SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2025, Vol. 82 ›› Issue (6): 165-175.DOI: 10.1016/j.cjche.2025.02.020

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Pressure drop force due to a non-closely fitting sphere settling along the central line in long rectangular tubes

Yelong Wang1, Zhaosheng Yu1, Jianzhong Lin1,2   

  1. 1. State Key Laboratory of Fluid Power and Mechatronic System, Department of Mechanics, Zhejiang University, Hangzhou 310027, China;
    2. Key Laboratory of Impact and Safety Engineering (Ningbo University), Ministry of Education, Ningbo 315211, China
  • Received:2024-11-21 Revised:2025-02-21 Accepted:2025-02-24 Online:2025-03-20 Published:2025-08-19
  • Contact: Zhaosheng Yu,E-mail:yuzhaosheng@zju.edu.cn;Jianzhong Lin,E-mail:jzlin@zju.edu.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (12132015, 12332015).

Pressure drop force due to a non-closely fitting sphere settling along the central line in long rectangular tubes

Yelong Wang1, Zhaosheng Yu1, Jianzhong Lin1,2   

  1. 1. State Key Laboratory of Fluid Power and Mechatronic System, Department of Mechanics, Zhejiang University, Hangzhou 310027, China;
    2. Key Laboratory of Impact and Safety Engineering (Ningbo University), Ministry of Education, Ningbo 315211, China
  • 通讯作者: Zhaosheng Yu,E-mail:yuzhaosheng@zju.edu.cn;Jianzhong Lin,E-mail:jzlin@zju.edu.cn
  • 基金资助:
    This work was supported by the National Natural Science Foundation of China (12132015, 12332015).

Abstract: The ratio of the pressure drop force to the drag force, CP, is concerned for a non-closely fitting spherical particle settling along the central line in long rectangular tubes with different Ar (Ar is W/H, where W, H is length of the longer and shorter side of the rectangle respectively). Under Stokes flow conditions, CP0 for an infinitely small sphere in long rectangular tubes and CP for a sphere in a long channel between two parallel layered barriers are both calculated. Then CP of a sphere settling in long rectangular tubes are conducted with the direct-forcing fictitious domain (DF/FD) method. At large Reynolds number, the sphere settles unstably with a fluctuating velocity and CP. The fluctuation of CP is much stronger than that of velocity and both fluctuations are stronger for less confined sphere. The influences of the particle Reynolds number (Rep) on CP is similar to the existing experimental results in long circular tubes. At low Rep, CP is a determined value and is calculated. For a given d/H (d sphere diameter), CP gets its maximum value at one Ar in the range of [1, 1.5]. For a given Ar, CP is a quadratic function of d/H similar to that in a circular tube, and parameters of the quadratic function are got by curve fitting from numerical data. The constant term coefficients got have almost no difference with CP0 and are furtherly replaced by the latter to get new quadratic coefficients CP1. Lastly, an algebraic correlation of CP1 to Ar is developed. The predictions of CP are good with a maximum relative error about 1.5% for a sphere with d/H not greater than 0.7, compared to numerical results.

Key words: Pressure drop, Numerical simulation, Stokes flow, Non-closely fitting, Sedimentation, Particle

摘要: The ratio of the pressure drop force to the drag force, CP, is concerned for a non-closely fitting spherical particle settling along the central line in long rectangular tubes with different Ar (Ar is W/H, where W, H is length of the longer and shorter side of the rectangle respectively). Under Stokes flow conditions, CP0 for an infinitely small sphere in long rectangular tubes and CP for a sphere in a long channel between two parallel layered barriers are both calculated. Then CP of a sphere settling in long rectangular tubes are conducted with the direct-forcing fictitious domain (DF/FD) method. At large Reynolds number, the sphere settles unstably with a fluctuating velocity and CP. The fluctuation of CP is much stronger than that of velocity and both fluctuations are stronger for less confined sphere. The influences of the particle Reynolds number (Rep) on CP is similar to the existing experimental results in long circular tubes. At low Rep, CP is a determined value and is calculated. For a given d/H (d sphere diameter), CP gets its maximum value at one Ar in the range of [1, 1.5]. For a given Ar, CP is a quadratic function of d/H similar to that in a circular tube, and parameters of the quadratic function are got by curve fitting from numerical data. The constant term coefficients got have almost no difference with CP0 and are furtherly replaced by the latter to get new quadratic coefficients CP1. Lastly, an algebraic correlation of CP1 to Ar is developed. The predictions of CP are good with a maximum relative error about 1.5% for a sphere with d/H not greater than 0.7, compared to numerical results.

关键词: Pressure drop, Numerical simulation, Stokes flow, Non-closely fitting, Sedimentation, Particle