Scholarlink

<p>The incompressible flows in a circular pipe with sudden expansion are numerically investigated in the laminar regime for both the Newtonian fluid and the non-Newtonian Herschel-Bulkley (HB) fluid, with the emphases on the difference caused by different rheological models. The Reynolds number, which is defined by the mean inlet velocity, inlet diameter, and viscosity of Newtonian model, ranges from 50 to 500. For uniform axial flow, steady and axisymmetric annular recirculation region develops after the expansion with the length increasing linearly with Reynolds number. The HB flow generates shorter recirculation region than the Newtonian flow. When a swirling flow is introduced at inlet, the axisymmetric flow breaks into helical flow with multiple vortices when the strength of swirling is large enough. The transition happens at weaker swirling for the Newtonian fluid than the HB fluid. The helical flow experiences the subcritical transition to a bubble shape structure when a azimuthally asymmetric mode with large enough amplitude is added to the inlet swirling flow for both fluid models. For all cases, the total pressure drop between the inlet and outlet is larger for the HB flow than the Newtonian flow under the same conditions.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Effects of different rheological models on the incompressible flow of complex fluid through a circular pipe with sudden expansion

  • 期刊论文

  • 发表日期：

    2026年5月5日

查看全文
  • Yongcang Ren,
  • Shaobo Feng,
  • Junhui Wei,
  • Bao Zhang,
  • Jun’an Lu,
  • Zhixiong Tu,
  • Nu Zeng,
  • Hongtao Jing,
  • Yantao Yang

摘要

The incompressible flows in a circular pipe with sudden expansion are numerically investigated in the laminar regime for both the Newtonian fluid and the non-Newtonian Herschel-Bulkley (HB) fluid, with the emphases on the difference caused by different rheological models. The Reynolds number, which is defined by the mean inlet velocity, inlet diameter, and viscosity of Newtonian model, ranges from 50 to 500. For uniform axial flow, steady and axisymmetric annular recirculation region develops after the expansion with the length increasing linearly with Reynolds number. The HB flow generates shorter recirculation region than the Newtonian flow. When a swirling flow is introduced at inlet, the axisymmetric flow breaks into helical flow with multiple vortices when the strength of swirling is large enough. The transition happens at weaker swirling for the Newtonian fluid than the HB fluid. The helical flow experiences the subcritical transition to a bubble shape structure when a azimuthally asymmetric mode with large enough amplitude is added to the inlet swirling flow for both fluid models. For all cases, the total pressure drop between the inlet and outlet is larger for the HB flow than the Newtonian flow under the same conditions.