Karafan Journal

Karafan Journal

Numerical study of the effect of a gap on heat transfer and pressure drop of a fluid passing over a cylindrical barrier

Document Type : Original Article

Authors
hamid Hassanzadeh Afrouzi 1
Seyyed Mostafa Seyyedi Taji 2
Atena Ghaderi 3
1 Department of Mechanical Engineering, Technical and Vocational University (TVU), Tehran, Iran.
2 Department of Mechanical Engineering, Technical and Vocational University (TVU), Tehran, Iran
3 Department of Mechanical Engineering, University College of Rouzbahan, Rouzbahan, Iran,
10.48301/kssa.2025.496677.3112
Abstract
Fluid flow around a rotating cylinder (or between two rotating cylinders) is a common phenomenon in various industrial processes. These processes range from contact drum dryers in chemical processing, food manufacturing, papermaking, and textile industries to cylindrical cooling devices used in glass and plastics industries. This study numerically investigates the flow field and heat transfer over a cylindrical obstacle. The effects of the cylinder’s orientation angle (0° ≤ 𝛼 ≤ 90°), gap thickness (0 ≤ S/D ≤ 0.2), and Reynolds number (100 ≤ Re ≤ 400) on the two-dimensional laminar flow patterns, pressure drop, and heat transfer characteristics are analyzed to assess the impact of these parameters on the hydrodynamic and thermal performance of the fluid flow. The results indicate that a cylinder with a gap exhibits superior thermal performance compared to a simple cylinder. The optimal thermal performance is achieved when the gap on the cylinder is oriented at 60 degrees relative to the horizontal axis. Furthermore, the study highlights that the best heat transfer efficiency is observed at a gap ratio of S/D=0.1S/D = 0.1. Based on these findings, it is recommended that for enhanced heat transfer, the cylindrical obstacle should have a gap ratio of S/D = 0.1 and be oriented at a 60-degree angle.
Keywords
Heat transfer
numerical simulation
cylinder
obstacle angle
slit thickness
Subjects
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Karafan Journal
Volume 23, Issue 1
Technical and Engineering
Spring 2026
Pages 54-76

  • Receive Date 12 January 2025
  • Revise Date 15 April 2025
  • Accept Date 15 November 2025