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Numerical investigation of impinging jet ventilation in ICUs: Is thermal stratification a problem?

Intensive care units (ICUs) are the high incidence sites of hospital-acquired infections, where impinging jet ventilation (IJV) shows great potential. Thermal stratification of IJV and its effect on contaminants distribution were systematically investigated in this study. By changing the setting of...

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Autores principales: Wang, Lei, Wang, Zhiqiang, Zhu, Sirui, Zhu, Zhe, Jin, Tao, Wei, Jianjian
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Tsinghua University Press 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10172721/
https://www.ncbi.nlm.nih.gov/pubmed/37359830
http://dx.doi.org/10.1007/s12273-023-1023-3
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author Wang, Lei
Wang, Zhiqiang
Zhu, Sirui
Zhu, Zhe
Jin, Tao
Wei, Jianjian
author_facet Wang, Lei
Wang, Zhiqiang
Zhu, Sirui
Zhu, Zhe
Jin, Tao
Wei, Jianjian
author_sort Wang, Lei
collection PubMed
description Intensive care units (ICUs) are the high incidence sites of hospital-acquired infections, where impinging jet ventilation (IJV) shows great potential. Thermal stratification of IJV and its effect on contaminants distribution were systematically investigated in this study. By changing the setting of heat source or the air change rates, the main driving force of supply airflow can be transformed between thermal buoyancy and inertial force, which can be quantitatively described by the dimensionless buoyant jet length scale ([Formula: see text] ). For the investigated air change rates, namely 2 ACH to 12 ACH, [Formula: see text] varies between 0.20 and 2.80. The thermal buoyancy plays a dominant role in the movement of the horizontally exhaled airflow by the infector under low air change rate, where the temperature gradient is up to 2.45 °C/m. The flow center remains close to the breathing zone of the susceptible ahead, resulting into the highest exposure risk (6.6‰ for 10-µm particles). With higher heat flux of four PC monitors (from 0 W to 125.85 W for each monitor), the temperature gradient in ICU rises from 0.22 °C/m to 1.02 °C/m; however, the average normalized concentration of gaseous contaminants in the occupied zone is reduced from 0.81 to 0.37, because their thermal plumes are also able to carry containments around them to the ceiling-level readily. As the air change rate was increased to 8 ACH ([Formula: see text] ), high momentum weakened the thermal stratification by reducing the temperature gradient to 0.37 °C/m and exhaled flow readily rose above the breathing zone; the intake fraction of susceptible patient located in front of the infector for 10-µm particles reduces to 0.8‰. This study proved the potential application of IJV in ICUs and provides theoretical guidance for its appropriate design.}
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spelling pubmed-101727212023-05-14 Numerical investigation of impinging jet ventilation in ICUs: Is thermal stratification a problem? Wang, Lei Wang, Zhiqiang Zhu, Sirui Zhu, Zhe Jin, Tao Wei, Jianjian Build Simul Research Article Intensive care units (ICUs) are the high incidence sites of hospital-acquired infections, where impinging jet ventilation (IJV) shows great potential. Thermal stratification of IJV and its effect on contaminants distribution were systematically investigated in this study. By changing the setting of heat source or the air change rates, the main driving force of supply airflow can be transformed between thermal buoyancy and inertial force, which can be quantitatively described by the dimensionless buoyant jet length scale ([Formula: see text] ). For the investigated air change rates, namely 2 ACH to 12 ACH, [Formula: see text] varies between 0.20 and 2.80. The thermal buoyancy plays a dominant role in the movement of the horizontally exhaled airflow by the infector under low air change rate, where the temperature gradient is up to 2.45 °C/m. The flow center remains close to the breathing zone of the susceptible ahead, resulting into the highest exposure risk (6.6‰ for 10-µm particles). With higher heat flux of four PC monitors (from 0 W to 125.85 W for each monitor), the temperature gradient in ICU rises from 0.22 °C/m to 1.02 °C/m; however, the average normalized concentration of gaseous contaminants in the occupied zone is reduced from 0.81 to 0.37, because their thermal plumes are also able to carry containments around them to the ceiling-level readily. As the air change rate was increased to 8 ACH ([Formula: see text] ), high momentum weakened the thermal stratification by reducing the temperature gradient to 0.37 °C/m and exhaled flow readily rose above the breathing zone; the intake fraction of susceptible patient located in front of the infector for 10-µm particles reduces to 0.8‰. This study proved the potential application of IJV in ICUs and provides theoretical guidance for its appropriate design.} Tsinghua University Press 2023-05-11 /pmc/articles/PMC10172721/ /pubmed/37359830 http://dx.doi.org/10.1007/s12273-023-1023-3 Text en © Tsinghua University Press 2023 This article is made available via the PMC Open Access Subset for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.
spellingShingle Research Article
Wang, Lei
Wang, Zhiqiang
Zhu, Sirui
Zhu, Zhe
Jin, Tao
Wei, Jianjian
Numerical investigation of impinging jet ventilation in ICUs: Is thermal stratification a problem?
title Numerical investigation of impinging jet ventilation in ICUs: Is thermal stratification a problem?
title_full Numerical investigation of impinging jet ventilation in ICUs: Is thermal stratification a problem?
title_fullStr Numerical investigation of impinging jet ventilation in ICUs: Is thermal stratification a problem?
title_full_unstemmed Numerical investigation of impinging jet ventilation in ICUs: Is thermal stratification a problem?
title_short Numerical investigation of impinging jet ventilation in ICUs: Is thermal stratification a problem?
title_sort numerical investigation of impinging jet ventilation in icus: is thermal stratification a problem?
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10172721/
https://www.ncbi.nlm.nih.gov/pubmed/37359830
http://dx.doi.org/10.1007/s12273-023-1023-3
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