论文部分内容阅读
以燃烧器四角切圆布置的超超临界塔式锅炉炉膛内的流动换热为背景,利用Fluent软件通过数值模拟研究了一个物理和几何结构完全对称的三维炉膛内冷态流场变化情况,选用6个燃烧器喷嘴出口速度作为不同的工况来计算炉内的流场,速度变化范围为5~30 m/s,湍流模型采用雷诺应力模型。计算结果表明,随着出口气流速度的增大,流动呈现出的切圆半径越来越大;当喷嘴出口速度小于等于10 m/s时,在所用计算模型下,流体速度场呈中心对称结构,切圆中心位于中央;随着出口速度的持续增加,流场从中心对称结构逐步转变成非中心对称结构,切圆中心发生明显偏斜.数值结果表明,即使几何结构完全对称且边界物理条件也完全对称的燃烧器四角切圆布置的炉膛中的流动,仍然可能是非对称的,这是造成烟气侧热偏差的可能的原因之一。
Taking the flow heat transfer inside the supercritical boiler of the four-corner tangential burner layout as the background, the change of the flow field in a three-dimensional furnace with symmetrical physical and geometrical structures was studied by numerical simulation using Fluent software. The outlet velocities of 6 burner nozzles were used as the different operating conditions to calculate the flow field in the furnace with a range of 5-30 m / s and the turbulence model using the Reynolds stress model. The calculated results show that the tangent radius of the flow increases with the increase of the velocity of the outlet air flow. When the nozzle outlet velocity is less than or equal to 10 m / s, the fluid velocity field shows a centrosymmetric structure , The center of the tangent circle is located in the center. With the continuous increase of outlet velocity, the flow field gradually changes from the center symmetry structure to the non-center symmetry structure, and the center of the tangent circle is obviously deflected. Numerical results show that even if the geometric structure is completely symmetrical and the boundary physical conditions The flow in the furnace, which is also perfectly symmetric, arranged in a square torus of the burner, may still be asymmetrical, which is one of the possible causes for the thermal deviation of the flue gas side.