axial variable-speed turbines are presented.

Suitable and accurate flow measurement in pumped storage hydropower plants (PSP) is a challenging task due to the entirely different hydraulic behaviour of the penstock. This study presents a novel approach to choosing a suitable flow measurement method and position. The focus is on the flow measurement in a specific short penstock of the largest peak-load hydropower plant, Orlík, after its transformation to a PSP. Our approach is based on three main pillars: numerical modelling of fluid flow (ANSYS CFX), standards, and scientific literature. First, the steady-state numerical model output for the current state is compared to historical measurements of point velocities using current meters and measured hydraulic losses in the penstock. Subsequently, for the planned conversion to the reversible Francis turbine, including shape modifications of the flow paths, a steady numerical simulation of the flow in the penstock was performed in both turbine and pump modes. By analysing the resulting pressure and velocity fields and comparing them to standards and scientific literature, the values of the uncertainty in the flow measurement were calculated. The outcome is a straightforward evaluation and comparison of three main flow measurement methods: current meter, pressure–time, and ultrasonic transit time.

Despite significant achievements in energy development in Georgia, the issue of energy independence is still relevant. The electricity produced in the country cannot meet the growing demands. In addition, Georgia has energy potential, which is not yet fully harnessed, in particular, in terms of hydropower resources. Based on existing studies, only 20–22 % of the hydropower potential is currently harnessed in the country. For a country like Georgia, it is promising to develop hydro resources of small river to generate electricity and partially meet local needs.

Discharge measurement is the base of proper water management. The effective design and operation of hydraulic structures under both normal and extreme flow conditions depend on the quality of hydrological data. Understanding the water system requires consistent and long-term measurement. Despite that, the gauging station network is sparse, and its numbers are declining worldwide. This article aims to draw attention to the possibility of accurate flow measurement using existing hydraulic structures. Flow over a hydraulic structure profile is a physically well-defined phenomenon as the construction shape is fixed and simple compared to river profiles. The discharge can be derived from rating curves, turbine characteristics, and several easily measured variables. That allows continuous discharge measurement. The accuracy is compared with the gauging station on the river. Suitable technical solutions for ensuring and monitoring ecological flow are discussed.