Verification and application of a mathematical model for the assessment of the effect of guiding walls on the hydraulic efficiency of chlorination tanks

A mathematical model is applied to the tank of Kipseli in Athens, Greece, which is used for storage, balancing and emergency chlorination. A Flow-Through Curve (FTC) experiment is performed for the initial geometry of the tank. The shape and the characteristics of the FTC show a very poor hydraulic efficiency, with extensive short-circuiting, intense mixing and low detention times. To improve the hydraulic efficiency of the tank the use of four alternative arrangements of guiding walls is examined by the model. Prior to its application, the model is verified by comparing the predicted FTC with the experimental. A satisfactory agreement is observed between the calculated and the experimental curves. Then the model is applied to calculate the flow field and the FTC for the four arrangements. Calculations are compared and the arrangement which shows the highest hydraulic efficiency is proposed for construction.

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Case Studies of Coupled Heat and Moisture Diffusion in Wool Beds

Textile Research Journal ◽

10.1177/004051756903900206 ◽

1969 ◽

Vol 39 (2) ◽

pp. 166-172 ◽

Cited By ~ 29

Author(s):

H. G. David ◽

P. Nordon

Keyword(s):

Mathematical Model ◽

Relative Humidity ◽

Heat Flow ◽

Case Studies ◽

Satisfactory Agreement ◽

Moisture Diffusion ◽

Wool Fabrics ◽

Flow Through ◽

Coupled Heat And Moisture ◽

Heat And Moisture

The predictions from a previously developed mathematical model for coupled heat and moisture diffusion in beds of hygroscopic fibers have been tested against experimental observations on wool bales and wool fabrics. The experiments on wool bales were concerned with the changes in regain and temperature consequent upon changes in the relative humidity and temperature of the surrounding air. The experiments on fabrics included measurements of temperature and regain during Hoffman pressing and measurements of heat flow through the fabric during changes in regain. Satisfactory agreement was found between the predictions from the model and the experimental observations.

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Theoretical Development of Mathematical Model to Predict Vertical Wicking Behavior of Flow through Terry Towels

Bulletin of the Faculty of Engineering. Mansoura University ◽

10.21608/bfemu.2020.99456 ◽

2020 ◽

Vol 41 (4) ◽

pp. 1-15

Author(s):

Hemdan Abou-Taleb ◽

Heba El-Fowaty

Keyword(s):

Mathematical Model ◽

Theoretical Development ◽

Vertical Wicking ◽

Flow Through

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Influence of M-EMS on Fluid Flow and Initial Solidification in Slab Continuous Casting

Materials ◽

10.3390/ma14133681 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3681

Author(s):

Guoliang Liu ◽

Haibiao Lu ◽

Bin Li ◽

Chenxi Ji ◽

Jiangshan Zhang ◽

...

Keyword(s):

Mathematical Model ◽

Flow Field ◽

Continuous Casting ◽

Casting Speed ◽

Liquid Pool ◽

Industrial Test ◽

Magnetic Flux Density ◽

Continuous Casting Mold ◽

Slab Continuous Casting ◽

Initial Solidification

A mathematical model coupled with electromagnetic field has been developed to simulate the transient turbulence flow and initial solidification in a slab continuous casting mold under different electromagnetic stirring (EMS) currents and casting speeds. Through comparing the magnetic flux density, flow field with measured results, the reliability of the mathematical model is proved. The uniform index of solidified shell thickness has been introduced to judge the uniformity of the solidified shell. The results show that a horizonal recirculation flow has been generated when EMS is applied, and either accelerated or decelerated regions of flow field are formed in the liquid pool. Large EMS current and low casting speed may cause the plug flow near the mold narrow face and a suitable EMS current can benefit to the uniform growth of solidified shell. Meanwhile, an industrial test exhibits that EMS can weaken the level fluctuation and number density of inclusion. Overall, a rational EMS current range is gained, when the casting speed is 1.2 m/min, the rational EMS current is 500–600 A.

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Analysis of Performance of the Wind-Driven Pulverizing Aerator Based on Average Wind Speeds in the Conditions of Góreckie Lake

Energies ◽

10.3390/en14102796 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2796

Author(s):

Andrzej Osuch ◽

Ewa Osuch ◽

Stanisław Podsiadłowski ◽

Piotr Rybacki

Keyword(s):

Mathematical Model ◽

Wind Speed ◽

Water Pump ◽

Average Wind Speed ◽

Flow Rates ◽

Wind Speeds ◽

Average Wind ◽

Flow Through ◽

Analysis Of Performance ◽

Research Period

In the introduction to this paper, the characteristics of Góreckie lake and the construction and operation of the wind-driven pulverizing aerator are presented. The purpose of this manuscript is to determine the efficiency of the pulverizing aerator unit in the windy conditions of Góreckie Lake. The efficiency of the pulverization aerator depends on the wind conditions at the lake. It was necessary to conduct thorough research to determine the efficiency of water flow through the pulverization segment (water pump). It was necessary to determine the rotational speed of the paddle wheel, which depended on the average wind speed. Throughout the research period, measurements of hourly average wind speed were carried out. It was possible to determine the efficiency of the machine by developing a dedicated mathematical model. The latest method was used in the research, consisting of determining the theoretical volumetric flow rates of water in the pulverizing aerator unit, based on average hourly wind speeds. Pulverization efficiency under the conditions of Góreckie Lake was determined based on 6600 average wind speeds for spring, summer and autumn, 2018. Based on the model, the theoretical efficiency of the machine was calculated, which, under the conditions of Góreckie Lake, amounted to 75,000 m3 per year.

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Influence of a Honeycomb Facing on the Flow Through a Stepped Labyrinth Seal

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1403460 ◽

2000 ◽

Vol 124 (1) ◽

pp. 140-146 ◽

Cited By ~ 22

Author(s):

V. Schramm ◽

K. Willenborg ◽

S. Kim ◽

S. Wittig

Keyword(s):

Flow Field ◽

Three Dimensional ◽

Theoretical Work ◽

Labyrinth Seal ◽

Honeycomb Structure ◽

Experimental Investigations ◽

Labyrinth Seals ◽

Numerical Predictions ◽

Flow Through ◽

Aero Engines

This paper reports numerical predictions and measurements of the flow field in a stepped labyrinth seal. The theoretical work and the experimental investigations were successfully combined to gain a comprehensive understanding of the flow patterns existing in such elements. In order to identify the influence of the honeycomb structure, a smooth stator as well as a seal configuration with a honeycomb facing mounted on the stator wall were investigated. The seal geometry is representative of typical three-step labyrinth seals of modern aero engines. The flow field was predicted using a commercial finite volume code with the standard k-ε turbulence model. The computational grid includes the basic seal geometry as well as the three-dimensional honeycomb structures.

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Interaction Between Two Closely Spaced Azimuthing Thrusters

Journal of Ship Research ◽

10.5957/jsr.1998.42.1.15 ◽

1998 ◽

Vol 42 (01) ◽

pp. 15-32 ◽

Cited By ~ 1

Author(s):

Paul Brandner ◽

Martin Renilson

Keyword(s):

Mathematical Model ◽

Satisfactory Agreement ◽

Vehicle Dynamics ◽

Operating Conditions ◽

Towing Tank ◽

Empirical Relations ◽

Series Of Experiments ◽

Flow Effects ◽

Semi Empirical

To assist in predicting the performance of omni-directional propelled vehicles a series of experiments has been conducted to measure the interaction between two closely spaced ductedazimuthing thrusters. The thrusters were tested below a shallow draft ground board in a towing tank at a spacing of approximately 2 propeller diameters. Measurements were made of forces acting on a single thruster for a range of operating conditions and similarly on two thrusters for a range of relative positions. The results show that forces from the trailing thruster are heavily affected by interaction, particularly due to impingement of the race from the leading thruster, where as forces from the leading thruster remain essentially unaffected despite its proximity to the trailing thruster. A semi-empirical mathematical model suitable for simulation of omni-directional vehicle dynamics is presented. The model is based on the trajectory of the race from the leading thruster derived from momentum considerations with additional empirical relations to account for other more minor flow effects. Comparison of the predicted and measured results show satisfactory agreement.

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