Numerical investigation of wind-driven natural ventilation performance in a multi-storey hospital by coupling indoor and outdoor airflow

Jin, Ruiqiu; Hang, Jian; Liu, Shanshan; Wei, Jianjian; Yang, Lixin; Xie, Jielan; Sandberg, Mats

doi:10.1177/1420326x15595689

Cited by 45 publications

(21 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Wind-induced ventilation depends strongly on the pressure distribution on building facades, and it is significantly affected by the upstream building characteristics and the prevailing wind [67]. Wind pressure is the main natural ventilation driving force in Beijing.…”

Section: Simulation Targetmentioning

confidence: 99%

Prediction of Wind Environment and Indoor/Outdoor Relationships for PM2.5 in Different Building–Tree Grouping Patterns

2018

View full text Add to dashboard Cite

Airflow behavior and indoor/outdoor PM 2.5 dispersion in different building-tree grouping patterns depend significantly on the building-tree layouts and orientation towards the prevailing wind. By using a standard k-ε model and a revised generalized drift flux model, this study evaluated airflow fields and indoor/outdoor relationships for PM 2.5 resulting from partly wind-induced natural ventilation in four hypothetical building-tree grouping patterns. Results showed that: (1) Patterns provide a variety of natural ventilation potential that relies on the wind influence, and buildings that deflect wind on the windward facade and separate airflow on the leeward facade have better ventilation potential; (2) Patterns where buildings and trees form a central space and a windward opening side towards the prevailing wind offer the best ventilation conditions; (3) Under the assumption that transported pollution sources are diluted through the inlet, the aerodynamics and deposition effects of trees cause the lower floors of a multi-storey building to be exposed to lower PM 2.5 compared with upper floors, and lower indoor PM 2.5 values were found close to the tree canopy; (4) Wind pressure differences across each flat showed a poor correlation (R 2 = 0.059), with indoor PM 2.5 concentrations; and (5) Patterns with the long facade of buildings and trees perpendicular to the prevailing wind have the lowest indoor PM 2.5 concentrations.

show abstract

Section: Simulation Targetmentioning

confidence: 99%

Prediction of Wind Environment and Indoor/Outdoor Relationships for PM2.5 in Different Building–Tree Grouping Patterns

2018

View full text Add to dashboard Cite

show abstract

“…Tominaga and Stathopoulos, 2013;Ho et al, 2015;Blocken, 2015;Meroney, 2016;Habilomatis and Chaloulakou, 2015) and those coupling indoor-outdoor airflows (e.g. Gao et al,8 2008; van Hooff and Blocken, 2010 and 2013; Ramponi and Blocken, 2012;Jin et al, 2015;Hang et al, 2016). Thus CFD software Ansys FLUENT (Fluent, 2006) with the RNG k- model was used to solve the steady-state isothermal urban airflows.…”

Section: Description Of Cfd Test Cases and Flow Modellingmentioning

confidence: 99%

The influence of street layouts and viaduct settings on daily carbon monoxide exposure and intake fraction in idealized urban canyons

Hang

Luo

Wang

et al. 2017

Environmental Pollution

Self Cite

145

View full text Add to dashboard Cite

Environmental concerns have been raised on the adverse health effects of vehicle emissions in micro-scale traffic-crowded street canyons, especially for pedestrians and residents living in near-road buildings. Viaduct design is sometimes used to improve transportation efficiency but possibly affects urban airflow and the resultant exposure risk, which have been rarely investigated so far. The personal intake fraction (P_IF) is defined as the average fraction of total emissions that is inhaled by each person of a population (1 ppm = 1 × 10), and the daily carbon monoxide (CO) pollutant exposure (E) is estimated by multiplying the average concentration of a specific micro-environment within one day. As a novelty, by considering time activity patterns and breathing rates in various micro-environments for three age groups, this paper introduces IF and E into computational fluid dynamic (CFD) simulation to quantify the impacts of street layouts (street width/building height W/H = 1, 1.5, 2), source location, viaduct settings and noise barriers on the source-exposure correlation when realistic CO sources are defined. Narrower streets experience larger P_IF (1.51-5.21 ppm) and CO exposure, and leeward-side buildings always attain higher vehicular pollutant exposure than windward-side. Cases with a viaduct experience smaller P_IF (3.25-1.46 ppm) than cases without a viaduct (P_IF = 5.21-2.23 ppm) if the single ground-level CO source is elevated onto the viaduct. With two CO sources (both ground-level and viaduct-level), daily CO exposure rises 2.80-3.33 times but P_IF only change slightly. Noise barriers above a viaduct raise concentration between barriers, but slightly reduce vehicular exposure in near-road buildings. Because people spend most of their time indoors, vehicular pollutant exposure within near-road buildings can be 6-9 times that at pedestrian level. Although further studies are still required to provide practical guidelines, this paper provides effective methodologies to quantify the impacts of street/viaduct configurations on human exposure for urban design purpose.

show abstract

“…The corresponding parameters of the building model are presented in Figure 2a, i.e., building height of 2.5 m and opening size of 0.84 m wide and 1.25 m tall. At the domain inlet, the vertical profiles of the stream-wise velocity and turbulent quantities are defined as follows [43]:…”

Section: Grid Independence Study and Model Validation By Wind Tunnel mentioning

confidence: 99%

“…where u * is the friction velocity and equals 1.068 m/s according to Jin et al [43], y 0 is the roughness length = 0.05 m in the wind tunnel experiment, velocity components in the y and z directions are zero. The parameter roughness height Ks and roughness constant Cs and their relationship with y 0 is K s = 9.793y 0 /C s , which has been built into models in Fluent [44].…”

Section: Grid Independence Study and Model Validation By Wind Tunnel mentioning

confidence: 99%

“…The cross-ventilation building model for CFD validation was built with fine grid (0.05 m), medium grid (0.1 m) and coarse grid (0.2 m) near wall surfaces and inside building models respectively. The data of the RNG k-ε model were derived from a validation study conducted by Jin et al [43]. A similar validation process has also been done by Ai, Mak and Niu [45,46].…”

Section: Grid Independence Study and Model Validation By Wind Tunnel mentioning

confidence: 99%

See 1 more Smart Citation

Natural Ventilation of a Small-Scale Road Tunnel by Wind Catchers: A CFD Simulation Study

et al. 2018

Self Cite

View full text Add to dashboard Cite

Providing efficient ventilation in road tunnels is essential to prevent severe air pollution exposure for both drivers and pedestrians in such enclosed spaces with heavy vehicle emissions. Longitudinal ventilation methods like commercial jet fans have been widely applied and confirmed to be effective for introducing external fresh air into road tunnels that are shorter than 3 km. However, operating tunnel jet fans is energy consuming. Therefore, for small-scale (~100 m–1 km) road tunnels, mechanical ventilation methods might be highly energetically expensive and unaffordable. Many studies have found that the use of wind catchers could improve buildings’ natural ventilation, but their effect on improving natural ventilation in small-scale road tunnels has, hitherto, rarely been studied. This paper, therefore, aims to quantify the influence of style and arrangement of one-sided flat-roof wind catchers on ventilation performance in a road tunnel. The concept of intake fraction (IF) is applied for ventilation and pollutant exposure assessment in the overall tunnel and for pedestrian regions. Computational fluid dynamics (CFD) methodology with a standard k-epsilon turbulence model is used to perform a three-dimensional (3D) turbulent flow simulation, and CFD results have been validated by wind-tunnel experiments for building cross ventilation. Results show that the introduction of wind catchers would significantly enhance wind speed at pedestrian level, but a negative velocity reduction effect and a near-catcher recirculation zone can also be found. A special downstream vortex extending along the downstream tunnel is found, helping remove the accumulated pollutants away from the low-level pedestrian sides. Both wind catcher style and arrangement would significantly influence the ventilation performance in the tunnel. Compared to long-catcher designs, short-catchers would be more effective for providing fresh air to pedestrian sides due to a weaker upstream velocity reduction effect and smaller near-catcher recirculation zone. In long-catcher cases, IF increases to 1.13 ppm when the wind catcher is positioned 240 m away from the tunnel entrance, which is almost twice that in short-catcher cases. For the effects of catcher arrangements, single, short-catcher, span-wise, shifting would not help dilute pollutants effectively. Generally, a design involving a double short-catcher in a parallel arrangement is the most recommended, with the smallest IF, i.e., 61% of that in the tunnel without wind catchers (0.36 ppm).

show abstract

Numerical investigation of wind-driven natural ventilation performance in a multi-storey hospital by coupling indoor and outdoor airflow

Cited by 45 publications

References 60 publications

Prediction of Wind Environment and Indoor/Outdoor Relationships for PM2.5 in Different Building–Tree Grouping Patterns

Prediction of Wind Environment and Indoor/Outdoor Relationships for PM2.5 in Different Building–Tree Grouping Patterns

The influence of street layouts and viaduct settings on daily carbon monoxide exposure and intake fraction in idealized urban canyons

Natural Ventilation of a Small-Scale Road Tunnel by Wind Catchers: A CFD Simulation Study

Contact Info

Product

Resources

About