This study aims to enhance the localized energy of the plasma arc to meet the requirement of thick metal plate welding. To achieve this, a novel hybrid heat source by coaxial arranging the laser and plasma arc was proposed, named laser-enhanced plasma arc (LPA). This special torch combines the two kind sources by a tubular tungsten electrode which the laser passes through, use laser to heat localized plasma arc to modify the energy distribution. The three-dimensional temperature field was measured to clarify the effect of laser on plasma arc energy distribution and the absorption characteristics of laser by plasma arc. The numerical simulation model was established to reveal the influence mechanism. Results show that there is a high laser absorption region in the plasma arc, and it exists obvious effects of plasma arc pressure and temperature on laser absorption rate. The location and size of the high laser absorption region change as the welding parameters because the temperature and pressure of plasma arc change. The results also substantiate that the hybrid source energy can be adjusted locally to increase the effective flame length of the plasma arc by changing the laser energy and plasma arc parameters, which is beneficial for thick metal plate welding.

这项研究旨在提高等离子弧的局部能量，以满足厚金属板焊接的要求。为此，提出了一种通过同轴布置激光和等离子弧的新型混合热源，称为激光增强等离子弧（LPA）。这种特殊的火炬通过激光穿过的管状钨电极将两种光源结合起来，利用激光加热局部等离子弧来改变能量分布。测量三维温度场，阐明激光对等离子弧能量分布的影响以及等离子弧对激光的吸收特性。建立了数值模拟模型，揭示了影响机制。结果表明，等离子弧中存在较高的激光吸收区域，等离子弧压和温度对激光吸收率的影响明显。由于等离子弧温度和压力的变化，高激光吸收区的位置和大小随着焊接参数的变化而变化。结果还证实，可以通过更改激光能量和等离子弧参数来局部调整混合源能量，以增加等离子弧的有效火焰长度，这对于厚金属板焊接是有利的。