Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Mechanical and Aerospace Engineering


H. Ezzat Khalifa


Breathing Zone, Chemical Reactions, Computational Modeling, Inhalation Exposure, Personal Ventilation

Subject Categories

Mechanical Engineering


This research investigates the use of personal ventilation (PV) in a typical office space as a means of contaminant removal from ones breathing zone (BZ). For this work, a validated computational model was developed and used for PV assessment under different scenarios. Experimental data of Khalifa et al. (2009), Ito (2007) and Rim et al. (2009) were used to validate a computational model that is capable of simulating indoor chemical reactions with excellent agreement compared with the experiments. Through the validation process, various computational parameters were determined to be significant for producing accurate results. Grid resolution, geometry, far field BCs, turbulence model and radiation were shown to impact the solutions accuracy and care must be taken. However, it was found that adding complex, realistic features, such as unsteady breathing or sweating, does not improve the accuracy of the inhaled air quality results of the solution. With this knowledge, the benefits of two PV nozzles, a conventional round nozzle and a novel low-mixing Co-flow nozzle, were investigated for an array of scenarios including: non-reacting indoor sources, different office and PV configurations and indoor surface and volumetric reactions. Specifically, the use of PV to remove reaction products of the oxidation by Ozone of Squalene and D-Limonene were analyzed and compared to a conventional ventilation system. The Co-flow nozzle was shown to exhibit superior performance and robustness over a single jet PV system and both PV systems improved air quality in the BZ over conventional systems. It was found that well mixed behavior is not exhibited especially with large velocity and concentration gradients that are developed by the use of PV and/or when indoor sources or chemical reactions are present.


Open Access