In this paper, the rheological properties of welan gum solutions with mass fractions of 2%, 3% and 4% are measured using an Anton paar MCR 302 rheometer. It is found that the liquids fit the five-parameter Jeffreys model of double fractional order with corresponding rheological parameters. The behaviors of these fluids over linear stretching surface are studied based on the experimental results. We find that, compared with the Newtonian fluid, there exists an inflection on viscoelastic fluid velocity curve, which separated velocity curve into two parts with different concave-convexity. For the interval from inflection to external boundary, which similar to Newtonian fluid, the viscosity plays a major role, while for the interval from stretching surface to inflection, the elasticity plays a major role. At the inflection, the velocity gradient curve arrives its extreme. It is also found that, as viscoelastic solutions mass fractions decrease, the thickness boundary layer becomes thinner and the elasticity effect is weakened. Those results reveal the complex physical mechanism of viscoelastic fluid film flow and provide a theoretical basis for relevant engineering design.

在本文中，使用安东帕 MCR 302 流变仪测量了质量分数为 2%、3% 和 4% 的威兰胶溶液的流变特性。发现液体符合具有相应流变参数的双分数阶五参数Jeffreys模型。基于实验结果研究了这些流体在线性拉伸表面上的行为。我们发现，与牛顿流体相比，粘弹性流体速度曲线存在一个拐点，将速度曲线分成具有不同凹凸的两部分。对于类似于牛顿流体的弯曲到外边界的区间，粘度起主要作用，而对于拉伸表面到弯曲的区间，弹性起主要作用。在拐点处，速度梯度曲线达到极值。还发现，随着粘弹性溶液质量分数的减少，厚度边界层变薄，弹性效应减弱。这些结果揭示了粘弹性流体膜流动的复杂物理机制，为相关工程设计提供了理论依据。