scholarly journals A Brief History of the Kaplan Turbine Invention

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6211
Author(s):  
Martin Polák
Keyword(s):  
Flow Rate ◽  
Axial Flow ◽  
Francis Turbine ◽  
Historical Documents ◽  
Flow Rates ◽  
Variable Flow ◽  
Kaplan Turbine ◽  
History Of ◽  
The Creation

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 The overall picture is then completed by a few less-known historical documents.

scholarly journals Investigation of the Flow Field in the Vicinity of an Axial Flow Fan During Low Flow Rates

2014 ◽  
Author(s):  
Francois G. Louw ◽  
Theodor W. von Backström ◽  
Sybrand J. van der Spuy
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
Flow Rate ◽  
Axial Flow ◽  
Operating Conditions ◽  
Design Flow ◽  
Low Flow ◽  
Axial Flow Fan ◽  
Free Vortex ◽  
Flow Rates

Large axial flow fans are used in forced draft air cooled heat exchangers (ACHEs). Previous studies have shown that adverse operating conditions cause certain sectors of the fan, or the fan as a whole to operate at very low flow rates, thereby reducing the cooling effectiveness of the ACHE. The present study is directed towards the experimental and numerical analyses of the flow in the vicinity of an axial flow fan during low flow rates. This is done to obtain the global flow structure up and downstream of the fan. A near-free-vortex fan, designed for specific application in ACHEs, is used for the investigation. Experimental fan testing was conducted in a British Standard 848, type A fan test facility, to obtain the fan characteristic. Both steady-state and time-dependent numerical simulations were performed, depending on the operating condition of the fan, using the Realizable k-ε turbulence model. Good agreement is found between the numerically and experimentally obtained fan characteristic data. Using data from the numerical simulations, the time and circumferentially averaged flow field is presented. At the design flow rate the downstream fan jet mainly moves in the axial and tangential direction, as expected for a free-vortex design criteria, with a small amount of radial flow that can be observed. As the flow rate through the fan is decreased, it is evident that the down-stream fan jet gradually shifts more diagonally outwards, and the region where reverse flow occur between the fan jet and the fan rotational axis increases. At very low flow rates the flow close to the tip reverses through the fan, producing a small recirculation zone as well as swirl at certain locations upstream of the fan.

An Updated Study of Recirculation at the Inlet of a Rotodynamic Impeller

2005 ◽  
Author(s):  
S. Yedidiah
Keyword(s):  
Flow Rate ◽  
Axial Flow ◽  
Present Knowledge ◽  
Flow Rates ◽  
Geometrical Features ◽  
Reduced Flow

This paper presents an updated report of certain causes and effects of recirculation at the inlet of a rotodynamic impeller. It demonstrates how certain geometrical features of the inlet parts of the blades are affecting the pattern of the inlet-recirculation, and how this pattern is affected by the flow-rate. It demonstrates the effects of recirculation on the steepness of the QH-curve at reduced flow-rates, and the occasionally observed hysteresis within a certain range of partial flow-rates. Also, it discusses the manner in which recirculation is producing very intense instabilities at reduced NPSH, in axial-flow impellers and inducers. The conclusions arrived at are supported by results of test, reported in different papers. In addition of the above, it lists some of the uses of our present knowledge of the causes and effects of inlet-recirculation, which have been successfully applied in practice.

State primary standard of gas volumetric and mass flow rate units GET 118-2017: history of creation, confirmation of calibration and measurement capabilities

2021 ◽  
pp. 22-26
Author(s):  
Aleksandr I. Gorchev ◽  
Aidar V. Mingaleev ◽  
Anatoly B. Yakovlev
Keyword(s):  
Mass Flow ◽  
Flow Rate ◽  
Primary Standard ◽  
Flow Rates ◽  
Calibration And Measurement Capabilities ◽  
History Of ◽  
Mass Flow Rates ◽  
The Russian Federation ◽  
Working Standards ◽  
Measurement Capabilities

The history of the creation of the State primary standard of gas volumetric and mass flow rate units GET 118-2017 is presented. The significant role of international comparisons was noted at various stages of the creation of GET 118-2017: the comparisons results confirmed and made it possible to include in the KCDB the calibration and measurement capabilities of the Russian Federation in the field of gas volumetric flow measurements, and also helped to determine the direction and list of measures to improve the standard. A patented comparison method for calibrating critical nozzles, implemented in GET 118-2017 for transfer the units of volumetric and mass flow rates of gas to working standards, is described. The design, composition and characteristics of GET 118-2017 are presented. Currently, more than 700 working standards of gas volumetric and mass flow rates used in the Russian Federation and some KOOMET member countries are traced to GET 118-2017, the total number of calls to GET 118-2017 for the transfer of measurement units exceeds 3500 per year.

Experimental Study to Test an Axial Flow Pump as a Turbine and Development of Performance Characteristics for Micro-Hydro Power Plant

2007 ◽  
Author(s):  
Javed A. Chattha ◽  
Mohammad S. Khan
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Axial Flow ◽  
Performance Characteristics ◽  
Centrifugal Pumps ◽  
Test Rig ◽  
Hydro Power ◽  
Flow Rates ◽  
Axial Flow Pump ◽  
Flow Pump

Standard centrifugal pumps are manufactured in a large number of sizes in order to cover a wide range of heads and flow rates. Conventional turbines, however, are not mass produced since they are custom designed and manufactured. Therefore, pumps are available in the market at comparatively lower cost and shorter delivery periods. In this paper an experimental study is presented in which the use of pumps as turbine (PAT) is explored for micro-hydro power generation. The objective of the study is to explore cheap alternate sources of energy production in remote locations of Pakistan. Extensive research has been carried out by Williams [1] in the field of using pumps as turbines. Only centrifugal pumps were studied to explore their use as turbines in that work. Since then quite a bit of advancement in this sector of technology has taken place. However, to the best of our knowledge, axial flow pumps have never been tested as turbines. The site conditions for micro-hydro power station usually find axial flow pumps to be more appropriate compared cross flow and pelton turbines. A commercially available axial flow pump was selected and test rig was designed and constructed in order to determine the performance characteristics of using the pump as a turbine. The test bed has a provision of simulating various head and flow rate conditions and dynamometer to measure the power output in order to determine the performance of the turbine. The simulated head and flow rates were varied for various typical conditions. Some minor modifications in the basic pump unit were made to accomplish these tests. The experimental study resulted in generating data for which head was varied from 4 to 12 m and flow rate from 700 to 900 m3/hr. For these conditions power developed ranged from 5–20 kW with a maximum efficiency of 70% corresponding to a head of 6.8 m and a flow rate of 800 m3/hr. Pump affinity laws and the data collected in this experimental study were then used to select a Kaplan turbine. This information was then used to choose a commercially available pump for typical low head and high flow rate conditions in Pakistan to generate about 100 kW of electric power, when running in turbine mode. This paper discusses the design and construction of the test rig to carry out experiments for testing pumps as turbines. Details of experimental procedure and results to determine performance characteristics are also presented. Finally selection procedure of a pump for a specific head and flow condition are also discussed in this paper.

scholarly journals Pressure Fluctuation on Casing Wall of Isolated Axial Compressor Rotors at Low Flow Rate

1992 ◽  
Author(s):  
Masahiro Inoue ◽  
Motoo Kurdumaru ◽  
Youichi Anoo
Keyword(s):  
Flow Rate ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Axial Compressor ◽  
Axial Flow ◽  
Tip Clearance ◽  
Low Flow ◽  
Flow Rates ◽  
Flow Compressor ◽  
Low Flow Rate

The pressure fluctuations on the casing wall of two axial flow compressor rotors with various tip clearances have been analyzed by the use of two kinds of correlation functions. Behavior of the pressure fluctuation varies depending on tip clearance and blade solidity. In the case of small tip clearance, the nature of disturbances becomes random as the flow rate is reduced to a stall condition. For moderate tip clearance, coherent-structured disturbances appear intermittently at low flow rate. They appear more frequently as the solidity is increased and the flow rate becomes lower. For large tip clearance, the coherent structured disturbances exist even at considerably higher flow rates. Corresponding to these features there are peculiar patterns in the correlation designated as “phase-locked correlation function”.

scholarly journals Performance of Variable Flow Rates for Photovoltaic-Thermal Collectors and the Determination of Optimal Flow Rates

2021 ◽  
Author(s):  
Tamo Dembeck-Kerekes ◽  
Jamie P. Fine ◽  
Jacob Friedman ◽  
Seth B. Dworkin ◽  
Jennifer J. McArthur
Keyword(s):  
Steady State ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Heat Removal ◽  
Heating Process ◽  
Ambient Conditions ◽  
Solar Simulator ◽  
Flow Rates ◽  
Variable Flow ◽  
Rate Optimization

A quasi-steady state model has been developed to asses of the potential of variable flow strategies to improve the overall thermal efficiency of Photovoltaic-thermal (PVT) collectors. An adaption of the Duffie-Beckman method is used to simulate the PVT, in which the overall loss coefficient and heat removal factor are updated at each timestep in response to changes in flow rate and ambient conditions. A novel calculation engine was also developed to simulate a building heating loop connected to the solar loop via a counterflow heat exchanger that calculates the steady-state conditions for the system at each timestep. The results from PVT simulation are in good agreement with test data obtained from the solar simulator –environmental chamber facility at Concordia University. Further validation for the overall system was carried out via a parallel simulation run in TRNSYS and the model-predicted annual solar heat gains were within 3.6%. The results of the investigation show that a variable flow rate strategy has significant potential to improve thermal efficiency. This benefit was found to be dependent on ambient and process loop conditions, and most effective for systems with greater difference between heating process supply and return temperatures. Keywords: Photovoltaic-thermal; Solar Thermal; Flow Rate Optimization; variable flow

scholarly journals Performance of Variable Flow Rates for Photovoltaic-Thermal Collectors and the Determination of Optimal Flow Rates

2021 ◽  
Author(s):  
Tamo Dembeck-Kerekes ◽  
Jamie P. Fine ◽  
Jacob Friedman ◽  
Seth B. Dworkin ◽  
Jennifer J. McArthur
Keyword(s):  
Steady State ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Heat Removal ◽  
Heating Process ◽  
Ambient Conditions ◽  
Solar Simulator ◽  
Flow Rates ◽  
Variable Flow ◽  
Rate Optimization

A quasi-steady state model has been developed to asses of the potential of variable flow strategies to improve the overall thermal efficiency of Photovoltaic-thermal (PVT) collectors. An adaption of the Duffie-Beckman method is used to simulate the PVT, in which the overall loss coefficient and heat removal factor are updated at each timestep in response to changes in flow rate and ambient conditions. A novel calculation engine was also developed to simulate a building heating loop connected to the solar loop via a counterflow heat exchanger that calculates the steady-state conditions for the system at each timestep. The results from PVT simulation are in good agreement with test data obtained from the solar simulator –environmental chamber facility at Concordia University. Further validation for the overall system was carried out via a parallel simulation run in TRNSYS and the model-predicted annual solar heat gains were within 3.6%. The results of the investigation show that a variable flow rate strategy has significant potential to improve thermal efficiency. This benefit was found to be dependent on ambient and process loop conditions, and most effective for systems with greater difference between heating process supply and return temperatures. Keywords: Photovoltaic-thermal; Solar Thermal; Flow Rate Optimization; variable flow

Flow-dependent potassium secretion by rabbit cortical collecting tubule in vitro

1987 ◽  
Vol 253 (5) ◽  
pp. F896-F903 ◽  
Author(s):  
B. G. Engbretson ◽  
L. C. Stoner
Keyword(s):  
Flow Rate ◽  
Axial Flow ◽  
Low Flow ◽  
Sodium Reabsorption ◽  
Flow Rates ◽  
Chemical Gradients ◽  
Special Diet ◽  
Potassium Secretion ◽  
Collecting Tubules

Cortical collecting tubules (CCT) dissected from rabbits fed a diet designed to stimulate potassium transport secreted potassium in direct proportion to the flow rate in the range of 0.4-3 nl/min (r = 0.79). This relationship was also evident in tubules from rabbits maintained on standard laboratory chow (r = 0.80). The slope of the line relating the two parameters was almost six times greater in tubules from animals fed the special diet. When the range of flow rates was expanded, potassium secretion in nine CCTs appeared to peak at 5-6 nl/min and then failed to increase despite further elevation of flow to nearly 15 nl/min. We investigated the effects of the electrical and chemical gradients on flow-dependent potassium secretion. Because transepithelial voltage was unaffected by changes in axial flow, we conclude that the flow-dependent fraction of potassium secretion is not explained by the electrical gradient. To evaluate the role of luminal potassium concentration on flow-dependent potassium secretion, 11 CCTs were perfused with both 5 and 50 mM potassium solutions at two flow rates (approximately 1.5 and 4.0 nl/min). Increases in both potassium secretion (15.6 +/- 3.9 peq.mm-1.min-1) and sodium reabsorption (11.9 +/- 5.2 peq.mm-1.min-1) were evident in the tubules perfused with 5 mM potassium. Potassium secretion was not reduced by 50 mM luminal potassium at the low flow rate when the largest chemical gradients opposing net secretion were generated. When 50 mM potassium was present in the lumen, increasing flow did not stimulate potassium secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Technique for Improving the Flow Rate Estimation Range by Using an Axial Flow Water Turbine Generator

2017 ◽  
Vol 137 (1) ◽  
pp. 30-35
Author(s):  
Hiroaki Narita ◽  
Makoto Saruwatari ◽  
Jun Matsui ◽  
Yasutaka Fujimoto
Keyword(s):  
Flow Rate ◽  
Axial Flow ◽  
Turbine Generator ◽  
Rate Estimation ◽  
Water Turbine ◽  
Estimation Range

Elite da Liberdade: a contribution to the history of black clubs in Brazil

2020 ◽  
Vol 9 (1) ◽  
pp. 396-411
Author(s):  
Petrônio José Domingues
Keyword(s):  
Social Inclusion ◽  
Black Identity ◽  
Sao Paulo ◽  
São Paulo ◽  
Educational Discourse ◽  
History Of ◽  
The Creation

This article investigates the trajectory of the Grêmio Dramático, Recreativo e Literário Elite da Liberdade (the Liberdade Elite Guild of Drama, Recreation, and Literature), a black club active in São Paulo, Brazil, from 1919 to 1927. The aim is to reconstruct aspects of the club’s history in light of its educational discourse on civility, which was used as a strategy to promote modern virtues in the black milieu. By appropriating the precepts of civility, Elite da Liberdade helped construct a positive black identity, enabled the creation of bonds of solidarity among its members, and made itself a place of resistance and struggle for social inclusion, recognition, and citizens’ rights.

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