Convective heating is used in materials processing industry for heat treatment and melting applications. Only recently, a new plasma device for convective heating at atmospheric pressure has become commercially available. In this paper, we have investigated heating of an aluminum sprue by conventional convective heating by air and by plasma flow. Transient temperature measurements were made in the sprue interior and the overall heat transfer coefficient was computationally predicted in the two cases. Results show that there is significant enhancement of heat transfer in convective plasma heating compared to heating due to unionized gas under identical flow and temperature conditions. For the cases considered in this study, close to a 60% increase in the heat transfer rate was obtained. The key finding is that even small amount of ionization (~ < 1%) can lead to significant increase in heat transfer coefficient.

1.
Boulos M. I., Fauchais, P., and Pfender, E., 1994, Thermal Plasmas: Fundamentals and Applications, Vol. 1, Plenum Press.
2.
Smith
R. W.
,
Wei
D.
and
Apelian
D.
,
1989
, “
Thermal plasma materials processing
,”
Plasma Chemistry and Plasma Processing
, vol.
9
, pp.
135S–165S
135S–165S
.
3.
Ayyaswamy, P. S. and Cohen, I. M., 2002, “Low Energy Plasma Heat Transfer as Applied to Microelectronic Packaging,” In Annual Review of Heat Transfer, Vol. 12, Chang-Lin Tien, V. Prasad, F. Incropera (eds.), Hemisphere Publication, New York.
4.
Chyou
Y. P.
, and
Pfender
E.
,
1989
, “
Behavior of particulates in thermal plasma flows
,”
Plasma Chemistry and Plasma Processing
, vol.
9
, pp.
45
71
.
5.
Laveroni
E.
and
Pfender
E.
,
1990
, “
A unitied approach to plasma-particle heat treansfer under non-continuum and non-equilibrium conditions
,”
Int. J. Heat Mass Transfer
, vol.
33
, pp.
1497
1509
.
6.
Petrie
T. W.
and
Pfender
E.
,
1972
, “
The effect of ionization on heat transfer to wires immersed in a highly thermally-ionized plasma
,”
Warme und Stoffubertragung
, vol.
5
, pp.
85
100
.
7.
Hader
M. A.
and
Jog
M. A.
,
1998
, “
Continuum plasma flow past a sphere
,”
Physics of Plasmas
, vol.
5
, pp.
902
909
.
8.
Jog
M. A.
, and
Huang
L.
,
1996
, “
Transient heating and melting of particles in plasma spray coating process
,”
ASME J. Heat Transfer
, vol.
118
, pp.
471
477
.
9.
Verma
A.
, and
Jog
M. A.
,
2000
, “
Plasma flow over an array of particles
,”
Int. J. Heat Mass Transfer
, vol.
43
, pp.
101
111
.
10.
Young
R. M.
, and
Pfender
E.
,
1987
, “
Nusselt number correlations for heat transfer to small spheres in thermal plasma flows
,”
Plasma Chemistry and Plasma Processing
, vol.
7
, No.
2
, pp.
211
226
.
11.
Chen
X.
,
1997
, “
Heat transfer to a metallic wire exposed to a plasma flow for great Knudsen numbers
,”
J. Phys. D: Appl. Phys.
, vol.
30
, pp.
1885
1892
.
12.
Gnedovets
A. G.
and
Uglov
A. A.
,
1992
, “
Heat transfer to non-spherical particles in a rarefied plasma flow
,”
Plasma Chemistry and Plasma Processing
, vol.
12
, pp.
383
401
.
13.
www.mhi-inc.com
14.
Brown, S. C., 1966, Basic Data of Plasma Physics, MIT Press, Cambridge, MA.
15.
Singh
A. K.
,
Saptharishi
S.
,
Basu
B.
, and
Sekhar
J. A.
,
2002
, “
The Influence of Heating Element Temperature on Productivity
,”
JOM
, Vol.
54
, No.
11
, pp.
76
80
.
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