Nurettin Yamankaradeniz

Investigation of the number of particles in an operating room at different ambient temperatures and inlet velocities

ABSTRACT This study presents some field measurements in an operating room of air velocity, ambient temperature and particle counts on the operating table. Moreover, computational fluid Dynamics analyses of the operating room were performed and compared with the measurements. Measurements were taken under the preferred operating conditions by surgical staff (at 19 °C) and then at different ambient temperatures (from 20 to 22 °C,varying by one-degree increments) and average inlet air velocities (Vi) (0.1 and 0.2 m/s). The preferred one by surgical staff is 0.1 m/s and the maximum that can be reached is 0.2 m/s, with the current system. The results show that the particle count decreased at Vi of 0.2 m/s and low temperatures.

Three-dimensional air distribution analysis of different outflow typed operating rooms at different inlet velocities and room temperatures

It is important to provide a regular unidirectional air distribution in an operating room to reduce the number of particles. Measurements were taken in the one of the operating rooms at Uludag University Medical School, with laminar air flow unit and two-cornered outlet which was thought to have some airflow problems. Moreover, a three-dimensional computational fluid dynamics model has been developed where the measurements were taken in. The distributions of air velocity, temperature, and relative humidity have been examined and compared with the measurements to validate the computational fluid dynamics analyses. In addition to present model, four-cornered outlet operating room has been analyzed and compared with the results of two-cornered one. It is concluded that the case of four-cornered outlet provides more suitable thermal distribution, which results in a reduction of the particle numbers in the interior. Although there is no significant change in temperature and relative humidity in the operating room, air distribution changes dramatically.

Minimization of thermal insulation thickness taking into account condensation on external walls

Condensation occurs in the inner layers of construction materials at whatever point the partial pressure of water vapor diffuses and reaches its saturation pressure. Condensation, also called sweating, damages materials, reduces thermal resistance, and by increasing the total heat transfer coefficient, results in unwanted events such as increased heat loss. This study applied minimization of thermal insulation thickness with consideration given to condensation in the external walls. The calculations of heat and mass transfers in the structure elements are expressed in a graphical form. While there was an increase in the required thermal insulation thickness subsequent to an increase in the internal environment’s temperature, relative humidity, and the external environment’s relative humidity, the required thickness decreased with an increase in the external environment’s temperature. The amount of water vapor transferred varied with internal or external conditions and the thickness of the insulation. A change in the vapor diffusion resistance of the insulation material can increase the risk of condensation on the internal or external surfaces of the insulation.