Research Project “HYDROVIO”

Development of reversible pumps / hydroturbines with optimized hydrodynamic and environmental design for high energy efficiency and safe fish passage (HYDROVIO)

Official project website:

The research project “HYDROVIO” is realized by the Laboratory of Hydrodynamic Turbomachines (LHT) of the NTUA and the manufacturing company DRAKOS – POLEMIS PUMPS, and concerns the study, optimal design and laboratory validation of reversible pumps-turbines of special hydrodynamic design to allow for safer fish passage to both directions, while maintaining a high degree of energy efficiency.

These machines can cover a multitude of applications, both in the field of hydroelectric projects and energy storage units with pumped storage, as well as in the fields of aquaculture, drying up of water areas and management of water reserves.




The "HYDROBIO" Project was implemented as part of the RESEARCH-CREATE-INNOVATE Action and was co-financed by the European Regional Development Fund (ERDF) of the European Union and by National Resources, through the Operational Program Competitiveness, Entrepreneurship and Innovation (project code:T1EDK-01334)

Εικόνα που περιέχει κείμενο, γραμματοσειρά, στιγμιότυπο οθόνης, Μπελ ηλεκτρίκ

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Main research objectives

1. Investigation of the international market and determination of the design and operation region (hydraulic head and discharge rate) of pumps and reversible machines ‘friendly’ to the fish fauna, which is of commercial interest.

2. Creation of an innovative methodology for the assessment and quantification through appropriate indicators of the degree of ‘fish friendliness’ of a hydraulic turbomachine (pump, hydroturbine or reversible machine).

3. Development and implementation of an integrated computational methodology for optimal, customized design of reversible hydrodynamic machines, with two competing objectives: Maximizing efficiency and minimizing impact on fish fauna.

4. Creation of an innovative system for reliable diagnosis of cavitation in hydrodynamic machines, with easy adaptation and portability.

5. Development and implementation of a telemetry system for the online monitoring of the operation of large installed pumps and reversible hydraulic turbomachines.

6. Publication and promotion in the international markets of the new products, and the capability of the Company for specialized research and development of innovation.

7. Strengthening through the cooperation with the LHT-NTUA of the research department of the Company in the area of ​​hydraulic turbomachines design with computational methods, and improvement of its infrastructure for testing and evaluation of new products.

8. Expansion and reinforcement of the research team of the LHT, and further enhance of its potential for development of new innovative tools and methods, at the forefront of the international scientific and technological research.


Project Methodology

The research project “HYDROVIO” includes 7 Work Packages, and its duration was four years. Its implementation is based on modern computer tools and software, on the advanced and well-equipped laboratory infrastructures of the participants and also on new innovative methodologies and techniques that are developed in the framework of the project.

The first key component of the proposed research includes the simulation and numerical solution of Reynolds-Averaged Navier-Stokes fluid mechanics equations (RANS) in the complex geometries of reversible mixed or axial flow hydraulic turbomachines. To this aim, commercial computational fluid dynamics software is used, in order to simulate at first the flow in the runner / impeller (blade-to-blade), and then in the entire geometry of the machines, including the inlet-outlet sections and the guide vanes.

The geometry of the runner/impeller and of the rest components of the machine is introduced in a parametric way, with techniques that are developed within the Project, so that a wide range of different geometries can be produced using a relatively small number of design variables. This parametric design allows for the investigation of the effect of the various design parameters on the operational behavior and performance of the reversible turbomachines, and then the numerical optimization of its design, using relevant software.

Two design objectives are set: Maximization of the energy efficiency of the reversible turbomachines and minimization of the possibility of injury or mortality of the fish fauna that passes through them. These two goals may be competitive, and hence, the multiparametric optimization procedure produces a set of optimal solutions, the so-called Pareto front, on which a manufacturer will be able to select a specific machine design, depending on the conditions and requirements of each application.

At this point there is a need to quantify the degree of 'fish-friendliness' of a hydraulic turbomachine, so that it can be set as an optimization target (cost function). For this purpose, a new innovative methodology is developed, according to which the motion of an object in the shape of a fish and with variable dimensions can be numerically simulated, as it passes through the machine. The hydrodynamic forces and pressures that are exerted on the object-fluid interface (normal and shear stresses) are being recorded during its trajectory, while at the same time they determine its motion in the flow field at all degrees of freedom, as well as its possible impingement on the inner solid surfaces of the machine.

Then, in order to certify the complete methodology of the optimal customized design of a pump / turbine, the Company D-P Pumps studied and manufactured on its premises two such models of reversible hydroturbines, suitably selected from the computationally obtained optimum design results. Then, the models are installed in the test rigs of D-P and LHT laboratories, and their characteristic operating curves are measured with modern equipment.

Especially for the mechanism of cavitation, an innovative detection methodology that was being studied in LHT is completed and applied, and it is combined with a telemetry technique, so that the whole device is portable and can be easily installed in a real pump or hydroturbine in operation.


Project Results:

The progress and implementation of the Project and all its Work Packages were made in accordance with the technical descriptions and objectives, as originally set and described in the Technical Appendix. All Work Packages completed successfully.

The collaboration of the Laboratory of Hydrodynamic Machines NTUA (LHT/NTUA) and the research department of the Company, DRAKOS-POLEMIS PUMPS was excellent, and the successful implementation of the Project enabled both NTUA and the Company to expand and strengthen their research groups, with further development of their capabilities to create new innovative tools and methods, at the cutting edge of international scientific and technological research.

Specifically, from the beginning of the Project to its completion, the following were carried out:

The international market was investigated and the area of design and operation (hydraulic head and nominal flow) of 'fish-friendly' pumps and reversible engines identified, for which there is commercial interest. Also, all the basic tasks & preparatory actions for the implementation of the Project were completed, regarding the selection of machines to be investigated, the literature review in order to identify the necessary design criteria for hydrodynamic machines with a low fish mortality index, and the investigation of the application range of pumps, hydro turbines and fish friendly reversible machines.

A new methodology was developed for the parametric design of the rotor/impeller and the other parts (inlet, outlet, casing, etc.) of two different types of reversible hydro-turbine pumps (axial and mixed flow), with the introduction of a number of variable parameters to describe the geometry of the various parts, so that modifications of the original design can be produced in an automated way and in the desired range. Next, the details of the final selection and generation of the computational domain and the numerical mesh, as well as the computational data, boundary conditions and numerical simulation procedure, were determined. Finally, the computational platform was configured, using appropriate computational fluid dynamics software, to solve the flow in these two types of machines, both for pumping and turbine producing operation.

Εικόνα που περιέχει στιγμιότυπο οθόνης, διάγραμμα, γραμμή, κείμενο

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Εικόνα που περιέχει μαύρο, στιγμιότυπο οθόνης, γραμμή, σχεδίαση

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Specific reversible hydrodynamic machines (pumps-hydroturbines) of different type and operating area were chosen for study: one axial flow machine, with low hydraulic head and two mixed flow, higher head machines (Francis and Deriaz). The main design parameters of these three machines were thoroughly investigated, with multiple numerical solutions of the flow, in order to draw conclusions on the effect of the various hydrodynamic design variables on their hydraulic performance and the potential effects on passing fish fauna, for both pump and hydroturbine operation. Appropriate correlations and indexes from the literature for the effect of the rate of change of static pressure, the magnitude of shear stresses and the probability of impingement on solid boundaries, along a representative number of flow lines, were used to assess the effects on fish fauna.

Εικόνα που περιέχει ζωγραφιά, ψάρι, σκίτσο/σχέδιο

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Εικόνα που περιέχει κείμενο, στιγμιότυπο οθόνης, διάγραμμα

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Then, after parametric investigation identified the most critical design parameters of the two machines and determined the desired range of their values, a numerical optimization of the design of the reversible axial flow machine and the Deriaz mixed flow machine was carried out, which showed better results against the Francis machine, regarding the effects on passing fish fauna. The optimization has two parallel objectives: maximizing the degree of energy efficiency of a complete pumping-production cycle and minimizing the impact on passing fish. These effects were defined based on the various relevant indicators and their combinations, and thus various optimization procedures were implemented for each machine. Applying the Design of Experiments method, multiple numerical solutions of the flow in the two machines for the pumping and production operations were carried out, in order to finally obtain sets of optimal solutions (Pareto fronts), on which the manufacturer can choose a specific machine, depending on the conditions and requirements of each specific application (e.g. operating program, species/size of fish, etc.).

 Εικόνα που περιέχει κύκλος, δημιουργικότητα

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In order to certify the integrated methodology of optimal customized design of the new machines, studies were carried out concerning the implementation of their scale models and their testing in the laboratory. The design was carried out in a two-dimensional and three-dimensional environment. The machines were studied in terms of the materials of the parts, their strength/stress, the sealing of the structures and their assembly. All the required construction engineering plans for the production process were completed, and the selection of materials and the determination of casting types were carried out, based on the choice of casting technique. International technical standards were followed for the engineering studies and the adoption of design methodology, such as tolerances of construction plans and assemblies. Finally, all individual stages of the production process were analyzed and the construction of the models of the two new machines was completed by the Company.

Εικόνα που περιέχει μπλε, αυλός, Μπελ ηλεκτρίκ, βάρκα

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Εικόνα που περιέχει Εξάρτημα αυτοκίνητου, χάλυβας, μηχανική, αυλός

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Εικόνα που περιέχει μπλε, εργαλείο, βάρκα, έδαφος

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Εικόνα που περιέχει έλικας, μέταλλο, καθισμένο, εσωτερικός χώρος

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Εικόνα που περιέχει μπλε, μηχανική, βάρκα, εσωτερικός χώρος

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Εικόνα που περιέχει Εξάρτημα αυτοκίνητου, τροχός, ελαστικό, εσωτερικός χώρος

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Εικόνα που περιέχει μπλε, μηχάνημα, χάλυβας, μηχανική

Περιγραφή που δημιουργήθηκε αυτόματα    Εικόνα που περιέχει έδαφος, μπλε

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The new machines were then delivered to carry out their laboratory evaluations. The laboratory test rigs of the Company and the NTUA Hydrodynamic Machines Laboratory were prepared with the necessary modifications, additions and configurations to the hydraulic circuits, in order to connect the new machines. Two different test circuits were set up in the LHT/NTUA, one for the axial flow model, which requires relatively large flow rates and small heads, and one for the mixed flow model, with smaller flow rates and pipe diameters. Also, the required measuring equipment was prepared and calibrated, with the control and calibration of the measuring instruments and their installation in the test rigs, as well as the software for taking and recording the measurements. The two new models of reversible machines were finally successfully installed in the laboratories by the staff of LHT and the Company.

Εικόνα που περιέχει ρουχισμός, παπούτσια, άτομο, εσωτερικός χώρος

Περιγραφή που δημιουργήθηκε αυτόματα   Εικόνα που περιέχει εσωτερικός χώρος, βιομηχανία, αυλός, εργοστάσιο

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Εικόνα που περιέχει αυλός, μηχάνημα, μηχανική, βιομηχανία

Περιγραφή που δημιουργήθηκε αυτόματα   Εικόνα που περιέχει μηχάνημα, αυλός, βιομηχανία, μηχανική

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An important goal also achieved was the creation of an innovative hardware-software system for the reliable detection/diagnosis of cavitation occurrence in hydrodynamic machines, with easy adaptation and portability. The Spectral Kurtosis method was applied, with the aim of constructing special filters, which can isolate the characteristics of the phenomenon from the total measured signal received by special sensors (accelerometers), which are placed in appropriate points on the machines' shell. This new methodology, which is an international innovation, was developed in laboratory pumps and successfully tested on the mixed flow model within the framework of the Project.

Εικόνα που περιέχει κείμενο, εσωτερικός χώρος, υπολογιστής, φορητός υπολογιστής

Περιγραφή που δημιουργήθηκε αυτόματαΕικόνα που περιέχει αυλός, μηχάνημα, κύλινδρος, μπλε

Περιγραφή που δημιουργήθηκε αυτόματαΕικόνα που περιέχει θήκη, αξεσουάρ, εργαλείο, βαλίτσα

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At the same time, with the use of modern technology based on IoT (Internet of Things), the Company developed and implemented a telemetry system to monitor the operation of machine models, but also potentially large installed pumps and reversible pumps-hydroturbines. The system includes custom sensors, combined with the Raspberry Pi microprocessor and PI tunnel web portal, and it is flexible and scalable, even for remote control of the machines. The system was connected to the internet and its capability of remote monitoring of the operation of the laboratory models was confirmed.

Another important objective of the Project was the development of a methodology for the assessment and quantification through appropriate indicators of the degree of 'friendliness' of a hydrodynamic machine (pump, hydro turbine or reversible), in terms of the fish fauna passing through the machine, which is applicable to any hydrodynamic reaction machine. The new, innovative methodology developed in the framework of the Project can simulate with satisfactory accuracy and low computational cost the 6 degrees of freedom motion of objects within complex flow fields. It was successfully applied to the monitoring and statistical analysis of fish trajectories through reversible pump-hydro turbines, such as those developed in this Project, confirming their improved environmental design. In addition to kinematics, it is possible to record data to extract indicators of fish injury, such as pressure, shear stresses and impacts on solid surfaces, allowing the definition of a proposed general index of 'friendliness' of hydrodynamic machines.

In order to certify the new methodology for customized optimal design of a pump/hydroturbine, the models of the two new machines were installed in the laboratory setups of the LHT/NTUA and the Company, and the specifications of testing procedures were determined. The machines were then operated as pumps and as hydroturbines, and series of measurements were taken in order to obtain the respective characteristic curves over a range of their operation. It was found that the performance of the models in both modes of operation is smooth, without dynamic phenomena, and in agreement with their theoretical and numerical design specifications.

Εικόνα που περιέχει κείμενο, ηλεκτρονικές συσκευές, εσωτερικός χώρος, οθόνη

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The sources of errors during the laboratory measurements were analyzed and the uncertainty of the measured quantities was calculated, and found to be adequately low. Finally, the repeatability of the measurements was checked and confirmed to be within the uncertainty limits of the tests.

As a final evaluation of the two new machines, the characteristic curves of the laboratory models were compared with the corresponding curves obtained from the numerical simulation, both for hydroturbine operation and for pump operation. The agreement was in all cases satisfactory, confiming the successful design of the machines. Finally, analyzing the laboratory and numerical results, and taking into account the observations and conclusions from all stages of the design and construction methodology of the two models, specific proposals for further improvements and modifications are formulated.

Εικόνα που περιέχει κείμενο, στιγμιότυπο οθόνης, γράφημα, διάγραμμα

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Εικόνα που περιέχει διάγραμμα, γράφημα, γραμμή, στιγμιότυπο οθόνης

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It is noted that the successful completion of the physical object of 'YDROVIO' Project was accompanied by the effective utilization of its funding, as well as the achievement of all its outflow and evaluation Indicators.

The benefits from the implementation of the Project for the two participants were multiple and important. The synergy throughout the duration of the Project was very successful, effectively utilizing the technical and research capabilities of the LHT/NTUA and the D-P Company, and consolidating our collaboration for further research and development of innovative products, competitive in the global market.



The research and technological results of the Project were published in the following international Scientific Journals and Conferences, presenting it to the international scientific community.

1.      I Kassanos, V Sanoudos-Dramaliotis, J Anagnostopoulos, Numerical modelling of fish passage and flow interaction in a hydroturbine, Intl. Conference HYDRO 2019, Concept to Closure: Practical Steps, Porto, Portugal, October 14-16, 2019.         


2.      G Mousmoulis1, C Yiakopoulos, I Kassanos, I Antoniadis, J Anagnostopoulos, Vibration and acoustic emission monitoring of a centrifugal pump under cavitating operating conditions, IAHR International Workshop on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems 9–11 October 2019, Stuttgart, German, .ΙOP Conference Series: Earth and Environmental Science, Volume 405, 012003, 2019..  DOI 10.1088/1755-1315/405/1/012003


3.      I Kassanos, V Alexopoulos, J. Anagnostopoulos, Numerical analysis of the behaviour of a Deriaz versus a Francis reversible turbine in terms of their energy efficiency and fish-friendly characteristics, Intl. Conference HYDRO 2020, Strategies for Future Progress,Online event, October 26-28, 2020.


4.      G. Mousmoulis, C. Yiakopoulos, G. Aggidis, I. Antoniadis, I. Anagnostopoulos, Application of Spectral Kurtosis on vibration signals for the detection of cavitation in centrifugal pumps, Applied Acoustics, 182, 108289, 2021.


5.      I Kassanos, V Alexopoulos, J Anagnostopoulos, Numerical design methodology for reversible Deriaz turbine with high energy performance and reduced fish impacts, 31st IAHR Symposium on Hydraulic Machinery and Systems, 6 June - 1 July 2022, Trondheim, Norway, IOP Conf. Series: Earth and Environmental Science, 1079, 012076, 2022.   doi:10.1088/1755-1315/1079/1/012076


6.      Ph Koukouvinis and J Anagnostopoulos, Simulating Fish Motion through a Diagonal Reversible Turbine, Energies, 16, 810, 2023. .


7.      Ph Koukouvinis and J Anagnostopoulos, State of the Art in Designing Fish-Friendly Turbines: Concepts and Performance Indicators, Energies, 16, 2661, 2023.


8.      Ph Koukouvinis and J Anagnostopoulos, A fast 6-DoF tracking method for submerged bodies: application to fish passage through a turbine, ICNAAM 2022 – 20th Intl Conf. on Numerical Analysis and Applied Mathematics 19-25 September 2022, Heraklion, Crete, Greece.  IOP (to be published).


9.      I Kassanos, V Alexopoulos J Anagnostopoulos,  Design verification of a reversible Deriaz turbine with increased efficiency and improved fish friendly characteristics, Applied Energy Journal (submitted).


An open Technical Workshop was also organized, live-streamed on social media, which is available online:

Finally, the Company, in collaboration with LHT/NTUA, created a specialized website exclusively for the Project, at the address:, providing an interactive space where the stakeholders can find more information and results of the Project.