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Unutar ovoga rada biti će dan pregled dimenzioniranja Peltonove turbine. Kako se pri radu turbine javljaju vrlo složeni uvjeti tečenja i fizikalni procesi, optimizacija i samo dimenzioniranje ovakvog sustava je izazov. Primjerice, u radu turbine javljaju se četiri režima tečenja: (i) stacionarno tečenje u uzvodnim i dovodnim cijevima, (ii) slobodni pad mlaza vode nakon izlaska s mlaznice, (iii) tečenje sa slobodnom vodnom površinom na lopaticama Peltonove turbine te (iv) raspršeno dvofazno tečenje na kućištu Peltonove turbine. S obzirom da postoji cijeli niz različitih formula i preporuka za dimenzioniranje, cilj ovoga rada bio je objediniti i dati pregled istih na jednom mjestu. Istraživanje za potrebe ovoga rada proizašlo je iz prethodnog istraživanja za potrebe izrade diplomskoga rada., This paper presents an overview of Pelton turbine design. Since very complex flow conditions and physical processes occur during the operation of the turbine, the optimization and design of such a system is, consequently, a challenge. There are several different formulas and recommendations for design and optimization. Therefore, the aim of this paper was to consolidate them and give an overview in one place. The research for the purposes of this paper arose from the previous research for a master thesis.

Pelton wheel works on Newton's law which converts the kinetic energy of fluid into mechanical energy. Bearing, nozzle, servomotor and buckets are the main components of the Pelton wheel that are prone to defects. Corrosion by reactive materials, degradation by strong slurry particles, the involvement of some metallurgical defects, cavitation, and poor bearing lubrication are some of the causes which induce defects in the Pelton wheel. These failures result in significant turbine disruption, costly disassembly, and, in some cases, full Pelton wheel shutdown. Hence, it becomes a necessity to monitor the Pelton wheel through some suitable methods. A novel artificial intelligence-based method has been investigated to describe the health condition of a Pelton wheel. Traditionally, extracted features from stationary wavelet transform (SWT) decomposed signal to increase the complexity and affect the classification accuracy. This issue is resolved by developing a new fault diagnosis scheme using improved Shannon entropy based on expectation maximization principal component analysis (EM-PCA) and extreme learning machine (ELM). In the proposed scheme, F-score is initially applied to select features and construct the feature matrix. At the same time, EM-PCA is used to reduce the dimension of the constructed feature matrix, which reduces the correlation between data and eliminate the redundancy to retain the essential features for the ELM classification model. The effectiveness of the proposed scheme is compared with other reduction techniques used for the purpose. A comparison has also been made with other classification methods. The results show that EM-PCA with improved Shannon entropy can effectively eliminate correlation and redundancy of data. Further, the use of the ELM can take on better adaptability, faster computation speed and higher classification rate. The proposed method is fast as it takes 0.0020 s of computation time for both training and testing with 89.14% and 96.33% training and testing accuracies, respectively.

In a bid to optimize the performance of a Pelton Wheel Turbine developed the performance evaluation of the turbine at various conditions was carried out using a portion of the overflow from the University of Ilorin (UNILORIN) dam. The collected overflow has a net head of 4 m, flow rate of 0.017m3/sec. and theoretical hydropower energy of 668W. The turbine was tested and the optimized value of operating conditions namely; angle of inclination (15o above tangent, tangential and 15o below tangent), height to impact point (200 mm, 250 mm and 300 mm) and length to impact point (50 mm, 100 mm and 150 mm) were pre-set at their various levels. The measured outputs were Turbine Speed, Turbine Torque, Alternator Speed as well as the output voltage. The optimum values of the process output or measured parameters were determined statistically using a 33X2 factorial experiment in three replicates. The optimum Turbine speed (538.38 rpm) in off load condition was achieved at 250 mm height to impact point, 150 mm length to impact point and angle at tangential inclination. Similar combination also yielded an optimum turbine torque of 46.16 kNm. The optimum Turbine speed (392.02 rpm) in on-load condition was achieved at 250 mm height to impact point, 150 mm length to impact point and angle at tangential inclination. Similar combination also yielded an optimum Turbine Torque of 36.46kNm, optimum Alternator speed of 1768.56 rpm and an optimum output voltage of 7.87V. The results therefore show that the turbine must be set at 250 mm height to impact point, 150 mm length to impact point and the water jet at a tangential flow for it to perform optimally.

The performance of two micro hydro power turbines (Pelton Wheel and Cross Flow Turbines) were evaluated at the University of Ilorin (UNILORIN) dam. The Dam has a net head of 4 m, flow rate of 0.017m3 and theoretical hydropower energy of 668W. The two turbines were tested and the optimized value of operating conditions namely; angle of inclination (15o above tangent, tangential and 15o below tangent), height to impact point (200mm, 250mm and 300mm) and length to impact point (50mm, 100mm and 150mm) were pre-set at their various levels for both Turbines. The optimum values of the process output or measured parameters were determined statistically using a 33X2 factorial experiment in three replicates. An optimum Turbine speed (538.38rpm) in off load condition was achieved at 250mm height to impact point, 150mm length to impact point and angle at tangential inclination. Similar combination also yielded an optimum turbine torque of 46.16kNm for Pelton Wheel Turbine. For the Crossflow Turbine, an optimum turbine speed of 330.09rpm was achieved by pre-setting 250mm height to impact point, 100mm length to impact point and 15º below tangent. Same combination also yielded an optimum turbine torque of 39.07kNm. The optimum Turbine speed (392.02rpm) in on-load condition was achieved at 250mm height to impact point, 150mm length to impact point and angle at tangential inclination. Similar combination also yielded an optimum Turbine Torque of 36.46kNm, optimum Alternator speed of 1768.56 rpm and an optimum output voltage of 7.87 V for Pelton Wheel Turbine while for Cross Flow Turbine, an optimum Turbine Speed of 197.66 rpm was achieved by pre-setting 250mm height to impact point, 100mm length to impact point and 15º below tangent. Same combination also yielded an optimum Turbine Torque of 25.02kNm, optimum Alternator speed of 879.24rpm and an optimum output voltage of 4.05V. Hence, from the results obtained, it was observed that the most efficient turbine at these pre-set conditions was the Pelton Wheel Turbine. This shows that if adequately optimized, the Pelton wheel can perform effectively at low heads.

A Pelton wheel turbine is a type of impulse turbine that uses the hydro-mechanical energy of water at an elevated head into mechanical work which is then converted into electrical energy using an electric generator. The objective of this study is to design a Pico hydropower plant for supplementary power storage using the velocity of water harvested from rooftops during rainfall. Complete design calculations of the turbine have been performed as well as analysis of the model Pico energy device. Three types of materials considered most appropriate for the production of the model micro Pelton wheel and buckets are Steel, A390 cast aluminium alloy and Plastic due to availability and cost. The investigation was carried out using Autodesk Inventor to help select the most suitable based on the high cycle fatigue due to continuous force and displacements from the water jet. The materials performances were measured by von Mises stress, strain and displacement; and the result shows that an optimum performance of the wheel and Bucket without an undesirable level of failure in service was achieved using the Aluminum alloy.

Hydro turbomachines are used since long as a water wheel, even before knowledge of fluid mechanics. A newly developed concept at runner, i.e., hooped is considered here for investigation purposes. This paper mainly focuses on the performance comparison between traditional and hooped type Pelton wheel turbine runner. The performance characteristic of any hydraulic machine describes the behavior of the machine under operating conditions. The downcomer jet impingement to the rotor buckets provides more velocity and thereby impulse to a runner. Efficient performance behavior of any turbomachine under consideration can be easily estimated from performance curves for that machine under specified conditions. In case of impulse type machines, it relies on the quality of jet and other aspects of jet-vane interaction too. In the present investigation, the performance of two types of runner has experimented on the same setup and flow conditions. The main objective of this paper is to compare the performance of a regular runner with a novel hooped runner. It has been found that hooped runner exhibits the same characteristics with some loss of efficiency due to overweight and loss of energy at buckets due to restricted passage created by a hoop (flanges) but on the contrary, the reliability and safety of buckets can be ensured. In addition, less deflection of the bucket can also be ensured under heavy jet force.

A deep learning-based defect identification scheme for the Pelton wheel has been developed. Initially, the raw vibration signal is passed through a time-varying filter based empirical mode decomposition (TVF-EMD). Filter parameters of TVF-EMD are optimized by a newly developed optimization algorithm i.e., amended grey wolf optimization (AGWO) with Kernel estimate for mutual information (KEMI) as its fitness function. The prominent IMF obtained is used to construct scalogram and prepare dataset. The training dataset trains the convolutional neural network (CNN) model whose accuracy was evaluated by the test dataset and founds to be 100%. The proposed AGWO algorithm was evaluated on twenty-three classical benchmark functions and the Wilcoxon test. Results obtained at benchmark functions and the Wilcoxon test validate the efficiency and superiority of the proposed method as compared to other techniques. A CNN classifier is compared with other learning models which suggested that CNN outperforms all learning models.

This paper describes the design and analyzes the Pelton wheel for generating power of 400 Watt. A Pelton wheel is considered as an impulse turbine, a turbine that converts pressure head into velocity head. This thesis is to calculate the input power, output power, buckets and speed ratio, length of belt and efficiency of the turbine. The turbine with a jet diameter of 0.0254 m has been designed for the operational conditions of the Pelton wheel installed at the Mone Ta Wa Cave, Ayetharyar. The diameter of the runner is 0.254 m and the width of a bucket is 0.1143 m. The turbine has undergone efficiency testing and visual inspection during operation at a gross head of 20 m. The hydraulic efficiency is 96.35 and the output power is 400 Watt. Ma Myat Win Khaing | Ma Yi Yi Khin | Mg Than Zaw Oo "Design and Analysis of Pelton Wheel" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26477.pdf

This paper presents a study on the comparative analysis of the penstock used in the micro-hydropower plants with the aim of inventing a new design of penstock with the efficiency benefits in the future. The Pelton wheel is designed for 0.000143 m3/s flow rate with a diameter of penstock 0.75 in., and detailed study is done on the benefits of the new penstock which is helical in shape, so the helical penstock can also be considered as a replacement of the old conventional penstock which is straight and its design strategies are discussed. It was found that the helical penstock was approximately 22–23% more efficient in the voltage generation with the additional benefits such as saving in the material cost, less land acquisition, and less wear and tear of the penstock line due to cavitation. This is thus more economical, more viable as it produces more with the same input of water, and thus helps in generating more power.

Fluctuations in the head, discharge, and contaminants in the flow can damage parts of the Pelton wheel. An artificial intelligence technique has been investigated for the automatic detection of bucket faults in the Pelton wheel. Features sensitive to defect conditions are extracted from the raw vibration signal and its variational mode decomposition (VMD). The issue of slow convergence speed of the genetic algorithm during optimization is duly addressed by implementing a Levy flight mutated genetic algorithm (LFMGA) while finding the optimal parameters (regularization parameter and kernel function) of a support vector machine (SVM). The efficacy of the proposed LFMGA is tested against different optimization benchmark functions. The results indicate that the proposed algorithm is stable on the basis of the small standard deviation. Using optimized SVM parameters, the SVM model is trained to prepare a classification model with 10-fold cross-validation. After training, the SVM model is tested for fitness evaluation. The overall recognition rate of the SVM model for identification of defects is found to be 98.84% with training time 27.06 s per iteration. A healthy condition is also compared with splitter wear, added mass defect, and missing bucket conditions separately using the VMD–SVM model and shows a recognition rate of 99.17%, 98.33%, and 98.12%, respectively.

Hydraulic Turbines are being used since the ancient times to harness the energy stored in flowing streams, rivers and lakes. The oldest and the simplest form of a hydraulic turbine was the waterwheel used for grinding grains. The basic idea of a Pelton Wheel Turbine is derived from this ancient waterwheel. Pelton wheel is the only hydraulic turbine of the impulse type in common use. It is named after the American engineer Laster A. Pelton, who contributed much to its development around the year 1880. Therefore, this machine is known as Pelton Turbine or Pelton Wheel. Pelton Wheels are the preferred turbine for hydro-power when the available water source has relatively high hydraulic head at low flow rates. In the present study, a complete analysis of the Pelton Wheel Test Rig with brake drum loading made available on college campus is carried out. The major input and output parameters along with their working ranges are identified. Stochastic analysis using Monte Carlo’s simulation is carried out by randomly generating a design matrix and thus calculating the responses using predetermined equations. Response Surface Methodology is adapted to identify the optimal set of inputs and also generate inputoutput relations. Furthermore, a design matrix is generated by taking practical readings on the Test Rig keeping speed constant and the respective outputs are calculated. Similar to the stochastic study, Response Surface Methodology is adapted by inputting the design matrix in a design expert software. Input-output relations are generated and also the optimal set of input parameters are determined using this software.

In this paper, a Pelton Turbine was being used to drive a pump to pump water. It was required to be replace the Mild Steel buckets with Aluminum alloy. The change in material will lead to changes in the values of Displacements, Stress, Strain, Max. Frequencies leading to resonance which will cause the failure of the equipment. Hence Static analysis and Modal analysis is to be done. Also, the proposed material is also to be subjected with a change in velocity of water striking the buckets. Hence, a CFD analysis is also done. The CFD analysis gives the changes in Pressures, Temperature and the Mass flow rates. From these analyses the Aluminum alloy is observed to be the suitable material for the requirement.

Pelton turbine (or Pelton wheel) is among the most efficient impulse turbines and has retained its existence in hydropower for well over a century. However unlike in the development of the reaction turbines, where Computational Fluid Dynamics (CFD) have been successfully applied for more than 20 years now, up until recently it was not feasible to perform CFD analysis of Pelton turbines due to the nature of the flow which is much more complex than in the reaction turbines. The recent developments in CFD models and tools together with the continuous increase in computational resource are bringing the CFD modelling up to a level suitable for industrial applications in development of Pelton turbines. Current published research in the field worldwide can be divided into two distinct branches of CFD models: the Eulerian specification of flow field, which tends to be more accurate, but also more computationally expensive, and the Lagrangian specification which is known to be less computationally demanding, however to date it cannot compete with Eulerian specification in terms of accuracy. This review paper is aiming at establishing the state of the art in numerical modelling of Pelton Turbines and would serve as guidance when choosing the optimum CFD modelling methodology and software available.

Small scale hydropower energy goes a long way to fire up community development. Until 1920-30s, Japanese hydropower techniques had been established on a global level in each local area. However, after the second World War, the main energy resource was changed. This has resulted in a local decline in micro-hydro technical expertise and fewer waterwheel makers throughout Japan. At the present, we are going to work to re-make small scale hydropower technologies and markets. In this paper, we discuss and propose improvements to the “Japanese” small scale hydropower technology and production techniques, especially Pelton type wheel. The Pelton wheel technology of Nepal was freely available in the public domain so we decided to design a system based on that. We decided to designed by 3D-CAD and to make our Pelton buckets using a 3D printer. We compared the power generation capacity of our waterwheel with one purchased from New Zealand to investigate its effectiveness and efficiency. In our results of the experiment, the power generation curves for each turbine are approximately equal. The power increases continuously with increases in the flow rate. The maximum power generated by each turbine is approximately the same. This shows that it is possible to design a Pelton bucket that has a power generation efficiency comparable to a purchased bucket. The next step, the Pelton turbine designed in this study was chosen to be included in the Itoshima micro-hydro power generation system. So we scaled up and redesigned the Pelton turbine. In addition, we conducted a survey involving waterwheel makers regarding connecting to cost reduction. Using a 3D printer has the following advantages: 1.) Design deficiencies and failed designs can be identified at an early stage. 2.) Different forms of waterwheel can be made at low cost and in a short amount of time, which can then be used to run water experiments.

Pico-hydropower is a viable technology that can be integrated into a decentralized, off-grid approach to rural electrification in regions that currently have only limited access to electricity. The Turgo turbine is classified as an impulse turbine, similar to the Pelton wheel, often used in pico-hydro systems. Both offer high efficiency for a broad range of site conditions, but the primary difference is that the Turgo can handle significantly higher water flow rates, allowing for efficient operation in lower head ranges and thus potentially expanding the geographic viability. Published data on Turgo operating performance are limited; despite the differences, discussion thereof in design manuals is generally lumped in with the discussion of Pelton wheels. In this study, a laboratory-scale test fixture was constructed to test the operating performance characteristics of impulse turbines. Tests were carried out to determine the effect on turbine efficiency of variations in speed ratio and jet misalignment on two Turgo turbines. The results were compared to similar tests in the same fixture on a Pelton turbine. Under the best conditions, the Turgo turbine efficiency was observed to be over 80% at a speed ratio of approximately 0.46, which is quite good for pico-hydro-scale turbines. Peak efficiencies for both the Pelton and the Turgo turbines occurred at lower than theoretical ideal speed ratios based on a momentum balance; the reduction in speed ratio at which peak efficiency occurs is likely caused by inefficiencies in the turbine. Tests of jet misalignment showed that moving the jet to the inside or outside edge of the turbine blades caused a drop in Turgo efficiency of 10–20% and reduced the optimal speed ratio by 0.03 (6.5%). Radial misalignment had a significant adverse impact on both Turgo and Pelton turbines, however, angular misalignment of the jet is more of a concern for the Turgo turbine. The results stress the importance of proper system design and installation, and increase the knowledge base regarding Turgo turbine performance that can lead to better practical implementation in pico-hydro systems.

Under normal operating conditions, the Pelton turbine is loaded by the electric generator which provides a mechanical counter-torque on the turbine shaft and in so doing ensures the dynamic balance of the rotating system. If this counter-torque falls out by load shedding of the generator, the rotation of the Pelton wheel under the full load of water jet begins to accelerate. The maximum speed that can be reached at the Pelton wheel is called the runaway speed, at which the jet almost completely bypasses the Pelton wheel, without transferring its energy to the rotating buckets. The runaway speed is about twice the nominal speed of the Pelton wheel. Regarding the mechanical safety and the construction costs primarily of the generator and occasionally of the gearbox, the runaway speed is an important factor that must be taken into account already in the design phase of a Pelton turbine.

In the design of Pelton turbines, it is extremely important to arrange the flow out of the bucket to freely leave the buckets and the Pelton wheel. The exit flow thus contains the kinetic energy which cannot be further exploited and thus will be lost. This type of flow loss is called (see Chap. 9). The associated exit flow conditions depend on the installation form, geometries, and the operation point of the turbine. They are, for instance, differently specified for horizontal and vertical Pelton turbines. At Pelton turbines with vertical axes, the water out of the upper bucket halves should not drop back onto the Pelton wheel. For this installation form of Pelton turbines, therefore, special exit conditions are required. Before this is discussed in detail, it should first be shown how the exit flow velocity and its distribution generally look like along the trailing edge of a bucket. This serves to derive the general exit flow condition.

For the hydraulic design of a Pelton turbine, the net head on the pressure side and the desired flow rate are two fundamental parameters. They determine the available hydraulic power supply and therefore the size of the turbine. The design of a Pelton turbine starts with the dimensioning of the Pelton wheel, the choice of the rotational speed, and the determination of the number of injectors. To this end the following indications arising from the practical operations of Pelton turbines aid in establishing the design procedure

Friction and windage losses in Pelton wheels arise because the air around the Pelton wheel is continuously entrained to circulate and the rotation of Pelton wheels is persistently resisted by air friction on the wheel surface. These effects are therefore referred to as , and in practical applications, these two types of losses depend on designs of the turbine casing, wheel size, and rotational speed of the wheel. They are strongly coupled so that they cannot be separated from each other, neither in calculations nor from measurements. In particular, air mixture as enriched by water sprays plays a special role because of its specific density.

Water in nature is a viscous fluid and adheres to solid surfaces when coming in contact with another material. In Pelton turbines, this viscous adhesion occurs in the form of frictional shear stresses between the moving water and the bucket surface. It has a direct consequence of slowing down the relative flow in the rotating bucket. The friction in the bucket flow additionally acts as both a positive driving and negative braking force on the rotation of Pelton wheel.

The hydraulic efficiency which is calculated according to Eq. (15.1) or (15.2) is a function of the peripheral speed coefficient k m. It is mathematically of symmetrical form about the nominal value k m,N at which the maximum efficiency is found. In reality, such a symmetrical function only applies for a limited variation of the independent peripheral speed coefficient around the nominal value. Under certain circumstances, the calculation can also be used and regarded as reliable for peripheral speed coefficients down to zero value when some inaccuracy is acceptable and a qualitative statement on the influence of the peripheral speed coefficient should be made. The validity of the calculations is, however, limited for values of k m not higher than \( {k}_{\mathrm{m}}=0.55 \) by the fact that beyond this value a part of the jet will bypass the Pelton wheel without making any energy exchange with the rotating buckets. Such occurrences will considerably distort the efficiency curve away from its symmetrical form according to Eq. (15.2). The peripheral speed coefficient at which any water particle in the jet bypasses the rotating buckets for the first time is referred to as the lower critical peripheral speed coefficient. Beyond this speed Eq. (15.2) is no longer applicable. The upper critical peripheral speed coefficient is reached when the bypass of water particles occurs for the first time in all jet layers simultaneously. Taking into account the partial bypass of the jet flow, the real hydraulic characteristics of a Pelton turbine in the upper range of the peripheral speed coefficient will be calculated in this chapter.

In fluid mechanics courses of engineering curricula, theoretical performance curves of hydraulic turbines are obtained by means of simple analytical expressions that tend to overestimate experimental data. As we show here in the analysis of a laboratory-scale Pelton wheel, a much deeper physical insight can be achieved by means of general-purpose commercial computational fluid dynamics (CFD) software programs, becoming a suitable tool for academic activities. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 684–690, 2013

The aim of this work was to design and build a control system to control the performance of the Pelton wheel and synchronous generator system at different upstream water flow and electrical load conditions. The turbine output power is determined by the upstream water flow and spear valve, whilst the generator output power is determined by the turbine output power and the electrical load. A spear valve is used to control the generator output power at different water and load conditions. An autotuning proportion integration (PI) arithmetic-based controller was built using a relay feedback tuning method. An on&ndash, off relay was used in the program in order to oscillate the system. The optimal PI gains can be estimated via the Ziegler&ndash, Nichols method. A fully open test was used to test the tuned PI gains. The performance of the original gains and the new tuned gains were discussed. A controller was used to maintain the frequency or voltage of the output power by automatic regulation of the turbine valve. The program could search for the maximum generation efficiency by entering the output current value of the generator into the program manually.

Thermo-economy is a useful and powerful tool that combines thermodynamics and economics. It can evaluate how irreversibility and costs of any process affect the exergoeconomic cost of the product. In this work, a number of comparisons for solar thermal-powered different recovery units for reverse osmosis desalination system are performed using thermo-economic analysis. Three different configurations are used for this comparison (Basic, Pelton Wheel Turbine, and the Pressure Exchanger) with Sharm El-Shiekh RO desalination plant for a total productivity about 145.8 m 3 /h (40.5 kg/s). As a result of this analysis, the unit product cost of Pelton Wheel Turbine (PWT) and Pressure Exchanger (PEX) configurations are 24% and 24.2% respectively less than that of the basic configuration. Thermo-economic analysis shows that the minimum investment and operating & maintenance costs are obtained by PEX configuration. Also, it achieves minimum exergy destruction against the two other configurations (Pelton Wheel and Basic systems). Therefore, the final conclusion of this work is that the PEX configuration is more economical than either stand alone or PWT configurations.

Response Surface Methodology (RSM) is used in this study as an experimental design to obtain optimum conditions for each parameter. This study uses pelton turbines on a laboratory scale. The purpose of this study is to determine the optimum number of buckets and flow rates against turbine performance. The performance measured in this study is turbine efficiency. RSM is used to obtain mathematical equations from the performance of the turbine at optimum conditions. The optimum results obtained from RSM is to improve the performance of Pelton turbines that are 15,7714 (16 pieces) and flow rate of 0.1583 ℓ / s (0.16 ℓ / s) resulting in turbine efficiency of 29.16%.

The inlet flow of the jet entering the rotating buckets of a Pelton wheel turbine is considered with respect to jet flow impact and the non-disturbing flow condition. In the first step the volume rate of flow in the rotating frame of reference is shown to be independent of the bucket rotational position. Next, kinematical distinctions are made between the inlet flow at the bucket cut-out and inlet flow at the bucket splitter. Then, based on calculations of the impact forces and the corresponding impact work, the percentage of total jet impact energy is estimated. For purposes of configuring the proper inlet flow, the non-disturbing flow condition is specified and the corresponding criterion for geometry layout of the bucket is shown to be a function of the Pelton wheel turbine specific speed.

A laboratory-scale Pelton turbine for hydroelectric generation has been constructed and used in the educational curriculum of The Renewable Energy Programme at the University of Jyvaskyla. The construction of the Pelton turbine, the experimental apparatus and the measurement procedure are described. The apparatus is simple to make and uses inexpensive components, most of which can be found in standard science laboratories. From the experimental results, the turbine was found to have a maximum mechanical efficiency of 0.47 ± 0.02 for a water flow rate of 0.17 l / s . The Pelton turbine and apparatus demonstrate the principles of hydropower and are well suited for education in renewable energy.

Theoretical analysis has been performed to investigate the flow interaction between the jet and the rotating buckets as well as the relative flow in the buckets of Pelton turbines. The detailed calculation of cut-off processes of the jet by the rotating buckets provides the foundation both in evaluating existing layouts of Pelton turbines and in designing new ones. For achieving regular impact of the jet onto the buckets with minimum force fluctuations, the coincidence condition has been introduced, with which the optimum number of buckets for the Pelton wheel can also be determined. The effects of both centrifugal and Coriolis forces in the rotating bucket have been outlined in detail. In using the energy law to describe the relative flow of water in the rotating bucket, the so-called invariance equation has been derived and extended to apply to all parallel jet layers. This extension greatly simplifies the calculation of relative flow and hydraulic efficiency. Detailed calculation processes have been presented to quantitatively estimate the hydraulic efficiencies and their dependence on both the operating conditions and the bucket exit shapes.

The research work disclosed in this publication is partly funded by the Malta Government Scholarship Scheme., The viability of offshore wind turbines is presently affected by a number of technical issues pertaining to the gearbox and power electronic components. Current work is considering the possibility of replacing the generator, gearbox and electrical transmission with a hydraulic system. Efficiency of the hydraulic transmission is around 90% for the selected geometries, which is comparable to the 94% expected for conventional wind turbines. A rotor-driven pump pressurises seawater that is transmitted across a large pipeline to a centralised generator platform. Hydroelectric energy conversion takes place in Pelton turbine. However, unlike conventional hydro-energy plants, the head available at the nozzle entry is highly unsteady. Adequate active control at the nozzle is therefore crucial in maintaining a fixed line pressure and an optimum Pelton turbine operation at synchronous speed. This paper presents a novel control scheme that is based on the combination of proportional feedback control and feed forward compensation on a variable area nozzle. Transient domain simulation results are presented for a Pelton wheel supplied by sea water from an offshore wind turbine-driven pump across a 10 km pipeline., peer-reviewed

The momentum analysis of Sharpe [3] is considered further. It is shown that the maximum wind energy conversion efficiency limit, or the Betz limit of 59.3%, deduced from conventional actuator disc theory is the limiting stationary maximum value as wind turbine rotor speed approaches infinity and rotor outlet swirl approaches zero. Theoretically, solution of the governing equations indicates 100% conversion efficiency could be possible with suitable wind turbine design and without wake limitations for all tip-speed ratios. Analogous to the thermodynamics laws for heat engines and similar to a Pelton wheel with hydro power, the wind turbine efficiency is not limited by the laws of fluid mechanics but by physical constraints only. Low tip-speed ratio would have greater prospects in achieving higher conversion efficiency in practice. Though the set of equations derived in the present technical note has assumed uniform bound circulation along the blade span, the same approach can be used for determination of optimum conditions for other blade designs or using other assumptions.

Dhekelia Desalination Plant in Cyprus has been in operation for 7 years. It includes eight 5,000 m3/d seawaterreverse osmosis trains operating with Mediterranean seawater with a TDS content of 41,800 ppm, with water temperature ranging from 17°C to 32°C. The energy recovery system originally installed at the plant is the Francis turbine, which, at the time, was considered one of the most efficient and economical devices on the market. Since then, however, market forces to reduce operational costs, by cutting down energy consumption, led to the advent of new energy recovery systems. Today several systems are in operation which reduce the RO energy consumption. Apart from the versions of the Francis turbine and Pelton wheel they include the hydraulic turbocharger, work exchanger and pressure exchanger, all harnessing the pressure energy of the brine. In our effort to be competitive for the years to come we decided to convert our existing energy recovery system from Francis turbines to the pressure exchanger. This paper outlines how it was decided to go ahead with the pressure exchangers, and gives comparisons with other energy recovery methods, and describes our operating experience with the pressure exchangers.

This paper explains why Euler's equation and the airfoil theory, while analytically correct, sometimes produce disappointing results. It also emphasizes the merits of a recently developed approach and demonstrates its usefulness in solving problems encountered in practice. The subject matter relates, directly, only to rotodynamic pumps. However, with proper modifications, it can be easily expanded to other fluids machines.

The aim of this work is to assess and evaluate the energy and the membrane replacement cost for the seawater reverse osmosis (SWRO) plants. As a result of that, suggestions are given for energy cost reduction as well as optimum membrane cleaning procedure. A detailed comparative study was conducted forthe energy recovery systems for SWRO plants available in the market. The energy consumption was measured in relation with other operating factors such as recovery, feed concentration, productivity, temperature, etc. All the data were collected from existing SWRO plants in different locations in Greece under real operating conditions. Four different energy recovery systems, which are used in seawater SWRO plants, were examined. These are the classical Pelton wheel, the turbocharger, the pressure exchanger and the Pelton wheel introduced by Grundfos company. The above energy recovery systems have been applied in small and medium size RO plants commissioned by different companies. The deterioration of the membrane performance is an actual fact leading after 2–5 years to the replacement of the membranes with a considerable cost. The lifetime of the membranes is greatly effected by the feed water quality and the pretreatment process. It was found that the normal cleaning procedure, which is recommended by the SWRO plant builders and the membrane makers, gives poor results especially for small size SWRO plants, with severe bio-fouling problems. As it is presented in this work, in some cases, destruction of the membrane modules is the result of severe bio-fouling. In this work data of the performance of the membranes before and afterthe cleaning procedure are presented and a different cleaning procedure is recommended. The later is based on the combination of hydrodynamic and chemical cleaning of the membranes, resulting in great improvement of the membranes performance. This cleaning procedure will extend the lifetime of the membranes and reduce the membrane replacement expenditures.