Tag Archives: pump as turbine (PAT)

xxx M. Polák
The influence of changing hydropower potential on performance parameters of pump in turbine mode
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The influence of changing hydropower potential on performance parameters of pump in turbine mode

M. Polák

Czech University of Life Sciences in Prague, Faculty of Engineering, Kamýcká 129, CZ16521 Praha 6, Czech Republic
Correspondence: karel@tf.czu.cz

Abstract:

Various types of hydromotors that enable energy recovery simultaneously with the required pressure reduction can be used in the field of fluid pumping systems. Similar principle is applied, for example, in the case of use of hydrodynamic pumps in turbine mode (PAT), which are also used as an alternative to conventional turbines in small hydropower plants. However, these pumps do not usually have the possibility of regulating hydraulic parameters, as it is common with conventional turbines. This specific feature needs to be taken into account, when designing such system. Article analyses computational methods for the conversion of the performance characteristics and compares these results with experimentally measured data on a particular pump in turbine mode. The results indicated that conversion can be well used in practice to predict outputs as well as to determine the optimum total head and flowrate to ensure maximum efficiency of PAT operation. Further computations were influenced by deviations resulting from the change in efficiency during PAT operation.

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1824-1829 M. Polák
Application of conversion model for designing hydrodynamic pumps in turbine mode
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Application of conversion model for designing hydrodynamic pumps in turbine mode

M. Polák

Czech University of Life Sciences in Prague, Faculty of Engineering, Kamýcká 129, CZ16521, Praha 6, Czech Republic
Correspondence: karel@tf.czu.cz

Abstract:

The use of the smallest water resources has been coming again to the centre of interest in recent years. A water engine – turbine, is the heart of these power plants. This is usually the highest expense for the investor, in terms of cost. The effort is therefore to seek investment less demanding alternatives. One of them is the use of hydrodynamic pumps in reverse turbine operation. This paper provides a methodology for conversion of parameters of the smallest power pumps (micro hydro sites) to turbine operation. The conversion model is based on the results of experimental research at the author’s workplace and is suitable for pumps with low specific speeds and outputs. The pump design process for turbine mode is complemented by a practical example for a specific deployment site. This example also serves to verify the accuracy of the conversion model.

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1200-1208 M. Polák
Determination of conversion relations for the use of small hydrodynamic pumps in reverse turbine operation
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Determination of conversion relations for the use of small hydrodynamic pumps in reverse turbine operation

M. Polák

Czech University of Life Sciences in Prague, Faculty of Engineering, Kamýcká 129, CZ16521, Praha 6, Czech Republic
Correspondence: karel@tf.czu.cz

Abstract:

In small-scale hydropower, hydrodynamic pumps used in reverse mode are an important economical alternative to conventional water turbines. Efficient utilisation of these devices however requires taking into account all the specifics of the reverse pump operation and optimise the pump design for maximum utilisation of the hydro-technical potential of the deployment site. The article compares existing conversion models, describes initial theoretical assumptions and determines new conversion relations for the design of pumps as turbines (PAT) for the lowest power and specific speed category. The validity of the conversion relations is experimentally verified on a hydraulic test circuit with a radial centrifugal pump tested in both pump and turbine operation modes. The results of the verification of the new conversion relations proved better correspondence to reality within this category of machines than that reported by the previously used conversion models.

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1189–1197 M. Polák
Experimental evaluation of hydraulic design modifications of radial centrifugal pumps
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Experimental evaluation of hydraulic design modifications of radial centrifugal pumps

M. Polák

Czech University of Life Sciences in Prague, Faculty of Engineering, Kamýcká 129, CZ165 21, Praha 6, Czech Republic
Correspondence: karel@tf.czu.cz

Abstract:

In the field of small hydropower, pump units in turbine mode (PAT) are frequently used as alternative to conventional turbines. In order to maximize their operation efficiency, it is possible to optimize the performances of these engines through various simple innovative modifications which relate mainly to the geometry of the flow parts. This paper deals with the results of several successful modifications verified on one such engine. While various simple modifications led to the increase of overall efficiency and power output by few percentages, power output increased by nearly 30% with the innovated runner blades geometry. The modifications also had positive effects on the pump’s operation, with significant increases in flow rate, head and total efficiency.

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