SECTION V:SECTION V: RheologyRheology 流变学流变学流变学流变学 Gasoline engines103 107Lubrication Spray-dying, painting, fuel atomization 103 104Spraying and brushing Application of creams and lotions to the skin 104 105Rubbing Paints, printing inks103 105Milling pigments in fluid bases Paper105 106High speed coating Polymers100 102Extruders Foods101 102Chewing and swallowing Paints, confectionery101 102Dip coating Manufacturing liquids101 103Mixing and stirring Pumping, blood flow100 103Pipe flow Medicines, Paints10-6 10-4 Sedimentation of fine powders in a suspending liquid Paints, printing inks10-2 10-1 Leveling due to surface tension Painting and coating, toilet bleaches 10-1 101Draining under gravity Application Typical range of shear rates (s-1) Situation FluidFluid ModelModel 流体模型流体模型 A=Area cm2A=Area cm2 V = Velocity (cm/sec) F = Force dynes dv Moveable Plates X = Distance Stationary Plates dx Shear Rate (Flow Gradient)Shear Rate (Flow Gradient) 剪切率（流动梯度）剪切率（流动梯度） Assumption: Plate length is significantly greater than distance between plates. EquationsEquations 公式公式 剪切应力（力剪切应力（力/ 单位面积）单位面积） Let =Force / Unit Area =Dynes / cm 2 =Shear Stress (dynes / cm 2) 剪切率（速度梯度）剪切率（速度梯度） Let =The Velocity Gradient = Shear Rate =dv/dx = V/X = Shear Rate =V(cm/sec) / X (cm) =Shear Rate (sec -1) EquationsEquations(continued) (continued) 粘度（剪切应力粘度（剪切应力/剪切率剪切率) Let =Shear Stress / Shear Rate =(Dynes / cm 2) / (sec-1) =Viscosity (Poise) 1 Poise = 100 Centipoise 动力粘度或旋转粘度动力粘度或旋转粘度: Brookfield SI UnitsmPas CommoncP Conversion1 cP = 1 mPas 运动粘度运动粘度: 毛细管、杯毛细管、杯 SI Unitsmm2/s CommoncSt “Centistokes” Conversion1 mm2/s = 1 cSt To convert from Kinematic to Dynamic, simply multiply by Specific Gravity: cStx SG = cP mm2/s x SG = mPas 只适用于牛顿流体只适用于牛顿流体 UnitsUnits 单位单位 FluidsFluids 流体流体 ?Newtonian牛顿流体牛顿流体:Mineral oil矿物油, water水, honey蜂蜜, silicone硅油, glycerin甘油 ?Non-Newtonian:非牛顿流体非牛顿流体 Pseudoplastic假塑性假塑性:hand lotion润手乳液, ink油墨, shampoo香波 Dilatant膨胀性膨胀性:cornstarch玉米淀粉, ceramic slurry陶瓷泥浆, cement水泥 Plastic塑性塑性:ketchup番茄酱, mayonnaise蛋黄酱 Thixotropic触变性触变性:latex paint乳胶涂料 NewtonianNewtonian 牛顿流体牛顿流体 NonNon- -NewtonianNewtonian非牛顿流体非牛顿流体 PseudoplasticPseudoplastic 假塑性假塑性 NonNon- -NewtonianNewtonian非牛顿流体非牛顿流体Plastic Plastic (with yield)(with yield)塑性（带屈服力）塑性（带屈服力） NonNon- -NewtonianNewtonian非牛顿流体非牛顿流体 DilatantDilatant膨胀性膨胀性 Time DependentTime Dependent时间依赖性时间依赖性 ThixotropicThixotropic触变性触变性 Time DependentTime Dependent时间依赖性时间依赖性 ThixotropicThixotropic触变性触变性 Time DependentTime Dependent时间依赖性时间依赖性 RheopecticRheopectic流凝性流凝性 Time DependentTime Dependent时间依赖性时间依赖性 RheopecticRheopectic流凝性流凝性 Summary Types of FlowSummary Types of Flow 流体类型流体类型