喷射方向对喷雾冷却换热的影响

Effect of Spraying Direction on Heat Exchange in Spray Cooling Process

以池内膜态沸腾为基础,将喷雾颗粒的冲击作为一种扰动,建立了喷雾冷却模型·模型中考虑了水流密度、喷雾水滴的大小、冲击力的影响·分析认为喷射方向上水膜厚度的差异是喷射方向影响铸坯表面传热系数的主要因素·将水膜厚度因素引入该模型中,进而计算分析出喷射方向对传热系数的影响状况·计算结果认为,在低水流密度下,90°处喷雾传热系数最大,其他喷射角度的传热系数大致以90°处对称·在高水流密度下,随喷射角度增加而显著增加·该理论分析结果与已有研究结果基本相同·

A spray cooling model was set up taking the impact of spraying droplets as a disturbance due to film boiling in cooling pond, of which the effects of water flow density, droplet size and impact force were taken into account. It was also found that the difference between thickness of water film in different spraying directions is the main influencing factor of spraying direction on the heat-exchange coefficient of continuous-cast ingot surface. The thickness of water film was therefore introduced into the model to analyze the influence of spraying direction on heat-exchange coefficient. The results indicated that the heat-exchange coefficient is maximum if the spraying angle is 90° with ingot surface at low waterflow density and, as a while, the coefficient distribution is symmetrical to the perpendicular spraying direction if the angle is different from 90°. The coefficient will increase greatly with spraying angle if the waterflow density is high. The result, as a theoretical analysis, is much the same to existing works done in other ways.