Simulation and Analysis of the Unsteady Flow within Nasal Airways

Abstract

The human nasal airways are building a very complex anatomical structure within the human head. In fact, the main airways together with their connected multiplicity of nasal cavities and sinuses are involved in the various functions of the nose. Besides warming and humidifying the inspired air, they filter out small particles and supports the olfaction process by transporting odor-bearing particles to the muscous membranes. Unfortunately, human nasal airways are often not idealy shaped leading to higher nasal flow resistance, malfunction of the smelling sense by mis-overflowing the olfactory region, fast drying soft tissue or even sleep apnea. In many cases patients are suffering from multiple nasal breathing difficulties or even limitations due to air flow blockages, hence, a septoplasty might be beneficial and could improve live quality significantly, and this is the point where numerical flow simulation (CFD) can be helpful. Modern numerical flow simulation studies of nasal airflow can be devided into three categories: basic research airflow studies on the physiological function of the nose itself, then studies on the transport of gases, heat, particles, aerosol, and drug delivery, and, finally, studies supporting virtual surgery for evaluating and predicting the impact and outcome of surgical intervention. In the latter case CFD is able to support the septoplasty and other nasal airway surgeries, since it is not only providing distinct details of significant flow information at suspect nasal airway regions to be addressed, but more, it allows for a virtual outlook of the entire flow situation within the nasal airways after a performed nasal airway surgery. This helps to enhance septoplasty success rates by targeting the most sensitive nasal airway geometry to be corrected.