Luftföring i operationsrum. Visualisering av olika luftföringsprinciper i modellskala.
Examensarbete för kandidatexamen
This bachelor thesis has the purpose to visualize and document the air movements provided by different ventilation principles in an operating theatre. The visualization will be made as simple as possible in a physical model. The model and the documentation should be able to use in educational purposes. The study is based on the two most common systems for airflow, currently used in operating theatres. The first principle is displacement ventilation in which the air is supplied at low velocity along the floor. The second principle is vertical parallel laminar airflow in which the air is compressed like a piston from ceiling to the floor. A review of literature resulted in the choice of size, design, and scale factor for the model, as well as choices of ventilation principles and airflows. When the model was completely built and ready to use the air movement were made visible with smoke. The visualization of the air movements was documented with videos. The series of experiments with vertical parallel airflow give a result of air movements, which looks reasonably the same for the different tested velocities of the supply air. The air is forced down over the operating table, and forming a sterile zone, obtaining the form of a cylinder around and over the table. Between the outer edge of the sterile zone and the walls the smoke accumulates in air eddies. The experiments with displacement ventilation provides a visualization of the air movements that spreads from the diffusers in the corners to the operating table via the floor, and then rise in a more turbulent pattern of movement towards the exhaust diffuser in the ceiling. The visualization of the two air supply principles in the model leads to the following conclusions: The model is suitable to visualize the air movement arising from the principle of vertical parallel airflow. The visualization of air movements with displacement ventilation will be more realistic if the experiments were made with lowered velocity of the supply air, if the supply air is colder than the air in the operating theatre and if heat sources are placed in the room. The model can be easily understood and used to visualize air movements in an operating theatre. The model can be used to give hospital staff a better idea of the importance of the ventilation in operation theatres. Eddies in the air movements are a problem in all experiments. Less eddies are detected at higher air velocities and with partial exhaust at roof height. To sort out what impact eddies have on protection ventilation requires more studies focusing on this factor. A continued development of the model will make the visualizations of the air movements in the model more realistic.
Byggnadsteknik , Building Futures , Building engineering , Building Futures