An investigation on airflow in pathological nasal airway by PIV

Abstract

Understanding of airflow characteristics in nasal cavity is closely related with the physiological functions, like air-conditioning and smelling, and pathological aspects in nasal breathing. Several studies have utilized physical models of the healthy nasal cavity to investigate the relationship between nasal anatomy and airflow. The next step on this topic is naturally studies for disordered nasal airways and this is the main purpose of this article. Airflows in the pathological nasal airways, including nasal cavity and upper pharynx, of Korean adults are investigated experimentally by PIV measurement technique and air resistance measurements. Quantitative data for normal and pathological nasal airway are obtained. Average and RMS velocity distributions are obtained for inspirational and expirational nasal airflows. The CBC PIV algorithm with window offset is used for PIV flow analysis. PIV measurements of nasal airflow for nasal cavities with 50% and 70% adenoid vegetation are conducted for the first time. The asymmetric nasal cavities, due to either congenital deformity or injury, are also investigated. Comparisons in nasal airflows for both normal and abnormal cases are also appreciated and airflow characteristics that are related with the abnormalities in nasal cavity are proposed.

Standardization of Malaysian Adult Female Nasal Cavity

“…Lack of meshing elements especially at the thin turbinates region inside the nasal cavity will cause failure in capturing nasal airflow in the crucial areas. The results showed that the grid dependency study resulted in an optimized meshing of 1,109,123 elements, and the computational results are validated with the pressure drop obtained from Kim and Son [31] and Wen et al [15, 17] as shown in Figure 5.…”

An investigation on airflow in disordered nasal cavity and its corrected models by tomographic PIV

“…Velocity distributions in the coronal planes provide better visualization for the direction of the main stream as shown in figure 7, where coloured levels denote the amplitude of average and RMS velocities. Flow characteristics related to abnormalities in nasal cavities can be conjectured from two-dimensional velocity and RMS data in the sagittal plane, as shown in figure 8 for the case of adenoid vegetation [8]. There are two re-circulating zones in the case of 70%, but there is only one in the case of 50% and the excessive value of RMS for the 70% adenoid vegetation case indicates the sharp increase in the flow resistance.…”

“…Creating accurate transparent flow passages is essential for analysing the inward flow through a complex flow passage by PIV. Kim and Son [7] improved the procedure for producing a better cavity model with high-resolution computerized tomogram (CT) scan data and surface rendering and extended this work to deal with airflow in an abnormal nasal cavity with adenoid vegetation and asymmetry [8]. Some conjectures are obtained as follows: adenoid vegetation exceeding 60% causes a rapid increase in the pressure drop between nares and nasopharynx.…”

Experimental investigation of oscillatory air flow in a bronchial tube model with HFOV mode

“…Fresconi et al (2003) presented experimental results on expiration flow in a symmetric bifurcation by using PIV and LIF techniques. And, Kim et al (2004) carried out an investigation on airflow in pathological nasal airway by PIV. However, the analysis on gas transfer and exchange mechanism related to flow pattern in the airways, especially at the respiratory zones from bronchioles to alveoli, has not been clarified in detail.…”