Numerical Characterization of the Performance Curve of a Regenerative Pump-As-Turbine

2020 ◽  
Author(s):  
Giulio Cantini ◽  
Simone Salvadori
Keyword(s):  
Helical Structure ◽  
Operating Mode ◽  
Numerical Approach ◽  
Pollutant Emissions ◽  
Small Scale ◽  
Centrifugal Pumps ◽  
Green Technologies ◽  
Small Hydropower ◽  
Working Region

Abstract Energy companies in the power generation field are continuously searching for green technologies to reduce pollutant emissions. In that context, small hydropower plants represent an attractive solution for distributed electricity generation. Reverse-running centrifugal pumps (also known as “pump-as-turbines”, PaT) are increasingly selected in that field. Amongst the existing type of pumps, drag-type regenerative pumps (RP) can perform similarly to radial centrifugal pumps in terms of head and efficiency for low specific speed values. For a fixed rotational speed, RPs with linear blades work as pump or turbine only depending on the flow rate. Such peculiarity makes it particularly intriguing to evaluate RPs working characteristic in the turbine operating mode. In the present paper, the performance of three Regenerative Pump-as-Turbine (RPaT) are analyzed using Computational Fluid Dynamics (CFD). The analysis is supported by an already validated in-house 1D code developed in cooperation with Pierburg Pump Technology Italy SPA. The obtained results are also discussed considering the theoretical behavior of the circulatory velocity in a regenerative machine as described by a widely used 1D model, which is extended in the present paper to the turbine working region. The numerical approach is validated using experimental data for both an RP (in the pump working region) and a regenerative turbine (RT) (in the turbine working region). Finally, the numerical simulation of a small-scale RP allows for the detailed characterization of both the pump and the turbine regions. The numerical analysis shows that for a RPaT it is possible to find a “switch region” where the machine turns from behaving as a pump to behaving as a turbine, the losses not being overcome by the turbine power output. The analysis of the RPaT also shows the inversion of the flow pattern and the positioning of the pivot around which the flow creates the typical helical structure that characterizes RPs.

Numerical Characterization of the Performance Curve of a Regenerative Pump-as-Turbine

2021 ◽  
Author(s):  
Giulio Cantini ◽  
Simone Salvadori
Keyword(s):  
Helical Structure ◽  
Operating Mode ◽  
Numerical Approach ◽  
Pollutant Emissions ◽  
Small Scale ◽  
Centrifugal Pumps ◽  
Green Technologies ◽  
Small Hydropower ◽  
Hydropower Plants ◽  
Working Region

Abstract Energy companies in the power generation field are continuously searching for green technologies to reduce pollutant emissions. In that context, small hydropower plants represent an attractive solution for distributed electricity generation. Reverse-running centrifugal pumps (also known as "pump-as-turbines", PaT) are increasingly selected in that field. Amongst the existing type of pumps, drag-type regenerative pumps (RP) can perform similarly to radial centrifugal pumps in terms of head and efficiency for low specific speed values. For a fixed rotational speed, RPs with linear blades work as pump or turbine only depending on the flow rate. Such peculiarity makes it particularly intriguing to evaluate RPs working characteristic in the turbine operating mode. In the present paper, the performance of three Regenerative Pump-as-Turbines (RPaT) are analyzed using Computational Fluid Dynamics (CFD). The numerical approach is validated using experimental data for both an RP (in the pump working region) and a regenerative turbine (RT) (in the turbine working region). Finally, the numerical simulation of a small-scale RP allows for characterizing both the pump and the turbine regions. Results shows that for a RPaT it is possible to find a "switch region" where the machine turns from behaving as a pump to behaving as a turbine, the losses not being overcome by the turbine power output. The analysis of the RPaT also shows the inversion of the flow pattern and the constant positioning of the pivot around which the flow creates the typical helical structure that characterizes RPs.

Optical and Chemical Characterization of Aerosols Emitted from Coal, Heavy and Light Fuel Oil, and Small-Scale Wood Combustion

2013 ◽  
Vol 48 (1) ◽  
pp. 827-836 ◽  
Author(s):  
Anna K. Frey ◽  
Karri Saarnio ◽  
Heikki Lamberg ◽  
Fanni Mylläri ◽  
Panu Karjalainen ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Fuel Oil ◽  
Small Scale ◽  
Wood Combustion

Development of Rotary Engine Based Micro-DG/CHP System

2016 ◽  
Author(s):  
Richard L. Hack ◽  
Max R. Venaas ◽  
Vince G. McDonell ◽  
Tod M. Kaneko
Keyword(s):  
Distributed Generation ◽  
Power Output ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Pollutant Emissions ◽  
Small Scale ◽  
Rotary Engine ◽  
Chp System ◽  
Performance Results

Small scale Distributed Generation with waste heat recovery (<50 kW power output, micro-DG/CHP) is an expanding market supporting the widespread deployment of on-site generation to much larger numbers of facilities. The benefits of increased overall thermal efficiency, reduced pollutant emissions, and grid/microgrid support provided by DG/CHP can be maximized with greater quantities of smaller systems that better match the electric and thermal on-site loads. The 3-year CEC funded program to develop a natural gas fueled automotive based rotary engine for micro-DG/CHP, capitalizing upon the unique attributes engine configuration will be presented including initial performance results and plans for the balance of the program.

Characterization of particle composition, organic vapor constituents, and mutagenicity of indoor air pollutant emissions

1986 ◽  
Vol 12 (1-4) ◽  
pp. 351-362 ◽  
Author(s):  
Ken Sexton ◽  
Lurance M. Webber ◽  
Steven B. Hayward ◽  
Richard G. Sextro
Keyword(s):  
Indoor Air ◽  
Air Pollutant ◽  
Pollutant Emissions ◽  
Particle Composition ◽  
Organic Vapor

Combined experimental-numerical approach to characterization of steel-glue-concrete interface

1995 ◽  
Vol 28 (9) ◽  
pp. 518-525 ◽  
Author(s):  
Y. N. Ziraba ◽  
M. H. Baluch ◽  
I. A. Basunbul ◽  
A. K. Azad ◽  
G. J. Al-Sulaimani ◽  
...  
Keyword(s):  
Numerical Approach ◽  
Concrete Interface

Some aspects of improving the energy efficiency of a mine centrifugal pumps.

2020 ◽  
Vol 23 (2) ◽  
pp. 48-51
Author(s):  
V. KONDRATENKO ◽  
◽  
V. KALYNYCHENKO ◽  
Keyword(s):  
Energy Efficiency ◽  
Mine Drainage ◽  
Experimental Studies ◽  
Operating Mode ◽  
Centrifugal Pumps ◽  
Pump Unit ◽  
Drainage Systems ◽  
Start Up ◽  
Discharge Unit ◽  
Pumping Units

Mine drainage systems, which are used at the main drainage of mining enterprises, have a drive capacity of up to 1600kW. To reduce non-productive energy losses, as well as for the continuous operation of the mining company, mine pumps must be energy efficient and reliable. Analysis of downtime of drainage systems shows that the weak point is the unloading device. This fact can lead not only to the failure of the pumping unit, but also to possible prolonged downtime of the mine. The main disadvantage of the existing disk unloading devices of mine pumps is their low reliability and low service life, due to the rapid wear of the components of the unloading unit. The most vulnerable elements of the unloading device are the unloading rings. The need for frequent replacement and adjustment of the elements of the discharge unit is associated with disassembly and assembly of the pump directly in the pump chamber. Such actions require significant costs of unproductive manual labor of service personnel, and rapid wear of parts of the unloading device necessitates their constant replenishment. Malfunctions in the unloading device can cause significant pump failures. To increase the reliability and energy efficiency of mine drainage systems, the method of control of the unloading device was used. During the experimental studies it was found that cavitation phenomena during the operation of pumping units are absent and, accordingly, can not be the cause of wear of the elements of the unloading unit. When the pumps are operating in steady state, the displacement of the rotors was monitored for 3-4 hours on each pump unit. After data processing, it was obtained that the wear of the surface of the unloading rings occurs at a rate of 0.05-0.15mm in one hour. To determine the wear of the rings of unloading during start-up - stop of the pump, at first the indicators of measuring devices at the established mode of operation of the pump unit were fixed. Then the pump was turned off and on again. After starting the pump unit, we made sure that the operating mode of the unloading device did not change and compared the readings of the shaft position indicator before stopping and after starting the pump. From the measurements made it followed that stopping and starting the pump does not lead to noticeable wear of the unloading device. Therefore, it can be assumed that mainly the wear of the discharge rings occurs during the steady operation of the pump unit.

A Reduced-Order Model for the Preliminary Design of Small-Scale Radial Inflow Turbines

2021 ◽  
Author(s):  
Marco Manfredi ◽  
Marco Alberio ◽  
Marco Astolfi ◽  
Andrea Spinelli
Keyword(s):  
Heat Recovery ◽  
Internal Combustion Engines ◽  
Reduced Order Model ◽  
Pollutant Emissions ◽  
Small Scale ◽  
Preliminary Design ◽  
Order Model ◽  
Reduced Order ◽  
Wide Range ◽  
Loss Models

Abstract Power production from waste heat recovery represents an attractive and viable solution to contribute to the reduction of pollutant emissions generated by industrial plants and automotive sector. For transport applications, a promising technology can be identified in bottoming mini-organic Rankine cycles (ORCs), devoted to heat recovery from internal combustion engines (ICE). While commercial ORCs exploiting turbo-expanders in the power range of hundreds kW to several MW are a mature technology, well-established design guidelines are not yet available for turbines targeting small power outputs (below 50 kW). The present work develops a reduced-order model for the preliminary design of mini-ORC radial inflow turbines (RITs) for high-pressure ratio applications, suitable to be integrated in a comprehensive cycle optimization. An exhaustive review of existing loss models, whose development pattern is retraced up to the original approaches, is proposed. This investigation is finalized in a loss models effectiveness analysis performed by testing several correlations over six existing geometries. These test case turbines, operating with different fluids and covering a wide range of target expansion ratio, size, and gross power output, are then employed to carry out the validation procedure, whose results prove the robustness and prediction capability of the proposed reduced-order model.

scholarly journals Characterization of small-scale fisheries in the Camamu-Almada basin, southeast state of Bahia, Brazil

2008 ◽  
Vol 68 (4) ◽  
pp. 711-719 ◽  
Author(s):  
TCM. Souza ◽  
M. Petrere-Jr
Keyword(s):  
Low Income ◽  
Small Scale ◽  
Income Generation ◽  
Target Species ◽  
Market Prices ◽  
Marine Fishery ◽  
Small Scale Fisheries ◽  
Main Factor ◽  
Stock Abundance

In the Camamu-Almada basin, marine fishery is exclusively small-scale, with several structural deficiencies such as boats with low or absent navigational technology, lack of credit and low income. Local fishers complain that shrimp and lobster trawling fishing is the main factor responsible for low stock abundance, but they still persist in these activities as these two species command the highest market prices. So they feel that the target species are already over-fished. We suggest that proper management action, alternative ways of income generation and the payment of job insurance would help to mitigate the problem.

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