scholarly journals Unconfined Dense Plunging Jets Used for Brine Disposal from Desalination Plants

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 696
Author(s):  
Aaron C. Chow ◽  
Ishita Shrivastava ◽  
E. Eric Adams ◽  
Fahed Al-Rabaie ◽  
Bader Al-Anzi
Keyword(s):  
Water Column ◽  
Penetration Depth ◽  
Laboratory Experiments ◽  
Buoyant Jets ◽  
Air Bubble ◽  
Plunging Jets ◽  
Desalination Plants ◽  
Entrained Air ◽  
Neutrally Buoyant ◽  
Receiving Water

Laboratory experiments were conducted to measure entrained air bubble penetration depth and dilution of a dense vertical unconfined plunging jet to evaluate its performance as an outfall to dilute brine from desalination plants as well as a means to aerate water column. Experiments involved neutrally buoyant or dense plunging jets discharging in quiescent receiving water. The density difference between effluent and receiving water, the plunging jet length (height above water surface), and the receiving water salinity were varied in the experiments. Observed penetration depth for neutrally buoyant jets was somewhat greater than previously reported, and increased modestly with jet density. Increasing density also resulted in an increasing number of fine bubbles descending together with the dense plume. These observations can help guide the design of plunging jets to mitigate anoxic conditions in the water column when brine is introduced to a receiving water body, as with seawater desalination.

scholarly journals Confined Plunging Liquid Jets for Dilution of Brine from Desalination Plants

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 856
Author(s):  
Ishita Shrivastava ◽  
Edward Eric Adams ◽  
Bader Al-Anzi ◽  
Aaron Chunghin Chow ◽  
Jongyoon Han
Keyword(s):  
Water Column ◽  
Penetration Depth ◽  
Water Surface ◽  
Liquid Jets ◽  
Laboratory Measurements ◽  
Surrounding Water ◽  
Plunging Jets ◽  
Desalination Plants ◽  
Negative Buoyancy

Confined plunging jets are investigated as potential outfalls for the discharge of desalination brine. Compared to offshore submerged outfalls that rely on momentum to induce mixing, plunging jets released above the water surface utilize both momentum and negative buoyancy. Plunging jets also introduce air into the water column, which can reduce the possibility of hypoxic zones. In contrast to unconfined plunging jets, confined plunging jets include a confining tube, or downcomer, around the jet, which increases the penetration depth of the bubbles and can provide better aeration. However, the presence of this downcomer can hinder mixing with surrounding water. Therefore, laboratory measurements of dilution are reported here and compared to the dilution of unconfined plunging jets. In addition, qualitative observations of bubble penetration depth are also used to discuss aeration potential. For designs that increase the bubble penetration depth as compared to unconfined plunging jets, results show that dilution decreases as the depth of the downcomer is increased. However, it is shown that confined plunging jets can be designed with a short downcomer to provide higher dilution than unconfined jets. The effect of the diameter of downcomer on dilution is also investigated and a non-monotonic effect is observed.

Schutzbehandlung von Beton mit Silan- und Siloxanpräparaten / Protective Treatment of Concrete with Silane or Siloxane

1999 ◽  
Vol 5 (3) ◽  
pp. 307-310
Author(s):  
B. Nyman
Keyword(s):  
Moisture Content ◽  
Penetration Depth ◽  
Laboratory Experiments ◽  
Protective Treatment

Abstract By means of laboratory experiments it is shown that the penetration depth of a treatment of concrete with Silane depends strongly on the duration of suction and on the moisture content of the concrete. The necessary duration of suction can be estimated for any required penetration depth.

scholarly journals Vertical Round Buoyant Jets and Fountains in a Linearly, Density-Stratified Fluid

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 232
Author(s):  
Panos N. Papanicolaou ◽  
George C. Stamoulis
Keyword(s):  
Steady State ◽  
Laboratory Experiments ◽  
Coefficient Function ◽  
Buoyant Jets ◽  
Asymptotic Values ◽  
Entrainment Coefficient ◽  
Source Level ◽  
The Mean ◽  
Negatively Buoyant ◽  
Negatively Buoyant Jets

Turbulent round buoyant jets and fountains issuing vertically into a linearly density-stratified calm ambient have been investigated in a series of laboratory experiments. The terminal (steady-state) height of rise and the mean elevation of subsequent horizontal spreading have been measured in positively buoyant jets (at source level), including pure momentum jets and plumes, as well in momentum-driven negatively buoyant jets (fountains). The results from experiments confirmed the asymptotic analysis that was based on dimensional arguments. The normalized terminal height and spreading elevation with respect to the elevation of injection of momentum-driven (positively) buoyant jets and fountains attained the same asymptotic values. The numerical results from the solution of entrainment equations, using an improved entrainment coefficient function, confirmed the results related to buoyancy dominant flows (plumes), while their predictions in momentum-driven flows were quite low if compared to measurements.

A model for the light-limited growth of buoyant phytoplankton in a shallow, turbid waterbody

1994 ◽  
Vol 45 (5) ◽  
pp. 847 ◽  
Author(s):  
BE Sherman ◽  
IT Webster
Keyword(s):  
Wind Speed ◽  
Water Column ◽  
Chlorophyll Concentration ◽  
Light Attenuation ◽  
Euphotic Zone ◽  
Limited Growth ◽  
Potential Growth ◽  
Column Temperature ◽  
Turbid Waters ◽  
Neutrally Buoyant

A computer model was used to explore the relationship between buoyancy and the light-limited growth of phytoplankton in very turbid waters. The model simulates the potential growth of phytoplankton as a function of flotation speed, using field observations of photosynthetically active radiation, wind speed, surface-layer thickness (from water-column temperature data), and light attenuation made at Rushy Billabong on the River Murray from 28 November 1991 to 26 March 1992. A unique feature of the model is the simulation of the development and dispersal of surface scums as a function of wind speed. Under nutrient-replete conditions, the model predicted that phytoplankton with a flotation speed of 1-10 m day-1 (typical of Anabaena flos-aquae and Microcystis aeruginosa) would grow up to four times faster than would neutrally buoyant phytoplankton with the same maximum specific growth rate. In the shallow system modelled, high flotation speeds allowed a large proportion of the total population to rise into the euphotic zone shortly after the onset of stratification each day. Surface scums played an important role in maintaining the more buoyant phytoplankton populations close to the water surface. Under the very turbid conditions in the billabong (100 nephelometric turbidity units), self-shading became significant only when the mean chlorophyll concentration in the water column approached 100 mg chla m-3.

Partitioning of unsubstituted Polycyclic Aromatic Hydrocarbons between surface sediments and the water column in the Brisbane River Estuary

1990 ◽  
Vol 41 (4) ◽  
pp. 443 ◽  
Author(s):  
SI Kayal ◽  
DW Connell
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Water Column ◽  
Aromatic Hydrocarbons ◽  
Partition Coefficients ◽  
Laboratory Experiments ◽  
River Estuary ◽  
Chemical Properties ◽  
Linear Relationships ◽  
Physico Chemical ◽  
Polycyclic Aromatic

In all, 23 sediment samples and 8 water column samples from the Brisbane River estuary, Queensland, Australia, were analysed for polycyclic aromatic hydrocarbons (PAHs) in order to assess the field partitioning behaviour of these hydrocarbons. Twelve PAHs, ranging in molecular weight from naphthalene to benzo[a]pyrene, were identified and quantified. Their partition coefficients, indexed to sediment organic carbon and lipid content, were calculated after filtering to remove particulates and making a calculated adjustment for colloids, or organic matter, in the water phase. In logarithmic form, the partition coefficients were related to the physico-chemical properties of the compounds (Kow, Sw, RRT) by relationships having a parabolic shape rather than being linear. However, compounds with log Kow values of less than 5.5 gave linear relationships comparable to, but distinctly different from, those obtained from laboratory experiments. It is suggested that field conditions have distinctive differences from laboratory experiments that do not allow the direct translation of laboratory-based relationships to the natural aquatic environment.

Distribution and transformation of elemental mercury in the St. Lawrence River and Lake Ontario

2000 ◽  
Vol 57 (S1) ◽  
pp. 155-163 ◽  
Author(s):  
Marc Amyot ◽  
David RS Lean ◽  
Laurier Poissant ◽  
Marie-Renée Doyon
Keyword(s):  
Water Column ◽  
Laboratory Experiments ◽  
Lake Ontario ◽  
Elemental Mercury ◽  
Volatile Species ◽  
Spatial And Temporal Patterns ◽  
First Order ◽  
Inland Lakes ◽  
First Order Kinetics ◽  
St Lawrence River

Elemental Hg (Hg0) is a volatile species that is responsible for water-to-air transfer of Hg in Lake Ontario and the St. Lawrence River. We conducted two cruises in 1998 to identify spatial and temporal patterns in Hg0 levels in these systems and performed field and laboratory experiments on redox transformations of Hg. Elemental Hg concentrations were higher in Lake Ontario than in the St. Lawrence River. At stations in Lake Ontario, Hg0 levels were higher at the bottom of the water column than at the surface, whereas they were homogeneous throughout the water column of the river. Elemental Hg concentrations were generally higher in July than in September and, in contrast with experiments on inland lakes, were relatively constant during the day except for a narrow peak at sunrise. Field and laboratory experiments showed that photoreduction of Hg(II) in St. Lawrence River water was substrate limited and was influenced by visible and ultraviolet radiation. Pseudo first-order kinetics best described photoreduction, with k values between 1 and 2·h-1.

Water-Column Separation at Two Pumping Plants

1968 ◽  
Vol 90 (4) ◽  
pp. 521-530 ◽  
Author(s):  
R. J. Brown
Keyword(s):  
Water Column ◽  
Detrimental Effect ◽  
Time History ◽  
Field Measurements ◽  
Measured Data ◽  
Operating Characteristics ◽  
Inherent Difficulty ◽  
Column Separation ◽  
History Of ◽  
Entrained Air

Results of field measurement of transients in two pump discharge lines show that the pressures were greater than had been predicted during design, and a theory and method of analysis are developed which explains the time-history of the transients measured. The field measurements were undertaken because of the complexity of the phenomena and because very little measured data were available. Results are presented graphically along with analytical solutions. Conclusions drawn were: (a) The inherent difficulty of prediction of water-column separation effects is further complicated by the uncertainty about complete pump operating characteristics and actual moment of inertia of pumps and motors; (b) the effects of air and gases entrained in solution in the water must be considered in the analytical solution; and (c) entrained air can have a detrimental effect on the water-hammer transient, i.e., larger pressure surges in the discharge line and higher reverse speeds of the pumps can be caused by its presence.

scholarly journals A Study of Bubble Entrainment as Related to Runner Velocity in Aluminum Sand Castings Using the Cosworth Process

2007 ◽  
Vol 539-543 ◽  
pp. 398-403 ◽  
Author(s):  
John C. Burford ◽  
Jerry Sokolowski
Keyword(s):  
Transient Flow ◽  
Metal Flow ◽  
Critical Value ◽  
Low Velocity ◽  
Air Bubble ◽  
Aluminum Castings ◽  
Bubble Entrainment ◽  
Open Production ◽  
Entrained Air ◽  
Flow Experiences

Traditional gravity pour down-sprue methods of filling moulds in the making of aluminum castings inherently lead to oxide and air bubble entrainment. The reason for this is found in the high velocities the metal flow experiences during the filling of a mould. The Nemak Windsor Aluminum Plant (WAP) produces cylinder blocks using the low-pressure Cosworth process, which includes low velocity up-hill filling of the sand mould package. This doctrine is followed in all except one part of the process: the runner system. The nature of the resulting defect is generally known as Head Deck Porosity. Runners were cast full in open production runners at three different velocities with the resulting quickly chilled castings analyzed using X-ray radioscopy, and Scanning Electron Microscopy. Results reveal that the subject bubble porosity is indeed the result of air entrained during initial transient flow within the production runner system whose velocity is higher than the critical value of 0.5ms-1. This theoretical value is corroborated by experimental results. In addition, a new "sessile" runner of optimized shape, filled at a velocity slower than the critical value, is proposed and analyzed using Magmasoft mould fill modelling software. The design can potentially replace the existing runner providing a casting free of entrained air.

Photographic survey of benthos provides insights into the Antarctic fish fauna from the Marguerite Bay slope and the Amundsen Sea

2012 ◽  
Vol 25 (1) ◽  
pp. 31-43 ◽  
Author(s):  
Joseph T. Eastman ◽  
Margaret O. Amsler ◽  
Richard B. Aronson ◽  
Sven Thatje ◽  
James B. McClintock ◽  
...  
Keyword(s):  
Water Column ◽  
Fish Fauna ◽  
Antarctic Fish ◽  
Amundsen Sea ◽  
Dissostichus Mawsoni ◽  
West Antarctic ◽  
Marguerite Bay ◽  
Macrourus Whitsoni ◽  
Photographic Survey ◽  
Neutrally Buoyant

AbstractWe reviewed photographic images of fishes from depths of 381–2282 m in Marguerite Bay and 405–2007 m in the Amundsen Sea. Marguerite Bay fishes were 33% notothenioids and 67% non-notothenioids. Channichthyids (47%) and nototheniids (44%) were the most abundant notothenioids. The deep-living channichthyidChionobathyscus dewitti(74%) and the nototheniid genusTrematomus(66%) were the most abundant taxa within these two families. The most abundant non-notothenioids were the macrouridMacrourus whitsoni(72%) and zoarcids (18%). Amundsen Sea fishes were 87% notothenioids and 13% non-notothenioids, the latter exclusivelyMacrourus whitsoni. Bathydraconids (38%) and artedidraconids (30%) were the most abundant notothenioids. We observed thatMacrourus whitsoniwas benthopelagic and benthic and infested by large ectoparasitic copepods. Juvenile (42 cm)Dissostichus mawsoniwas not neutrally buoyant and resided on the substrate at 1277 m.Lepidonotothen squamifronswas seen near and on nests of eggs in early December. APogonophrynesp. from 2127 m was not a member of the deep-living unspottedP. albipinnagroup.Chionobathyscus dewittiinhabited the water column as well as the substrate. The pelagic zoarcidMelanostigma gelatinosumwas documented in the water column a few metres above the substrate. The zoogeographic character of the Marguerite Bay fauna was West Antarctic or low-Antarctic and the Amundsen Sea was East Antarctic or high-Antarctic.

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