ABSTRACT

The authors [Tomita, 1999] El1 have shown that the temperature distribution near the plate can be estimated by calculating the heat flow of non-combustion impinging jet instead of the impinging combustion jet flame. For 2-dimensional impinging combustion jet flame, close agreement between measured and calculated temperature near the plate surface has been verified when the highest temperature within the flame, the velocity of mixed gas at the upstream side of the nozzle and the width of the actual combustion flame are employed as temperature, velocity and width of the impinging jet at the exit. The gas flame used in the actual line heating process is 3-dimensional. It is needed to measure the transient temperature distribution of 3-dimensional flame near the plate surface accurately. In this report, for 3-dimensional axial symmetry jet, the transient temperature distribution near the plate surface in the spot heating is measured in detail by a high - performance L.I.E measurement system. The temperature in this case is also calculated by the numerical method proposed in the previous paper. The calculated and experimental results are compared, and the tendency of the temperature distribution is discussed.

1. INTRODUCTION

The shell plates of ships are composed of complicated 3-dimensional curved structures, which are formed using the line heating by the skilled workers. In recent years, the number of skilled workers has decreased and it becomes gradually difficult to succeed to the engineering skill of line heating. It is strongly desired to analyze the line heating process and to make automation of the line heating procedure. Analysis of the physical phenomena associated with the line heating is divided into the following two;

  1. heat transfer from impinging combustion jet flame to steel plate and

  2. heat conduction in the steel plate and thermal elasto-plastic deformation of the steel plate.

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