﻿ 射流冲击对旋转圆盘换热特性的影响

# 射流冲击对旋转圆盘换热特性的影响Effects of Jet Impingement on Heat Transfer Characteristics of Rotating Disk

Abstract: To investigate the effect of the jet impingement on the heat transfer characteristics of rotating disk, the heat transfer of rotating disk under different nozzle aperture, jet Reynolds number, disk Reynolds number, impact distance, injection angle and injection position was studied by using STAR-CCM+ software based on K-Epsilon turbulence and achievable K-Epsilon model. The simulation method was verified by comparing with experimental results. The results show that as the Reynolds number of the jet increases, the heat transfer increases. When the heat transfer area is large, the jet with a large aperture should be adopted. The ratio between injection dis-tance and nozzle aperture has the best value. When the disk Reynolds number is high, the heat transfer coefficient increases slowly; there is the best injection angle and injection position to make the average temperature of disk be the minimum.

1. 引言

2. 模型建立

2.1. 几何模型

2.2. 仿真模型

Figure 1. Schematic diagram of physical model

(a) (b)

Figure 2. Schematic diagram of the physical model of non central vertical jet; (a) Different injection angles; (b) Different injection position

Table 1. Parameter range of variable

${\mathrm{Re}}_{j}=\frac{Vd}{v}$ (1)

(2)

3. 仿真方法验证

4. 结果与分析

4.1. 射流雷诺数的影响

Figure 3. Schematic diagram of mesh model

(a) (b)

Figure 4. Comparison between simulation and experimental results of disk surface temperature; (a) Experimental result; (b) Simulation result

Figure 5. Variation of surface average temperature with the Rej

Figure 6. Variation of average heat transfer coefficient of surface with the Rej

4.2. 射流冲击距离的影响

4.3. 旋转雷诺数的影响

Figure 7. Variation of surface average temperature with the z/d

Figure 8. Variation of average heat transfer coefficient of surface with the z/d

Figure 9. Streamline diagram near the surface of the disk

Figure 10. Variation of surface average temperature with the ReR

Figure 11. Variation of average heat transfer coefficient of surface with the ReR

4.4. 喷射角度的影响

4.5. 喷射位置的影响

(a) α = 30˚ (b) α = 45˚(c) α = 60˚ (d) α = 90˚

Figure 12. Temperature nephogram of disc surface at different angle of injection

Figure 13. Variation of average heat transfer coefficient of surface with injection angle

(a) H/d = 0 (b) H/d = 10 (c) H/d = 20 (d) H/d = 30 (e) H/d = 45

Figure 14. Temperature nephogram of disc surface at different position of injection

Figure 15. Variation of average heat transfer coefficient of surface with the injection location

5. 结论

1) 随射流雷诺数增大，圆盘表面平均换热系数增大，射流雷诺数越高，平均换热系数增加幅度变缓。

2) 圆盘表面平均换热系数随旋转雷诺数的增大而增大，在高旋转雷诺数时，圆盘表面换热系数增幅变缓，继续增加旋转雷诺数对圆盘换热性能的改善有限。

3) 射流距离与喷孔直径之比z/d存在最佳值，过大或过小都会使圆盘的换热性能变差。

4) 随射流喷射角度增大，圆盘表面温度分布逐渐均匀，温度梯度减小，圆盘表面平均换热系数逐渐增大。随喷射位置偏离圆盘轴心距离增加，圆盘表面最大温度逐渐增大，喷射位置为圆盘中心时，圆盘表面平均温度为最小。

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