Skin: Thermal TransferBEBC>Heat loss/generation under normal conditions·Heat loss by radiationQrad = 0c(T4 - T)Where is the emissivity of skin surface and is the Stefanconstant, T. is the skin surface temperature, and T, is thesurrounding air temperature
➢Heat loss/generation under normal conditions •Heat loss by radiation ( ) 4 4 Q T T rad s a = − Where ε is the emissivity of skin surface and σ is the Stefan constant, Ts is the skin surface temperature, and Ta is the surrounding air temperature. Skin: Thermal Transfer
Skin: Thermal TransferBEBC>Heatloss/generationundernormalconditions·Heat loss bysweat evaporationQ, = Qair +QrswQayr = 3.054(0.256T,-3.37- P.) W/m2W/mQrsw =16.7h,Wrsw (0.256T, -3.37- P)福rswwhere T, is the temperature of ambient fluid, Qdif heat loss byevaporation of implicit sweat secretion when the skin is dry, Qrws isthe heat loss by evaporation of explicit sweat secretion, Wrsw skinhumidity, Pa ambient vapor pressure, h, convective heat transfercoefficient
➢Heat loss/generation under normal conditions •Heat loss by sweat evaporation ( ) 2 Q T P W m dif s a = − − 3.054 0.256 3.37 ( ) 2 Q h W T P W m rsw f rsw s a = − − 16.7 0.256 3.37 Q Q Q s dif rsw = + where Tf is the temperature of ambient fluid, Qdif heat loss by evaporation of implicit sweat secretion when the skin is dry, Qrws is the heat loss by evaporation of explicit sweat secretion, Wrsw skin humidity, Pa ambient vapor pressure, hf convective heat transfer coefficient. Skin: Thermal Transfer
Skin: Thermal DamageBEBCEpidermisDermis388888HypodermisNormalSuperficial secondThird degreeFirst degreeDeep secondskinburndegree burndegreeburnburnMaterialparameterTissue temperaturek(T)= d2/ dt =@exp(-Ea /RT)Description:Q=Aexp(-E/RT)dtUniversal gas constantThermal damage Denaturation activationenergyClinical classification ofburn:1st Degree:Q=0.53;2nd Degree:Q=1;3rd Degree:Q=1.0x104
( ) ( ) 0 ( ) / exp exp a t a k T d d A E RT A E RT dt = = − = − Material parameter Denaturation activation energy Universal gas constant Tissue temperature Description: Thermal damage Clinical classification of burn: 1 st Degree: Ω = 0.53; 2nd Degree: Ω = 1; 3rd Degree: Ω = 1.0x104 Skin: Thermal Damage
TASkin: Thermal DamageBEBCCross-plot ofArrhenius parameters8Ea=15798.964+2702.434In(A)>A linear relationship6.betweenthe(lou/ ,01x)ArrheniusHenriques19475Fugitt1955parameters forskinStoll19594Weaver1969tissueMehta1973Takata1974Wu1982E2Pearce1991Pearce1993Xu2009150200250100300In(A) (In(s-))
Cross-plot of Arrhenius parameters A linear relationship between the Arrhenius parameters for skin tissue Skin: Thermal Damage
Skin: ContentBEBCSkin StructureSkinThermalBehaviourSkin Biothermomechanical BehaviourSkin Thermal Pain Sensation
◆ Skin Structure ◆ Skin Thermal Behaviour ◆ Skin Biothermomechanical Behaviour ◆ Skin Thermal Pain Sensation Skin: Content