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Construction of a physical model of airflow, droplets, and droplet nuclei ejected by human respiratory activity

Research Project

Project/Area Number 21K18763
Research Category

Grant-in-Aid for Challenging Research (Exploratory)

Allocation TypeMulti-year Fund
Review Section Medium-sized Section 23:Architecture, building engineering, and related fields
Research InstitutionThe University of Tokyo

Principal Investigator

Ooka RYOZO  東京大学, 生産技術研究所, 教授 (90251470)

Co-Investigator(Kenkyū-buntansha) 菊本 英紀  東京大学, 生産技術研究所, 准教授 (80708082)
呉 元錫  東京大学, 生産技術研究所, 助教 (10889009)
Project Period (FY) 2021-07-09 – 2023-03-31
Project Status Completed (Fiscal Year 2022)
Budget Amount *help
¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000)
Fiscal Year 2022: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Fiscal Year 2021: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Keywords飛沫 / 飛沫核 / CFD / PIV / IMI / 飛沫感染 / 空気感染 / 呼吸活動 / エアロゾル / パーティクルカウンター / パーティ クルカウンター / 呼吸器感染症 / 数値解析(CFD) / 粒子画像流速計測法(PIV) / 干渉画像法(IMI)
Outline of Research at the Start

人の呼吸活動を通じて噴出される飛沫・飛沫核が室内環境へ飛散および拡散する物理的な現象を計測により明確に把握し、数値解析手法(CFD)で再現することを目的とする。咳、くしゃみ、会話等の行為は、気流(気体)と飛沫・飛沫核(液体)が混在する流れを生成する。気流と飛沫・飛沫核の粒径分布の計測には、粒子画像流速計測法(PIV)および干渉画像法技術技術(IMI)を使用してCFDモデルに活用する。構築したCFDモデルは、咳、くしゃみ、会話等の可視化実験により交差検証を行う。本研究の成果は、今後、室内環境における感染拡大予防の対策に貢献すると期待される。

Outline of Final Research Achievements

The purpose of this study is to clearly grasp the physical phenomenon that droplets and droplet nuclei ejected by human respiratory activities (coughing, sneezing, talking) scatter and diffuse into the indoor environment by measurement, and develop numerical analysis method (CFD). intended to reproduce. Human respiratory activity generates a mixed flow of airflow and droplets/droplet nuclei . Particle image velocimetry (PIV) and interferometric imaging (IMI) techniques need to be realized to accurately measure the particle size distribution of airflow and droplets/droplet nuclei. In this study, we performed airflow and particle measurements in various respiratory activities using PIV and IMI techniques under unsteady airflow conditions. These results were used as boundary conditions and validation data for CFD. In addition, we modeled the droplet evaporation phenomenon. The constructed CFD model was cross-validated by a visualization experiment of human respiratory activity.

Academic Significance and Societal Importance of the Research Achievements

室内環境では、換気システムを効率的に運用することで、空気中に広がって浮遊する飛沫・飛沫核の濃度を減らし空気感染のリスクを抑えることができる。換気システムにおける感染リスクの評価や感染経路の予測には、CFD解析が有効である。今回の研究では、室内環境における飛沫・飛沫核の動態を予測するCFD解析手法を開発することができた。本研究の成果は、今後、室内環境における感染拡大予防の対策に貢献すると期待される。

Report

(3 results)
  • 2022 Annual Research Report   Final Research Report ( PDF )
  • 2021 Research-status Report
  • Research Products

    (15 results)

All 2022 2021

All Journal Article (5 results) (of which Int'l Joint Research: 5 results,  Peer Reviewed: 5 results,  Open Access: 3 results) Presentation (10 results) (of which Int'l Joint Research: 8 results)

  • [Journal Article] Numerical modeling of cough airflow: Establishment of spatial-temporal experimental dataset and CFD simulation method2022

    • Author(s)
      Wonseok Oh, Ryozo Ooka, Hideki Kikumoto, Mengtao Han
    • Journal Title

      Building and Environment

      Volume: 207 Pages: 108531-108531

    • DOI

      10.1016/j.buildenv.2021.108531

    • Related Report
      2022 Annual Research Report 2021 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Influence of various factors on indoor/outdoor pollen concentration ratio based on experimental research: A review2022

    • Author(s)
      Wang Wenchao、Ooka Ryozo、Kikumoto Hideki、Oh Wonseok、Han Mengtao
    • Journal Title

      Building and Environment

      Volume: 219 Pages: 109154-109154

    • DOI

      10.1016/j.buildenv.2022.109154

    • Related Report
      2022 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Numerical modeling of sneeze airflow and its validation with an experimental dataset2022

    • Author(s)
      Oh Wonseok、Ooka Ryozo、Kikumoto Hideki、Han Mengtao
    • Journal Title

      Indoor Air

      Volume: 32 Issue: 11

    • DOI

      10.1111/ina.13171

    • Related Report
      2022 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Experimental measurements of airflow features and velocity distribution exhaled from sneeze and speech using particle image velocimetry2021

    • Author(s)
      Mengtao Han, Ryozo Ooka, Hideki, Kikumoto, Wonseok Oh, Yunchen Bu, Shuyuan Hu
    • Journal Title

      Building and Environment

      Volume: 205 Pages: 108293-108293

    • DOI

      10.1016/j.buildenv.2021.108293

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Measurements of exhaled airflow velocity through human coughs using particle image velocimetry2021

    • Author(s)
      Mengtao Han, Ryozo Ooka, Hideki, Kikumoto, Wonseok Oh, Yunchen Bu, Shuyuan Hu
    • Journal Title

      Building and Environment

      Volume: 202 Pages: 108020-108020

    • DOI

      10.1016/j.buildenv.2021.108020

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Presentation] Measurements of Exhaled Airflow Velocity Via Human Coughs Using Particle Image Velocimetry (PIV)2022

    • Author(s)
      Mengtao Han, Ryozo Ooka, Hideki Kikumoto, Wonseok Oh, Yuchen Bu, Shuyuan Hu
    • Organizer
      IAQ 2020: Indoor Environmental Quality Performance Approaches
    • Related Report
      2022 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Numerical analysis of airflow dynamics generated by human coughing based on PIV experimental results2022

    • Author(s)
      Wonseok Oh. Ryozo Ooka, Hideki Kikumoto, Mengtao Han
    • Organizer
      IAQ 2020: Indoor Environmental Quality Performance Approaches
    • Related Report
      2022 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Numerical analysis of particle dispersion and removal in differently ventilated rooms2022

    • Author(s)
      Wenchao Wang, Ryozo Ooka , Hideki Kikumoto, Wonseok Oh , Chao Lin, Mengtao Han
    • Organizer
      INDOOR AIR 2022: Healthy People in Healthy Indoor Environments
    • Related Report
      2022 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Numerical investigation of the transmission route of infectious particles produced by human2022

    • Author(s)
      Wonseok Oh. Ryozo Ooka, Hideki Kikumoto, Sihwan Lee
    • Organizer
      REHVA 14th HVAC Wold Congress, CLIMA 2022
    • Related Report
      2022 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Numerical Analysis on the Applicability of Air Purifier for Removal of Indoor Viral Contaminants2022

    • Author(s)
      Yunchen Bu, Ryozo Ooka, Hideki Kikumoto, Wonseok Oh
    • Organizer
      IAQ 2020: Indoor Environmental Quality Performance Approaches
    • Related Report
      2022 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Measurements of Exhaled Airflow Velocity Via Human Coughs Using Particle Image Velocimetry (PIV)2022

    • Author(s)
      Mengtao Han, Ryozo Ooka, Hideki, Kikumoto, Wonseok Oh, Yunchen Bu, Shuyuan Hu
    • Organizer
      IAQ 2020: Indoor Environmental Quality Performance Approaches
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research
  • [Presentation] Numerical analysis of airflow dynamics generated by human coughing based on PIV experimental results2022

    • Author(s)
      Wonseok Oh, Ryozo Ooka, Hideki Kikumoto, Mengtao Han
    • Organizer
      IAQ 2020: Indoor Environmental Quality Performance Approaches
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research
  • [Presentation] Numerical analysis on the applicability of air purifier for removal of indoor viral contaminants2022

    • Author(s)
      Yunchen Bu, Ryozo Ooka, Hideki Kikumoto, Wonseok Oh
    • Organizer
      IAQ 2020: Indoor Environmental Quality Performance Approaches
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research
  • [Presentation] 人の咳により噴出する気流及び飛沫・飛沫核の運動特性の把握(その1) PIVを用いた咳気流の速度分布の測定2021

    • Author(s)
      韓梦涛、大岡龍三、菊本英紀、呉元錫、卜韻諶、胡書媛
    • Organizer
      日本建築学会大会学術講演梗概集
    • Related Report
      2021 Research-status Report
  • [Presentation] 呉元錫、大岡龍三、菊本英紀、韓梦涛2021

    • Author(s)
      人の咳により噴出する気流及び飛沫・飛沫核の運動特性の把握(その2)数値解析を用いた咳による気流モデルの構築
    • Organizer
      日本建築学会大会学術講演梗概集
    • Related Report
      2021 Research-status Report

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Published: 2021-07-13   Modified: 2024-01-30  

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