Experimental research on the thermal and mechanical response of flowing pipelines under the horizontal jet flame

Abstract

The safe operation of parallel pipelines has become a focus of attention. The jet flame generated by the initial pipe accident may cause adjacent pipe section failure. Therefore, it is necessary to study the thermal impact of jet flame on adjacent pipelines. In this paper, we design and establish a thermal effect test platform to determine the change in pipe wall temperature and mechanical properties under the horizontal jet flame. Firstly, the flame combustion characteristics, such as flame form, temperature, and heat flux, are tested and analyzed. Then, the quantitative variation law of the pipe wall and oil temperature under different flow rates, wall thicknesses, and heating lengths is obtained. Combined with the mechanical test results of experimental pipelines, a pipe-bearing capacity calculation model is established via the GA-BP machine learning algorithm. Finally, the safety evaluation method and classification of the stress margin are established. The results indicate that the temperature and heat flux of the fire-facing surface is significantly higher than other clock orientations, where the values are 1287.38 ℃ and 12.37 kW/m2, respectively. As the flow rate decreases and the wall thickness and heating length increase, the pipe wall temperature rises linearly, and the tensile strength and impact toughness reduce logarithmically. The average relative error of the pipe strength prediction model is less than 2.44 %. The established safety evaluation method can be applied to determine the thermal risk level of steel pipelines under the jet flame.