scholarly journals Odor Problems in Toilets with Reduced Ventilation Frequencies

2019 ◽  
Vol 111 ◽  
pp. 02025
Author(s):  
Madoka Kimura ◽  
Takashi Akimoto ◽  
Nobuhiro Hirasuga ◽  
Yu Sakamoto ◽  
Sakurako Yamakita ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Exchanger ◽  
Questionnaire Survey ◽  
Ammonia Concentration ◽  
Degree Of Contamination ◽  
Ventilation Frequency ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses ◽  
The Relationship

Japan’s toilets are generally ventilated 15 times per hour. Despite the development in toilets, the ventilation frequency in toilets has not been changed in recent times. Therefore, there is a possibility that toilets are being excessively ventilated. Reducing the ventilation frequency increases the return air to the heat exchanger and improves the efficiency of the heat exchanger. For an optimal ventilation frequency, we introduce a system that could control the exhaust air using sensors. The primary issue is the odor caused by reducing the ventilation frequency. In this study, we aim to eliminate the odor as quickly as possible by providing an exhaust port at the bottom of the wall (hereinafter referred as “baseboard deodorization”). First, we examined the relationship among the odor sensor, human’s olfactory odor identification and ventilation volumes with the toilet in operation to verify the usefulness of the sensors. Next, the air environment was analyzed using computational fluid dynamics (CFD). The results of the measurements and questionnaire survey indicate a correlation between the degree of contamination in the air and the odor intensity. The CFD analyses demonstrated, even after the frequency of ventilation reduced to 5 times per hour, that the ammonia concentration obtained was equivalent to 15 times per hour. To solve the odor problem due to the ventilation reduction, it is important to evacuate air immediately after the odor is generated. Among others, it was observed that a baseboard deodorization system contributes significantly to the reduction in ammonia concentration.

Optimal Hardware Placement in a Minitower Computer Enclosure System

2011 ◽  
Author(s):  
M. Alfaro Cano ◽  
A. Hernandez-Guerrero ◽  
C. Rubio Arana ◽  
Aristotel Popescu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Simulation ◽  
Operating Temperature ◽  
Optimal Placement ◽  
Cfd Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
The Relationship ◽  
Key Questions

One of the requirements for existing personal computers, PCs, is that the hardware inside must maintain an operating temperature as low as possible. One way to achieve that is to place the hardware components at locations with enough airflow around it. However, the relationship between the airflow and temperature of the components is unknown before they are placed at specific locations inside a PC. In this work a Computational Fluid Dynamics (CFD) analysis is coupled to a Design of Experiment (DOE) methodology to answer typical minitower key questions: a) how do the possible positions of hardware components affect their temperature?, and b) is it possible to get an optimal placement for these hardware components using the data collected by the CFD simulation results? The DOE methodology is used to optimize the analysis for a very large number of possible configurations. The results help in identifying where the efforts need to be placed in order to optimize the positioning of the hardware components for similar configurations at the designing stage. Somehow the results show that general conclusions could be drawn, but that there are not specific rules that could be applied to every configuration.

scholarly journals An Examination of the Relationship between Flow Parameters and Symptoms According to Fire Phase in a Mine Model

2017 ◽  
Vol 6 (2) ◽  
pp. 58
Author(s):  
Selçuk Keçel
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Boundary Conditions ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Ventilation System ◽  
Underground Mine ◽  
Computational Fluid Dynamics Cfd ◽  
The Relationship

This study examines the relationship between temperature, CO dispersions, symptoms, and COHb% levels accumulated in the blood on available ventilation conditions in cases of fire at point in an underground mine model. Based on operating parameters (air velocity and direction) of the ventilation system in the underground mine model, fast growing phase fire analyses were conducted according to the heat release rate (HRR) value in the range of 0-61.34MW. In fire scenarios prepared according to the hydrocarbon fuel type (C2.3H4.2O1.3), boundary conditions were calculated depending on the combustion equation considering fuel lower heating value (Qc). CO dispersions inside the tunnel were examined by transferring the time-dependent boundary conditions to the computational fluid dynamics (CFD) program.  yCO, COHb%, and COHb%/∆t changes were calculated according to the HRR value.  Findings regarding the effects of CO emission (acute and chronic poisoning), were expressed according to the HRR value. Keywords Combustion Model Design, Heat Release Rate (HRR), Carbon Monoxide emission, Symptoms and Survival Time, Computational Fluid Dynamics (CFD);

scholarly journals Computational Fluid Dynamics (CFD) simulation to analyze the performance of tube-in-tube helically coiled of a heat exchanger

2014 ◽  
Vol 9 (7) ◽  
pp. 181-188 ◽  
Author(s):  
A. Chaves C. ◽  
R. F. de Castro D. ◽  
Q. Lamas W. ◽  
R. Camargo J. ◽  
J. Grandinetti F.
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Exchanger ◽  
Cfd Simulation ◽  
Computational Fluid Dynamics Cfd

scholarly journals Smoke and heat flow in a large volume building in case of fire

2014 ◽  
Vol 13 (4) ◽  
pp. 057-065
Author(s):  
Wojciech Węgrzyński
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Flow ◽  
Design Process ◽  
Turbulence Model ◽  
Large Volume ◽  
Ansys Fluent ◽  
Design Recommendations ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

In the paper the author presents some chosen methodologies used in the design process of natural smoke and heat ventilation systems and the use of Computational Fluid Dynamics (CFD) tools. Comparison of the performance of various systems was conducted on the basis of performed CFD analyses. The analysis was prepared with the use of ANSYS Fluent 14.5 package, with the use of RNG k-ε turbulence model. The results of analysis are presented, together with the additional design recommendations.

scholarly journals Improving resistance properties of high-speed ships

2020 ◽  
Vol XXIII (2) ◽  
pp. 8-18
Author(s):  
Gürsel K.Turgut
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Carbon Emission ◽  
Container Ship ◽  
Commercial Software ◽  
Sustainable Engineering ◽  
Speed Range ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

Sustainable engineering solutions facilitate and/or force the use of energy more efficiently and, thus, reducing the carbon emission to the atmosphere. This study is related to improving resistance properties of ships, especially in the high speed range, in which they consume large amount of fuels. In this investigation, the model of the Kriso Container Ship (KCS) was taken as the basis to be studied and she was hydrodynamically analysed through the commercial software STAR-CCM+. After the successful validation of the results obtained in these computational fluid dynamics (CFD) analyses by those of the experiments of this model published in [1], the simulations carried out on the models equipped with stern flaps and a combination of stern flaps and interceptors for reducing resistance of the models, were performed in the same manner using the same software. Then the results obtained in all analyses were discussed by comparing those with the test ones.

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