共查询到19条相似文献,搜索用时 835 毫秒
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毛细管粘度计结构简单,测量方便,被广泛用来测量液体的粘度(牛顿液体和某些非牛顿液体)。例如,高分子化学、高分子物理、物理化学中,通过测量粘度以确定聚合物的分子量;化学工业、物理实验及血液研究中,用来测量液体和血液的粘度。用毛细管粘度计测液体粘度的方法有二: 相似文献
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奥氏粘度计原理的简单证明陈百万(山东潍坊医学院261042)用奥氏粘度计(如图所示)采用比较法测量液体粘度的公式是式中η0、ρ0分别为标准液体的粘度和密度,η、ρ分别是待测液体的粘度和密度,t0和t分别是一定体积的两种液体流过竖直毛细管所用的时间.一... 相似文献
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单板机在粘度测量实验中的应用韩玖荣,詹鼎(扬州大学225001)一、引言在大学物理实验中,特别是农业院校一般都有粘度测量这个实验.液体粘度的测量有多种方法,旋转法、毛细管法、落球法,最近还有人制成功了超声粘度计[1]。在学生实验中,一般采用毛细管法和... 相似文献
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测定了不同分子量聚氧化乙烯 (PEO)在水和苯溶剂中的粘度 ,发现在低浓度区PEO水溶液的比浓粘度出现负偏离 ,PEO苯溶液比浓粘度与浓度之间依旧满足线性关系 .表面张力测定结果表明 ,PEO分子显著降低了水的表面张力 ,而苯的表面张力则不受影响 .PEO水溶液和纯溶剂水表面张力的不同干扰了高分子溶液和溶剂在粘度计中流过时间的测量 ,导致低浓度区PEO水溶液比浓粘度出现负偏离 .利用PEO水溶液和水表面张力测定结果 ,结合乌式粘度计的几何尺寸 ,定量分析了PEO水溶液和纯溶剂水表面张力的差异对粘度测量结果的影响 ,计算结果与实验结果基本相符 .如果用PEO水溶液流过时间对浓度作图的外推值t0 计算相对粘度 ,可以完全消除PEO水溶液和水表面张力差异对粘度测量的影响 相似文献
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将气轨与粘度计相结合,利用气轨的测速仪测量粘度计砝码匀速下降的速度,以测量液体粘滞系数,该方法既减小了计时误差,又可准确判断系统的运动状态。 相似文献
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C. Barentin P. Muller C. Ybert J.-F. Joanny J.-M. di Meglio 《The European physical journal. E, Soft matter》2000,2(2):153-159
The surface shear viscosity of monolayers formed at the surface of water by adsorbed polyethyl- eneoxyde and by stearic acid
is measured as a function of the surface pressure of the monolayer using a new surface viscometer. The principle of the viscometer
is the measurement of the drag force on a circular disk undergoing a uniform translation at the water surface: a hydrodynamic
model based on the lubrication approximation allows a calculation of the surface viscosities from the absolute measurement
of the drag forces.
Received: 26 August 1999 相似文献
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A newly developed theory regarding solute adsorption effect in viscometry of a polymer solution is reviewed and extended for determining the adsorbed layer thickness of polystyrene on a glass surface in viscosity measurements. This theory can adequately describe the concentration dependence of the viscosity of a polymer solution measured by glass capillary viscometer to the extremely dilute concentration region. Using this theory, both the free polymer chains in solution and the adsorbed polymer chain on the viscometer inner wall surface can be characterized. Examples are given for the characterization of six polystyrene samples with different molar masses by measuring their solution viscosity in benzene. 相似文献
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This paper is a comparative study on the characteristics of high-speed liquid jets injected in surrounding water and air using shadowgraph technique. One of the main objectives is to investigate the effects of liquid’s physical properties, used to generate the high-speed liquid jets, on jet generation’s characteristics. Moreover, comparative investigations on effects of those liquid jets after injected in water and air are reported. The high-speed liquid jets were generated by the impact of a projectile launched by a horizontal single-stage power gun. The impact-driven high-speed liquid jets were visualized by shadowgraph technique and images were recorded by a high-speed digital video camera. The process of impact-driven high-speed liquid jet injection in air and water, oblique shock waves, jet-induced shock waves, shock waves propagation, the bubble behavior, bubble collapse-induced rebound shock waves and bubble cloud regeneration were clearly observed. It was found that different properties of liquid (surface tension and kinematic viscosity) affect the jet maximum velocity and shape of the jet. Bubble behaviors were only found for the jet injected in water. From the shadowgraph images, it is found that the maximum average jet velocity, expansion and contraction velocities of bubble in axial direction increase when the value of the multiplied result of surface tension by kinematic viscosity increases. Therefore, surface tension and kinematic viscosity are the significant physical properties that affect characteristics of high-speed liquid jets. 相似文献
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Yulong Li Congde Qiao Lei Shi Qingwei Jiang 《Journal of Macromolecular Science: Physics》2014,53(5):893-901
An investigation of the influences of the adsorption, electrolyte, shear rate, and temperature on the viscometric behavior of collagen solutions was performed using a photoelectric viscometer. The experimental results showed an abnormal behavior of the reduced viscosity (ηsp/C) of dilute collagen solutions measured by a viscometer with or without a hydrophobic surface treatment; the reduced viscosity increased with decreasing concentration. This phenomenon can be completely eliminated by increasing the concentration of an added salt. It indicated that the abnormal viscosity resulted from a long-ranged, inter-molecular electrostatic force. The reduced viscosity decreased as the shear rate increased. The shear-thinning cavitation phenomenon resulted from the high aspect ratio of the collagen molecules. The reduced viscosity of the collagen solutions increased with an increase in temperature, which was due to the association of collagen molecules at high temperature. 相似文献
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针对以往气泡幕降噪效果研究中气泡幕模型设置过于理想,无法真实反映气泡幕降噪效果空间不均匀性的问题,该文采用有限元-抛物方程混合模型对包含气泡幕的水下打桩噪声场进行了仿真模拟,分析了应用气泡幕时打桩噪声的传播特性,并重点研究了气泡幕的厚度、占空比以及布放位置等不同参数下气泡幕的降噪效果。结果表明,增加气泡幕的厚度可有限提高气泡幕的降噪量,气泡幕的占空比应保持在0.5%~1%,气泡半径较大的气泡幕在较低频率有更好的降噪效果,此外应合理调整气泡幕的布放位置以应对打桩噪声的多途传播特性。该文方法和分析研究结果对打桩施工时气泡幕的参数设置具有指导意义和一定应用参考价值。 相似文献
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采用理论分析的方法考察了磁场中非理想流体中Rayleigh-Taylor(RT)不稳定性气泡的演化过程,在与磁场垂直的平面中,综合考虑流体黏性和表面张力的影响,推导了二维非理想磁流体RT不稳定性气泡运动的控制方程组,给出了不同情况下气泡速度的渐近解和数值解,分析了流体黏性、表面张力和磁场对气泡发展的影响,分析结果表明:流体黏性和表面张力能够降低气泡速度和振幅,即能够抑制RT不稳定性;而磁场对RT不稳定性的影响是由非线性部分引起的,并且磁场非线性部分的方向决定了磁场是促进还是抑制RT不稳定性的发展, 相似文献
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With the high-temperature viscometer and magnetic susceptibility measurement device designed by our group, the viscosity and
the magnetic susceptibility of the Cu65Sn35 melt were measured during the cooling process. An anomalous change can be found in the curves of viscosity and magnetic susceptibility
at a certain temperature. The structure of the melt was studied by the high-temperature X-ray diffractometer. The anomalous
change also can be found in the pair distribution function, correlation radius, and coordination number at the approximate
temperature, which shows the microstructural change of the Cu65Sn35 melt. From the results, it was confirmed that the Cu6Sn5 compound occurs in the melt, which leads to the structural change of the melt.
Supported by the National Natural Science Foundation of China (Grant Nos. 50395101 and 50571052) 相似文献
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V. I. Kartsovnik R. Worlitsch F. Hermann Y. Tsoglin 《Journal of Macromolecular Science: Physics》2016,55(2):149-157
On the basis of a model of polymer flow, considering the forces of entropic elasticity of extended macromolecules within the Eyring's concept, the relationships between the shear rate, shear stress, viscosity, and recovered rubber-like deformation were derived. The reduction of activation energy of the flow, by an amount proportional to the recovered rubber-like deformation, leads to an exponential decrease of viscosity with increasing shear rates; this nonlinear dependence of viscosity on shear rate (and shear stress) is defined as the viscosity anomaly of polymers. The measurement of deformation recovery after the cessation of polymer flow in the mode of constant shear rate or shear stress on a rotational viscometer confirmed the validity of the theoretical dependences. 相似文献
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P. Snabre F. Magnifotcham 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,4(3):369-377
The continuous emission of gas bubbles from a single ejection orifice immersed in a viscous fluid is considered. We first
present a semi empirical model of spherical bubble growth under constant flow conditions to predict the bubble volume at the
detachment stage. In a second part, we propose a physical model to describe the rise velocity of in-line interacting bubbles
and we derive an expression for the net viscous force acting on the surrounding fluid. Experimental results for air/water-glycerol
systems are presented for a wide range of fluid viscosity and compared with theoretical predictions. An imagery technique was used to determine the bubble size and rise velocity.
The effects of fluid viscosity, gas flow rate, orifice diameter and liquid depth on the bubble stream dynamic were analyzed.
We have further studied the effect of large scale recirculation flow and the influence of a neighbouring bubble stream on
the bubble growth and rising velocity.
Received: 23 July 1997 / Revised: 16 December 1997 / Accepted: 11 May 1998 相似文献