Effects of the ambient temperature on the airflow across a Caucasian nasal cavity

Abstract

We analyse the effects of the air ambient temperature on the airflow across a Caucasian nasal cavity under different ambient temperatures using CFD simulations. A three-dimensional nasal model was constructed from high-resolution computed tomography images for a nasal cavity from a Caucasian male adult. An exhaustive parametric study was performed to analyse the laminar-compressible flow driven by two different pressure drops between the nostrils and the nasopharynx, which induced calm breathing flow rates ࣈ 5.7 L/min and ࣈ 11.3 L/min. The inlet air temperature covered the range - 10(o) C ⩽ To ⩽50(o) C. We observed that, keeping constant the wall temperature of the nasal cavity at 37(o) C, the ambient temperature affects mainly the airflow velocity into the valve region. Surprisingly, we found an excellent linear relationship between the ambient temperature and the air average temperature reached at different cross sections, independently of the pressure drop applied. Finally, we have also observed that the spatial evolution of the mean temperature data along the nasal cavity can be collapsed for all ambient temperatures analysed with the introduction of suitable dimensionless variables, and this evolution can be modelled with the help of hyperbolic functions, which are based on the heat exchanger theory.

Robust nondimensional estimators to assess the nasal airflow in health and disease

“…The validation of numerical simulations was performed by using a grid convergence study that was performed following the procedure described in Burgos et al In particular, the flow rate Q , the static temperature T , and the velocity modulus U were calculated at strategic locations on 3 successively refined meshes. The absolute error between meshes for these quantities was less than 1%.…”

The impact of endoscopic sinus surgery on paranasal physiology in simulated sinus cavities

“…To assist with providing a velocity boundary to represent inspiration by the lungs, a straight tube was attached to the nasopharyngeal end of the geometries, and a constant flow rate of 15 L/minute was specified at this boundary. Temperature and absolute humidity were solved as separate scalar variables, in the usual manner . Briefly, transport of temperature and water vapor concentration (absolute humidity) inside the nasal passage are governed by the scalar transport equation.…”

Linking Chronic Otitis Media and Nasal Obstruction: A CFD Approach

“…The three steps necessary for resolving the flow inside a nasal cavity, namely segmentation, mesh generation, and solving and postprocessing are described elsewhere. 13,14,16,[19][20][21][22] Airflow from 60 patients suffering COM and 81 from control groups was analyzed using Flowgy©. Using the CFD results and geometries from every nasal cavity the values for the parameters R À ϕ were calculated.…”