PET聚酯切片粘度测试的影响因素探讨（一）
Discussion on Influencing Factors of PET Polyester Chip Viscosity Test (I)
一、粘度的相关知识
One, the knowledge of viscosity
1、粘度的基本概念
1、The basic concept of viscosity
液体在流动时，在其分子间产生内摩擦的性质，称为液体的粘性，粘性的大小用粘度表示，用来表征液体性质相关的阻力因子。粘度又分为动力粘度、运动粘度和条件粘度。
The nature of the liquid's internal friction as it flows is known as the viscosity of the liquid. Viscosity is expressed in terms of viscosity and is used to characterize the fluid-related resistance factor. Viscosity is divided into dynamic viscosity, kinematic viscosity, and conditional viscosity.
将流动着的液体看作许多相互平行移动的液层，各层速度不同，形成速度梯度(dv/dx)，这是流动的基本特征。由于速度梯度的存在，流动较慢的液层阻滞较快液层的流动，因此，液体产生运动阻力。为使液层维持一定的速度梯度运动，必须对液层施加一个与阻力相反的反向力。在单位液层面积上施加的这种力称为切应力或剪切力τ(N/m2)。切变速率(D) D=d v /d x (S-1) 切应力与切变速率是表征体系流变性质的两个基本参数。两不同平面但平行的流体，拥有相同的面积”A”，相隔距离”dx”，且以不同流速”V1”和”V2”往相同方向流动，牛顿假设保持此不同流速的力量正比于流体的相对速度或速度梯度，即：τ= ηdv/dx =ηD（牛顿公式） 其中η与材料性质有关，我们称为“粘度”。
The flowing liquid is regarded as many liquid layers that move in parallel with each other. The speed of each layer is different, forming a velocity gradient (dv/dx), which is the basic feature of the flow. Due to the presence of a velocity gradient, the slower flowing liquid layer blocks the flow of the faster liquid layer, and therefore, the liquid generates a resistance to movement. In order for the liquid layer to maintain a certain velocity gradient motion, a counter force against the resistance must be applied to the liquid layer. This force exerted on a unit liquid layer area is called a shear stress or shear force τ(N/m2). Shear rate (D) D = d v /d x (S-1) Shear stress and shear rate are two basic parameters characterizing the rheological properties of the system. Two different planar but parallel fluids have the same area "A", separated by distance "dx", and flow in the same direction with different flow rates "V1" and "V2". Newton assumes that the force of this different flow rate is proportional to the fluid's Relative velocity or velocity gradient, ie: τ = ηdv/dx = ηD (Newton's formula) where η is related to the material properties, we call it "viscosity".
将两块面积为1㎡的板浸于液体中，两板距离为1米，若加1N的切应力，使两板之间的相对速率为1m/s，则此液体的粘度为1Pa.s。
Two plates with an area of 1m2 were immersed in the liquid. The distance between the two plates was 1m. If a shear stress of 1N was applied, the relative velocity between the two plates was 1m/s. The viscosity of the liquid was 1Pa.s. .
牛顿流体：符合牛顿公式的流体。 粘度只与温度有关，与切变速率无关， τ与D为正比关系。
Newtonian fluid: Fluid that conforms to Newtonian formulae. Viscosity is only related to temperature and has nothing to do with shear rate. τ and D are directly proportional to each other.
非牛顿流体：不符合牛顿公式 τ/D=f（D），以ηa表示一定（τ/D）下的粘度，称表观粘度。
Non-Newtonian fluid: does not comply with Newton's formula τ/D = f(D), and ηa denotes the viscosity at a certain value (τ/D), which is called the apparent viscosity.
又称粘性系数、剪切粘度或动力粘度。流体的一种物理属性，用以衡量流体的粘性，对于牛顿流体，可用牛顿粘性定律定义之：
Also known as viscosity, shear viscosity or dynamic viscosity. A physical property of the fluid used to measure the viscosity of the fluid. For Newtonian fluids, the Newtonian viscosity law can be defined as:
式中μ为流体的粘度；τyx为剪切应力；ux为速度分量；x、y为坐标轴；dux/dy为剪切应变率。流体的粘度μ与其密度ρ的比值称为运动粘度，以v表示。
Where μ is the viscosity of the fluid; τyx is the shear stress; ux is the velocity component; x, y are the coordinate axes; dux/dy is the shear strain rate. The ratio of the viscosity μ of the fluid to its density ρ is called kinematic viscosity and is represented by v.
粘度随温度的不同而有显著变化，但通常随压力的不同发生的变化较小。液体粘度随着温度升高而减小，气体粘度则随温度升高而增大。对于溶液，常用相对粘度μr表示溶液粘度μ和溶剂粘度μ之比，即：
Viscosity varies significantly with temperature, but usually varies less with pressure. Liquid viscosity decreases with increasing temperature, and gas viscosity increases with increasing temperature. For the solution, the relative viscosity μr is commonly used to indicate the ratio of the solution viscosity μ to the solvent viscosity μ, that is:
相对粘度与浓度C的关系可表示为：
The relationship between relative viscosity and concentration C can be expressed as:
μr=1+【μ】C+K′【μ】C+…
式中【μ】为溶液的特性粘度，
K′为系数。【μ】、K′均与浓度无关。
Where μ is the intrinsic viscosity of the solution,
K' is a coefficient. Both μ and K′ have nothing to do with the concentration.
不同流体的粘度差别很大。在压强为101.325kPa、温度为20℃的条件下，空气、水和甘油的动力粘度和运动粘度为：
The viscosity of different fluids varies greatly. At a pressure of 101.325 kPa and a temperature of 20°C, the dynamic viscosity and kinematic viscosity of air, water, and glycerin are:
Air μ=17.9×10-6Pa·s， v=14.8×10-6 m2/s
Water μ=1.01×10-3Pa·s， v=1.01×10-6m2/s
Glycerin μ=1.499Pa·s， v=1.19×10-3m2/s
由于粘度的作用，使物体在流体中运动时受到摩擦阻力和压差阻力，造成机械能的损耗（见流动阻力）。
Due to the effect of viscosity, the frictional resistance and differential pressure resistance are caused when the object moves in the fluid, resulting in the loss of mechanical energy (see flow resistance).
各种流体的粘度数据，主要由实验测得。常用的粘度计有毛细管式、落球式、锥板式、转筒式等。在工业上有时用特定形式的粘度计来测定特定的条件粘度。如炼油工业中常用恩氏粘度（或恩格拉粘度）作为石油产品的一个指标，它表示某一温度下200cm油品与同体积20℃纯水，从恩氏粘度计中流出所需时间之比。恩氏粘度与动力粘度的关系可按经验公式换算。又如橡胶工业中常用门尼粘度为衡量橡胶平均分子量及可塑性的一个指标。
The viscosity data of various fluids are mainly measured by experiments. The commonly used viscometers include capillary type, falling ball type, cone and plate type, and drum type. Industrially, certain types of viscometers are sometimes used to determine the specific conditional viscosity. For example, the Enzi's viscosity (or Engela viscosity) commonly used in the oil refining industry is an index of petroleum products. It represents the ratio of time required for a 200-centimeter oil and a 20-degree-percent pure water at a certain temperature to flow out from an Enzi's viscometer. . The relationship between Enzi's viscosity and dynamic viscosity can be converted by an empirical formula. Another example is the Mooney viscosity commonly used in the rubber industry as an indicator of the average molecular weight and plasticity of rubber.
在缺少粘度实验数据时，可按理论公式或经验公式估算粘度。对于压力不太高的气体，估算结果较准；对于液体则较差。对非均相流体（如低浓度悬浮液）的粘度，可以用爱因斯坦公式估算：
In the absence of viscosity test data, the viscosity can be estimated from the theoretical formula or empirical formula. For gases with lower pressure, the estimates are more accurate; for fluids, they are worse. The viscosity of a heterogeneous fluid, such as a low-level suspension, can be estimated using the Einstein formula:
式中μm为悬浮液的粘度；μ为连续相液体的粘度;φ为悬浮液中分散相的体积分数；μd为分散相粘度。当分散相为固体颗粒时，μd→∞，；当分散相为气泡时，μd→0，μm=(1+φ)μ。
式中μm为悬浮液的粘度；μ为连续相液体的粘度;φ为悬浮液中分散相的体积分数；μd为分散相粘度。当分散相为固体颗粒时，μd→∞，；当分散相为气泡时，μd→0，μm=(1+φ)μ。
Where μm is the viscosity of the suspension; μ is the viscosity of the continuous phase liquid; φ is the volume fraction of the dispersed phase in the suspension; μd is the viscosity of the dispersed phase. When the dispersed phase is a solid particle, μd→∞, and when the dispersed phase is a bubble, μd→0, μm=(1+φ) μ.
粘度是流体粘滞性的一种量度，是流体流动力对其内部摩擦现象的一种表示。粘度大表现内摩擦力大，分子量越大，碳氢结合越多，这种力量也越大。 粘度对各种润滑油、质量鉴别和确定，用途及各种燃料用油的燃烧性能及用度等有决定意义。在同样馏出温度下，以烷烃为主要组份的石油产品粘度低，而粘温性较好，即粘度指数较高，也就是粘度随温度变化而改变的幅度较小；含环烷烃（或芳烃）组份较多的油品粘度较高，即粘温性较差；含胶质和芳烃较多油品粘度最高，粘温性最差，即粘度指数最低。 粘度常用运动粘度表示，单位mm2/s。重质燃料油粘度大，经预热使运动粘度达到18~20mm2/s（40℃），有利于喷油嘴均匀喷油。
Viscosity is a measure of the viscosity of a fluid and is a representation of the internal friction phenomena of a fluid flow force. The large viscosity shows a large amount of internal friction, and the larger the molecular weight, the more hydrocarbons are combined and the greater the power. Viscosity has a decisive significance for various kinds of lubricating oils, quality identification and determination, use, and combustion properties and cost of various fuel oils. At the same distillation temperature, petroleum products with alkane as the main component have low viscosity and good viscosity-temperature property, ie, a higher viscosity index, that is, a small change in viscosity with temperature change; and contain naphthenes (or Aromatic hydrocarbons have a higher viscosity of the oil composition, ie, poorer viscosity and temperature; gums and aromatics have the highest viscosity and viscosity and temperature have the lowest viscosity index, ie, the lowest viscosity index. Viscosity is commonly expressed as kinematic viscosity in mm2/s. The heavy fuel oil has a large viscosity, and after preheating, the kinematic viscosity reaches 18-20 mm2/s (40° C.), which is favorable for even injection of the fuel injector.
粘度测定有：动力粘度、运动粘度和条件粘度三种测定方法。
Viscosity is measured by three methods: dynamic viscosity, kinematic viscosity, and conditional viscosity.
(1)动力粘度：ηt是二液体层相距1厘米，其面积各为1(平方厘米)相对移动速度为1厘米/秒时所产生的阻力，单位为克/厘米·秒。1克/厘米·秒=1泊一般：工业上动力粘度单位用泊来表示。
(1) Dynamic viscosity: ηt is the resistance generated when two liquid layers are separated by 1 cm and each area is 1 (square centimeter) with a relative moving speed of 1 cm/s, and the unit is g/cm·sec. 1g/cm·sec = 1 poise General: The dynamic viscosity unit in the industry is expressed in berth.
(2)运动粘度：在温度t℃时，运动粘度用符号γ表示，在国际单位制中，运动粘度单位为斯，即每秒平方米(m2/s)，实际测定中常用厘斯，(cst)表示厘斯的单位为每秒平方毫米(即 1cst=1mm2/s)。运动粘度广泛用于测定喷气燃料油、柴油、润滑油等液体石油产品深色石油产品、使用后的润滑油、原油等的粘度，运动粘度的测定采用逆流法
(2) Kinematic viscosity: When the temperature is t°C, the kinematic viscosity is expressed by the symbol γ. In the international system of units, the kinematic viscosity is S, which is m 2 /s, and the actual measurement is commonly used in COS. Cst) means that the unit of centiseconds is square millimeters per second (ie, 1 cst=1 mm2/s). Kinematic viscosity is widely used to determine the viscosity of liquid petroleum products such as jet fuel oil, diesel oil, and lubricating oil, dark petroleum products, used lubricating oils, and crude oil. The kinematic viscosity is measured using the countercurrent method.
(3)条件粘度：指采用不同的特定粘度计所测得的以条件单位表示的粘度，各国通常用的条件粘度有以下三种：
(3) Conditional viscosity: refers to the viscosity measured in conditional units measured by different specific viscometers. The following conditions are commonly used in various countries:
①恩氏粘度又叫思格勒(Engler)粘度。是一定量的试样，在规定温度(如：50℃、 80℃、100℃)下，从恩氏粘度计流出200毫升试样所需的时间与蒸馏水在20℃流出相同体积所需要的时间(秒)之比。温度t时，恩氏粘度用符号Et表示，恩氏粘度的单位为条件度。
①Enn's viscosity is also called Engler viscosity. Is the amount of time required for a given amount of sample to flow out of a 200 ml sample from an Enzi's viscometer at the specified temperature (eg, 50, 80, and 100) and the same volume of distilled water at 20? (seconds) ratio. At temperature t, the Enzi's viscosity is represented by the symbol Et, and the unit of the Enzi's viscosity is the conditional degree.
②赛氏粘度，即赛波特(sagbolt)粘度。是一定量的试样，在规定温度下从赛氏粘度计流出200毫升所需的秒数，以“秒”单位。赛氏粘度又分为赛氏通用粘度和赛氏重油粘度(或赛氏弗罗(Furol)粘度)两种。
②Salinity viscosity, sagbolt viscosity. The number of seconds required for a given amount of sample to flow out of 200 ml from the Siegel viscometer at the specified temperature, in seconds. The Syrian viscosity is divided into two kinds: Syrian's universal viscosity and Saybolt's heavy oil viscosity (or Furol's viscosity).
③雷氏粘度即雷德乌德(Redwood)粘度。是一定量的试样，在规定温度下，从雷氏度计流出50毫升所需的秒数，以“秒”为单位。雷氏粘度又分为雷氏1号(Rt表示)和雷氏2号(用RAt表示)两种。
③The Rayleigh viscosity is the Redwood viscosity. The number of seconds required for a given amount of sample to exit from the Raeometer at 50 ml at the specified temperature, in seconds. Rayleigh's viscosity is divided into two types: Rees 1 (Rt) and Reb 2 (represented by RAt).
上述三种条件粘度测定法，在欧美各国常用，我国除采用恩氏粘度计测定深色润滑油及残渣油外，其余两种粘度计很少使用。三种条件粘度表示方法和单位各不相同，但它们之间的关系可通过图表进行换算。同时恩氏粘度与运动粘度也可换算，这样就方便灵活得多了。
The above three kinds of conditional viscosity measurement methods are commonly used in Europe and the United States. In addition to the deep-colored lubricating oils and residual oils measured by the Enzi's viscometer in China, the remaining two viscometers are rarely used. The three conditions of viscosity indicate that the method and unit are different, but the relationship between them can be converted by the chart. At the same time Enn's viscosity and kinematic viscosity can also be converted, which is much more convenient and flexible.
粘度的测定有许多方法，如转桶法、落球法、阻尼振动法、杯式粘度计法、毛细管法等等。对于粘度较小的流体，如水、乙醇、四氯化碳等，常用毛细管粘度计测量；而对粘度较大流体，如蓖麻油、变压器油、机油、甘油等透明（或半透明）液体，常用落球法测定；对于粘度为0.1～100Pa·s范围的液体，也可用转筒法进行测定。
There are many methods to determine the viscosity, such as the barrel method, falling ball method, damping vibration method, cup viscometer method, capillary method and so on. For small-viscosity fluids such as water, ethanol, carbon tetrachloride, etc., commonly used capillary viscometer measurement; and for large viscosity fluids, such as castor oil, transformer oil, oil, glycerin and other transparent (or translucent) liquid, commonly used Falling ball method measurement; for the viscosity of the liquid range of 0.1 ~ 100Pa · s, can also be measured by the drum method.
2、高分子粘度测试
2, polymer viscosity test
实验室测定粘度的原理一般大都是由斯托克斯公式和泊肃叶公式导出有关粘滞系数的表达式，求得粘滞系数。粘度的大小取决于液体的性质与温度，温度升高，粘度将迅速减小。因此，要测定粘度，必须准确地控制温度的变化才有意义。粘度参数的测定，对于预测产品生产过程的工艺控制、输送性以及产品在使用时的操作性，具有重要的指导价值，在印刷、医药、石油、汽车等诸多行业有着重要的意义。
The principle of viscosity measurement in the laboratory is generally derived from the Stokes formula and the Poiseuille formula for the expression of the viscosity coefficient, and the viscosity coefficient is obtained. The amount of viscosity depends on the nature and temperature of the liquid. As the temperature increases, the viscosity will decrease rapidly. Therefore, to determine the viscosity, it is necessary to accurately control the temperature change to make sense. The determination of viscosity parameters has important guiding value for predicting the process control, transportability, and operability of the product during use. It has important significance in many industries such as printing, pharmaceuticals, petroleum, and automobiles.
1845年，英国数学家、物理学家斯托克斯（G. G. Stokes, 1819-1903）和法国的纳维（C.L.M.H. Navier）等人分别推导出粘滞流体力学中最基本的方程组，即纳维-斯托克斯方程，奠定了传统流体力学的基础。
In 1845, the British mathematician, physicist Stokes (GG Stokes, 1819-1903), and CLMH Navier (France) deduced the most basic equations in viscous fluid mechanics. Stokes equation laid the foundation of traditional fluid mechanics.
1851年，斯托克斯推导出固体球体在粘性介质中作缓慢运动时所受的阻力的计算公式，得出在给定力（重力）的作用下，阻力与流速、粘滞系数成比例，即关于阻力的斯托斯公式。
In 1851, Stokes deduced the formula for the resistance of a solid sphere subjected to slow motion in a viscous medium, and concluded that under a given force (gravity), the resistance is proportional to the flow velocity and the viscous coefficient. The Stows formula for resistance.
纳维-斯托克斯方程是数学中最为难解的非线性方程中的一类，寻求它的精确解是非常困难的事。直至今天，大约也只有70多个精确解，只有大约一百多个特解被解出来，是最复杂的、尚未被完全解决的世界级数学难题之一。
纳维-斯托克斯方程是数学中最为难解的非线性方程中的一类，寻求它的精确解是非常困难的事。直至今天，大约也只有70多个精确解，只有大约一百多个特解被解出来，是最复杂的、尚未被完全解决的世界级数学难题之一。
The Navier-Stokes equation is one of the most difficult nonlinear equations in mathematics. Finding its exact solution is very difficult. Up to today, there are only about more than 70 precise solutions, and only about a hundred specific solutions have been solved. It is one of the most complicated and yet to be completely solved.
