Air movement around a worker in a low-speed flow field

Johnson, A.E.; Fletcher, B.; Saunders, Caroline

doi:10.1016/0003-4878(95)00060-7

Cited by 37 publications

(31 citation statements)

References 3 publications

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“…These factors will determine the extent of disturbance that invading flow exerts over the human natural convection flow. Similar study performed in a low-speed uniform environment revealed that heated and non-heated manikin creates very distinctive airflow patterns with respect to the free air stream (Johnson et al, 1996). An airflow of 6 l/s supplied from the front was able to penetrate the CBL, while personalized jet at the lower flow rate was deflected upwards by the CBL without reaching the breathing zone.…”

Section: Introductionmentioning

confidence: 55%

Human convective boundary layer and its interaction with room ventilation flow

et al. 2014

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This study investigates the interaction between the human convective boundary layer (CBL) and uniform airflow with different velocity and from different directions. Human body is resembled by a thermal manikin with complex body shape and surface temperature distribution as the skin temperature of an average person. Particle image velocimetry (PIV) and pseudocolor visualization (PCV) are applied to identify the flow around the manikin's body. The findings show that the direction and magnitude of the surrounding airflows considerably influence the airflow distribution around the human body. Downward flow with velocity of 0.175 m/s does not influence the convective flow in the breathing zone, while flow at 0.30 m/s collides with the CBL at the nose level reducing the peak velocity from 0.185 to 0.10 m/s. Transverse horizontal flow disturbs the CBL at the breathing zone even at 0.175 m/s. A sitting manikin exposed to airflow from below with velocity of 0.30 and 0.425 m/s assisting the CBL reduces the peak velocity in the breathing zone and changes the flow pattern around the body, compared to the assisting flow of 0.175 m/s or quiescent conditions. In this case, the airflow interaction is strongly affected by the presence of the chair.

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Section: Introductionmentioning

confidence: 55%

Human convective boundary layer and its interaction with room ventilation flow

et al. 2014

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“…Bjørn and Nielsen [5] and Johnson et al [7] found that buoyant upward flow in the vicinity of an occupant affects pollutant dispersion in breathing zone. The effect of the buoyant thermal plume becomes significant in a space with little or no air mixing, such as a space in which a mechanical ventilation system is not operating or a room with displacement ventilation [8,9].…”

Section: Introductionmentioning

confidence: 98%

Transport of particulate and gaseous pollutants in the vicinity of a human body

Rim

Novoselac

2009

Building and Environment

148

121

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“…Some existing studies have investigated the interaction between the thermal plume and indoor ventilation. Johnson et al (1996) studied airflow interaction between the human free convection flow and ventilation in a low-speed uniform environment. Yang et al (2009a) studied the interaction of the personalized airflow supplied from ceiling mounted nozzle with the thermal plume generated by a seated thermal manikin.…”

Section: Introductionmentioning

confidence: 99%

The ventilation needed to control thermal plume and particle dispersion from manikins in a unidirectional ventilated protective isolation room

Yang

Zhao

2015

Build. Simul.

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Infection is a major cause of death for the immunocompromised patients whose immune mechanisms are deficient. The most effective way of protecting these patients is the total environment protection such as protective isolation room (PIR). Unidirectional airflow ventilation is usually used in PIR. The supply air velocity in PIR can affect not only the cleanliness level of the room and total environment protection effects to the patients, but also the energy consumption and initial equipment investment of the room. Computational fluid dynamics (CFD) program is used to simulate the airflow field and the concentration distribution of the particles from human body and breathing. Three scenarios when the manikin is standing, sitting and lying are investigated in this study. The intensities of supply airflow with different velocities and the upward airflow induced by thermal plume with different postures are compared. The qualitative and quantitative analysis of the simulation results show that the required supply air velocity to control the thermal plume and particle dispersion from human body and breathing is at least 0.25 m/s when the manikin is standing or sitting, and 0.2 m/s when the manikin is lying. Keywordsunidirectional airflow ventilation, computational fluid dynamics (CFD), air distribution, protective isolation Article History

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Air movement around a worker in a low-speed flow field

Cited by 37 publications

References 3 publications

Human convective boundary layer and its interaction with room ventilation flow

Human convective boundary layer and its interaction with room ventilation flow

Transport of particulate and gaseous pollutants in the vicinity of a human body

The ventilation needed to control thermal plume and particle dispersion from manikins in a unidirectional ventilated protective isolation room

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