Abstract Non-Newtonian fluids are a constant presence in several industrial applications so it becomes interesting to understand their behavior and to optimize their use. One behavior of commercial interest is the viscoplastic behavior characterized by an abrupt change of the apparent viscosity when a certain amount of stress is achieved. The present work performs a study of the effect of Reynolds number, the plastic number, and the flow intensity over flow parameters of industrial interest, namely, mean Nusselt number, displacement efficiency, and head loss. The mechanical model is approximated by a finite volume method implemented by an OpenFOAM® routine developed by the authors. The SMD model was chosen to model the viscoplastic behavior. The adopted geometry is of a planar channel with an abrupt expansion followed by an abrupt contraction. The channel walls are kept insulated and heat transfer occurs only at the cavity formed between the expansion and contraction planes. For the studied range of parameters, mean Nusselt number has a positive dependence on Reynolds number and flow intensity but a negative dependence on plastic number; displacement efficiency has a positive dependence on Reynolds number and flow intensity but a negative dependence on plastic number. The head loss has a negative dependence on Reynolds number and plastic number and an overall positive dependence on flow intensity.

中文翻译：

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雷诺数、塑性数和流动强度对流过平面膨胀然后收缩的粘塑性流体的流动和传热的影响

摘要 非牛顿流体一直存在于多种工业应用中，因此了解它们的行为并优化它们的使用变得很有趣。一种具有商业价值的行为是粘塑性行为，其特征在于当达到一定量的应力时表观粘度的突然变化。目前的工作研究了雷诺数、塑性数和流动强度对工业利益流动参数的影响，即平均努塞尔数、驱替效率和水头损失。机械模型由作者开发的 OpenFOAM® 例程实现的有限体积方法近似。选择 SMD 模型来模拟粘塑性行为。所采用的几何形状是平面通道，突然膨胀，然后突然收缩。通道壁保持绝缘，热传递仅发生在膨胀平面和收缩平面之间形成的空腔处。对于研究的参数范围，平均努塞尔数与雷诺数和流动强度呈正相关，而与塑性数呈负相关；置换效率与雷诺数和流动强度呈正相关，而与塑性数呈负相关。水头损失与雷诺数和塑性数呈负相关，而与流动强度总体呈正相关。置换效率与雷诺数和流动强度呈正相关，而与塑性数呈负相关。水头损失与雷诺数和塑性数呈负相关，而与流动强度总体呈正相关。置换效率与雷诺数和流动强度呈正相关，而与塑性数呈负相关。水头损失与雷诺数和塑性数呈负相关，而与流动强度总体呈正相关。