流变学流体的蠕动传输:食道中食物块的运动模型

研究食道中蠕动传输的流体力学.对任意的波形和任意的管道长度,建立起流变学流体蠕动传输的数学模型.用粘性流体的Ostwald-de Waele幂定律,描述非Newton流体的流动特性.解析公式化模型,详细且精确地给出食物块在食道中蠕动传输相关的一些重要性质.分析中应用了润滑理论,本研究特别适合于Reynolds数不大的情况.将食道看作环形的管道,通过食道壁周期性的收缩来传输食物块.就单个波和周期性收缩一组波的传播,研究与传输过程有关变量的变化,如压力、流速、食物颗粒轨迹以及流量等.局部压力的变化,对流变指数n有着高度的敏感性.研究结果清晰地表明,食物块在食道中蠕动传输时,Newton流体或流变学流体构成的连续流体,以组合波传播比大间隔单波传播,传输效率要高得多.

Peristaltic Transport of a Rheological Fluid:Model for Movement of Food Bolus Through Esophagus

Fluid mechanical peristaltic transport through esophagus had been of concern.A mathematical model had been developed with an aim to study the peristaltic transport of a rheological fluid for arbitrary wave shapes and tube lengths.The Ostwald-de Waele power law of viscous fluid was considered here to depict the non-Newtonian behaviour of the fluid.The model was formulated and analyzed with the specific aim of exploring some important information concerning the movement of food bolus through the esophagus.The analysis had been carried out by using lubrication theory.The study was particularly suitable for cases where the Reynolds number was small.The esophagus was treated as a circular tube through which the transport of food bolus takes places by periodic contraction of the esophageal wall.Variation of different variables concerned with the transport phenomena such as pressure,flow velocity,particle trajectory and reflux were investigated for a single wave as well as for a train of periodic peristaltic waves.Locally variable pressure was seen to be highly sensitive to the flow index n.The study clearly showes that continuous fluid transport for Newtonian/rheological fluids by wave train propagation is much more effective than widely spaced single wave propagation in the case of peristaltic movement of food bolus in the esophagus.