Committee on Hydraulic Machinery and Systems

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30th IAHR Symposium on Hydraulic Machinery and Systems, July 5-10, 2020, Lausanne, Switzerland | Contact Prof. Francois Avellan |



The IAHR-Committee on Hydraulic Machinery and Systems deals with the advancement of technology associated with the understanding of steady and unsteady flow characteristics in hydraulic machinery and conduit systems connected to the machinery. The technology elements include the fluid behaviour within machine components, hydro-elastic behaviour of machine components, cavitation, and two phase flow in turbines and pumps, hydraulic machine and plant control systems, the use of hydraulic machines to improve water quality, and even considerations to improve fish survival in their passage through hydro plants. Included in two phase pumping are gas oil pumps and sand laden water. Because model tests and laboratory tests carried out in laboratories must be scaled down from the prototypes, studies of size and pressure scale effects are also a central research field. The research work in the Committee forms the basic study for the IEC standards code dealing with hydraulic machinery for hydroelectric power plants.

The main emphases of the IAHR Committee on Hydraulic Machinery and Systems are to stimulate research and understanding of the technologies associated with hydraulic machinery and to promote interaction between the machine designers, machine users, the academic community, and the community at large. Hydraulic machinery is both cost effective and environmentally responsible. The increasing atmospheric content of carbon dioxide related to pollution from thermal power plants, is one of the most significant threats to our global ecology. The problem is exacerbated by the need for increased energy production in third world countries. This results in rising global temperatures and dramatic changes in climate which may also result in flooding in parts of our globe. Energy conservation together with replacement of coal and oil-fired power plants are, therefore, needed. The development and installation of more efficient hydroelectric power plants which work hand in hand with water storage and flood protection is part of this strategy. Waterpower is the most significant "renewable resource". The goals of this IAHR Committee are to improve the value of hydraulic machinery to the end user and to society and to improve society's understanding and appreciation of that value.

To meet its objectives, the Committee focuses on the best possible exchange of technical knowledge through collegial contacts by arranging Committee Symposia every second year, between the IAHR Congresses. The Symposia are designed to attract scientists and engineers from industry, universities, consultants and users of hydraulic machinery. In addition, specialised symposia are organised focusing on the subjects of its 3 working groups:

  • WG1 - "Cavitation and Dynamic Problems in Hydraulic Machinery and Systems";

  • WG2 - "Latin America Working Group";

  • WG3 - "Asian Working Group"

The Committee on Hydraulic Machinery and Systems will stimulate the following activities through its symposia and working groups:

  1. The production of "environmentally friendly" turbines with higher efficiencies, wider operating ranges, smoother operating characteristics, and increased life-spans for new hydropower installations.

  2. The upgrading, uprating, and life extension of existing hydropower facilities.

  3. The production of inexpensive small hydro.

  4. The production of large pumping systems for transport of water for drinking and irrigation, for cooling in thermal power plants and for pumped-storage applications. 

  5. The production of improved digital systems for cost effective and environmentally effective plant operation, maintenance, and energy recovery.

Research Agenda

The continuous development seen in the standard topics like performance, cavitation, scale-up and unsteady phenomena should progress to a more advanced level, especially through improved computational methods and measuring techniques. Because hydropower is often exposed to public scrutiny it is also necessary to reduce any adverse effects from hydraulic energy generation and also to explain the benefits to experts in other fields and to the general public. Therefore, research and development in the future shall also consider biological aspects and generally take into account the interaction between hydraulic machines, their surrounding structures, and the environment. Key elements of the research agenda are:

  • Flow analysis within machines: The viscous 3-D numerical simulation of steady-state flows in turbines and pumps and the resultant refined knowledge of internal flow physics have led to a significant improvement in the performance characteristics of hydraulic machines. Further improvements in the operating qualities and performance of hydraulic machines can be made using advances in computational modelling. Faster computers, improved computational methods, advances in turbulence modelling, and the inclusion of unsteady multi-phase flow physics in the "Numerical Laboratory," combined and correlated with laser doppler and dynamic pressure measurements of rotating and stationary parts in turbines in the "physical Model Laboratory" will provide the basis for these improvements. Analyses accounting for unsteady 3-D viscous flows including the interaction between stationary and rotating components will be a central research theme in the future. The activities of WG 4 will use advanced flow analysis technologies to advance the state of the art in understanding scale effects.

  • Machinery and systems under steady oscillatory flow: The increased size and head of machines with higher rotational speed can lead to problems of a dynamic character. Dynamic analyses in frequency and time domain for control and behaviour of machines as well as hydro-elastic analyses of pipes and turbine structural components are main activities currently being studied. The most important parts of these analyses may be the study of unsteady behaviour of diffuser flow in turbines and pumps and high frequency interference in the rotating and stationary cascades. The activities of WG 1 stimulate research and an interchange of ideas on these subjects.

  • Water column separation and transient flow: The work in this field will continue, including further research on two-phase flow operation of pumps and turbines and taking into account the dynamic behaviour of conduit systems. 

  • Scale effect: The efficiency of pumps and turbines is normally measured on scale models, and is assumed to be valid for the prototype, after adjustment for scale by the effect formula. In this field, the need for research is great because of the need for an improved scale effect formula in the IEC TC4 code dealing with standards for efficiency measurement of water turbines. Basic research work is also underway for specific scaling relationships for the various losses in a turbine. The activities of WG 3 and WG 4 stimulate research and an interchange of ideas on this subject.

  • Cavitation and erosion and corrosion: The influence of water quality and sediment on cavitation, erosion, and corrosion and their effects on machine performance and materials remain the subject of great interest to designers and users of hydro machinery. This Committee includes research related to the above in its activities. The activities of WG 2 stimulate research and an interchange of ideas on these subjects.

  • Other activities: Future activities will include research on pumps dealing with two-phase flow and non-linear problems solved by new techniques such as chaos theory. Draft tube flow appears to be one of the subjects suitable to be studied by such methods. As a consequence of the wishes of hydro plant owners for improved reliability and reduced downtime, considerations for the future will also include the development of new materials and manufacturing methods for hydraulic machines, as well as the analytic tools for design and evaluation of machine components. Research to improve the environmental friendliness of hydraulic machines will become a significant theme, including methodologies for increasing fish passage survival and for reducing water borne pollution. Methodologies for sensing and diagnosing impending plant problems and for making recommendations for mitigation are also subjects of growing interest.

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