Evaluation of laminar airflow heating, ventilation, and air conditioning system for particle dispersion control in operating room including staffs: A non-Boussinesq Lagrangian study

Abstract

Impacts of the laminar airflow ventilation system design factors on contaminant removal and thermal comfort condition in an operating room have been investigated by means of Lagrangian-based particle transport using the non-Boussinesq modeling of the buoyancy effects. An operating room including staffs and a patient with realistic human geometries and two surgery lights are included in simulations. The laminar airflow system is placed on the ceiling with a surrounding fixed-height partial wall and the air barrier supply grills. Effects of density change in mixed convection flow regime are included by the non-Boussinesq modeling of the exact air density variation. The predicted mean vote, the age of air, the colony-forming units per cubic meter, the average temperature, the average velocity, the relative humidity, the density distribution, and the positions of particles are calculated to assess the indoor air ventilation quality. A total of 27 simulation cases have been considered to determine the impact of three main design factors including the laminar airflow system area, the supply air, and the air barrier velocities on the performance of the system. It is concluded that for the curtain velocity of 2 m/s, the thermal comfort reduces with increasing the laminar airflow velocity, but for the third staff, the results show that for small laminar airflow areas, the speed of the inlet port should be reduced and for the larger sizes, the inverse of this trend is recommended. Moreover, for all cases the humidity varies within the range of 55%–56%, which agrees well with the suggested standard humidity range between 50% and 60%. It is concluded that the cases of the laminar airflow velocity equal to 0.3 and 0.5 at the curtain velocity of 1 m/s are generally more appropriate than other cases due to less accommodation of particles near the entire body of the patient.

Influence of the Built Environment on Airflow, Contamination, and Infection in the Operating Room: A Systematic Literature Review

“…Of the 86 total articles investigating OR ventilation, 30 used modeling approaches to investigate the effects of HVAC components on the built environment. 31,41,[128][129][130][131][132][133][134][135][136][137]64,[138][139][140][141][142][143][144][145][146][147][121][122][123][124][125][126][127] Twenty-seven of those 30 articles utilized computational fluid dynamics (CFD) modeling. The numerical parameters in CFD models are often validated to some degree via small-scale or simplified experimental setups, or using previously published measurements.…”

“…Of the 86 total articles investigating OR ventilation, 30 used modeling approaches to investigate the effects of HVAC components on the built environment. 31,41,[128][129][130][131][132][133][134][135][136][137]64,[138][139][140][141][142][143][144][145][146][147][121][122][123][124][125][126][127] Twenty-seven of those 30 articles utilized computational fluid dynamics (CFD) modeling. 31,41,[128][129][130][131][132][133][134][135][136][137]64,[138][139][140][141][142]…”

“…31,41,[128][129][130][131][132][133][134][135][136][137]64,[138][139][140][141][142][143][144][145][146][147][121][122][123][124][125][126][127] Twenty-seven of those 30 articles utilized computational fluid dynamics (CFD) modeling. 31,41,[128][129][130][131][132][133][134][135][136][137]64,[138][139][140][141][142][143][144]…”

“…Six of these studied inlet airflow velocity's effects on contamination, particle count, and particle deposition, but did not come to a consensus on an optimal inlet air velocity value. 31,123,125,126,133,134 One article concluded that contamination was minimized at a velocity of 2.37 m/s, but cautioned that airflow can easily be disrupted by slight changes in the design of the OR air curtain and exhaust vents 124 . The last article studied inlet airflow and its impact on airflow patterns.…”

Investigation of Thermal Comfort in University Offices: The Case of the Bingöl University

“…People feel cooler when the air velocity is higher in the equivalent comfort environment. In low ambient temperatures, if the air velocity is above 0.3-0.5 m/s, heat stress occurs on peoples [24]. By increasing the ambient air velocity rate by 1 m/s, the ambient temperature can be reduced up to 2.7℃ [25][26][27].…”