Parametric study of natural convection showing effects of geometry, number and orientation of fins on a finned tube system: A numerical approach

Abstract

The present study provides a thorough numerical analysis of natural convection heat transfer from a horizontal cylinder with external longitudinal fins. The Three-dimensional(3D) forms of Continuity, Navier-stokes, and the energy equations have been solved to understand the flow field and temperature distribution using the Ansys Fluent software. The purpose of the study is to investigate the effects of fin length L f , fin thickness (t), number of fins (N) and material of fin (Aluminum & Steel) on the parameters namely, the heat transfer rate from the inner isothermal wall and effectiveness (Q*)of the system for a constant Rayleigh number in the laminar range (Ra ≤ 10 6 ). Additionally, the effect of two different orientations (A&B) of fins has been discussed. Orientation-A consists of fins starting from horizontal plane placed at equal angular spacing subsequently, whereas the fins in orientation-B originate from the vertical plane followed with equal angular spacing. Non-dimensional fin length (L*) is being varied from 0.222 to 2, non-dimensional fin thickness (t*) as 0.022 ~0.044 and the number of fins (N) between 6~24. It is observed that for a fixed number of fins there exists an optimum fin length and for a fixed fin length there exists an optimum fin thickness & an optimum number of fins. For a fixed number of fins there exist an optimum fin length and maximum effectiveness, the maximum possible effectiveness for the taken fin-tube system is 4.34 for 12 fins. Th e ma ximum effectiveness rep orted in the cur rent stu dy was 1.86 for L*=0.444, t*=0.022 and N=12. Furthermore, the optimum length for N=12 came out to be L*=1.8.

Surface modification techniques for cooling by impinging jets-a review

“…Enhancement factor of 1.24 was obtained when disrupting pins were used in the study. Krishnayatra et al [36] numerically studied the effect of fin parameters such as length, thickness, number of fins and material of fins from a horizontal cylinder. Heat transfer enhancement was characterized by effectiveness and maximum effectiveness of 4.34 was recorded for the system.…”