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本文利用计算流体力学CFD技术,对内置发热圆的方腔内双扩散混合对流的振荡特性进行了数值模拟研究。发热圆为高温高浓度且位于方腔中心,低温低浓度的流体从方腔左侧底部流进,右侧顶部流出。在不同的理查德数Ri(0.001≤Ri≤1.0)和发热圆直径和方腔边长的比值S(0.2≤S≤0.6)下,利用时间历程和相空间轨迹法来量化分析方腔内部的振荡特性。研究结果表明:当Ri=0.001时,在S=0.6的情况下,方腔内双扩散混合对流呈现出周期性振荡状态;在S=0.2和0.4的情况下,方腔内双扩散混合对流呈现出非周期性振荡状态。而当Ri≥0.005时,无论S为多大,方腔内双扩散混合对流均呈现出稳定流动状态。
In this paper, the computational fluid dynamics (CFD) technique is used to simulate the oscillation characteristics of double diffusive mixed convection in a square cavity with built-in heating circles. The heating circle is high temperature and high concentration and is located in the center of the cavity. The low-temperature and low-concentration fluid flows in from the left bottom of the cavity and flows out to the top of the right side. Under different Richard number Ri (0.001≤Ri≤1.0) and the ratio of the diameter of the heating circle and the side length of the cavity S (0.2≤S≤0.6), the time history and phase space trajectory method are used to quantify the inner part of the cavity The oscillation characteristics. The results show that when Ri = 0.001, the double-diffused mixed convection presents a periodic oscillation at S = 0.6. In the case of S = 0.2 and 0.4, the double-diffused mixed convection in the cavity presents A non-periodic oscillation state. When Ri≥0.005, no matter how big S is, the double diffusion mixed convection in the square cavity shows a steady flow state.