Winglet vortex generators can be used to enhance the heat transfer performance of finned flat tube bank fin. The effects of the height of vortex generators (VG) on local heat transfer were studied using the naphthalene sublimation method and the optimum height of winglet VG are screened by using JF, a dimensionless factor of the larger the better characteristics. In order to get JF, the local heat transfer coefficient obtained in experiments and a numerical method were used to get the heat transferred from the fin. For the configurations studied in this paper: for local characteristic, as increasing height of VG, heat transfer is enhanced, but the mostly enhanced region moves away from the tube wall; with increasing height of VG to certain degree, the width of enhanced region does not increase significantly; the effects of VG’s height on span-average Nusselt number (Nu) are more mixed on fin surface mounted with VGs and its back surface, with increasing height of VG, in some region heat transfer is worsened, and in other region heat transfer is enhanced; in real working condition, the heat transferred from fin surface mounted with VGs is larger than the heat transferred from the other surface of the fin; increasing the height of VG (H) increases average Nu and friction factor (f ), but with considering the fin efficiency, there is an optimum H to get best heat transfer performance; the optimum height of VG is dependent on the thickness of fin and its heat conductivity, for mostly used fin thickness and material, the optimum height of VG is 0.8 times of net fin spacing.

1.
Fiebig
,
M.
,
1998
, “
Vortices, Generators and Heat Transfer
,”
Chem. Eng. Res. Des.
,
76
(
A2
), pp.
108
123
.
2.
Fiebig
,
M.
,
1995
, “
Vortex Generators for Compact Heat Exchangers
,”
J. Enhanced Heat Transfer
,
2
, pp.
43
61
.
3.
Jacobi
,
A. M.
, and
Shah
,
R. K.
,
1995
, “
Heat Transfer Surface Enhancement Through the Use of Longitudinal Vortices: A Review of Recent Progress
,”
Exp. Therm. Fluid Sci.
,
11
, pp.
295
309
.
4.
Tiggelbeck
,
S.
,
Mitra
,
N. K.
, and
Fiebig
,
M.
,
1994
, “
Comparison of Wing-Type Vortex Generators for Heat Transfer Enhancement in Channel Flows
,”
J. Heat Transfer
,
116
, pp.
880
885
.
5.
Fiebig
,
M.
,
Valencia
,
A.
, and
Mitra
,
N. K.
,
1994
, “
Local Heat Transfer and Flow Losses in Fin-Tube Heat Exchanger With Vortex Generators: A Comparison of Round and Flat Tubes
,”
Exp. Therm. Fluid Sci.
,
8
, pp.
35
45
.
6.
Chen
,
Y.
,
Fiebig
,
M.
, and
Mitra
,
N. K.
,
1998
, “
Heat Transfer Enhancement of a Finned Oval Tube With Punched Longitudinal Vortex Generator In-line
,”
Int. J. Heat Mass Transfer
,
41
, pp.
3961
3978
.
7.
Wang
,
L. B.
,
Ke
,
F.
,
Gao
,
S. D.
, and
Mei
,
Y. G.
,
2002
, “
Local and Average Characteristics of Heat/Mass Transfer Over Flat Tube Bank Fin With Four Vortex Generators Per Tube
,”
J. Heat Transfer
,
124
, pp.
446
552
.
8.
Wang
,
L. B.
,
Zhang
,
Y. H.
,
Su
,
Y. X.
, and
Gao
,
S. D.
,
2002
, “
Local and Average Heat/Mass Transfer Over Flat Tube Bank Fin Mounted In-line Vortex Generators With Small Longitudinal Spacing
,”
J. Enhanced Heat Transfer
,
9
(
2
), pp.
77
87
.
9.
Yun
,
Y. L.
, and
Lee
,
K. S.
,
2000
, “
Influence of Design Parameters on the Heat Transfer and Flow Friction Characteristics of the Heat Exchanger With Slit Fins
,”
Int. J. Heat Mass Transfer
,
43
, pp.
2529
2539
.
10.
Goldstein
,
R. J.
,
1995
, “
A Review of Mass Transfer Measurements Using Naphthalene Sublimation
,”
Exp. Therm. Fluid Sci.
,
10
, pp.
416
434
.
11.
Saboya
,
F.
, and
Sparrow
,
E. M.
,
1974
, “
Local and Average Transfer Coefficients for One-Row Plate Fin and Tube Heat Exchanger Configurations
,”
J. Heat Transfer
,
96
, pp.
265
272
.
12.
Kylikof, U. A., 1988, The Cooling System of Diesel Locomotive, Machine-Manufacturing, Moscow, (in Russian).
13.
Moffart
,
R. J.
,
1982
, “
Contribution to the Theory of Single-Sample Uncertainty Analysis
,”
J. Heat Tansfer
,
104
, pp.
250
260
.
14.
Tiggelbeck
,
S.
,
Mitra
,
N. K.
, and
Fiebig
,
M.
,
1992
, “
Flow Structure and Heat Transfer in a Channel With Multiple Longitudinal Vortex Generators
,”
Exp. Therm. Fluid Sci.
,
5
, pp.
425
436
.
15.
Tiggelbeck
,
S.
,
Mitra
,
N. K.
, and
Fiebig
,
M.
,
1993
, “
Experimental Investigations of Heat Transfer Enhancement and Flow Losses in a Channel With Double Rows of Longitudinal Vortex Generators
,”
Int. J. Heat Mass Transfer
,
36
, pp.
2327
2337
.
You do not currently have access to this content.