Numerical Investigation of Turbulent Combustion during Line Heating Process

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The aim of this study is to develop a method of numerical investigation of the heat transmission from the heating gas to the plate during line-heating process.New modified-eddy-dissipation combustion model is proposed. The validity of the proposed model is demonstrated by comparing the calculated and measured gas temperature during spot heating.The transient temperature distribution is measured using a LIF apparatus in oxygen-methane gas flame from a torch moving linearly. The changing nature of temperature field during spot and line heating is investigated closely and carefully.The effectiveness of low-Reynolds number k-ε turbulence model is also investigated.As results, the followings are found ;1) From the result of L.I.F. measurement, it has been found that the relative distribution of gas temperature around the torch is almost the same as that in spot heating. It has also been found that this relative distribution is almost unchanged regardless of the temperature increase in the s … More teel plate.2) The above result leads us to a new hypothesis that the relative distributions of gas temperature and local heat transfer coefficient around the torch remain unchanged and they are almost the same as those in spot heating during line heating process. A new method of heat input estimation for line heating process based on this hypothesis, by which plate temperature distribution history can be accomplished for desired plate shape, dimensions, and torch movement history, solely from spot heating experimental results, has been propounded.3) The calculated gas temperature distribution during spot heating is in good agreement with measured one when proposed modified-eddy-dissipation combustion model is employed. It is preferable to employ the proposed model in analysis of impinging jet flame during line heating process.4) The calculation result in which low-Reynolds number k-e turbulence model is employed shows that heat flow in the immediate neighborhood of the plate surface is greatly affected by turbulent flow. This suggests that the precision of gas temperature and heat transmission calculation within the turbulent boundary layer can be improved by employing low-Reynolds number k-e turbulence model. Less