Vanadium flow batteries at variable flow rates

2022 ◽  
Vol 45 ◽  
pp. 103623
Author(s):  
A. Karrech ◽  
K. Regenauer-Lieb ◽  
F. Abbassi
Keyword(s):  
Flow Rates ◽  
Variable Flow ◽  
Flow Batteries

Effect of Precursory Cooling on Falling-Film Rewetting

1975 ◽  
Vol 97 (3) ◽  
pp. 360-365 ◽  
Author(s):  
K. H. Sun ◽  
G. E. Dix ◽  
C. L. Tien
Keyword(s):  
Atmospheric Pressure ◽  
Present Model ◽  
Front Velocity ◽  
Falling Film ◽  
Vapor Mixture ◽  
Thin Slab ◽  
Flow Rates ◽  
Variable Flow ◽  
Order Of Magnitude ◽  
Hot Surface

An analytical model for falling-film wetting of a hot surface has been developed to account for the effect of cooling by droplet-vapor mixture in the region immediately ahead of the wet front. The effect of precursory cooling is characterized by a heat transfer coefficient decaying exponentially from the wet front. Based on the present model, the wet front velocity, as well as the temperature profile along a thin slab, can be calculated. It is demonstrated that the precursory cooling can increase the wet front velocity by an order of magnitude. Existing experimental data with variable flow rates at atmospheric pressure are shown to be successfully correlated by the present model.

Innovative Devices That Enable Variable Flow Systems for Energy Savings

2011 ◽  
Author(s):  
A. Keith Miller ◽  
John R. Bode ◽  
Robert Sachs ◽  
Kirt Jensen
Keyword(s):  
Energy Savings ◽  
Low Cost ◽  
Department Of Energy ◽  
Operating Life ◽  
Flow Rates ◽  
Variable Flow ◽  
The Past ◽  
The Us ◽  
Industrial Operations ◽  
Mechanical Devices

Over the past decade numerous studies both conducted by and authorized by the US Department of Energy Office of Industrial Technology have identified significant energy savings potential by adjusting flow rates to meet process demands. As much as 40% energy savings have been achieved when variable flow pumping systems were implemented in some DOE demonstration projects. To date, only a small fraction of the identified companies in various industries which can benefit in energy savings resulting from adjustable pumping flow rates have installed the requisite capabilities. One reason for the slow rate of adoption of variable pumping is that there are few commercially available methods for adjusting pump rates. Electronic Variable Frequency Drives (VFDs) are the most commonly implemented method of varying pump speeds, usually resulting in reduced operating life of the electric drive motors and sometimes in significant costs of plant modifications. Veritran Inc. with the support of Team Technologies, Inc. is developing low-cost mechanical devices for varying electric motor speeds without the large initial investment associated with VFDs nor the other detracting features of the need to install larger electric motors and reduced motor life expectancy. Veritran’s Infinitely Variable Transmissions (IVTs), such as SM-15IVT (www.veritraninc.com) are installed between the motor and the load, which allows for soft starts, and precise output set speeds, all under programmable microprocessor control. The amount of power demanded from the motor varies as the output speed of the transmission is changed or the load torque is changed. This paper will describe the engineering development that Veritran has been pursuing over the past decade of their novel IVTs, and will present some of the test data collected to date. Results will also be presented of systems analyses where IVTs are inserted into various industrial operations and significant energy savings result.

scholarly journals Recovery of Extracellular Lipolytic Enzymes from Macrophomina phaseolina by Foam Fractionation with Air

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Claudia Schinke ◽  
José Carlos Germani
Keyword(s):  
Macrophomina Phaseolina ◽  
Enrichment Ratio ◽  
Foam Fractionation ◽  
Lipolytic Enzymes ◽  
Flow Rates ◽  
Variable Flow ◽  
Simple Medium ◽  
Column Design ◽  
Triton X ◽  
Culture Supernatants

Macrophomina phaseolina was cultivated in complex and simple media for the production of extracellular lipolytic enzymes. Culture supernatants were batch foam fractionated for the recovery of these enzymes, and column design and operation included the use of P 2 frit (porosity 40 to 100 μm), air as sparging gas at variable flow rates, and Triton X-100 added at the beginning or gradually in aliquots. Samples taken at intervals showed the progress of the kinetic and the efficiency parameters. Best results were obtained with the simple medium supernatant by combining the stepwise addition of small amounts of the surfactant with the variation of the air flow rates along the separation. Inert proteins were foamed out first, and the subsequent foamate was enriched in the enzymes, showing estimated activity recovery (R), enrichment ratio (E), and purification factor (P) of 45%, 34.7, and 2.9, respectively. Lipases were present in the enriched foamate.

Performance of a deoiling hydrocyclone during variable flow rates

2007 ◽  
Vol 20 (4) ◽  
pp. 368-379 ◽  
Author(s):  
Trygve Husveg ◽  
Odile Rambeau ◽  
Tormod Drengstig ◽  
Torleiv Bilstad
Keyword(s):  
Flow Rates ◽  
Variable Flow

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.

Hydrodynamic Focused Passive Separation Under Continuous Flow

2011 ◽  
Author(s):  
Jad Kanbar ◽  
David Clague
Keyword(s):  
Velocity Profile ◽  
Continuous Flow ◽  
Particle Trajectory ◽  
Hydrodynamic Focusing ◽  
Flow Rates ◽  
Separation Device ◽  
Variable Flow ◽  
Passive Separation ◽  
Axis Of Symmetry ◽  
Separation Results

A continuous flow symmetric passive separation device was designed using an equivalent circuit to create variable flow rates to drain channels and collection outlets. The inlet reservoir was placed in the axis of symmetry and in line to downstream buffer inlets for hydrodynamic focusing. This inlet reservoir was sufficiently larger than the different inlet connections that were punched into it. By varying the diameter of the inlet connection into the reservoir, the distribution and therefore separation of particles could be influenced to significance. Not only was the ratio of sample inlet diameter to reservoir important, but so was the relative position along the y-axis of the reservoir. We found that a 2:1 ratio and placement at the top and middle of the reservoir yielded the best separation results. Further analysis of the velocity profile in the reservoir was explored using COMSOL Multyphysics®. The observed paths of particle trajectory corroborated with the models. Lastly this device aimed to provide an aspect of separation simple enough to be included in conjunction with other passive separation geometries to further enhance results and throughput.

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