火焰切割割缝宽度的实验与数值模拟研究

Experiments and Numerical Simulation on the Gap Width of Flame Cutting

使用数控火焰切割机对150 mm厚的铁块进行了切割,并研究了丙烷和预热氧流量对割缝宽度的影响,实验结果表明割缝宽度平均为4.8 mm,且有随着丙烷流量的增大,割缝宽度逐渐降低的趋势。使用重铬酸钾滴定法滴定熔渣样品,得到熔渣中铁及其氧化物的含量,并结合切割速度3.5 mm/s计算出切割过程中铁氧燃烧在单位时间内的放热量为91.1 k W。忽略预热氧的影响,以铁氧燃烧放热为主要热源,使用C语言建立了火焰切割的三维数值模型,对达到稳态后铁块的温度场及割缝宽度进行了计算。通过调节模型中的参数,使模拟得到的割缝宽度为4.8 mm,与实验结果相吻合。

A 150 mm thick steel plate is cut by a NC flame cutting machine. The influence of propane and preheating oxygen on the gap width is studied. The results show that the average gap width is 4.8 mm and it decreases with propane flow increases. The contents of each valence state of Fe and oxides in the slag can be titrated by using K2 Cr2 O7. The result shows that the energy generated by the steel combustion is 91.1 k W,which is calculated with the cutting speed of 3.5 mm/s. A numerical model is built based on this energy without the influence of preheating flame. As a result,the temperature distribution of the steel plate and the width of the gap is calculated by this model. By calibrating the parameters of the model,the calculated gap width is 4.8 mm.