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首页> 外文期刊>International Journal of Heat and Mass Transfer >Up-flow boiling of R1234yf in aluminum multi-port extruded tubes
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Up-flow boiling of R1234yf in aluminum multi-port extruded tubes

机译：铝多口挤压管中R1234yf的上流沸腾

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摘要

The characteristics of local heat transfer and pressure drop were experimentally investigated for the vertical up-flow boiling of refrigerant R1234yf in two types of aluminum multi-port extruded tubes. One with 16 channels with a cross-section of 0.91 × 0.21 mm (tube A), and one with 40 channels with a cross-section of 0.34 × 0.21 mm (tube B). At an evaporating temperature of 15 °C, the local heat transfer coefficient and pressure drop for the heat flux range of 3-16 kW/m~2, and mass flux range of 60-240 kg/m~2 s were measured. The heat transfer coefficient decreased nearly linearly with increasing vapor quality in both tubes. As the vapor quality increased, the dry patch areas became larger in these rectangular channels, which degraded the heat transfer performance significantly. Compared with the multi-port extruded tube (tube C), with 16 channels with a cross-section of 0.9 × 0.9 mm, at a mass flux of 60 kg/m~2 s, tube C demonstrated better heat transfer performance than tubes A and B. When the mass flux increased to 120 kg/m~2 s, the dry-out was alleviated in tubes A and B, and better performance was observed for low vapor quality regions, while in high vapor quality regions the dry patches reoccupied the heat transfer area, thereby resulting in worse heat transfer performance in tubes A and B. The pressure drop and heat transfer coefficient was not effectively predicted by the existing correlations.
机译：通过实验研究了两种类型的铝多口挤压管中制冷剂R1234yf的垂直上升流沸腾的局部传热和压降特性。一种带有16个通道的横截面为0.91×0.21mm（管A），另一个带有40个通道的横截面为0.34×0.21mm（管B）。在15°C的蒸发温度下，对于3-16 kW / m〜2的热通量和60-240 kg / m〜2的质量通量，测量了局部传热系数和压降。随着两个管中蒸汽质量的提高，传热系数几乎呈线性下降。随着蒸汽质量的提高，这些矩形通道中的干斑面积变大，这大大降低了传热性能。与多端口挤压管（C管）相比，具有16个横截面为0.9×0.9 mm的通道，质量通量为60 kg / m〜2s的管，C管表现出比A管更好的传热性能和B.当质量通量增加到120 kg / m〜2 s时，管A和B的干燥变缓，在低蒸汽质量区域观察到更好的性能，而在高蒸汽质量区域中干燥的斑块重新占据传热面积，从而导致管A和B中的传热性能变差。现有的相关性不能有效地预测压降和传热系数。

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