Publication Cover
Numerical Heat Transfer, Part A: Applications
An International Journal of Computation and Methodology
Volume 69, 2016 - Issue 6
293
Views
26
CrossRef citations to date
0
Altmetric
Original Articles

3D Numerical study on the flow topology and heat transfer characteristics of turbulent forced convection in spirally corrugated tube

, &
Pages 607-629 | Received 07 Jan 2015, Accepted 28 Apr 2015, Published online: 05 Jan 2016
 

ABSTRACT

This paper presents a numerical analysis on flow configurations and heat transfer characteristics of turbulent forced convection in spirally corrugated tubes. The influences of corrugation depth (DR = 0.02–0.16), pitch ratio (PR = 0.10–1.00), and Reynolds number (Re = 5,000–20,000) on flow structure and heat transfer characteristics are described. Comparisons between the full length and periodic domains are also reported. The results show that spirally corrugated tubes induced vortex flows which helped to increase heat transfer due to enhanced fluid mixing. The maximum thermal enhancement factor of 1.16 was obtained by using the spirally corrugated tube with DR = 0.06, PR = 0.25 at Re = 5,000.

NOMENCLATURE

A=

cross-sectional area, m2

D=

characteristic diameter of spirally corrugated tube

DR=

corrugation depth ratio, (e/D)

PR=

corrugation pitch ratio, (p/D)

e=

corrugation depth, m

f=

friction factor

h=

convective heat transfer coefficient, W m−2 K−1

k=

turbulent kinetic energy, ()

ka=

thermal conductivity of air, W m−1 K−1

Nu=

Nusselt number

p=

corrugation pitch, m

P=

static pressure, Pa

Pr=

Prandtl number

PR=

pitch spacing ratio, p/D

Re=

Reynolds number, (ρu0D/μ)

T=

temperature, K

TEF=

thermal performance enhancement factor, (Nu/Nu0)/(f/f0)1/3

ui=

velocity component in xi-direction, m s−1

ui'=

fluctuation velocity in xi-direction, m s−1

u0=

mean or uniform velocity in smooth tube, m s−1

x=

coordinate direction

μ=

dynamic viscosity, kg s−1 m−1

Γ=

thermal diffusivity

ε=

dissipation rate

ρ=

density, kg m−3

Subscripts=
0=

smooth tube

pp=

pumping power

NOMENCLATURE

A=

cross-sectional area, m2

D=

characteristic diameter of spirally corrugated tube

DR=

corrugation depth ratio, (e/D)

PR=

corrugation pitch ratio, (p/D)

e=

corrugation depth, m

f=

friction factor

h=

convective heat transfer coefficient, W m−2 K−1

k=

turbulent kinetic energy, ()

ka=

thermal conductivity of air, W m−1 K−1

Nu=

Nusselt number

p=

corrugation pitch, m

P=

static pressure, Pa

Pr=

Prandtl number

PR=

pitch spacing ratio, p/D

Re=

Reynolds number, (ρu0D/μ)

T=

temperature, K

TEF=

thermal performance enhancement factor, (Nu/Nu0)/(f/f0)1/3

ui=

velocity component in xi-direction, m s−1

ui'=

fluctuation velocity in xi-direction, m s−1

u0=

mean or uniform velocity in smooth tube, m s−1

x=

coordinate direction

μ=

dynamic viscosity, kg s−1 m−1

Γ=

thermal diffusivity

ε=

dissipation rate

ρ=

density, kg m−3

Subscripts=
0=

smooth tube

pp=

pumping power

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.