Proposal of a new hydraulic turbine capable of high efficiency operation over a wide range of flow rate and effective head

This paper’s aim is enhancement of efficiency for fans adjusting by turn of rotor blades. A high load axial fan and a fan with decreased rotor’s pitch chord ratio by reduction of blades number were investigated. Have been performed tests of the fan with design characteristics as follows: theoretical head coefficient Ht = 0,3, mass flow rate Ca = 0,4, hub’s relative diameter ν = 0.6, and with blades, graded on the law of permanent circulation. The area of effective adjustment was estimated by the performance factor value η* ≥ 0,8. When changing the stagger angles in a wide range from 26° to 70°, the area of highly economical work was in variation ranges 0,26–0,78 for the mass flow rate Ca , and 0,24–0,5 for the theoretical head coefficient Ht accordingly. Tests of fans with a reduced blades number in the rotor (12 instead of 16 for the original fan) has showed that under the same stagger angles the fan’s high-efficiency operating mode is approximately in the same range of Ca variation at slightly reduced values of theoretical head coefficient. Maximal performance factor has increased on 2.5%. Decreasing the number of rotary blades, simplifying the turning mechanism and reducing the weight are possible in the design of fans with increased values of aerodynamic load coefficients.

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Computational Investigation of the Flow Field Inside an Submersible Tubular Pump

ASME-JSME-KSME 2011 Joint Fluids Engineering Conference: Volume 1, Symposia – Parts A, B, C, and D ◽

10.1115/ajk2011-06024 ◽

2011 ◽

Author(s):

Yan Jin ◽

Chao Liu ◽

Jiren Zhou ◽

Fangping Tang

Keyword(s):

Flow Field ◽

Flow Rate ◽

Optimization Design ◽

High Efficiency ◽

Simple Algorithm ◽

Operating Conditions ◽

Rotating Speed ◽

Pumping System ◽

Wide Range ◽

Engineering Costs

Submersible tubular pump is particularly suitable for ultra-low head (net head less than 2 m) pumping station which can reduce the excavation depth, lower engine room height, simplify hydraulic structure, and save civil engineering costs. Submersible tubular pump with smaller motor unit can reduce the flow resistance. The flow field inside the submersible tubular pump is simulated in a commercial computation fluid dynamics (CFD) code FLUENT. The RNG k-ε turbulent model and SIMPLE algorithm are applied to analyze the full passage of a submersible tubular pump, the performance of pump such as head, shaft power and efficiency are predicted based on the calculation of different operating conditions. The simulations are carried out over a wide range of operating points, from 0.8 of the reference mass flow rate at the best efficiency point (BEP) to the 1.28 of the BEP flow rate at the same rotating speed. For verifying the accuracy and reliability of the calculation results, a model test is conducted. The comparison of simulation results and the experiment data show that the calculation performances are agree with the experiment results in the high efficiency area and large discharge condition, but in the condition of low discharge, it exists deviations between the two results. Compare with the numerical simulation and experiment, which can provide more evidences for the hydraulic performance prediction and optimization design of submersible tubular pump pumping system.

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Effect of Flow Rate and Filter Efficiency on Indoor PM2.5 in Ventilation and Filtration Control

Atmosphere ◽

10.3390/atmos11101061 ◽

2020 ◽

Vol 11 (10) ◽

pp. 1061 ◽

Cited By ~ 1

Author(s):

Ji-Hye Kim ◽

Myoung-Souk Yeo

Keyword(s):

Flow Rate ◽

High Efficiency ◽

Residential Buildings ◽

Critical Role ◽

Particle Model ◽

Flow Rates ◽

Filter Efficiency ◽

Wide Range ◽

Low Efficiency ◽

Indoor Pm2.5

Ventilation and filtration control play a critical role in determining indoor PM2.5 (particles less than 2.5 μm in aerodynamic diameter) concentrations of outdoor or indoor origin in residential environments. The objective of this study was to investigate the combined effects of flow rates and filter efficiency on indoor PM2.5 concentrations of residential buildings in Seoul, Korea. Using a particle model based on a mass–balance equation, parametric analysis was performed to examine indoor PM2.5 concentrations according to flow rates and filter efficiency under a wide range of outdoor concentrations and indoor generations. Results showed that ventilation control equipped with a medium–efficiency filter was as effective as that with a high-efficiency filter under normal outdoor concentration and high indoor generation rate conditions. It is not recommended to apply a low-efficiency filter because indoor concentration increases rapidly as outdoor PM2.5 increases when ventilation flow rate is high. For filtration control, it is important to increase both flow rate and filter efficiency in order to improve indoor PM2.5 concentration.

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Laboratory Modeling of an Axial Flow Micro Hydraulic Turbine

Applied Sciences ◽

10.3390/app12020573 ◽

2022 ◽

Vol 12 (2) ◽

pp. 573

Author(s):

Daniil Suslov ◽

Ivan Litvinov ◽

Evgeny Gorelikov ◽

Sergey Shtork ◽

David Wood

Keyword(s):

High Efficiency ◽

Experimental Studies ◽

Axial Flow ◽

Operating Mode ◽

Hydraulic Turbine ◽

Hydraulic Unit ◽

Impeller Outlet ◽

Wide Range ◽

Operation Control ◽

Swirled Flow

This article is devoted to detailed experimental studies of the flow behind the impeller of an air model of a propeller-type microhydroturbine in a wide range of operating parameters. The measurements of two component distributions of averaged velocities and pulsations for conditions from part load to strong overload are conducted. It is shown that the flow at the impeller outlet becomes swirled when the hydraulic turbine operating mode shifts from the optimum one. The character of the behavior of the integral swirl number, which determines the state of the swirled flow, is revealed. Information about the flow peculiarities can be used when adjusting the hydraulic unit mode to optimal conditions and developing recommendations to expand the hydraulic turbine operation control range with preservation of high efficiency. This stage will significantly save time at the stage of equipment design for specific field conditions of water resource.

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Synthesis of Elaborate Benzofuran-2-Carboxamide Derivatives Through a Combination of 8-Aminoquinoline Directed C–H Arylations and Transamidations

10.26434/chemrxiv.7925489.v1 ◽

2019 ◽

Author(s):

Michael Oschmann ◽

Linus Johansson Holm ◽

Oscar Verho

Keyword(s):

Small Molecule ◽

High Efficiency ◽

Synthetic Strategy ◽

Small Molecule Screening ◽

Physiological Properties ◽

Wide Range ◽

Directing Group ◽

Synthetic Sequence

Benzofurans are everywhere in nature and they have been extensively studied by medicinal chemists over the years because of their chemotherapeutic and physiological properties. Herein, we describe a strategy that can be used to access elaborate benzo-2-carboxamide derivatives, which involves a synthetic sequence of 8-aminoquinoline directed C–H arylations followed by transamidations. For the directed C–H arylations, Pd catalysis was used to install a wide range of aryl and heteroaryl substituents at the C3 position of the benzofuran scaffold in high efficiency. Directing group cleavage and further diversification of the C3-arylated benzofuran products were then achieved in a single synthetic operation through the utilization of a two-step transamidation protocol. By bocylating the 8-aminoquinoline amide moiety of these products, it proved possible to activate them towards aminolysis with different amine nucleophiles. Interestingly, this aminolysis reaction was found to proceed efficiently without the need of any additional catalyst or additive. Given the high efficiency and modularity of this synthetic strategy, it constitute a very attractive approach for generating structurally-diverse collections of benzofuran derivatives for small molecule screening.

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To the 70th anniversary of World Meteorological Organization. Scientific and technical cooperation of Hydrometeorological Center of the USSR/Russia in the Programs of World Meteorological Organization

Hydrometeorological research and forecasting ◽

10.37162/2618-9631-2020-4-117-138 ◽

2020 ◽

pp. 117-138

Author(s):

S.V. Borshch ◽

◽

R.M. Vil’fand ◽

D.B. Kiktev ◽

V.M. Khan ◽

...

Keyword(s):

Environmental Monitoring ◽

High Efficiency ◽

World Meteorological Organization ◽

70Th Anniversary ◽

Technical Level ◽

Technical Cooperation ◽

Wide Range

The paper presents the summary and results of long-term and multi-faceted experience of international scientific and technical cooperation of Hydrometeorological Center of Russia in the field of hydrometeorology and environmental monitoring within the framework of WMO programs, which indicates its high efficiency in performing a wide range of works at a high scientific and technical level. Keywords: World Meteorological Organization, major WMO programs, representatives of Hydrometeorological Center of Russia in WMO

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Integrated Design and Multi-Objective Optimization of a Single Stage Heat-Pump Turbocompressor

Volume 3B: 39th Design Automation Conference ◽

10.1115/detc2013-12180 ◽

2013 ◽

Author(s):

J. Schiffmann

Keyword(s):

Design Optimization ◽

High Efficiency ◽

Integrated Design ◽

Heat Pumps ◽

Small Scale ◽

Multi Objective Optimization ◽

Design Constraints ◽

Multi Objective ◽

Wide Range ◽

Standard Design

Small scale turbomachines in domestic heat pumps reach high efficiency and provide oil-free solutions which improve heat-exchanger performance and offer major advantages in the design of advanced thermodynamic cycles. An appropriate turbocompressor for domestic air based heat pumps requires the ability to operate on a wide range of inlet pressure, pressure ratios and mass flows, confronting the designer with the necessity to compromise between range and efficiency. Further the design of small-scale direct driven turbomachines is a complex and interdisciplinary task. Textbook design procedures propose to split such systems into subcomponents and to design and optimize each element individually. This common procedure, however, tends to neglect the interactions between the different components leading to suboptimal solutions. The authors propose an approach based on the integrated philosophy for designing and optimizing gas bearing supported, direct driven turbocompressors for applications with challenging requirements with regards to operation range and efficiency. Using previously validated reduced order models for the different components an integrated model of the compressor is implemented and the optimum system found via multi-objective optimization. It is shown that compared to standard design procedure the integrated approach yields an increase of the seasonal compressor efficiency of more than 12 points. Further a design optimization based sensitivity analysis allows to investigate the influence of design constraints determined prior to optimization such as impeller surface roughness, rotor material and impeller force. A relaxation of these constrains yields additional room for improvement. Reduced impeller force improves efficiency due to a smaller thrust bearing mainly, whereas a lighter rotor material improves rotordynamic performance. A hydraulically smoother impeller surface improves the overall efficiency considerably by reducing aerodynamic losses. A combination of the relaxation of the 3 design constraints yields an additional improvement of 6 points compared to the original optimization process. The integrated design and optimization procedure implemented in the case of a complex design problem thus clearly shows its advantages compared to traditional design methods by allowing a truly exhaustive search for optimum solutions throughout the complete design space. It can be used for both design optimization and for design analysis.

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Low Power Cusped Field Thruster Developed for the Space-Borne Gravitational Wave Detection Mission in China

Applied Sciences ◽

10.3390/app11146549 ◽

2021 ◽

Vol 11 (14) ◽

pp. 6549

Author(s):

Hui Liu ◽

Ming Zeng ◽

Xiang Niu ◽

Hongyan Huang ◽

Daren Yu

Keyword(s):

Low Power ◽

Gravitational Wave ◽

Attitude Control ◽

High Efficiency ◽

Experimental Investigations ◽

Attitude Control System ◽

Gravitational Wave Detection ◽

Wave Detection ◽

Wide Range ◽

Institute Of Technology

The microthruster is the crucial device of the drag-free attitude control system, essential for the space-borne gravitational wave detection mission. The cusped field thruster (also called the High Efficiency Multistage Plasma Thruster) becomes one of the candidate thrusters for the mission due to its low complexity and potential long life over a wide range of thrust. However, the prescribed minimum of thrust and thrust noise are considerable obstacles to downscaling works on cusped field thrusters. This article reviews the development of the low power cusped field thruster at the Harbin Institute of Technology since 2012, including the design of prototypes, experimental investigations and simulation studies. Progress has been made on the downscaling of cusped field thrusters, and a new concept of microwave discharge cusped field thruster has been introduced.

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A general approach to high-efficiency perovskite solar cells by any antisolvent

Nature Communications ◽

10.1038/s41467-021-22049-8 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Alexander D. Taylor ◽

Qing Sun ◽

Katelyn P. Goetz ◽

Qingzhi An ◽

Tim Schramm ◽

...

Keyword(s):

Solar Cells ◽

High Efficiency ◽

Perovskite Solar Cells ◽

Precursor Solution ◽

Microstructural Characterization ◽

Application Rate ◽

Perovskite Layer ◽

Highly Efficient ◽

Application Procedure ◽

Wide Range

AbstractDeposition of perovskite films by antisolvent engineering is a highly common method employed in perovskite photovoltaics research. Herein, we report on a general method that allows for the fabrication of highly efficient perovskite solar cells by any antisolvent via manipulation of the antisolvent application rate. Through detailed structural, compositional, and microstructural characterization of perovskite layers fabricated by 14 different antisolvents, we identify two key factors that influence the quality of the perovskite layer: the solubility of the organic precursors in the antisolvent and its miscibility with the host solvent(s) of the perovskite precursor solution, which combine to produce rate-dependent behavior during the antisolvent application step. Leveraging this, we produce devices with power conversion efficiencies (PCEs) that exceed 21% using a wide range of antisolvents. Moreover, we demonstrate that employing the optimal antisolvent application procedure allows for highly efficient solar cells to be fabricated from a broad range of precursor stoichiometries.

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Octane Index Applicability over the Pressure-Temperature Domain

Energies ◽

10.3390/en14030607 ◽

2021 ◽

Vol 14 (3) ◽

pp. 607

Author(s):

Tommy R. Powell ◽

James P. Szybist ◽

Flavio Dal Forno Chuahy ◽

Scott J. Curran ◽

John Mengwasser ◽

...

Keyword(s):

High Efficiency ◽

National Laboratory ◽

Operating Conditions ◽

Dominant Factor ◽

Compression Ignition ◽

Oak Ridge ◽

Operating Modes ◽

Wide Range ◽

Thermodynamic Conditions ◽

Si Engines

Modern boosted spark-ignition (SI) engines and emerging advanced compression ignition (ACI) engines operate under conditions that deviate substantially from the conditions of conventional autoignition metrics, namely the research and motor octane numbers (RON and MON). The octane index (OI) is an emerging autoignition metric based on RON and MON which was developed to better describe fuel knock resistance over a broader range of engine conditions. Prior research at Oak Ridge National Laboratory (ORNL) identified that OI performs reasonably well under stoichiometric boosted conditions, but inconsistencies exist in the ability of OI to predict autoignition behavior under ACI strategies. Instead, the autoignition behavior under ACI operation was found to correlate more closely to fuel composition, suggesting fuel chemistry differences that are insensitive to the conditions of the RON and MON tests may become the dominant factor under these high efficiency operating conditions. This investigation builds on earlier work to study autoignition behavior over six pressure-temperature (PT) trajectories that correspond to a wide range of operating conditions, including boosted SI operation, partial fuel stratification (PFS), and spark-assisted compression ignition (SACI). A total of 12 different fuels were investigated, including the Co-Optima core fuels and five fuels that represent refinery-relevant blending streams. It was found that, for the ACI operating modes investigated here, the low temperature reactions dominate reactivity, similar to boosted SI operating conditions because their PT trajectories lay close to the RON trajectory. Additionally, the OI metric was found to adequately predict autoignition resistance over the PT domain, for the ACI conditions investigated here, and for fuels from different chemical families. This finding is in contrast with the prior study using a different type of ACI operation with different thermodynamic conditions, specifically a significantly higher temperature at the start of compression, illustrating that fuel response depends highly on the ACI strategy being used.

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