Download Full Kaplan Turbine Design |LINK|
CLICK HERE ->>->>->> https://urlin.us/2t8ihZ
The Kaplan turbine is an inward flow reaction turbine, which means that the working fluid changes pressure as it moves through the turbine and gives up its energy. Power is recovered from both the hydrostatic head and from the kinetic energy of the flowing water. The design combines features of radial and axial turbines.
The turbine does not need to be at the lowest point of water flow as long as the draft tube remains full of water. A higher turbine location, however, increases the suction that is imparted on the turbine blades by the draft tube. The resulting pressure drop may lead to cavitation.
Inexpensive micro turbines on the Kaplan turbine model are manufactured for individual power production designed for 3 m of head which can work with as little as 0.3 m of head at a highly reduced performance provided sufficient water flow.
Large Kaplan turbines are individually designed for each site to operate at the highest possible efficiency, typically over 90%. They are very expensive to design, manufacture and install, but operate for decades.
The original cross-flow turbine was designed by Anthony Michell, an Austrian engineer, in the early 1900s. Later, Donát Bánki, a Hungarian engineer, improved upon it, and it was improved even further by German engineer Fritz Ossberger. A cross-flow turbine is drum-shaped and uses an elongated, rectangular section nozzle directed against curved vanes on a cylindrically shaped runner. It resembles a "squirrel cage" blower. The cross-flow turbine allows water to flow through the blades twice. On the first pass, water flows from outside of the blades to the inside; the second pass goes from the inside back out. A guide vane at the entrance to the turbine directs the flow into a limited portion of the runner. The cross-flow turbine was developed to accommodate larger water flows and lower heads than the Pelton can handle.
To make the Kaplan turbine technology comparable to both the Pelton and the Francis turbine, the master equation for the Kaplan turbine has been established by analyses similar to that-for the Francis turbine. The analysis begins with the descriptions of free vortex flows at the runner inlet and the swirl flow at the impeller exit. By considering the Euler equation for specific work and by further evaluating the most significant shock and swirling losses, the first and the second energy equations in the form of hydraulic efficiency were formulated. The master equation is then established by combining both energy equations. In addition, three design equations and a new design parameter are presented. The master equation relates the turbine hydromechanics to the geometrical design of both the runner and the guide-vane parameters. It enables the complete hydraulic characteristics of a given Kaplan turbine to be analytically and simply computed. A computation example demonstrates the functionality and applicability of the method. With the reconstructed master equation, the runaway speed of the Kaplan turbine and its dependence on the guide-vane setting can be easily and precisely computed. For bulb turbines with guide vanes directly ahead of the turbine runner in the same tube, all computations are also applicable using another equivalent control parameter.
Using fluid flow (CFD) simulation in particular allows you to explore the localized conditions. Along with this, CFD simulation lets you hone in on and analyze parameters including flow rate, pressure drop, efficiency, unexpected turbulence and unwanted vapor pressure. For a detailed video and case study of how you can use CFD to improve your Francis turbine design, watch the webinar below, and follow along with these slides.
Evaluating the flow around the blades is imperative to decrease recirculation, which expends energy that could have been extracted for power. The simulation found that this appeared to be the case in the initial turbine design.
Assessing the static pressure on the turbine blades is also important. It must be guaranteed that the fluid vapor pressure is never reached and that cavitation is avoided. It is critical to be able to guarantee the life of the turbine. The simulation found that the blade design could be improved upon to further prevent the risk of causing cavitation.
The implemented design modifications led to an increase of 1.5% in the peak efficiency of the Francis turbine, to an additional 450 kWh of energy.Clearly, there is more gain here. Optimizing two things together is never sensible. The next step would be to understand the impact of the draft tube modification alone, then to optimize the stator separately.
A reaction turbine is a kind of turbine with rotating blades curved and arranged to develop torque from the gradual reduction of steam pressure from inlet to outlet. Typically, a pressure frame is needed to hold the working fluid when it acts on the turbine, or the turbine must be fully covered in the fluid flow, such as wind turbines. The responsibility of the casing is to hold and direct the working fluid and maintain the suction presented by the draft tube. Reaction turbines are most effective in higher flow velocities, or wherever upstream pressure (in other words, fluid head) is low. The well-known members of the reaction turbine family are Francis and Kaplan turbines.
The Sensor Fish was designed at the Pacific Northwest National Laboratory and it's design has been licensed to ATS, Inc. A paper authored by PNNL researchers provides complete details of the Sensor Fish and its design. Further, PNNL makes available to Sensor Fish users the Hydropower Biological Evaluation Toolset software package (HBET), at nominal cost. The software allows you to input your data, and then models mortality outcomes for varying types of dams, turbines, and fish species. Contact your ATS Consultant for complete details.
The five nozzle, 25 MW Vertical Pelton turbine wasdesigned, engineered, manufactured and installedby Canyon Hydro. The site, along Harrison Lake, BC, has a net head of 565 meters andmaximum flow rate of 5.5 cubic meters per second.Canyon specified a five nozzle Pelton turbine with a pitch diameter of 1340mm (52.75 inches).
Since 1862, The James Leffel & Co. has specialized in the design and manufacture of hydraulic turbines in a wide range of capacities and types. Leffel equipment can best be summarized as efficient, durable and trouble-free in its construction.
A hydropower station essentially needs water to be diverted from the stream and brought to the turbines without losing the elevation/head. Given below are some of the important factors that must be kept in mind while designing a hydropower system: Available head: The design of the system has effects on the net head delivered to the turbine. Flow variations: The river flow varies during the year but the hydro installation is designed for almost a constant flow. Sediment: Flowing water in the river sometimes carry small particles of hard abrasive matter (sediment) which can cause wear to the turbine if they are not removed before the water enters the penstock. Floods: Flood water will carry larger suspended particles and will even cause large stones to roll along the stream bed. Turbulence: In all parts of the water supply line, including the weir, the intake and the channel, sudden alterations to the flow direction will create turbulence which erodes structures and causes energy losses. Most common civil structures used in a hydro power scheme are:
Impulse turbines are usually cheaper than reaction turbines because there is no need for a pressure casing nor for carefully engineered clearances, but they are also only suitable for relatively higher heads.
Impulse turbines are more widely used for micro-hydro applications as compared to reaction turbines because they have several advantages such as simple design (no pressure seals around the shaft and better access to working parts - easier to fabricate and maintain), greater tolerance towards sand and other particles in the water, and better part-flow efficiencies. The impulse turbines are not suitable for low head sites as they have lower specific speeds and to couple it to a standard alternator, the speed would have to be increased to a great extent. The multi-jet Pelton, crossflow and Turgo turbines are suitable for medium heads.
The Turgo turbine is an impulse turbine designed for medium head applications. These turbines achieve operational efficiencies of up to 87%. Developed in 1919 by Gilkes as a modification of the Pelton wheel, the Turgo has certain advantages over Francis and Pelton designs for some applications. Firstly, the runner is less expensive to make than a Pelton wheel while it does not need an airtight housing like the Francis turbines. Finally the Turgo has higher specific speeds and at the same time can handle greater quantum of flows than a Pelton wheel of the similar diameter, leading to reduced generator and installation cost. Turgo turbines operate in a head range where the Francis and Pelton overlap. Turgo installations are usually preferred for small hydro schemes where low cost is very important.
The more popular reaction turbines are the Francis turbine and the propeller turbine. Kaplan turbine is a unique design of the propeller turbine. Given the same head and flow conditions, reaction turbines rotate faster than impulse turbines. This high specific speed makes it possible for a reaction turbine to be coupled directly to an alternator without requiring a speed-increasing drive system. This specific feature enables simplicity (less maintenance) and cost savings in the hydro scheme. The Francis turbine is suitable for medium heads, while the propeller is more suitable for low heads.
The reaction turbines require more sophisticated fabrication than impulse turbines because they involve the use of larger and more intricately profiled blades together with carefully profiled casings. The higher costs are often offset by high efficiency and the advantages of high running speeds at low heads from relatively compact machines. Expertise and precision required during fabrication make these turbines less attractive for use in micro-hydro in developing countries. Most reaction turbines tend to have poor part-flow efficiency characteristics 2b1af7f3a8