Fuzzy decoupling predictive functional control for nonlinear hydro-turbine governing systems with mechanical time delay of the hydraulic servo system

This study presents fuzzy decoupling predictive functional control for nonlinear hydro-turbine governing systems with time delay and strong coupling. Here, the Takagi–Sugeno fuzzy approach and fuzzy neural network decoupling algorithm are implemented in the pretreatment of a four-dimensional time delay hydro-turbine governing system model, aiming to solve the nonlinearity and separate coupling variables of the hydro-turbine governing system effectively. Then, a new fuzzy decoupling predictive functional control strategy proposed by combining the simplified hydro-turbine governing system model and predictive function control as well as the robustness and stability of the designed controller are verified by theoretical derivation. Numerical experiment demonstrates effectiveness and superiority of the proposed approach in comparison with fuzzy control under different operation conditions.

Method of calculation of water-diverting structures of low-head hydroelectric power plant for power supply of small power consumers

In recent years and in many countries the economic development of distant regions is increasingly dependent on energy resources. This fact makes the world scientific community pay more attention to the renewable energy sources. Special attention is paid to the solar, wind and small hydropower for electrical consumers who have no possibility to connect to the central power supply lines. In the countries that have water resources the financial support is given to the development of small and micro hydropower stations. The present work presents the results of the research on the improved method of calculation of water-diverting structures of low-head hydroelectric power plant with an installed cross-jet hydro turbine that is actual for the power supply of small power consumers. The presented method can be used for the preliminary analysis of morphometric characteristics of water course as well as the basic parameters of a cross-jet hydro turbine.

RANCANG BANGUN PROTOTYPE HYDRO TURBINE JENIS CROSS-FLOW UNTUK PERKOTAAN

The problem of fossil fuel crisis, both petroleum and coal, and the phenomenon of climatechange due to global warming, trigger the use of renewable energy that can overcome these problems.Cross-flow water turbine is one of the machine that can be used to produce small scale electric energy insmall scope. This turbine can be used in urban areas to assist industrial activities and their usefulness indaily life. The use of the right materials and strong construction can produce a good shape so that thiswater turbine is not only make efficient energy but also efficient and ergonomic in its use. This study isconducted theoretically to a cross-flow turbine which assumed to operate at 10m water height with 1.4L/s, outer diameter 150mm and 75mm thickness. The turbine consist of 15 blades with angle of attack ofthe blades is 30o. The results show that the turbine generate 119 Watt

Pressure fluctuation on casing wall and investigation to tip leakage flow of contra-rotating small hydro-turbine

Renewable energy is strongly recommended to replace the traditional fossil fuels to solve the severe environmental pollution. However, small hydro-turbine performs lower efficiency, and it is also easy to be blocked and impacted. Therefore, the contra-rotating rotors are adopted to overcome the disadvantages of small hydro-turbine. The performance and internal flow condition of contra-rotating small hydro-turbine have been clarified. In this paper, a new transparent casing is manufactured, and pressure fluctuation experiments are conducted. The pressure fluctuation experiments are to clarify the pressure fluctuation during the running of contra-rotating small hydro-turbine. Then the hydraulic stability of contra-rotating small hydro-turbine can be further investigated. According to the experiment results, for the new model, most of the amplitudes of pressure fluctuation are decreased. The maximum decreasing percentage of peak-to-peak value is 74.22%, and it is appeared on the point of Pr3. On frequency domain, the dominant frequencies of pressure fluctuation are rotation frequency and blade passing frequency. The investigation to tip leakage flow of contra-rotating small hydro-turbine is conducted based on the pressure fluctuation experiment and numerical simulation. The tip leakage vortex is identified by Q-criterion. The pressure distributions in tip clearance area show that the tip leakage vortex of new model is suppressed, and this helps to reduce the amplitude of pressure fluctuation in tip clearance area.

The swirl number as a method for determining the optimal operating mode of the micro hydro turbine

The paper presents the data of a detailed study of the flow characteristics behind the runner of an air model of a propeller-type micro hydro turbine with varying operating modes from partial load to severe overload. Detailed measurements of the flow field distributions were carried out using an automated system for contactless optical diagnostics (LDA). The obtained data made it possible to link the identified features of the development of the flow structure when changing the operating mode of the installation with the nature of the evolution of the integral swirl number that determines the state of the swirled flow. Eventually, the work results can be used in the elaboration of recommendations for extending the regulation range of the operating regimes of hydraulic microturbines and providing their high efficiency.

Experimental investigation of Archimedes Screw Hydro Turbine rotation with and without deflector

The Archimedes screw water turbine (AST) is a device that works mechanically to produce electrical energy with an energy source that comes from the flow of water. Archimedes screw hydro turbines operate at low head and flow rates and can generate electricity at micro levels. This type of turbine is very suitable for use in small waters such as irrigation and rivers. The research was conducted by building a prototype of a small-scale Archimedes screw hydro turbine with and without deflector. The purpose of this research is to compare the rotation produced by the two turbines and whether the installation of a deflector can improve turbine performance. The turbine is constructed with a screw length of 1 m, outer diameter is 30 cm, the number of blades 15, and each has a pitch distance is 13 cm. Turbine angle variations are 30°, 35°, and 40°. The results showed that the best rotor rotation was produced by the screw without deflector at an angle of 30°. This shows that the addition of a deflector reduces the resulting screw rotation.