Preferential flow: first results of a full-scale flow model

The distribution of velocity, sludge, and dissolved oxygen in a full-scale anaerobic-anoxic-oxic (A2/O) oxidation ditch was numerically simulated under three rotation speed scenarios. The viscosity and settling rate of activated sludge were defined through a user-defined function (UDF), and the sludge phase was calculated using the mixture multiphase flow model. Dissolved oxygen (DO) was set as a user-defined source (UDS) and its generation and consumption rates were defined with UDFs. The relationship between velocity and sludge concentration was found to be contradictory, with dead zones leading to large sludge concentrations at the bottom of the oxidation ditch (OD), but not at the middle-curved wall of the anoxic pool. The flow rate of the reflux slot and aerator oxygenation rate were checked and correlated with DO concentrations in the anaerobic pool. The majority of the large sludge concentrations were concentrated in the biological selection pool and these remained constant with bed height. With reduced propeller and agitator rotation speed, the sludge concentrations reduced in the biological selection pool, but increased in the anaerobic and anoxic pools.

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Infrared Signature Suppression for Marine Gas Turbines: Comparison of Sea Trial and Model Test Results for the DRES Ball IRSS System

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.2906812 ◽

1994 ◽

Vol 116 (1) ◽

pp. 75-81 ◽

Cited By ~ 11

Author(s):

A. M. Birk ◽

D. VanDam

Keyword(s):

Model Test ◽

Gas Turbines ◽

Flow Model ◽

Full Scale ◽

Scale Model ◽

Test Results ◽

Sea Trial ◽

Infrared Signature ◽

Plume Temperature ◽

Better Than

Sea Trials have recently been underway for Canada’s new City Class Patrol Frigate (CPF). These trials provided the first opportunity to measure the performance of the new DRES Ball Infrared Signature Suppression (IRSS) system installed on a ship. Prior to these trials 1/4-scale hot flow model test and computer simulation performance results were available. The CPF DRES Ball IRSS systems are installed on the exhaust uptakes of the GE LM2500 main gas turbines. The DRES Ball provides both metal surface cooling for all view angles and plume cooling. The DRES Ball significantly reduces the IR signature of the LM2500 exhaust. This paper presents a comparison between the 1/4-scale hot flow model test results with the full-scale sea trial results. Performance variables included in the comparison are: metal surface temperatures, back pressure, plume temperature distribution, and surface static pressures. Because of the confidential nature of the DRES Ball system performance, all classified data have been nondimensionalized so that only relative comparisons can be made between the full-scale and 1/4-scale data. The results show that the full-scale system performs better than the 1/4-scale model because of Reynolds number effects. The plume temperature, surface temperatures, and back pressure were all lower (better) than in the 1/4-scale model tests. One of the original concerns with the installation was that relative wind would degrade the performance of the DRES Ball onboard a ship. The wind effect was found to be benign during the trials.

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Comparison of the lung ventilation assessed by a full-scale airway network flow model and xenon-enhanced dual-energy CT of patients with COPD

10.1183/13993003.congress-2020.2197 ◽

2020 ◽

Author(s):

Minsuok Kim ◽

Ozkan Doganny ◽

Hae Jeon Hwang ◽

Joon Beom Seo ◽

Fergus Gleeson

Keyword(s):

Network Flow ◽

Flow Model ◽

Lung Ventilation ◽

Dual Energy ◽

Full Scale ◽

Dual Energy Ct ◽

Network Flow Model

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Estimation of unsaturated zone traveltimes for Rainier Mesa and Shoshone Mountain, Nevada Test Site, Nevada, using a source-responsive preferential-flow model

10.2172/964260 ◽

2009 ◽

Cited By ~ 1

Author(s):

Brian A Ebel ◽

John R Nimmo

Keyword(s):

Unsaturated Zone ◽

Preferential Flow ◽

Flow Model ◽

Test Site ◽

Nevada Test Site

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‘Technology transfer-oriented research and development in the wastewater sector – validation at industrial-scale plants’ (EXPOVAL) – Subgroup 6: solar sewage sludge drying: first results from investigations with a pilot plant

Water Practice & Technology ◽

10.2166/wpt.2015.045 ◽

2015 ◽

Vol 10 (2) ◽

pp. 371-380

Author(s):

R. Dellbrügge ◽

K. Bauerfeld ◽

N. Dichtl ◽

A. Großer ◽

S. Paris

Keyword(s):

Sewage Sludge ◽

Pilot Plant ◽

Subsequent Development ◽

Pilot Scale ◽

Full Scale ◽

Fecal Coliforms ◽

Climate Data ◽

First Results ◽

Sludge Drying ◽

Kjeldahl Nitrogen

Drying sewage sludge is a major aspect of biosolids management. Several investigations were performed in a pilot-scale solar dryer for the subsequent development of design rules for solar dryers. The pilot dryer was operated outside simultaneously with a full-scale dryer and, later, in a building. Total solids in the sludge and climate data were analyzed and logged regularly during drying. The fecal coliform and ammonium content was measured as well. Operation next to the full-scale plant was intended to enable comparison of their evaporation rates. The pilot plant was operated in a building in order to assess the influence of external heat input on the drying process. The results showed constant drying progress and that drying was feasible. Although differences in evaporation rates arising from operation, aeration and scaling existed, evaporation rates comparable to full-scale dryers were observed. Under floor heating improved evaporation rates by 25%. More than 50% of total Kjeldahl nitrogen was degraded, and this could be detected as NH3 in the discharged air. Reduction in fecal coliforms could be achieved without reaching secure disinfection, as required by USEPA standard 503 (USEPA 2007).

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