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shows the relations between Ts and q after t=l.Osec at various points. This figure shows that such
linear relationship is approximately established.
From Eq. (l), distributions of local heat coefficient a and gas temperature right on the plate TG can be
obtained by performing a hear regression analysis on the relation of Ts and q. Figures 12 and 13
shows the calculated distributions of a and To.
Plate back face temperature TB can be calculated from the estimated a and TG by direct therm0
conduction fide element analysis. Figure 14 shows the dcdated and measured values Of TB. In this
figure, it is found that calculated values agree well with the experimental results. It is considered that
this result shows the accuracy of the inverse analysis, and it has also strongly supported the hypotheses
proposed in this paper.
According to the proposed hypotheses, thermal-flow field and local heat transfer remain unchanged
when the size and/or shape of plate is changed. It can be considered that the hypotheses approximately
holds true during a line heating process when torch traveling speed is much smaller than the velocity of
gas flow. This leads to an assumption that the relative diitribution patterns of gas temperature and
local heat transfer coefficient around the stagnation point during line heating with arbitrary torch
traveling history are almost the Same as those in spot heating using the same torch and gas condition.
Therefore, it is anticipated that the temperature distribution in a plate during line heating with arbitrary
torch traveling history and plate size can be calculated as far as a spot heating experiment with the
same torch and gas condition is performed.

4 CONCLUSIONS
The transient 3-dimensiod temperatwe distribution of the gas flame of the spot heating experimCnt
using a small power metbane torch is measured by a L.I.F. measurement system. The distributions of
plate heating face temperature and heat flux during the spot heating experiment using a high power
oxyacetylene line heating torch are calculated by inverse heat conduction analysis.
The main results are as follows:
1) For the spot heating experiment using a small methane torch, it has been found that the thennal-flow
field within the combustion flame remains almost unchanged regardless of the temperature increase in
the steel plate.
2) The hypothesis that, the gas temperature near the plate surface and local heat transfer coefficient are
time independent and they depend only on the distance fiom the torch, is built up.
3) For the spot heating experiment using a high power line heating torch, the measured back face plate
temperature agree well with the calculated ones which are derived fiom the plate heating face
temperature and heat flux estimated by inverse heat conduction analysis. This result shows the
accuracy of the inverse analysis, and it support the hypotheses proposed in this paper.

Acknowledgement

The measurement of temperature within the flame in L.I.F. experiment is carried out at Mitsubishi
Heavy Industries, Co. Ltd. Inc. Nagasaki Research Institute. The authors would like to express to Dr.
Watanabe, E. and Dr. Deguchi, Y. our deepest gratitude for their cooperation.
The measurement of plate back face temperature during spot heating with high power torch is carrid
out at Hitachi Zosen, Co. Ltd. Inc. Ariake Shipyard as a part of the research program of Panel SW46
of the Shipbuilding Research Association of Japan, sponsored financially by the Nippon Foundation.
The authors would like to express to Mr. Ohsawa M. and Mr. Nakatani M. our deepest gratitude for
their cooperation.