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本文对从具有对称结构的锅炉炉膛内流动问题抽象出的二维流动模型进行了数值模拟,探讨在这种对称结构下出现的非对称流动的机理.数值模拟结果表明,无论采用层流模型还是湍流模型,在某些参数范围内,流场的数值结果都出现了非对称现象,在层流模型下,当Re<1500时,计算得到的流场呈对称分布;当Re达到2500时,流场开始不对称;而当Re达到4000时,所获得的流场明显不对称,并且速度值发生振荡.在湍流模型下,Re<4000时,流速时均值呈对称分布;当Re≥8000时,速度时均值不对称,且出现振荡.本文分析表明,对于具有完全对称结构的流动问题,由于内部的原因可能出现非对称的流场,这为分析锅炉炉膛中出现的热偏差机理提供了基础.
In this paper, we simulate the two-dimensional flow model abstracted from the symmetric structure in the furnace and discuss the mechanism of asymmetric flow in this symmetrical structure.The numerical results show that both the laminar flow model and In the turbulent model, the numerical results of the flow field appear asymmetric in some parameters. Under the laminar flow model, when Re <1500, the calculated flow field is symmetrical; when Re reaches 2500, the flow The field begins to be asymmetric, and when Re reaches 4000, the obtained flow field is obviously asymmetric and the velocity value oscillates.In the turbulence model, when Re <4000, the mean value of flow velocity is symmetrical distribution; when Re≥8000, The mean value of velocity is not symmetrical and the oscillation occurs.The analysis of this paper shows that asymmetric flow field may exist due to internal reason for the flow with completely symmetrical structure, which provides the basis for analyzing the thermal deviation mechanism in the boiler hearth.