Local heat transfer and thermal performance on periodically dimple-protrusion patterned walls for compact heat exchangers

Sang Dong Hwang, Hyun Goo Kwon, Hyung Hee Cho

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

In this study, heat transfer and thermal performance of a periodically dimple-protrusion patterned surface have been investigated to enhance energy-efficiency in compact heat exchangers. The local heat transfer coefficients on the dimple/protrusion walls are derived using a transient TLC (Thermochromic Liquid Crystal) technique. The periodically patterned surface is applied to the bottom wall only or both the bottom and top walls in the test duct. The ratio of dimple (or protrusion) depth to duct height is 0.25, and the ratio of duct height to dimple (or protrusion) print diameter is 1.15. The Reynolds number is tested in low range values from 1000 to 10000. On the single-side patterned walls, various secondary flows generated from the dimple/protrusion coexist. The vortices induced from the upstream affect strongly on the downstream pattern. For the double-side patterned wall case, vortex interaction affected by the opposite wall enhances highly the heat transfer. The heat transfer augmentation is higher in the lower Reynolds number due to the effective vortex interactions. Therefore, the performance factor considering both heat transfer enhancement and pressure loss increases with decreasing the Reynolds number.

Original languageEnglish
Pages (from-to)5357-5364
Number of pages8
JournalEnergy
Volume35
Issue number12
DOIs
Publication statusPublished - 2010 Dec

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Heat exchangers
Ducts
Heat transfer
Vortex flow
Reynolds number
Secondary flow
Liquid crystals
Heat transfer coefficients
Energy efficiency
Hot Temperature

All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Building and Construction
  • Pollution
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering

Cite this

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Local heat transfer and thermal performance on periodically dimple-protrusion patterned walls for compact heat exchangers. / Hwang, Sang Dong; Kwon, Hyun Goo; Cho, Hyung Hee.

In: Energy, Vol. 35, No. 12, 12.2010, p. 5357-5364.

Research output: Contribution to journalArticle

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AB - In this study, heat transfer and thermal performance of a periodically dimple-protrusion patterned surface have been investigated to enhance energy-efficiency in compact heat exchangers. The local heat transfer coefficients on the dimple/protrusion walls are derived using a transient TLC (Thermochromic Liquid Crystal) technique. The periodically patterned surface is applied to the bottom wall only or both the bottom and top walls in the test duct. The ratio of dimple (or protrusion) depth to duct height is 0.25, and the ratio of duct height to dimple (or protrusion) print diameter is 1.15. The Reynolds number is tested in low range values from 1000 to 10000. On the single-side patterned walls, various secondary flows generated from the dimple/protrusion coexist. The vortices induced from the upstream affect strongly on the downstream pattern. For the double-side patterned wall case, vortex interaction affected by the opposite wall enhances highly the heat transfer. The heat transfer augmentation is higher in the lower Reynolds number due to the effective vortex interactions. Therefore, the performance factor considering both heat transfer enhancement and pressure loss increases with decreasing the Reynolds number.

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