One of the most important milestones in the history of hydropower is the invention of the Kaplan turbine. It is a machine stemming from the Francis turbine, which Viktor Kaplan was originally trying to improve. However, it gradually developed into the creation of a completely new solution of an impeller with an axial flow rate and adjustable blades. The first patent relating to the new invention dates from 1913. Shortly afterwards, the Kaplan turbine became the most widely used type of device for the use of low heads and variable flow rates. That meant a significant expansion of the potential of economically usable hydropower. The article briefly introduces the history of turbine development. The overall picture is then completed by a few less-known historical documents.
Pumps as turbines (PAT) are used as an alternative to water turbines in small hydropower plants. The same devices can also be used for energy recovery in water distribution networks. They can replace pressure reduction valves that often lead to energy loss. However, PATs lack the parts that regulate flow so that when a hydropower potential change occurs, efficiency is reduced, as is economic gain. This article summarizes the influence of changing hydropower potential on PAT efficiency and presents comparisons of experimental results with the commonly used predictive model stemming from the theory of physical similarity, which presumes constant PAT efficiency. Our research indicates that the deviation between the model and the real power output calculation at varying potentials was minimal. Similarly, the affine parabola can be used to determine the relationship between total head and flow rate. Other relationships differ from reality the more the PAT efficiency changes. The flow rate and total head dependence on shaft speed are the main factors when setting the optimum operational parameters at varying hydropower potentials. Therefore, a change in efficiency must be included in predictive calculations to correctly optimize PAT operation. The problem is that a change in efficiency cannot be reliably predicted in advance, especially in the case of small-scale devices. For this reason, further research on the issue of changes in PAT efficiency is necessary.
The effective utilization of micro hydropower sources is often realized through the use of pumps as turbines (PAT). The efficiency of PAT is about the same as that of the original pump. A further increase in efficiency and power output can be achieved by modifying the parts interacting with the flow, especially the impeller and the adjacent volute casing and draft tube. This paper presents a user-friendly calculation model of Francis turbine design and its application for PAT geometry modification. Two different modifications of a single-stage radial centrifugal pump were designed according to this model. The first modification (Turbine) consisted of a complete revision of the impeller geometry, volute casing and draft tube, which corresponded to a conventional Francis turbine. The second modification (Hybrid) was based on altered calculation model and consisted of a modification of only the impeller, which can be used in the original volute casing. Both modifications were tested on hydraulic test circuit at different heads. A comparison of the results of the Hybrid and the Turbine modification with the unmodified machine (Original) proved an increase in overall efficiency by 10%. Both modifications provided a higher flow rate and torque. This resulted in an overall power output increase—an increase of approximately 25% and 40% due to the Turbine and Hybrid modifications, respectively.
Dlabal L., Polák M. (2015): Characteristics of bladeless turbine. Res. Agr. Eng., 61: 87-91.The project objective was to perform laboratory tests of the SETUR DVE 120 bladeless turbine and to analyse its measured parameters. Operating characteristics were then determined based on the measured values. The measurement was performed in a closed hydraulic testing circuit in a laboratory of the Department of Mechanical Engineering, Faculty of Engineering, Czech University of Life Sciences Prague. The first part of the article describes the workplace and the method of measurement of the main and the auxiliary parameters. The second part deals with the turbine characteristics. The characteristics describe the relationship between the water flow rate and the usable water gradient and between the water flow rate and the electrical power output of DVE 120, which is important from the user's point of view. The conclusion features a comparison of the bladeless turbine operating characteristics (dependency of the overall efficiency on the waterpower) and the characteristics of the Francis turbine.
Polák M., Dlabal L. (2015): Operating characteristics of a bladeless turbine for irrigation purposes. Soil & Water Res., 10: 278-283.Irrigation and pumping systems are still important issues in agriculture. There are many places on the Earth where water needs to be pumped, however no energy sources are available to power the pumps. The bladeless turbine offers a possible solution. This machine can utilize even low-potential sources of water-borne energy working as autonomous energy sources. The turbine has been developed only recently and therefore no comprehensive operating characteristics has existed as yet. The article summarizes the results of experimental measurements carried out on the SETUR DVE 120, a commercially available bladeless turbine sold in a monoblock together with an electricity generator. "User" characteristics have been created from the measured data: dependence of output electrical power and the efficiency of the set on speed, etc.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.