Variable-speed Pelton turbine for an efficient exploitation of the reserved flow: an Italian case study (original) (raw)
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Performance of Pelton Turbine for Hydroelectric Generation in Varying Design Parameters
IOP Conference Series: Materials Science and Engineering
Water power is a renewable energy source which has great potential in replacing fossil energy for generating electricity. The aim of this research is to analyze the influence of vertical distance of water source (water head) and nozzle diameter on the electrical power generated by Pelton turbine. It used Pelton turbine type with 22 buckets (vanes) which employed a PMG 200 watts generator with 1 : 2 pulley transmission system. Four different values of nozzle diameter and three different values of water head were chosen as the design parameters of the turbine. The electrical power was measured in three replications for each combination of the design parameters. The research showed that water head and nozzle diameter significantly affect the power generated by the Pelton turbine. The higher the water head from the surface, the more power generated. It was found that the electric power linearly increases with the increasing of nozzle diameter. However, it reaches the peak in 9 mm nozzle diameter and is getting lower in a larger diameter. The highest electric power of 16.89 watt is observed by adjusting the water head on 4.6 m with 9 mm nozzle diameter. Those design parameters are able can produce a rotation speed at 320 rpm in the generator. By identifying the appropriate parameters, it is possible to have more power generated by the water turbine used for hydroelectric power generation plant.
A reference Pelton turbine design
2012
The designs of hydraulic turbines are usually close kept corporation secrets. Therefore, the possibility of innovation and cooperation between different academic institutions regarding a specific turbine geometry is difficult. A Ph.D.-project at the Waterpower Laboratory, NTNU, aim to design several model Pelton turbines where all measurements, simulations, the design strategy, design software in addition to the physical model will be available to the public. In the following paper a short description of the methods and the test rig that are to be utilized in the project are described. The design will be based on empirical data and NURBS will be used as the descriptive method for the turbine geometry. In addition CFX and SPH simulations will be included in the design process. Each turbine designed and produced in connection to this project will be based on the experience and knowledge gained from the previous designs. The first design will be based on the philosophy to keep a near constant relative velocity through the bucket.
International Journal of Rotating Machinery, 2017
This paper addresses the design, modeling, and performance analysis of a Pelton turbine using CFD for one of the selected micro hydro potential sites in Ethiopia to meet the requirements of the energy demands. The site has a net head of 47.5 m and flow rate of 0.14 m 3 /s. The design process starts with the design of initial dimensions for the runner based on different literatures and directed towards the modeling of bucket using CATIA V5. The performance of the runner has been analyzed in ANSYS CFX (CFD) under given loading conditions of the turbine. Consequently, the present study has also the ambition to reduce the size of the runner to have a cost effective runner design. The case study described in this paper provides an example of how the size of turbine can affect the efficiency of the turbine. These were discussed in detail which helps in understanding of the underlying fluid dynamic design problem as an aid for improving the efficiency and lowering the manufacturing cost for future study. The result showed that the model is highly dependent on the size and this was verified and discussed properly using flow visualization of the computed flow field and published result.
A reference pelton turbine - design and efficiency measurements
IOP Conference Series: Earth and Environmental Science, 2014
The Pelton turbine has been subject to a varying degree of research interest since the debut of the technology over a century ago. Despite its age there are gaps in the knowledge concerning the flow mechanisms effecting the flow through the turbine. A Pelton turbine has been designed at the Waterpower Laboratory at NTNU. This has been done in connection to a Ph.D. project focusing on the flow in Pelton turbine buckets. The design of the turbine has been conducted using in-house knowledge in addition to some comments from a turbine producer. To describe the geometry multiple Bézier curves were used and the design strategy aimed to give a smooth and continuous gradient along the main flow directions in the bucket. The turbine has been designed for the operational conditions of the Pelton test rig installed at the Waterpower Laboratory which is a horizontal single jet test rig with a jet diameter(ds) of 35 mm. The diameter(D) of the runner was set to 513 mm and the width(W) of a bucket 114 mm, leading to a D /W ratio of 4.5. Manufacturing of the turbine has been carried out in aluminium and the turbine has undergone efficiency testing and visual inspection during operation at a head of 70 m. The turbine did not performed as expected and the maximum efficiency was found to be 77.75%. The low efficiency is mainly caused by a large amount of water leaving the bucket through the lip and hence transferring close to zero of its energy to the shaft. The reason for the large lip loss is discussed and two possible causes are found; the jet is located too close to the lip, and the inner surface of the bucket does not lead the water away from the lip. The turbine geometry and all data from both measurements and simulations will be available upon request in an effort to increase the amount of available data concerning Pelton turbines. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Performance analysis of Pelton turbine under different operating conditions: An experimental study
Ain Shams Engineering Journal, 2022
In this article, an experimental work has been carried out to examine the effect of varying operating conditions on performance of Pelton turbine. The experiments have been performed for various nozzle jet diameters (d), volume flowrate (Q) and pressure head (H). The experimental results display that the rise in d leads to reduce the input power due to decrease in H. For a certain nozzle diameter, the results indicated that the maximum brake power increases with increasing in Q owing to increase the torque and consequently, the optimum operational condition can be achieved when using smaller d and higher Q. The best turbine performance has been found when using d = 9.5 mm and Q = 85 L/min owing to produce higher efficiency and cover large range of wheel speed. The maximum efficiency of nozzle diameters 9.5 mm, 10.5 mm, 11.5 mm and 12.5 mm have been found equal 35.5%, 33%, 29.2% and 21.6%, respectively. Hence, d has inversely effect on the turbine performance. The data clearly also indicate that d and Q have substantially influences on the power that generated by turbine. By recognizing the effects of related parameters, it is now possible to generate a higher electric power in hydroelectric power plants that operated by using Pelton turbine.
Inventions, 2022
The difficulty of delivering electrical power to rural areas motivated the researchers to explore more accessible power sources. Hydropower is considered a desirable option due to its sustainability and lower costs. Pelton turbines have been widely used in hydropower plants because of their low installation and maintenance costs. This study provides a computational fluid dynamics (CFD) model for Pelton turbine performance under various flow conditions. The model is based on the conservation of mass principle, Newton’s second law, and the first law of thermodynamics. It is used to predict the torque produced by a turbine at different rotational speeds. Previously published experimental results for the same turbine geometry and flow parameters were used to validate the model’s predictions. Validation revealed that the model can reproduce the experimental results. This provides the required robustness for its use as a tool for turbine design and modification.
Design of a Pelton Turbine for a Specific Site in Malawi
International Journal of Sustainable and Green Energy, 2020
Malawi's poor electrification rate can be improved through the maximum utilization of available renewable energy resources. Malawi has several rivers which can be utilized for electricity generation. However, most rivers such as Lichenya are not utilized to its full capacity. This paper presents the theoretical designing of a pelton turbine for Lichenya River in Malawi for maximum generation of electricity. Hydropower plants can either be impoundment, diversion or pumped storage type. The turbine used for any type of plant depends on the available head and river flow rate. The hydraulic turbines are classified into impulse turbines and reaction turbines. Pelton turbine is under impulse turbines and are usually associated with very high head and low discharges with low specific speeds. Additionally, Pelton turbine is simple to manufacture, are relatively cheap, and have good efficiency and reliability. The river flow data for Lichenya River were collected from the Ministry of Irrigation and Water Development in Malawi. The design flow of 3.2 m 3 /s for the river was determined form the data. The river is within the catchment area of 62.3 km 2 and gross head of 304 m. The calculation of dimensions were carried out with the aid of EES software and spreadsheet. The designed turbine can generate 8067 kW of power with a turbine hydraulic efficiency of 95.4%. The detailed dimensions of the bucket, runner, penstock, and nozzle are presented. Therefore, this study can be the best guideline for further energy developments on Lichenya River in Malawi.
Advances in Fluid Mechanics VI, 2006
Free-jet turbines working under backpressure conditions represent an economical alternative to conventional hydroelectric plant configurations. However, the air introduced into the tailwater generates an air/water mixture. Its reaction to a rising ambient pressure is at present being studied at the above Institute. This report deals with the effect an increase in ambient pressure has on the volume and consistency of the two-phase mixture and the rise velocity of air bubble swarms. In addition, a test setup is described which was used to study the physical reaction of the water/air mixture to a change in ambient pressure conditions. The results and their effects on the configuration of free-jet turbines working under backpressure are discussed.
Numerical prediction of efficiency and cavitation for a Pelton turbine
IOP conference series, 2019
The first part of the paper illustrates the setup and the methodologies adopted for the numerical analysis of the flow in a 6-jet Pelton turbine with vertical axis. At first, steady state simulations of flow in a distributor for three positions of needle stroke were performed. The results were used for the calculation of flow energy losses, analysis of jet quality and setting inlet boundary conditions for runner analysis. Runner analysis was done only for the maximal opening. The purpose of runner analysis for the model size was efficiency prediction. Numerical results were validated with the results from the test rig. Simulations for the prototype were done in order to check whether water sheets evacuating from the buckets impact the previous bucket and whether there is any interaction between the evacuating water sheets and the incoming jets. Analysis was done also for one nozzle operation. In the second part of the paper cavitation prediction for the prototype of a 2-jet Pelton turbine is presented. The problem, because of computational cost, was reduced to five runner buckets and one jet. A multiphase flow consists of water, air and water vapour. For cavitation pitting the vapour has to stick to the buckets and mass transfer from vapour to water has to happen in a very short time without the presence of air. With detailed analysis of numerical results it was concluded that in this case no cavitation pitting is expected.