This study provides a new systematic approach to predicting the effects of spray inclination on critical heat flux (CHF). Experiments were performed with three pressure spray nozzles over a broad range of inclination angles at five flow rates and subcoolings of 15°C and 25°C. These experiments also included high-speed video analysis of spray formation, impact, and recoil for a 1.0×1.0cm2 test surface. Inclined sprays produced elliptical impact areas, distorted by lateral liquid flow that provided partial resistance to dryout along the downstream edge of the impact ellipse. These observations are used to determine the locations of CHF commencement along the test surface. A new theoretical model shows that increasing inclination angle away from normal decreases both the spray impact area and the volumetric flux. These trends explain the observed trend of decreasing CHF with increasing inclination angle. Combining the new model with a previous point-based CHF correlation shows great success in predicting the effects of spray inclination on CHF.

1.
Toda
,
S.
, 1972, “
A Study in Mist Cooling
,”
Trans. Jpn. Soc. Mech. Eng.
0375-9466,
38
, pp.
581
588
.
2.
Mudawar
,
I.
, and
Valentine
,
W. S.
, 1989, “
Determination of the Local Quench Curve for Spray Cooled Metallic Surfaces
,”
ASM J. Heat Treating
,
7
, pp.
107
121
.
3.
Totten
,
G. E.
,
Bates
,
C. E.
, and
Clinton
,
N. A.
, 1993,
Handbook of Quenchants and Quenching Technology
,
ASM International
,
Materials Park, OH
.
4.
Hall
,
D. D.
, and
Mudawar
,
I.
, 1995, “
Predicting the Impact of Quenching on Mechanical Properties of Complex-Shaped Aluminum Alloy Parts
,”
ASME J. Heat Transfer
0022-1481,
117
, pp.
479
488
.
5.
Hall
,
D. D.
, and
Mudawar
,
I.
, 1995, “
Experimental and Numerical Study of Quenching Complex-Shaped Metallic Alloys With Multiple, Overlapping Sprays
,”
Int. J. Heat Mass Transfer
0017-9310,
38
, pp.
1201
1216
.
6.
Bernardin
,
J. D.
, and
Mudawar
,
I.
, 2002, “
A Cavity Activation and Bubble Growth Model of the Leidenfrost Point
,”
ASME J. Heat Transfer
0022-1481,
124
, pp.
864
874
.
7.
Estes
,
K. A.
, and
Mudawar
,
I.
, 1995, “
Correlation of Sauter Mean Diameter and CHF for Spray Cooling of Small Surfaces
,”
Int. J. Heat Mass Transfer
0017-9310,
38
, pp.
2985
2996
.
8.
Mudawar
,
I.
, and
Estes
,
K. A.
, 1996, “
Optimizing and Predicting CHF in Spray Cooling of a Square Surface
,”
ASME J. Heat Transfer
0022-1481,
118
, pp.
672
679
.
9.
Mudawar
,
I.
, 2001, “
Assessment of High-Heat-Flux Thermal Management Schemes
,”
IEEE Trans. Compon. Packag. Technol.
1521-3331,
24
, pp.
122
141
.
10.
Rini
,
D. P.
,
Chen
,
R.-H.
, and
Chow
,
L. C.
, 2002, “
Bubble Behavior and Nucleate Boiling Heat Transfer in Saturated FC-72 Spray Cooling
,”
ASME J. Heat Transfer
0022-1481,
124
, pp.
63
72
.
11.
Lin
,
L.
, and
Ponnappan
,
R.
, 2003, “
Heat Transfer Characteristics of Spray Cooling in a Closed Loop
,”
Int. J. Heat Mass Transfer
0017-9310,
46
, pp.
3737
3746
.
12.
Lefebvre
,
A. H.
, 1989,
Atomization and Sprays
,
Hemisphere
,
New York
, NY.
13.
Silk
,
E. A.
,
Kim
,
J.
, and
Kieger
,
K.
, 2006, “
Spray Cooling of Enhanced Surfaces: Impact of Structured Surface Geometry and Spray Axis Inclination
,”
Int. J. Heat Mass Transfer
0017-9310,
49
, pp.
4910
4920
.
14.
Li
,
B. Q.
,
Cader
,
T.
,
Schwarzkopf
,
J.
,
Okamoto
,
K.
, and
Ramaprian
,
B.
, 2006, “
Spray Angle Effect During Spray Cooling of Microelectronics: Experimental Measurements and Comparison With Inverse Calculations
,”
Appl. Therm. Eng.
1359-4311,
26
, pp.
1788
1795
.
15.
Visaria
,
M.
, and
Mudawar
,
I.
, 2007, “
Theoretical and Experimental Study of the Effects of Spray Inclination on Two-Phase Spray Cooling and Critical Heat Flux
,”
Int. J. Heat Mass Transfer
0017-9310, doi: 10.1016/j.ijheatmasstransfer.2007.08.010.
16.
Rybicki
,
J. R.
, and
Mudawar
,
I.
, 2006, “
Single-Phase and Two-Phase Cooling Characteristics of Upward-Facing and Downward-Facing Sprays
,”
Int. J. Heat Mass Transfer
0017-9310,
49
, pp.
5
16
.
17.
Bernardin
,
J. D.
,
Stebbins
,
C. J.
, and
Mudawar
,
I.
, 1997, “
Mapping of Impact and Heat Transfer Regimes of Water Drops Impinging on a Polished Surface
,”
Int. J. Heat Mass Transfer
0017-9310,
40
, pp.
247
268
.
You do not currently have access to this content.