IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) e-ISSN: 2278-1684,p-ISSN: 2320-334X, Volume 11, Issue 2 Ver. VIII (Mar- Apr. 2014), PP 40-46 www.iosrjournals.org www.iosrjournals.org 40 | Page Computational Fluid Dynamics Modeling and Investigation of Horizontal Airflow Ventilation System in Surgical Site in Hospital S B Thool 1 , S L Sinha 2 Department of Mechanical Engineering 1 Rungta College of Engineering and Technology, Bhilai, India 2 National Institute of Technology, Raipur, India Abstract: The present paper deals with the numerical study of horizontal laminar flow ventilation system for surgical site in hospital. When the orientation of supplies openings and exhausts are altered, the performance of ventilation system in terms of effectiveness of removal of contaminated particles is also affected. In this investigation, the performance of new horizontal Single Sided Supply and Exhaust (SSSE) ventilation system have been evaluated and compared withconventional Vertical Unidirectional (Laminar) ventilation system using Computational Fluid Dynamics (CFD) technique. It has beenobserved that contaminant control is found more effective in the case of SSSE horizontal ventilating system over the Vertical Unidirectional ventilation system. It is so happened because the airflow pattern over the critical area of surgery is not affected by the overhead obstacle i.e., surgical lamp. Investigation also reveals that the thermal plume induced by the surgical wound and the surgical lamp, is not counteracted by the supply airflow pattern, which plays an important roll in positive way. Keywords: Ventilation system, Airflow pattern, Infection control, surgical site infection, CFD, Single Sided Supply and Exhaust (SSSE) ventilation system. I. Introduction In order to control the Surgical Site Infection (SSI) caused by airborne particles, application of ventilation systems is well known. Infectious particles can be effectively isolated, diluted and get escaped from surgical site through the proper distribution of ultraclean air [1]. Now a days, downwardunidirectional (laminar) flow [2] is widely adopted air distribution for creating an aseptic environment around patient [3,4]. Even though the downward unidirectional airflow pattern is recommended as a regular design, current research demonstrates some disadvantages. Overhead accessories such as medical lamps can easily affect the unidirectional airflow pattern of downward airflow and thermal plume around the wound. [5,6]. Though some methods to reduce these negative effects have been recommended adequately, some disadvantages cannot be eliminated due to the vertical unidirectional flow pattern [7]. The main influencing factor for airflow pattern is to consider the indoor obstacles, thus counteracting the function of clean air in isolating infectious particles. Facilities placed upstream of patient such as a medical lamp may cause serious whirlpool and particulate accumulation [8]. Further, the temperature of human body surface is usually higher than the one of his surrounding air, whichcauses thebuoyancy driven upward airflow plumes. This can easily disturb the downward airflow pattern formed by the ventilating system and carry infectious particles to the wound, leading to serious surgical site infection. To overcome the disadvantages of the conventional airflow pattern applied to operating room, an alternative of horizontal airflow pattern should be studied to find out its feasibility, characteristics and contamination control effect in operating room. The main sources of infectious particles and bacteria in an operating room are the surgeons relatedto their activities. Isolating patient from surgeon can effectively prevent SSI by formation of proper airflow pattern. A horizontal airflow with single sided supply and exhaust ventilation system supplying ultraclean air will avoid the obstacles, such as medical lamps. Again the horizontal airflow with a direction perpendicular to the airflow direction of thermal plume around surgeon and patient can avoid direct counteractive effect between the two airflows. The existing design of horizontal airflow system i.e. opposite sided supply and exhaust ventilation system causes a relatively long air path length. It makes it difficult to maintain a washing effect around the patient with unidirectional flow. At most time the surgical staff and necessary furniture are serious obstacles to damage the unidirectional airflow [9]. Investigating and comparing above stated ventilation system experimentally, is very costly and time consuming. Due to technological and economical difficulties found when performing and comparing experiments, numerical studies of the problem appears to be a promising method for quantifying the effect of the various parameters that influence the design of best ventilation system.