A One-Dimensional Numerical Model for Calculating the Efficiency of Pumps as Turbines for Implementation in Micro-Hydro Power Plants

Volume 1 ◽  
2004 ◽  
Author(s):  
Mario Amelio ◽  
Silvio Barbarelli
Keyword(s):  
Flow Rate ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Numerical Code ◽  
Geometrical Parameters ◽  
Centrifugal Pumps ◽  
Simple Method ◽  
Hydro Power ◽  
One Dimensional ◽  
Specific Speed

Increasing interest in renewable energy sources makes attractive the exploitation of many small power hydraulic resources (micro-hydro – less than 100 kW). However, the high cost of hydraulic turbines hinders the actual realization of micro-hydro plants. An alternative cheaper solution could be to replace the turbine with a reverse-mode centrifugal pump, developing therefore a pump as turbine (PAT) system. Unfortunately, although a wide number of centrifugal pumps are commercially available for micro-hydro engineering plant, manufacturers do not provide information regarding the performance of centrifugal pumps in turbine mode. In this paper, a simple method based on a one-dimensional numerical code is presented for deriving the turbine efficiency of commercially available centrifugal pumps. The code estimates a sizing of the component using information such as impeller diameter, specific speed, head and flow rate at pump BEP, machine overall dimension which are provided in manufacturer catalogues, to deduce geometrical parameters of the machine, calculating the losses and thus determining PAT performances. The method was validated by a comparison of the predicted characteristic curves with some experimental measurements available on PATs working in a range of specific speed (Head in meters and flow rate in m3/s) from 9 to 65. The numerical code calculations effectively predicted the measured efficiency of PATs. At BEP, the efficiency was estimated with a relative error of ±10% which is a value much lower than one obtained by using the available in literature correlations. A prediction within this error range is generally accepted for this kind of application.

scholarly journals Effects of a Combination Impeller on the Flow Field and External Performance of an Aero-Fuel Centrifugal Pump

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 919
Author(s):  
Jia Li ◽  
Xin Wang ◽  
Yue Wang ◽  
Wancheng Wang ◽  
Baibing Chen ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Power Plants ◽  
Flow Characteristics ◽  
Significant Feature ◽  
Geometrical Parameters ◽  
Centrifugal Pumps ◽  
Flow Losses ◽  
Simulation And Experiment ◽  
Aero Engines

Aero-fuel centrifugal pumps are important power plants in aero-engines. Unlike most of the existing centrifugal pumps, a combination impeller is integrated with the pump to improve performance. First, the critical geometrical parameters of the combination impeller and volute are given. Then, the effects of the combination impeller on the flow characteristics of the impeller and volute are clarified by comparing simulation results with that of the conventional impeller, where the effectiveness of the selected numerical method is validated by an acceptable agreement between simulation and experiment. Finally, the experiment is set to test the external performance of the studied pump. A significant feature of this study is that the flow characteristics are significantly ameliorated by reducing the flow losses that emerged in the impeller inlet, impeller outlet, and volute tongue. Correspondingly, the head and efficiency of a combination impeller are higher with comparison to a conventional impeller. Consequently, it is a promising approach in ameliorating the flow field and improving external performance by applying a combination impeller to an aero-fuel centrifugal pump.

scholarly journals SMALL HYDRO-POWER PLANT PROJECT SELECTION USING FUZZY AXIOMATIC DESIGN PRINCIPLES

2015 ◽  
Vol 21 (5) ◽  
pp. 756-772 ◽  
Author(s):  
Anant V KHANDEKAR ◽  
Jurgita ANTUCHEVIČIENĖ ◽  
Shankar CHAKRABORTY
Keyword(s):  
Information Content ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Axiomatic Design ◽  
Design Principles ◽  
Energy Sources ◽  
Hydro Power ◽  
Hydro Power Plants ◽  
The Government ◽  
The One

There has been a rapid growth in construction activities during the last few decades owing to overall development in all facets of humanity. Due to technological advancements and ever increasing civilization, there is a persistent need of energy. Along with the conventional energy sources, the renewable energy sources have also significantly contributed to the rising energy needs. As a renewable source of energy, numerous small hydro-power plants (SHPPs) have been built up across the world in the recent past. Usually these SHPPs are being built and operated by the private developers complying with the government regulations. In order to assist a developer in selecting the most profitable and feasible SHPP for construction and subsequent operation, a method based on fuzzy axiomatic design principles is employed in this paper. The techno-commercial and socioeconomic criteria as considered for analyzing the feasibility of the candidate SHPPs are expressed qualitatively using trapezoidal fuzzy numbers. The performance of each SHPP is evaluated in terms of its total information content and the one with the least information content is selected to be the best venture for the required construction activity. The adopted methodology is found to have immense potential to the developers while selecting the most feasible project for construction.

scholarly journals Small Hydro Power Schemes: Technical Aspects

2017 ◽  
Vol 6 (1) ◽  
pp. 55
Author(s):  
Hira Singh Sachdev ◽  
Ashok Kumar Akella
Keyword(s):  
Power Plants ◽  
Renewable Energy Sources ◽  
Electrical Energy ◽  
Environment Friendly ◽  
Hydro Power ◽  
Energy Lowering ◽  
High Initial Cost ◽  
Small Discharge ◽  
Hydro Power Plants ◽  
Increasing Demand

<p>Small hydro systems play a major role in meeting power requirements of remote, isolated, hilly areas in a decentralized manner by tapping water streams, rivulets and canals of small discharge. Small hydroelectric system captures the energy in flowing water and converts it to electricity.</p>Of all the non-conventional renewable energy sources, small hydro stands first as it is more resourceful, reduces system  losses, environment friendly, non-consumptive and source is renewable due to their enormous advantages over large hydro and other power plants, lot of small hydro-power plants have come up across the world to meet the ever increasing demand of electrical energy. Lowering the high initial cost of the small hydro-power plants and its popularization is today’s challenges. This paper describes basic techniques design of the small hydro-power development.

scholarly journals Geometrical Optimization of Pump-As-Turbine (PAT) Impellers for Enhancing Energy Efficiency with 1-D Theory

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4120
Author(s):  
Longyan Wang ◽  
Stephen Ntiri Asomani ◽  
Jianping Yuan ◽  
Desmond Appiah
Keyword(s):  
Theoretical Model ◽  
Cfd Simulation ◽  
Latin Hypercube Sampling ◽  
Geometric Optimization ◽  
Design Flow ◽  
Geometrical Parameters ◽  
Optimization Strategy ◽  
Centrifugal Pumps ◽  
One Dimensional ◽  
Design Variables

This paper presents a multi-objective optimization strategy for pump-as-turbines (PAT), which relies on one-dimensional theory and analysis of geometrical parameters. In this strategy, a theoretical model, which considers all possible losses incurred (mainly by the components of pipe inlet, impeller and volute), has been put forward for performance prediction of centrifugal pumps operating as turbines (PAT). With the established mathematical relationship between the efficiency of PAT (both at pump and turbine mode) and the impeller controlling variables, the geometric optimization of the PAT impeller is performed with constant rotational speed. Specifically, the optimization data consist of 50 sets of impellers generated from Latin Hypercube Sampling method with its corresponding efficiencies calculated. Subsequently, the pareto-based genetic algorithm (PBGA) was adopted to optimize the geometic parameters of the impellers through the theoretical model. To validate the theoretical optimization results, the high-fidelity Computational Fluid Dynamics (CFD) simulation and the experimental data are employed for comparison of the PAT performance. The findings show that the efficiencies of both the pump and PAT optimized variables increased by 0.27% and 16.3% respectively under the design flow condition. Based on the one-dimensional theoretical optimization results, the geometry of the impeller is redesigned to suit both pump and PAT mode operations. It is concluded that the chosen design variables (b2, β1, β2, and z) have a significant impact on the PAT efficiency, which demonstrates that the optimization scheme proposed in this study is practicable.

scholarly journals Development of a One-Dimensional Model for the Prediction of Leakage Flows in Rotating Cavities Under Non-Uniform Tangential Pressure Distribution

2019 ◽  
Vol 4 (3) ◽  
pp. 19
Author(s):  
Giulio Cantini ◽  
Simone Salvadori ◽  
Massimiliano Insinna ◽  
Giorgio Peroni ◽  
Gilles Simon ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Pressure Gradient ◽  
Flow Rate ◽  
Control Volume ◽  
Performance Estimation ◽  
Leakage Flow ◽  
Centrifugal Pumps ◽  
One Dimensional ◽  
Leakage Flows ◽  
Aspect Ratios

Regenerative pumps are characterized by a low specific speed that place them between rotary positive displacement pumps and purely radial centrifugal pumps. They are interesting for many industrial applications since, for a given flow rate and a specified head, they allow for a reduced size and can operate at a lower rotational speed with respect to purely radial pumps. The complexity of the flow within regenerative machines makes the theoretical performance estimation a challenging task. The prediction of the leakage flow rate between the rotating and the static disks has the greatest impact on the prediction of global performance. All the classical approaches to the disk clearance problem assume that there is no relevant circumferential pressure gradient. In the present case, the flow develops along the tangential direction and the pressure gradient is intrinsically non-zero. The aim of the present work is to develop a reliable approach for the prediction of leakage flows in regenerative pumps. A preliminary numerical simulation on a virtual model of a regenerative pump where the disk clearance is part of the control volume has been performed for three different clearance aspect ratios. The outcome of that campaign allowed the authors to determine the behavior of the flow in the cavity and choose correctly the baseline hypotheses for a mathematical-physical method for the prediction of leakage flows. The method assumes that the flow inside of the disk clearance is two-dimensional and can be decomposed into several stream-tubes. Energy balance is performed for each tube, thus generating a system that can be solved numerically. The new methodology was tuned using data obtained from the numerical simulation. After that, the methodology was integrated into an existing one-dimensional code called DART (developed at the University of Florence in cooperation with Pierburg Pump Technology Italy S.p.A.) and the new algorithm was verified using available numerical and experimental data. It is here demonstrated that an appropriate calibration of the leakage flow model allows for an improved reliability of the one-dimensional code.

Effect of the Section Area of Volute in Low Specific Speed Centrifugal Pumps on Hydraulic Performance

2009 ◽  
Author(s):  
Xiang Zhang ◽  
Yang Wang ◽  
Jianhui Fu ◽  
Cui Dai ◽  
Caihong Wang
Keyword(s):  
Flow Rate ◽  
Low Flow ◽  
Centrifugal Pumps ◽  
Blade Angle ◽  
Rate Condition ◽  
Section Area ◽  
Impeller Outlet ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Experimental Researches

The volute of low specific speed centrifugal pumps has a great impact on the performance of the pump in that the highest efficiency can only be achieved when the impeller is matched with a well-designed volute. At off-BEP conditions, the performance of pumps declines as a consequence of a mismatch between characteristics of the impeller and the volute. The section area is the most important factor of volute. Numerical simulations and experimental researches have been carried out on the routine-designed impeller and the non-overloading designed impeller (different impeller outlet blade angle between two types of impellers) in the hope of finding out the effect of the section area of volute on low specific speed centrifugal pumps. It has been found that the uneven flow rate on different volute sections caused by the backflow between volute and impeller is one of the reasons for the efficiency decline of pumps at off-BEP conditions, especially in the low flow rate condition. It has also been found that the routine-designed impeller is more easily affected by the section area of volute than non-overloading designed impeller.

scholarly journals Determination of critical operating and geometrical parameters in diesel injectors through one dimensional modelling, design of experiments and an analysis of variance

2017 ◽  
Vol 232 (13) ◽  
pp. 1762-1781 ◽  
Author(s):  
Francisco J Salvador ◽  
Marcos Carreres ◽  
Marco Crialesi-Esposito ◽  
Alejandro H Plazas
Keyword(s):  
Design Of Experiments ◽  
Mass Flow Rate ◽  
Analysis Of Variance ◽  
Mass Flow ◽  
Flow Rate ◽  
Control Volume ◽  
Geometrical Parameters ◽  
One Dimensional ◽  
Injection Process ◽  
Rate Profile

In this paper, a design of experiments and a statistical analysis of variance (ANOVA) are performed to determine the parameters that have more influence on the mass flow rate profile in diesel injectors. The study has been carried out using a one dimensional model previously implemented by the authors. The investigation is split into two different parts. First, the analysis is focused on functional parameters such as the injection and discharge pressures, the energizing time and the fuel temperature. In the second part, the influence of 37 geometrical parameters, such as the diameters of hydraulic lines, calibrated orifices and internal volumes, among others, are analysed. The objective of the study is to quantify the impact of small variations in the nominal value of these parameters on the injection rate profile for a given injector operating condition. In the case of the functional parameters, these small variations may be attributed to possible undesired fluctuations in the conditions that the injector is submitted to. As far as the geometrical and flow parameters are concerned, the small variations studied are representative of manufacturing tolerances that could influence the injected mass flow rate. As a result, it has been noticed that the configuration of the inlet and outlet orifices of the control volume, together with the discharge coefficient of the inlet orifice, among a few others, play a remarkable role in the injector performance. The reason resides in the fact that they are in charge of controlling the behaviour of the pressure in the control volume, which importantly influences injector dynamics and therefore the injection process. Variations of only 5% in the diameter of these orifices strongly modify the shape of the rate of injection curve, influencing both the injection delay and the duration of the injection process, consequently changing the total mass delivered.

scholarly journals Impact of new power investments up to year 2020 on the energy system of Bosnia and Herzegovina

2015 ◽  
Vol 19 (3) ◽  
pp. 771-780 ◽  
Author(s):  
Zihnija Hasovic ◽  
Boris Cosic ◽  
Adisa Omerbegovic-Arapovic ◽  
Neven Duic
Keyword(s):  
Renewable Energy ◽  
Bosnia And Herzegovina ◽  
Power Plants ◽  
Fossil Fuels ◽  
Renewable Energy Sources ◽  
Energy System ◽  
Energy Potential ◽  
Hydro Power ◽  
Thermal Plant ◽  
Hydro Power Plants

This paper investigates current and planned investments in new power plants in Bosnia and Herzegovina and impact of these investments on the energy sector, CO2 emission and internationally committed targets for electricity from renewable sources up to year 2020. Bosnia and Herzegovina possesses strong renewable energy potential, in particular hydro and biomass. However, the majority of energy production is conducted in outdated power plants and based on fossil fuels, resulting in environment pollution. New major investments The Stanari Thermal plant (300 MW) and the investment in Block 7 (450 MW) at the Thermal Plant Tuzla are again focused on fossil fuels. The power sector is also highly dependent on the hydrology as 54% of current capacities are based on large hydro power. In order to investigate how the energy system of Bosnia and Herzegovina will be affected by these investments and hydrology, the EnergyPLAN model was used. Based on the foreseen demand for year 2020 several power plants construction and hydrology scenarios have been modelled to cover a range of possibilities that may occur. This includes export orientation of Stanari plant, impact of wet, dry and average year, delayed construction of Tuzla Block 7, constrained construction of hydro power plants, and retirement of thermal units. It can be concluded that energy system can be significantly affected by delayed investments but in order to comply with renewables targets Bosnia and Herzegovina will need to explore the power production from other renewable energy sources as well.

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