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1、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 c
2、oating 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-
3、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
4、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 Ve
5、locity 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 Unit
6、smPas 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:
7、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 NonN
8、on- -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
