scholarly journals Propagation of Mouth-Generated Aerosols in a Modularly Constructed Hospital Room

2021 ◽  
Vol 13 (21) ◽  
pp. 11968
Author(s):  
Mutaz Suleiman ◽  
Ahmed Elshaer ◽  
Muntasir Billah ◽  
Mohammed Bassuony
Keyword(s):  
Air Conditioning ◽  
Ventilation System ◽  
Engineering Industry ◽  
Limited Capacity ◽  
Modular Construction ◽  
Direct Flow ◽  
Construction Methods ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations ◽  
Airborne Viruses

Modular construction methods have been widely used in the civil engineering industry due to ease of assembly, the convenience of design, and allowing for flexibility in placement while making the construction more sustainable. With the increasing number of COVID-19 cases, the capacity of the hospital is decreasing as more intensive care units (ICU) are allocated to COVID-19 cases. This limited capacity can be addressed by using modular construction to provide field hospitals. This paper adopts transient Lagrangian computational fluid dynamics simulations to investigate the importance of having an appropriate ventilation system in place to ensure sustainable infection control against airborne viruses and pathogens within a modular room. The performance of having a ventilation system using 10, 20, and 40 air changes per hour (ACH) was examined. In addition, different room configurations were also compared to provide useful guidelines for air conditioning units placement. It was determined that as the ACH rate increases while maintaining a direct flow field between the inlet and outlet, the rate of aerosol removal increases. Furthermore, the flowfield in which can be controlled by the placement of the inlet and outlet can impact the removal of aerosols, as it dictates how far the droplets travel before being removed from the enclosure.

scholarly journals CFD Study on Thermal Implication towards Human Body in Office Environment

2021 ◽  
Vol 85 (1) ◽  
pp. 125-134
Author(s):  
Ahmad Rasdan Ismail ◽  
Norfadzilah Jusoh ◽  
Nor Kamilah Makhtar ◽  
Nor Kamaliana Khamis ◽  
Raemy Md Zein ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Work Productivity ◽  
Environmental Parameters ◽  
Thermal Conditions ◽  
Air Conditioning System ◽  
Operative Temperature ◽  
Office Environment ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations ◽  
Radiant Temperature

Temperatures are rising gradually around the world due to the issue of global warming. This condition also affects those who have to work for long hours. A comfortable work environment helps employees to increase work productivity. Thermal comfort is the occupant’s satisfaction with the surrounding thermal conditions. Therefore, the objective of this study is to evaluate the thermal environmental conditions of air conditioning through Computational Fluid Dynamics simulations. The distributions of environmental parameters such as air velocity, air temperature, radiant temperature, inside an o?ce room with air-conditioning are presented. Based on these distributions, spatial pro?les of Predicted Mean Vote Index (PMV) are obtained to illustrate thermal conditions intuitively. This study was conducted under controlled environment inside special laboratory. To achieve this model office environment has been built in an environmental chamber. The distribution of PMV indicates that operative temperature at the 23 oC shows that the PMV is comfortable. The value of PMV in operative temperature at 23 oC is 0.79 near the skin of an occupant. The research outputs provide useful information for designers of the air-conditioning system to build a comfortable indoor environment in the office environment.

Design of Fire Ventilation System for an Underground Car Park by CFD Simulations

2019 ◽  
Vol 887 ◽  
pp. 459-466
Author(s):  
Miroslava Kmecová ◽  
Peter Buday ◽  
Jozef Vojtaššák ◽  
Michal Krajčík
Keyword(s):  
Fluid Flow ◽  
Ventilation System ◽  
Computer Software ◽  
Contamination Level ◽  
Cfd Simulations ◽  
Car Park ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations ◽  
Fluid Behaviour ◽  
Two Alternatives

The aim of this study is to design a fire ventilation system with impulse jet fans for an underground car park. During the planning, it is necessary to consider all aspects of fluid behaviour however, there is a number of parameters that can affect the flow of smoke that need to be considered. There is a good chance of miscalculations when computing the overall fluid flow using conventional plain calculations. To avoid mistakes, visualize the fluid flow and also to directly compare the different design variants it can be practical to use computer software, specifically CFD (Computational Fluid Dynamics) simulations. By CFD it is possible to better analyse and keep control of the flow of fluid, heat transfer and other related phenomena. It also helps predict the contamination level of Carbon Monoxide, heat and smoke intensity and distribution. In this study CFD simulations were used to design, test and compare two alternatives of fire ventilation system. The two alternatives differed from each other in the location of the impulse jet fans and exhaust ventilation shafts, and in the ventilation intensity (10-times per hour in the first alternative and 15-times per hour in the second alternative). The results have shown that the first alternative is not suitable as the car park was not sufficiently ventilated after 1500 seconds after the simulation had begun, whereas in the second alternative the smoke was almost completely exhausted and the visibility was significantly improved. The simulation results emphasize the important effect of design and location of the different elements on the functionality and efficiency of a fire protection system.

scholarly journals Aerodynamic analysis of uphill drafting in cycling

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
T. van Druenen ◽  
B. Blocken
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Scientific Literature ◽  
Sensitivity Analyses ◽  
Air Resistance ◽  
Wind Tunnel Measurements ◽  
Aerodynamic Effect ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

AbstractSome teams aiming for victory in a mountain stage in cycling take control in the uphill sections of the stage. While drafting, the team imposes a high speed at the front of the peloton defending their team leader from opponent’s attacks. Drafting is a well-known strategy on flat or descending sections and has been studied before in this context. However, there are no systematic and extensive studies in the scientific literature on the aerodynamic effect of uphill drafting. Some studies even suggested that for gradients above 7.2% the speeds drop to 17 km/h and the air resistance can be neglected. In this paper, uphill drafting is analyzed and quantified by means of drag reductions and power reductions obtained by computational fluid dynamics simulations validated with wind tunnel measurements. It is shown that even for gradients above 7.2%, drafting can yield substantial benefits. Drafting allows cyclists to save over 7% of power on a slope of 7.5% at a speed of 6 m/s. At a speed of 8 m/s, this reduction can exceed 16%. Sensitivity analyses indicate that significant power savings can be achieved, also with varying bicycle, cyclist, road and environmental characteristics.

scholarly journals Evaluation of Active Heat Sinks Design under Forced Convection—Effect of Geometric and Boundary Parameters

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2041
Author(s):  
Eva C. Silva ◽  
Álvaro M. Sampaio ◽  
António J. Pontes
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Additive Manufacturing ◽  
Pressure Drop ◽  
Forced Convection ◽  
Thermal Performance ◽  
Heat Sinks ◽  
Trapezoidal Shape ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

This study shows the performance of heat sinks (HS) with different designs under forced convection, varying geometric and boundary parameters, via computational fluid dynamics simulations. Initially, a complete and detailed analysis of the thermal performance of various conventional HS designs was taken. Afterwards, HS designs were modified following some additive manufacturing approaches. The HS performance was compared by measuring their temperatures and pressure drop after 15 s. Smaller diameters/thicknesses and larger fins/pins spacing provided better results. For fins HS, the use of radial fins, with an inverted trapezoidal shape and with larger holes was advantageous. Regarding pins HS, the best option contemplated circular pins in combination with frontal holes in their structure. Additionally, lattice HS, only possible to be produced by additive manufacturing, was also studied. Lower temperatures were obtained with a hexagon unit cell. Lastly, a comparison between the best HS in each category showed a lower thermal resistance for lattice HS. Despite the increase of at least 38% in pressure drop, a consequence of its frontal area, the temperature was 26% and 56% lower when compared to conventional pins and fins HS, respectively, and 9% and 28% lower when compared to the best pins and best fins of this study.

scholarly journals Verification of the effect of sleeping environment and humidification on middle-aged people in whole-house air-conditioning ventilation system housing

2019 ◽  
Vol 111 ◽  
pp. 02044
Author(s):  
Akemi Iwaki ◽  
Takashi Akimoto ◽  
Naho Misumi ◽  
Takuya Furuhashi
Keyword(s):  
Blood Pressure ◽  
Moisture Content ◽  
Air Conditioning ◽  
Sleep Latency ◽  
Ventilation System ◽  
Circulation Type ◽  
Living Environment ◽  
Aged People ◽  
Air Circulation ◽  
Skin Moisture

This study focused on the thermal comfort of air circulation-type whole-house air-conditioning ventilation systems. We studied the influence of 24-h continuous whole-house air-conditioning on the living environment in which the occupant is sleeping. A survey was conducted in the summer of 2016 and winter of 2017 to ascertain the influence on the sleeping environment, skin moisture content, and blood pressure. We then compared the results with those of the sleeping environment of residents in air-conditioned housing surveyed the previous year. The sleeping environment when using a personal humidifier around the occupant’s head was examined during winter when the humidity is low. The results indicated that sleep latency was significantly shortened in the 24-h continuous whole-house air-conditioning ventilation system in both summer and winter because the temperature control of the bedroom before going to bed affects the sleep latency. Subjectively, no participants felt dryer than the values measured in the bedroom environment. The results implied that the comfort of the entire building was improved with continuous air-conditioned housing.

Sign in / Sign up

Export Citation Format

Share Document