Cross transmission of normal breathing-released contaminants in a general hospital ward with impinging jet supply: A numerical study

Chao Qin, Shan Shan Cai, Xiaopu Lyu*, Wei Zhen Lu*

*Corresponding author for this work

    Research output: Contribution to journalJournal articlepeer-review


    Impinging jet ventilation (IJV) system is promising to improve air quality in hospital wards compared with traditional mixing systems, while previously studied IJV systems for hospital wards were, in fact, personalized ventilation systems. This study investigates the cross-transmission of contaminants in a 4-bed hospital ward ventilated by one diffuser, including the impacts of occupants’ posture and mask, and to suggest low-risk positions for healthcare workers. A numerical model is established and validated to simulate the airflow and contaminant distribution in the enclosure. The results include: a) the supply velocity of 1.3 m/s and temperature of 18 °C maintains an overall thermoneutral environment; b) the supply diffuser creates an overall recirculated airflow though the ambient air velocity in most regions (93.8 % of the ward space) is lower than 0.1 m/s; c) the root mean square of velocity along the height is 0.003 m/s between lying and sitting conditions, and the root mean square of temperature is 0.16 °C, indicating the impacts of posture on velocity and temperature fields are ignorable; d) the transfer of lying patient-released contaminants is dominated by the recirculated airflow, while in the sitting cases, it is dominated by thermal plumes; e) healthcare workers are advised to position themselves opposite the supply diffuser for lying patients, and alongside the walls for sitting patients to reduce infection risk; f) exhaled contaminants flows upward straightly when masks are functioning well. These outputs indicate that the work position of healthcare workers should be adjusted according to patients’ posture.

    Original languageEnglish
    Article number109766
    Number of pages12
    JournalJournal of Building Engineering
    Publication statusPublished - 1 Sept 2024

    Scopus Subject Areas

    • Civil and Structural Engineering
    • Architecture
    • Building and Construction
    • Safety, Risk, Reliability and Quality
    • Mechanics of Materials

    User-Defined Keywords

    • Cross-transmission
    • Healthcare workers
    • Hospital ward
    • Impinging jet ventilation
    • Occupant posture


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