PIV and CFD studies on analyzing intragastric flow phenomena induced by peristalsis using a human gastric flow simulator
PIV and CFD studies on analyzing intragastric flow phenomena induced by peristalsis using a human gastric flow simulator
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使用人体胃流模拟器分析蠕动引起的胃内流动现象的 PIV 和 CFD 研究
DOI：
10.1039/c4fo00041b
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发表时间：
2014
影响因子：
6.1
通讯作者：
Sosaku Ichikawa
中科院分区：
文献类型：
--
作者：
Hiroyuki Kozu;Isao Kobayashi;Marcos A. Neves;Mitsutoshi Nakajima;Kunihiko Uemura;Seigo Sato;Sosaku Ichikawa
本研究利用人体胃流模拟器（GFS）定量分析了胃蠕动诱导的胃内容物模型的流动现象。GFS的主要功能包括通过控制橡胶壁变形来模拟胃蠕动，以及通过平行透明窗口直接观察胃内流动。对于液体胃内容物（水和淀粉糖浆溶液），使用颗粒图像测速（PIV）和计算流体动力学（CFD）观察了逆蠕动方向的反推流动。在被蠕动遮挡的区域流速最大。以健康成人的标准肠蠕动速度（UACW = 2.5 mm s - 1）为标准，其最大值为9 mm s - 1。胃内流场为层流，最大雷诺数Re = 125。胃内容液的粘度对本研究应用范围（1 ~ 100 mPa s）内的最大流速影响不大。PIV计算结果与CFD计算结果吻合较好。在UACW = 2.5 mm s - 1时，胃液内容物的最大剪切速率小于20 s - 1。我们还测量了含有模型固体食物颗粒（塑料珠）的胃内容物的流场。速度矢量的方向受模型固体食物颗粒表面存在的影响。在UACW = 2.5 mm s−1时，模型固体食物颗粒附近的最大流速为8 ~ 10 mm s−1。模型固体食物颗粒周围的最大剪切速率较低，可达20 s−1。
This study quantitatively analyzed the flow phenomena in model gastric contents induced by peristalsis using a human gastric flow simulator (GFS). Major functions of the GFS include gastric peristalsis simulation by controlled deformation of rubber walls and direct observation of inner flow through parallel transparent windows. For liquid gastric contents (water and starch syrup solutions), retropulsive flow against the direction of peristalsis was observed using both particle image velocimetry (PIV) and computational fluid dynamics (CFD). The maximum flow velocity was obtained in the region occluded by peristalsis. The maximum value was 9 mm s−1 when the standard value of peristalsis speed in healthy adults (UACW = 2.5 mm s−1) was applied. The intragastric flow-field was laminar with the maximum Reynolds number (Re = 125). The viscosity of liquid gastric contents hardly affected the maximum flow velocity in the applied range of this study (1 to 100 mPa s). These PIV results agreed well with the CFD results. The maximum shear rate in the liquid gastric contents was below 20 s−1 at UACW = 2.5 mm s−1. We also measured the flow-field in solid–liquid gastric contents containing model solid food particles (plastic beads). The direction of velocity vectors was influenced by the presence of the model solid food particle surface. The maximum flow velocity near the model solid food particles ranged from 8 to 10 mm s−1 at UACW = 2.5 mm s−1. The maximum shear rate around the model solid food particles was low, with a value of up to 20 s−1.