Numerical study on abnormal airflow patterns and particle deposition characteristics in the realistic HUA model with pharyngeal obstruction

Yan, Weiwei; Tang, Chenwei; Liu, Yang; Li, Guozhan

doi:10.1016/j.powtec.2019.08.007

Cited by 15 publications

(9 citation statements)

References 31 publications

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“…7–13 Among these previous researches, few numerical studies have been executed on flow characteristics in the upper airway of OSA patients. 14 Moreover, earlier work on CFD simulation in the OSA airways used simplified geometry models and 1D/2D analysis, which could not predict airway flow features accurately. 15 In the last two decades, simulation in the realistic UA models based on the CT/MRI scans has shown the potential of CFD in gaining a better understanding of flow features and the pathogenesis of OSA.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the transitional and turbulent flow in an OSA UA was modeled by the LES. 14 The LES was confirmed to be much more economical in terms of computing power required than the DNS, and it can resolve the most energetic flow scales while modeling only the smallest dissipative scales. Currently, more and more CFD studies on airway flow are adopting the LES, which has become the preferred tool for capturing relevant flow features.…”

Section: Introductionmentioning

confidence: 99%

“…Currently, more and more CFD studies on airway flow are adopting the LES, which has become the preferred tool for capturing relevant flow features. 12,14,16–18…”

Section: Introductionmentioning

confidence: 99%

“…It was observed that the LES calculation on flow velocity was consistent with the LDA measurement. 14…”

Section: Introductionmentioning

confidence: 99%

“…Almost all of the previous in vitro experiments were concentrated on either comparison between measured and calculated pressure or velocity measurement only in the UA models, and the direct comparison between measured and calculated velocity in the same OSA UA model was extremely scarce. 14 It was found that different turbulence models would produce a similar pressure distribution, but there was great discrepancy in velocity distribution among different turbulence models. 17 It is necessary to assess the accuracy of turbulence models in simulation of velocity profile in the OSA airways.…”

Section: Introductionmentioning

confidence: 99%

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Numerical simulations and experimental measurements on flow features in a patient-specific upper airway model with obstructive sleep apnea

Yan

Zhang

Liu

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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In this article, the turbulent flow features in a patient-specific upper airway model with obstructive sleep apnea before and after surgery are numerically and experimentally studied by applying the large eddy simulation and laser Doppler anemometry. Two three-dimensional anatomically accurate numerical models are reconstructed based on the CT-scan of one severe obstructive sleep apnea patient for both pre- and post-surgery. Two experimental models of the same upper airway are established by using the three-dimensional printing technique according to the numerical models. The first direct comparison of flow velocity profiles between measurement and simulation at different locations and cross-sections is conducted in two upper airway models. The simulated result indicates that the especially large axial velocity and negative pressure appear in the narrowest cross-section before surgery, but they either reduce or vanish after surgery. Both measurement and simulation can capture the “pharyngeal jet” flow and the reversed flow in two upper airway models, and the agreement between the measured and calculated velocity profiles at different locations and cross-sections is excellent, which gives us great confidence that the large eddy simulation can be a reliable method for predicting the flow features associated with obstructive sleep apnea airway. Although this work represents significant advance, there still exists some limitations, such as the discrepancies between measurement and simulation in the interface of main stream velocity and reverse velocity due to the flow complexity, in the reversed flow region owing to the uncertainty of laser Doppler anemometry measurement at low velocity range, and the incapability of capturing flow near the wall due to the intrinsic feature of laser Doppler anemometry measurement. Besides, it is very difficult to find the corresponding locations exactly between experimental and numerical models, which could also cause the deviation between experiment and simulation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Currently, more and more CFD studies on airway flow are adopting the LES, which has become the preferred tool for capturing relevant flow features. 12,14,16–18…”

Section: Introductionmentioning

confidence: 99%

“…It was observed that the LES calculation on flow velocity was consistent with the LDA measurement. 14…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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