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Numerical study on heat transfer enhancement for laminar flow in a tube with mesh conical frustum inserts

Cao, Zhen LU ; Wu, Zan LU ; Luan, Huibao LU and Sunden, Bengt LU (2017) In Numerical Heat Transfer; Part A: Applications 72(1). p.21-39
Abstract

Enhanced heat transfer tubes (EHTT) with segmented mesh-conical frustums are considered. Tube diameter and frustum apex angle are fixed as 20 mm and 60o, respectively. The height ratio of frustum and sliced part are set as a golden ratio (1.618). Laminar thermal-hydraulic performance and effects of some parameters, e.g., bottom frustum diameter and pitch, are numerically simulated. The equal equivalent diameter and total flow area criteria are adopted to simplify 3D mesh pores to 2D ones. Flow and temperature fields show large velocities and gradients close to the wall and smaller velocities in the bulk region. This enhances heat transfer with a limited pressure drop. EHTTs obtain 1.4 - 3.3 times higher heat transfer than bare tubes and... (More)

Enhanced heat transfer tubes (EHTT) with segmented mesh-conical frustums are considered. Tube diameter and frustum apex angle are fixed as 20 mm and 60o, respectively. The height ratio of frustum and sliced part are set as a golden ratio (1.618). Laminar thermal-hydraulic performance and effects of some parameters, e.g., bottom frustum diameter and pitch, are numerically simulated. The equal equivalent diameter and total flow area criteria are adopted to simplify 3D mesh pores to 2D ones. Flow and temperature fields show large velocities and gradients close to the wall and smaller velocities in the bulk region. This enhances heat transfer with a limited pressure drop. EHTTs obtain 1.4 - 3.3 times higher heat transfer than bare tubes and the performance evaluation criterion (PEC) varies from 1.3 to 1.8. Nusselt number (Nu) and friction factor (f) correlations are proposed. New insights into heat transfer enhancement and tube configuration are provided.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Numerical Heat Transfer; Part A: Applications
volume
72
issue
1
pages
19 pages
publisher
Taylor & Francis
external identifiers
  • scopus:85027079857
  • wos:000407958600002
ISSN
1040-7782
DOI
10.1080/10407782.2017.1353386
language
English
LU publication?
yes
id
010cec6e-0809-45ca-b585-b3191c49f99d
date added to LUP
2017-08-29 13:48:10
date last changed
2017-09-18 11:43:22
@article{010cec6e-0809-45ca-b585-b3191c49f99d,
  abstract     = {<p>Enhanced heat transfer tubes (EHTT) with segmented mesh-conical frustums are considered. Tube diameter and frustum apex angle are fixed as 20 mm and 60o, respectively. The height ratio of frustum and sliced part are set as a golden ratio (1.618). Laminar thermal-hydraulic performance and effects of some parameters, e.g., bottom frustum diameter and pitch, are numerically simulated. The equal equivalent diameter and total flow area criteria are adopted to simplify 3D mesh pores to 2D ones. Flow and temperature fields show large velocities and gradients close to the wall and smaller velocities in the bulk region. This enhances heat transfer with a limited pressure drop. EHTTs obtain 1.4 - 3.3 times higher heat transfer than bare tubes and the performance evaluation criterion (PEC) varies from 1.3 to 1.8. Nusselt number (Nu) and friction factor (f) correlations are proposed. New insights into heat transfer enhancement and tube configuration are provided.</p>},
  author       = {Cao, Zhen and Wu, Zan and Luan, Huibao and Sunden, Bengt},
  issn         = {1040-7782},
  language     = {eng},
  month        = {07},
  number       = {1},
  pages        = {21--39},
  publisher    = {Taylor & Francis},
  series       = {Numerical Heat Transfer; Part A: Applications},
  title        = {Numerical study on heat transfer enhancement for laminar flow in a tube with mesh conical frustum inserts},
  url          = {http://dx.doi.org/10.1080/10407782.2017.1353386},
  volume       = {72},
  year         = {2017},
}