Effects of mechanical aeration on evaporation rate and water temperature in aquaculture ponds

2018 ◽  
Vol 49 (6) ◽  
pp. 2184-2192 ◽  
Author(s):  
Hisham A Abdelrahman ◽  
Claude E Boyd
Keyword(s):  
Water Temperature ◽  
Evaporation Rate ◽  
Aquaculture Ponds ◽  
Mechanical Aeration

scholarly journals Effect of air parameters, water temperature, and number of pool occupants on moisture gains

2018 ◽  
Vol 70 ◽  
pp. 02006
Author(s):  
Agnieszka Garnysz-Rachtan ◽  
Zbigniew Zapałowicz
Keyword(s):  
Water Temperature ◽  
Water Surface ◽  
Evaporation Rate ◽  
Water Evaporation ◽  
Physical Parameters ◽  
Air Humidity ◽  
Air Velocity ◽  
Relative Air Humidity ◽  
Thermal Calculations ◽  
The Right

Thermal calculations for indoor swimming pools require that amount of water evaporated from the pool's water surface, as well as water evaporated from the floor surrounding the pool and from the bodies of the occupants are to be determined. It means in practice that amount of vapor transferred to the air in the pool hall depends most of all on physical parameters of water and air. One of more important factors that affect water evaporation is also the way the pool is operated. The present article shows only chosen relations applied to determine the values of evaporation rate from occupied pool. The relations also account for the mode of pool's operation. The aim of the paper is to analyse the effect of changes of temperature and of relative air humidity in the hall, of water temperature and of air velocity above the water surface, as well as of the number of occupants on moisture gains in the hall. The above data let choose the right relation to be applied in calculations for the water evaporation rate.

Effect of fluctuation of surface sea water temperature and ambient pressure on evaporation rate of evaporator in barometric type OC-OTEC system

1995 ◽  
Vol 115 (6) ◽  
pp. 33-40
Author(s):  
Masatsugu Amano ◽  
Hiroyuki Takazawa ◽  
Tadayoshi Tanaka
Keyword(s):  
Water Temperature ◽  
Evaporation Rate ◽  
Sea Water ◽  
Ambient Pressure

Validation of ASHRAE Equation to Find Evaporation Rates in Humid Cavity

2004 ◽  
Author(s):  
Suma Kuravi ◽  
Dereje Agonafer
Keyword(s):  
Vapor Pressure ◽  
Water Temperature ◽  
Evaporation Rate ◽  
Dew Point ◽  
Cfd Model ◽  
Saturation Vapor Pressure ◽  
Steady State Condition ◽  
Factors Affecting ◽  
Small Pool ◽  
Saturation Vapor

Presence of Humidity has many undesired effects in many applications. Moisture balance of the air has become an important task and dehumidification has become a necessity for many applications in many industries. This paper discusses about the study of the factors affecting the evaporation rate of water in cavities exposed to humid conditions. The ASHRAE equation to find the evaporation rate in swimming pools is considered and validated for a small pool of water in humid conditions in humid cavity with fixed dimensions. The equation states that, the evaporation rate, W = (95+0.425*V)*(Pw-Pa)/Y, where W is the Evaporation rate in lb/h-ft2; V is the air velocity at water surface; ft/min; Pw is the saturation vapor pressure at water temperature, in. Hg; Pa is saturation vapor pressure at air dew point, in. Hg; and Y is latent at water temperature, Btu/lb. The evaporation rate inside the humid cavity is found and compared with that of the equation. The evaporation rate obtained inside the humid cavity is 95% of the evaporation rate obtained by the use equation. The factors responsible for the low evaporation rate are identified. A CFD Model is developed using FLUENT to represent the time averaged steady state condition of the humid cavity. The temperature and velocity values at particular points are probed in CFD model and are obtained. The results are compared with the actual physical model. These values are used to find the evaporation rate occurring inside the cavity using the ASHRAE equation. The evaporation rate found in the humid cavity is found to be 76% of the evaporation rate that is calculated from the values of the CFD model, using the equation. Factors affecting the evaporation rate inside the humid cavity are discussed and the effects of these factors are illustrated using the CFD Model. Propositions are made to improve the evaporation rates inside the humid cavity. Future studies are planned to do a multi species modeling to include humidity in the CFD analysis for humid cavity.

scholarly journals Effect of fluctuation of Surface Sea Water Temperature and Ambient Pressure on Evaporation Rate of Evaporator in Barometric Type OC-OTEC System

1994 ◽  
Vol 114 (10) ◽  
pp. 1038-1043
Author(s):  
Masatugu Amano ◽  
Hiroyuki Takazawa ◽  
Tadayosi Tanaka
Keyword(s):  
Water Temperature ◽  
Evaporation Rate ◽  
Sea Water ◽  
Ambient Pressure

scholarly journals The use of mechanical aeration and its effects on water mass

1999 ◽  
Vol 59 (1) ◽  
pp. 33-42 ◽  
Author(s):  
L. H. SIPAÚBA-TAVARES ◽  
A. M. FREITAS ◽  
F. M. S. BRAGA
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Chlorophyll A ◽  
Water Mass ◽  
Fish Ponds ◽  
Direct Influence ◽  
Sampling Points ◽  
Abiotic Variables ◽  
Nitrate And Nitrite ◽  
Mechanical Aeration

Due to the increasing use of artificial aerators in fish ponds, and to the lack of studies on this subject, this work studied some of the aspects associated with their use. The influence of a diffuser type aerator (AR 120) on the biotic and abiotic variables was evaluated in a fish pond. Three points of the pond were marked for the taking of samples: 5, 10 and 23 m from the aerator. Samples were taken every day for 15 consecutive days: 5 days before the use of the aerator, 5 days with the aerator functioning and 5 days with it not functioning. The limnological variables studied did not show significant differences (P > 0.05) when the three sampling points were compared, but regarding the use of the aerator, variables such as water temperature, transparency, pH, dissolved oxygen, bicarbonate, free CO2, total phosphorus, orthophosphate, ammonia nitrate and nitrite concentrations showed significant differences (P < 0.05) when the water was mechanically agitated. There were no significant differences (P > 0.05) with the use of the aerator regarding conductivity, alkalinity, total CO2 and chlorophyll a values. The phytoplanktonic community suffered as a direct influence of the aerator (P < 0.05). The community was dominated by Chlorophyta, representing more than 70% of the total organisms present, followed by Cyanophyta and Chrysophyta which tended to increase in number after the use of the aerator. This probably occurred because these groups adapt quickly to changes in the environment.

Hole Formation in Gold Films

1972 ◽  
Vol 30 ◽  
pp. 510-511
Author(s):  
R. W. Vook ◽  
R. Cook ◽  
R. Ziemer
Keyword(s):  
Deposition Rate ◽  
Quartz Crystal ◽  
Evaporation Rate ◽  
Gold Films ◽  
Hole Density ◽  
Hole Formation ◽  
Microscope Slide ◽  
Crystal Film ◽  
Glass Microscope Slide ◽  
Glass Microscope

During recent experiments on Au films, a qualitative correlation between hole formation and deposition rate was observed. These early studies were concerned with films 80 to 1000A thick deposited on glass at -185°C and annealed at 170°C. In the present studies this earlier work was made quantitative. Deposition rates varying between 5 and 700 A/min were used. The effects of deposition rate on hole density for two films 300 and 700A thick were investigated.Au was evaporated from an outgassed W filament located 10 cm from a glass microscope slide substrate and a quartz crystal film thickness monitor. A shutter separating the filament from the substrate and monitor made it possible to obtain a constant evaporation rate before initiating deposition. The pressure was reduced to less than 1 x 10-6 torr prior to cooling the substrate with liquid nitrogen. The substrate was cooled in 15 minutes during which the pressure continued to drop to the mid 10-7 torr range, where deposition was begun.

EFFECT OF FIELD-EVAPORATION RATE ON QUANTITATIVE ATOM-PROBE ANALYSIS

1986 ◽  
Vol 47 (C2) ◽  
pp. C2-415-C2-424 ◽  
Author(s):  
A. WAGNER ◽  
D. N. SEIDMAN
Keyword(s):  
Evaporation Rate ◽  
Atom Probe ◽  
Field Evaporation ◽  
Probe Analysis ◽  
Atom Probe Analysis
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