Power input of aerated agitator system of high-speed fermenter

1987 ◽  
Vol 52 (9) ◽  
pp. 2181-2187 ◽  
Author(s):  
Pavel Seichter
Keyword(s):  
Simple Model ◽  
High Speed ◽  
Power Input ◽  
Model Idea

A correlation complying a simple model idea about function of an agitator in aerated high hold-up system has been found on basis of power input measurement of four fermenter agitators.

Surface Aeration Threshold in Agitated Vessels

1996 ◽  
Vol 61 (5) ◽  
pp. 681-690
Author(s):  
Kamil Wichterle ◽  
Tomáš Svěrák
Keyword(s):  
Simple Model ◽  
Liquid Surface ◽  
Power Input ◽  
Power Number ◽  
Region Analysis ◽  
Surface Aeration ◽  
Liquid Dispersion ◽  
Mixing Vessels ◽  
Number Curve

Violent agitation of liquids in mixing vessels may result in the regime of surface aeration being attained when the bubbles formed at the liquid surface enter the impeller region. Analysis of data on surface aeration for different liquids in a set of geometrically similar agitated vessels is presented. Data on the just aerated state as observed visually in transparent liquids, and data for the efficient aeration as determined from the break on the power number curve are considered. A simple model is developed for correlation of the data which enables the threshold of aeration to be predicted from the value of the recirculation number Nc = Nd (ρ/σg)1/4. The possibility of interpreting various literature data for the aeration threshold and for the power input with use of Nc is demonstrated. Similar modelling rules hold also for the correlation of beginning of the efficient liquid-liquid dispersion.

A simple model for the shock wave induced by high-speed impact.

1972 ◽  
Vol 9 (1) ◽  
pp. 13-18 ◽  
Author(s):  
PETER J. TORVIK ◽  
RONALD J. F. PRATER
Keyword(s):  
Shock Wave ◽  
Simple Model ◽  
High Speed ◽  
High Speed Impact ◽  
Wave Induced

BLENDING CHARACTERISTICS OF HIGH-SPEED ROTARY IMPELLERS

2013 ◽  
Vol 34 (4) ◽  
pp. 427-434 ◽  
Author(s):  
Ivan Fořt ◽  
Pavel Seichter ◽  
Luboš Pešl ◽  
František Rieger ◽  
Tomáš Jirout
Keyword(s):  
Turbulent Flow ◽  
Flow Regime ◽  
High Speed ◽  
Large Scale ◽  
Energy Savings ◽  
Axial Flow ◽  
Power Input ◽  
Maximum Energy ◽  
Cylindrical Vessel ◽  
Turbulent Flow Regime

Abstract This paper presents a comparison of the blending efficiency of eight high-speed rotary impellers in a fully baffled cylindrical vessel under the turbulent flow regime of agitated charge. Results of carried out experiments (blending time and impeller power input) confirm that the down pumping axial flow impellers exhibit better blending efficiency than the high-speed rotary impellers with prevailing radial discharge flow. It follows from presented results that, especially for large scale industrial realisations, the axial flow impellers with profiled blades bring maximum energy savings in comparison with the standard impellers with inclined flat blades (pitched blade impellers).

Experimental Study on Oscillating Heat Pipe With a Hydraulic Diameter Far Exceeding the Maximum Hydraulic Diameter

2020 ◽  
Vol 12 (6) ◽  
Author(s):  
Lilin Chu ◽  
Yulong Ji ◽  
Hongbin Ma ◽  
Yantao Li ◽  
Chao Chang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Input ◽  
High Speed ◽  
Heat Transfer Performance ◽  
Power Input ◽  
Hydraulic Diameter ◽  
Working Fluid ◽  
Transfer Performance ◽  
Vertical Orientation ◽  
Oscillating Heat Pipe

Abstract In order to understand the heat transfer performance, startup, and fluid flow conditions of oscillating heat pipes (OHPs) with a hydraulic diameter far exceeding the maximum hydraulic diameter (MHD) defined by dh,max≤2σBo/(ρl−ρv)g, an experimental investigation on the OHP heat transfer performance and visualization was conducted. The effects of heat input, working fluid, and orientation on the oscillating motion and heat transfer performance of the investigated OHPs have been conducted. In addition, the detailed flow patterns of the tested OHPs were recorded by a high-speed camera from both vertical and horizontal orientations. Results show that the maximum hydraulic diameter, which can form a train of liquid plugs and vapor bubbles, which is essential for an OHP to function, depends on the heat input, working fluid, and orientation. At a power input of 1000 W, the OHP can still function well even when the tube diameter exceeds the MHD of 91.6%. This maximum hydraulic dimeter depends on the orientation. While the OHP with a dimeter far exceeding the MHD can still function, the heat transfer performance of the OHP in a vertical orientation is better than in a horizontal orientation.

Energetic efficiency of two impellers on the same shaft in a cylindrical baffled vessel of high height/diameter ratio

1989 ◽  
Vol 54 (9) ◽  
pp. 2345-2356 ◽  
Author(s):  
Ivan Fořt ◽  
Jiří Hájek ◽  
Václav Machoň
Keyword(s):  
High Speed ◽  
Power Input ◽  
Vessel Diameter ◽  
Diameter Ratio ◽  
Energetic Efficiency ◽  
Turbulent Regime ◽  
Inclined Plane ◽  
Pumping Effect ◽  
Charge Flow ◽  
Turbine Impeller

The paper deals with the experimental study of the indicating particle circulation and the impeller power input in a liquid mechanically agitated with two high-speed impellers (combination of the standard turbine impeller and the six inclined (at 45°) plane blades impeller) on the same shaft in a slender vessel (its height is equal double of the vessel diameter) equipped with four radial baffles at its walls under the turbulent regime of agitated charge flow. By the visual method of the indicating particle it is examined its circulation in the lower part of the system pumping effect of the lower impeller), its circulation in the upper part of the system (pumping effect of the upper impeller), and the exchangeable circulation between the upper and lower part of the system and vice versa. The impeller power input is ascertained from the measured current electricity in the anchor of the direct current driving motor. It follows from the calculated energetic efficiency (the ratio of the cube of the sum of the impeller flow rate numbers and the sum of the impeller power numbers) of the investigated combinations of impellers that the highest value of this quantity is exhibited for two standard turbine impellers on the same shaft and for a combination of the lower standard turbine impeller and the upper impeller with inclined plane blades pumping upwards; slightly less value of the impeller energetic efficiency appears for the combination of two impellers with six inclined plane blades, the upper one pumps liquid upwards and the lower one downwards. For all the configurations the vertical distance of impellers on the same shaft has to be longer than the vessel diameter.

scholarly journals A LABORATORY STUDY OF OFFSHORE TRANSPORT OF SEDIMENT AND A MODEL FOR ERODING BEACHES

1980 ◽  
Vol 1 (17) ◽  
pp. 64 ◽  
Author(s):  
Tsuguo Sunamura
Keyword(s):  
Simple Model ◽  
Water Waves ◽  
High Speed ◽  
Sediment Flux ◽  
Data Sets ◽  
Two Dimensional ◽  
Shallow Water Waves ◽  
Picture Analysis ◽  
Offshore Transport ◽  
Existing Data

A two-dimensional laboratory investigation of sediment transport, induced by shallow-water waves, showed that the sediment motion over suspension-dominant asymmetric ripples is closely related to the development of eroding beaches. High-speed motion picture analysis revealed that vortices, formed over this type of ripple, play a crucial role in transporting the sediment to the offshore region. A relation for net offshore sediment flux was formulated for sand 0.02 cm in diameter. A simple model for eroding beaches was proposed and its validity was checked by using two existing data sets for 0.02-cm sand beaches; the model could predict fairly well profile and shoreline changes in the early stages.

Turbulent mixing in a pulsed plasma-jet exhaust

1984 ◽  
Vol 148 ◽  
pp. 207-224 ◽  
Author(s):  
D. R. Topham ◽  
R. M. Clements ◽  
P. R. Smy
Keyword(s):  
Simple Model ◽  
Turbulent Mixing ◽  
High Speed ◽  
Good Description ◽  
Plasma Jet ◽  
High Energy ◽  
Pulsed Plasma ◽  
Internal Temperature ◽  
Turbulent Structures ◽  
Laboratory Models

High-speed schlieren cinéphotography of the firing of a high-energy plasma-jet igniter reveal turbulent structures similar in appearance to laboratory models of thermals or turbulent puffs. Measurements of the growth rates of these features together with those of their impulse and thermal energy confirm this similarity. A simple model based on the entrainment assumption gives a good description of the motion of the element and also of the decay of the internal temperature.

High Speed Rotary Pulse Width Modulated On/Off Valve

2007 ◽  
Author(s):  
Haink C. Tu ◽  
Michael B. Rannow ◽  
James D. Van de Ven ◽  
Meng Wang ◽  
Perry Y. Li ◽  
...  
Keyword(s):  
High Speed ◽  
Viscous Friction ◽  
Power Input ◽  
Axial Position ◽  
Reverse Direction ◽  
Duty Ratio ◽  
Concept Design ◽  
Hydraulic Systems ◽  
Output Pressure ◽  
Acceleration And Deceleration

A key enabling technology to effective on/off valve based control of hydraulic systems is the high speed on/off valve. High speed valves improve system efficiency for a given PWM frequency, offer faster control bandwidth, and produce smaller output pressure ripples. Current valves rely on the linear translation of a spool or poppet to meter flow. The valve spool must reverse direction twice per PWM cycle. This constant acceleration and deceleration of the spool requires a power input proportional to the PWM frequency cubed. As a result, current linear valves are severely limited in their switching frequencies. In this paper, we present a novel fluid driven PWM on/off valve design that is based on a unidirectional rotary spool. The spool is rotated by capturing momentum from the fluid flow through the valve. The on/off functionality of our design is achieved via helical barriers that protrude from the surface of a cylindrical spool. As the spool rotates, the helical barriers selectively channel the flow to the application (on) or to tank (off). The duty ratio is controlled by altering the axial position of the spool. Since the spool no longer accelerates or decelerates during operation, the power input to drive the valve must only compensate for viscous friction, which is proportional to the PWM frequency squared. We predict that our current design, sized for a nominal flow rate of 40l/m, can achieve a PWM frequency of 84Hz. This paper presents our valve concept, design equations, and an analysis of predicted performance. A simulation of our design is also presented.

scholarly journals Dynamics of carving runs in alpine skiing. I.The basic centrifugal pendulum.

2019 ◽  
Author(s):  
Serguei Komissarov
Keyword(s):  
Simple Model ◽  
Centrifugal Force ◽  
High Speed ◽  
Inverted Pendulum ◽  
Vertical Position ◽  
Alpine Skiing ◽  
Supercritical Regime ◽  
Current Form ◽  
Speed Regime ◽  
Fall Line

We studied perfect carving turns of alpine skiing using the simple model of an inverted pendulum which is subject to the gravity force and the force mimicking the centrifugal force emerging in the turns. Depending on the turn speed the model describes two different regimes. In the subcritical ( low speed) regime, there exist three equilibrium positions of the pendulum where the total torque applied to the pendulum vanishes -- the marginally stable vertical position and two unstable tilted positions on both sides of the vertical. The tilted equilibria correspond to the ski turns executed in perfect balance. The vertical equilibrium corresponds to gliding down the fall line without turns. In the supercritical (high speed) regime, the tilted equilibria disappear. In addition to the equilibria the model allows fall-rise solutions, where the pendulum (skier) hits (rises from) the ground, and oscillations about the vertical. These oscillations correspond to the so-called dynamic skiing where the skier never settles to a balanced position in the turn. Analysis of the available data on FIS WC races shows that elite races ski mostly in the supercritical regime. In its current form the model of centrifugal pendulum has no feedback components associated with the skier control over their runs and therefore describes a riderless mono ski. Hence the theory predicts that such a vehicle can execute carving turns automatically.

scholarly journals Flagellar energetics from high-resolution imaging of beating patterns in tethered mouse sperm

2020 ◽  
Author(s):  
Ashwin Nandagiri ◽  
Avinash S. Gaikwad ◽  
David L. Potter ◽  
Reza Nosrati ◽  
Julio Soria ◽  
...  
Keyword(s):  
High Resolution ◽  
High Speed ◽  
Power Input ◽  
Internal Resistance ◽  
Mechanical Power ◽  
Secretory Proteins ◽  
Mouse Sperm ◽  
Kirchhoff Rod ◽  
Internal Dissipation ◽  
Processing Techniques

AbstractWhile much is known about the microstructure of sperm flagella, the mechanisms behind the generation of flagellar beating patterns by the axoneme are still not fully understood. We demonstrate a technique for investigating the energetics of flagella or cilia. We record the planar beating of tethered wildtype and Crisp2-knockout mouse sperm at high-speed and high-resolution and extract centerlines using digital image processing techniques. We accurately reconstruct beating waveforms using a Chebyshev-polynomial based Proper Orthogonal Decomposition of the centerline tangent-angle profiles. External hydrodynamic forces and the internal resistance from the passive flagellar material are calculated from the observed kinematics of the beating patterns using a Soft, Internally-Driven Kirchhoff-Rod (SIDKR) model. Energy conservation is employed to further compute the flagellar energetics. We thus obtain the distribution of mechanical power exerted by the dynein motors without any further assumptions about mechanisms regulating axonemal function. We find that, in both the mouse genotypes studied, a large proportion of the mechanical power exerted by the dynein motors is dissipated internally, within the passive structures of the flagellum and by the motors themselves. This internal dissipation is considerably greater than the hydrodynamic dissipation in the aqueous medium outside. The net power input from the dynein motors in sperm from Crisp2-knockout mice is significantly smaller than in corresponding wildtype samples. The reduced power is correlated with slower beating and smaller amplitudes. These measurements of flagellar energetics indicate that the ion-channel regulating cysteine-rich secretory proteins (CRISPs) may also be involved in regulating mammalian sperm motility.

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