Air%20flow%20and%20Thermal%20distribution%20in%20An%20Infant%20incubator%20Analysis%20By%20Using%20Finite%20Element%20Method

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Air flow and Thermal distribution in An Infant
incubator AnalysisBy Using Finite Element Method

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Outline
Introduction
Theory
Model and Metrology
Simulation Results
Future work
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• Introduction

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????????? ????????????

• ???????? 3 ?????????
• ?????????? (Infant Chamber/Hood)
• ?????????? (Control Unit/Section)
• ??? (Cabinet)

Hood
Control
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???????????????????????????????

• ????????????????? (premature baby)
• ??????????????, ???????????????????????????
• ???? lt750 ???? gt2000 ????
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  0.3 ??????
• ????????????????????? ? ??????????????????????????
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• ???????????????????????????
• ???? ? 35.5 C ??? 37.5C ????????
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• ???????? ? ??????????????????????????? 4.5 ??? 5
  W/kg
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• ??????????????????
• - ????????????? (Conduction) ???????????????????
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• - ????????????? (Convection) ?
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• - ??????????? (Radiant) ? ???????????????????????
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• - ???????? (Evaporation) ????????????????????????
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• Infant Incubator

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• Infant Incubator

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• Infant Incubator

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• Infant Incubator

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????????? HOOD ????????
Single wall
Double wall
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Variables Temperature, Velocity Field
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Theory of Fluid Mechanics and Heat Transfer
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Incompressible Navier-Stokes Equation
Dynamic Viscosity(Ns/m2)
Pressure (Pa)
Volume Force Field (N/m3)
Fluid Dynamics
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Conduction and Convection Equation
T Temperature (K)
Q Heat Source (W)
C Heat Capacity (J/kgK)
K Isotropic Thermal Conductivity (W/mK)
Heat Transfer
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Comsol multiphysics 3.4 a
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4. Finite Element Method
Partial Differential Equation (PDE)
Boundary Condition
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Cubic shape
Pentagon shape
semi-hexagonal shape
velocity fields inside the incubator of each model
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Stream Line
Hexagonal Shape
Dome Shape
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Temperature plot at head, body, foot of infant
Hexagonal Shape
Dome Shape
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Incubator Model
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Infant Model
????????????????????? ??????? 3dsmax ???
Unigraphics NX
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Material name Air Air
Axial initial velocity of the air uz 0.41 m/s
Air density ?a 1.43 kg/m3
Heat capacity of the air cp,a 1006 J/kgK
Thermal conductivity of the air ka 0.0268 W/mK
Viscosity of the air µa 1.90 x 10-5 kg/ms
Thermal expansion coefficient of the air ß 0.003326 1/K
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Material name Infant Infant
Newborns weight 1500 (kg)
Newborns height 0.4 (m)

Age 1 (days)
Gestation 32 (weeks)
Tissue conductivity 0.34 W/mK
Tissue density 1000 kg/m3
Tissue specific heat 4000 J/kgK
Blood perfusion rate 1.8 (kg m-3 s-1)
Blood density 1050 kg/m3
Blood specific heat 3800 J/kgK
Initial temperature 308 K
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Boundary condition of fluid dynamics
Fluid Dynamics Boundary Condition
Inflow u u0
Outflow P00
Chamber u0
Infant model u0
Boundary condition of heat transfer
Fluid Dynamics Boundary Condition
Inflow Temperature
Outflow Convective Flux
Chamber Thermal insulator
Infant model Temperature
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Mesh of model
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Initial value
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Improvement

• Other parameter, humid, Heat Loss
• Real Situation and parameter,infant,room
• Simulink with mathlab Control temperature

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