Evaluation of Droplet Evaporation Models and the Incorporation of Natural Convection Effects

Pinheiro, Abgail Paula; Vedovoto, João Marcelo

doi:10.1007/s10494-018-9973-8

Cited by 30 publications

(11 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If the particle becomes completely desiccated, the droplet diameter during drying,

, can be determined by the following equation [ 14 ]:

where

and

are the initial diameters of droplets, density of mixed solutes after drying (g/mL) and initial concentration of non-volatile compounds in droplets (g/mL), respectively. The droplets generated from coughing is in the size range of 1–750 μm [ 15 ] and can become smaller quickly in the air by evaporation, because they are quite small and have large surface area [ 16 ]. Small droplets become stable aerosols and can be suspended in the air for a long time without settling down to the ground and they can be transported to distant position by airflow by air conditioner or other ventilation systems.…”

Section: Introductionmentioning

confidence: 99%

Behavior of cough droplets emitted from Covid-19 patient in hospital isolation room with different ventilation configurations

Dao

Kim

2022

Building and Environment

View full text Add to dashboard Cite

The world is now facing the Covid-19 pandemic and the control of Covid-19 spread in health care facilities is a serious concern. The ventilation system in hospital isolation rooms with infectious patients plays a significant role in minimizing the spread of viruses and the risk of infection in hospital. In this study, computational fluid dynamics (CFD) simulation is applied to investigate the important factors on transport and evaporation of multi-component cough droplets in the isolation room with different ventilation configurations. We analyzed the effects of various air outlet positions on the removal efficiency of infectious droplets in isolation room and proposed the optimum location of exhaust vent in hospital isolation room to maximize the droplet removal efficiencies. We found that the evaporation rate of droplets is strongly dependent on the relative humidity (RH) and, at low RH, the large-sized droplets with Covid-19 virus can evaporate quickly and become small-sized aerosols to stay in air for a long time and the Covid-19 can propagate more easily through the respiratory organs during breathing. It also explains why the Covid-19 can propagate faster in winter with low humidity than in summer with high humidity.

show abstract

“…If the particle becomes completely desiccated, the droplet diameter during drying,

, can be determined by the following equation [ 14 ]:

where

and

Section: Introductionmentioning

confidence: 99%

Behavior of cough droplets emitted from Covid-19 patient in hospital isolation room with different ventilation configurations

Dao

Kim

2022

Building and Environment

View full text Add to dashboard Cite

show abstract

“…It should be noted that the rate of evaporation of droplets and aerosols depend on ambient temperature, RH and natural and forced convections [30,31]. The effect of forced convection due to free flow of wind is minimal in confined spaces.…”

Section: Discussionmentioning

confidence: 99%

“…The total energy of such small particles is significantly dominated by surface energy. Once all these effects are considered, the analyticity of the mathematical treatment regarding evaporation is lost [30,31]. In this study, our focus has been on a simple analytic methodology to estimate the droplet/aerosol suspension time in air in confined spaces.…”

Section: Discussionmentioning

confidence: 99%

“…In this study, our focus has been on a simple analytic methodology to estimate the droplet/aerosol suspension time in air in confined spaces. Still, we have tried to estimate roughly the effect of evaporation on droplet suspension time in air under standard atmospheric conditions following the methodology developed by Pinheiro and Vedovodo [30]. For large droplets (with sub-millimeter radius) the effect of mass-loss due to evaporation is small.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Droplet and Aerosol Suspension Times in Ambient Air in Confined Spaces and Transmission of COVID-19: Influence of Environmental Factors

Islam

Naqib

2021

J. Sci. Res.

View full text Add to dashboard Cite

The COVID‑19 pandemic, alternatively known as the coronavirus pandemic, is an unfolding pandemic of coronavirus disease 2019 (COVID‑19) across the entire globe in an unprecedented proportion. COVID-19 is caused by severe acute respiratory syndrome coronavirus 2. The mode of transmission of COVID-19 is a subject of intense research. The airborne transmission is one prime possibility. Breathing and talking are natural processes which generate exhaled particles. The exhaled air is an aerosol/droplet composed of naturally produced particulates of varying size. The duration over which the aerosols/droplets are suspended in the air is an important factor. Long suspended aerosols/droplets are potential source of transmission, particularly in confined spaces. We have calculated times of suspension by considering various environmental factors, namely, the ambient temperature and relative humidity in a confined space, in this work. Both temperature and relative humidity affect the suspension time of the exhaled aerosols/droplets with varying degree. The effects of environmental factors are significant for aerosols, particularly for those with small radii. We have discussed the possible implications of our findings in this paper.

show abstract

“…State-of-the-art numerical methods are based on the aforementioned classical models (Fang et al 2019;Ciottoli et al 2020;Poulton et al 2020). However, several unsolved problems have been still existing; therefore, improving, testing, and validating vaporization models are critical even today (Sazhin 2017;Pinheiro and Vedovoto 2019).…”

Section: Introductionmentioning

confidence: 99%

A Two-Parameter Corresponding States Method for Calculating the Steady-State Evaporation Rate of C2–C9 n-Alkane Droplets in Air for Elevated Pressures and Temperatures

Csemány

Józsa

2021

Flow Turbulence Combust

View full text Add to dashboard Cite

Advanced gas turbine and internal combustion engine combustion chambers operate at highly elevated pressures and temperatures. Therefore, spray vaporization analysis cannot be limited to the atmospheric environment since evaporation strongly depends on ambient conditions. Presently, the effect of air pressure and temperature on droplet evaporation rate was investigated by using both a transient and a steady-state approach. A corresponding states model was derived for the steady-state evaporation rate for n-alkanes in the range of C2–C9 with an excellent fit quality and < 1% model uncertainty, considering the thermophysical data uncertainties. The model was tested for C1, C10, and C12 n-alkanes as well with low success. The ambient conditions were evaluated in terms of reduced pressures and temperatures, covering the range of 0.02–0.5 and 1.2–1.5, respectively. However, the applicability of the model was limited to reduced temperature of 1.3–1.5, as higher discrepancy was observed between the trends of the different n-alkanes at lower temperatures. Since the heat-up phase of practical sprays in combustion chambers is often short, the present model might significantly reduce the computational effort required for liquid evaporation calculations.

show abstract

Evaluation of Droplet Evaporation Models and the Incorporation of Natural Convection Effects

Cited by 30 publications

References 44 publications

Behavior of cough droplets emitted from Covid-19 patient in hospital isolation room with different ventilation configurations

Behavior of cough droplets emitted from Covid-19 patient in hospital isolation room with different ventilation configurations

Droplet and Aerosol Suspension Times in Ambient Air in Confined Spaces and Transmission of COVID-19: Influence of Environmental Factors

A Two-Parameter Corresponding States Method for Calculating the Steady-State Evaporation Rate of C2–C9 n-Alkane Droplets in Air for Elevated Pressures and Temperatures

Contact Info

Product

Resources

About