31 1 2012 2 Vol. 31 No. 1 Chinese Journal of Biomedical Engineering February 2012 * 300161 30 L / min 4. 99 mm 30. 34 Pa 7. 85 m / s R332. 02 A 0258-8021201201-0089-07 Numerical Simulation on Characteristics of Airflow Movement in Human Upper Respiratory Tract under Fluid-Solid Coupling SUN Dong LI Fu-Sheng XU Xin-Xi * ZHAO Xiu-Guo TAN Shu-Lin Institute of Medical EquipmentAcademy of Military Medicine SciencesNational Biological Protection Engineering Center Tianjin 300161China AbstractResearch the effect of fluid-solid coupling on human upper respiratory tract can lead to deep understanding of the characteristics of the airflow in human upper respiratory tract and plays a very important role in analyzing the diffusiontransition and deposition patterns of aerosol in human upper respiratory tract. The numerical simulation of fluid-solid interaction mechanics was applied to simulate airflow movement in human upper respiratory tract model in the conditions of low intensive respiratory patterns respiratory flow is 30 L / minthe shape variation and shear stress distribution in human upper respiratory tract was discussedand the airflow movement in human upper respiratory tract was analyzed. Results showed that in the low intensive respiratory patternshuman upper respiratory tract moves backwardthe maximum displacement of the tertiary bronchus was 4. 99 mmthe anterior wall was stretchedand the posterior wall was compressed. The wall shearing stress in the mouth-throat model was larger than that in the trachea-triple bifurcationand the maximum shearing stress was 30. 34 Pa. The maximum of airflow velocity reached maximum at 7. 85 m / s in the glottis. The phenomenon of airflow separation appeared near the outer wall of the pharynx and the tracheaand the high velocity zone was created near the inner wall of the trachea. The airflow split at the divider and high velocity zone was generated near the inner wall of the trachea. Key wordsfluid-solid couplingupper respiratory tractwall shearing stressairflow movementnumerical simulation doi10. 3969 / j. issn. 0258-8021. 2012. 01. 014 2011-04-25 2011-11-04 31070832 * E-mailxuxxl@ sohu. com
90 31 1 1 Wang Fig. 1 Human upper respiratory tract model 2 Nithiarasu Menter Menter's SST 3 Langtry-Menter Menter Langtry 3 4 - PIV 5 CFD SST - 9-10 γ ργ + ρu iγ = t x i μ + μ t γ x i [ ( σ ) x ] + P γ - E γ σ γ = 1 1 γ i P γ E γ P γ = 2ρSF length F 0. onsetγ 5 0. 5 1 - γ 2 E γ = 0. 06ρΩF turb γ50γ - 1 3 F turb = e - R T /4 R T = ρk / ωμ 4 Re v F onset1 = Re 2. 193 Re v = Reρy 2 S / μ 5 θc 1 = minmaxf onset1 1 1. 2 1. 2. 1 Re v Langtry- 1 P 2. 193Re γ γ θc F onset2 F 4 onset1 2. 0 6 [ ] 1. 1 F onset3 = max 1 - R T 2. 5 3 0 7 F onset = maxf onset2 - F onset3 0 8 3 ρ t u i μ G0 ~ G3 μ t S Ω ARLA Aerosol Research Laboratory of y F Alberta 6 Stapleton K W 7 length 3 Re Weibel 8 θc R T Re v F turb E γ F onset P γ
1 91 Re 珟 θt σ s ρ s a s ρ Re 珟 θt + ρu 珟 jre θt = t x j d s = d f σ s n s = σ f n f u s = u f 15 P θt + σ x θt μ + μ t Re 珟 θt j [ ( x ) ] σ θt = 2 d n s f j 9 1. 3 P θt - P θt = 0. 03 ρ t Re θt - Re 珟 θt 1. 0 - F θt t = 500μ - ρu 2 10 U F θt min max F wake e - y 4 ( δ ) 2 1. 0-1 / 50 ) 1. 0 ) 11 Re 珟 θt μ θ BL = δ BL = 15 ρu 2 θ BL δ = 50Ωy U δ BL 12 F wake = e - Re 2 ( ω 105 ) Re ω = ρωy2 13 μ F θt = ( ( 1. 0 - γ - 1 /50 ( ) θ BL δ 30 L / imn F θt P θt Re 珘 θt F wake F θt 0 1. 2. 2 1. 4 particle image velocimetry PIV 30 L / min 11 9 MPa 0. 4 1 1-2 σ s = ρ s a s 14 2 a PIV 2 a b Fig. 2 Comparison of airflow patterns between experimental results and large eddy simulation results of the larynx. aexperimental results blarge eddy simulation results
92 31 2 b d x d y d z d = d x + d y + d z 3b 3 c 3d 8. 51 m / s 7. 85 m / 3a 30 L / min 10% 2 2. 1 3c 3 d 3 3 a 3b 3 3 30 L / min a b c d Fig. 3 The deformation of human upper respiratory tract model with breathing intensity Q = 30 L / min. acomparison of pre- and post- deformation b Longitudinal displacement c and d Lateral displacement
1 93 4 a b 2. 2 4 a b c d 4 c d 30. 34 Pa 4 30 L / min Von Mises stress a b c d Fig. 4 The Von Mises stress distribution of human upper respiratory tract model with breathing intensity Q = 30 L / min. afront view of anterior wall in human mouth-throat model bfront view of posterior wall in human mouth-throat model cfront view of anterior wall in trachea to triple bifurcation region dfront view of posterior wall in trachea to triple bifurcation region
94 31 5c C-C' 2. 3 5c D-D'E-E' 5 30 L / min 5a 5b 5c F-F' 5c H-H ' G2 G3 5 30 L / min a b c Fig. 5 Axial velocity contours at different cross section in human upper respiratory tract model with breathing intensity Q = 30 L / min. athe vertical section of human mouth-throat model bthe vertical section of trachea to triple bifurcation region cthe cross sections 2 3 3 3 1 30 L / min
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