The attractive and repulsive behaviours of a pair of initially spherical gas bubbles rising side-by-side in a channel with non-uniformly heated walls containing a self-rewetting liquid are investigated numerically. The surface tension of a self-rewetting fluid exhibits a parabolic temperature dependence with a well-defined minimum, as opposed to linear (common) fluids whose surface tension decreases almost linearly with the increasing temperature. It is found that, for low Reynolds numbers, while in an isothermal medium, two gas bubbles display a repulsive behaviour, they attract in non-isothermal systems. The bubbles in the self-rewetting fluid undergo a plastic collision and show a ‘squeezing and relaxing’ behaviour, whereas they attract and then bounce in the linear fluid. A regime map demarcating the repulsive and attractive behaviours for a self-rewetting fluid is plotted in the Weber number $\left(We\right)$ and the dimensionless linear component of the surface tension gradient $\left(M_1\right)$ space. It is found that the bubbles in the self-rewetting fluid remain spherical even for high Weber numbers while they deform considerably in the case of the linear fluid indicating that the attractive behaviour of the bubbles in the self-rewetting fluid is due to the lift force generated by the thermocapillary stresses and not due to the deformation. The mechanism underlying the observed phenomenon is elucidated by studying the drag and lift forces acting on the bubbles, their orientations, and the flow field around them.

数值研究了一对最初球形的气泡在一个通道内并排上升的吸引力，该通道的加热壁不均匀，其中包含自粘性液体。自润滑流体的表面张力表现出抛物线温度依赖性，且具有明确定义的最小值，这与线性（常见）流体的表面张力随温度升高几乎呈线性下降相反。已经发现，对于低雷诺数，在等温介质中，两个气泡表现出排斥行为，它们吸引了非等温系统。自粘性流体中的气泡发生塑性碰撞，表现出“挤压和松弛”的行为，而它们在线性流体中吸引然后反弹。$（\mathrm{w\; ^}Ë）$ 和表面张力梯度的无量纲线性分量 $（{\mathrm{中号}}_{\mathrm{1个}}）$空间。已经发现，即使对于高韦伯数，自润湿流体中的气泡仍保持球形，而在线性流体的情况下，它们会明显变形，这表明自润湿流体中的气泡的吸引力是由于升力引起的。由热毛细应力产生而不是由于变形产生的。通过研究作用在气泡上的阻力和升力，气泡的方向以及气泡周围的流场，可以阐明观察到的现象的机理。