不同特征尺寸管式降膜太阳能海水蒸馏器热性能分析

THERMAL PERFORMANCE ANALYSIS OF TUBULAR FALLING FILM SOLAR SEAWATER DISTILLATION DISTILLER WITH DIFFERENT CHARACTERISTIC SIZES

为提高小型太阳能海水蒸馏器热能利用效率和产水速率,设计一种管式降膜太阳能海水蒸馏器,基于小高径比环形封闭空间水蒸气传热传质特性,分析特征尺寸和运行温度对装置单位冷凝面积产水速率的影响机理,研究不同特征尺寸管式降膜太阳能海水蒸馏器蒸发冷凝温差、竖直方向冷凝温度梯度等变化规律。结果表明,运行温度为85℃时,特征尺寸为0.015 m的管式降膜太阳能海水蒸馏器单位冷凝面积产水速率为0.696 kg/(h·m^(2)),比特征尺寸为0.035 m的蒸馏器增加10.48%,冷凝温度T4为81.94℃,比特征尺寸为0.035 m的蒸馏器高3.83℃,在测试范围内蒸发冷凝温差最小为1.9℃,该研究可为强化管式太阳能海水淡化装置热质传递过程提供技术参考。

This study aims to improve the heat utilization efficiency and water production rate of small-scale solar seawater distiller,thereby a tubular falling film solar seawater distillation device was specifically designed. Based on the heat and mass transfer characteristics of water vapor in the annular enclosed space with low aspect ratio,the influence mechanism of characteristic size and operating temperature on the water production rate per unit condensing area was analyzed. Meanwhile,the tubular falling film solar seawater distillation devices with different characteristic sizes were studied. The variation of the temperature difference between the evaporation and condensation surface and vertical condensation temperature gradient of devices were recorded and investigated. The results show that when the operating temperature is 85 ℃,the water production rate per condensation area of the tubular falling film solar seawater distillation device with the characteristic size of 0.015 m is 0.696 kg/(h·m^(2)),which is 10.48% higher than that of the device with the characteristic size of 0.035 m. The condensation temperature of T4 is 81.94 ℃ and 3.83% higher than that of the characteristic size of 0.035 m. The minimum temperature difference between the evaporation and condensation surface is 1.9 ℃ within the test range. The findings can increase our understanding of the heat and mass transfer process of tubular solar seawater desalination device and contribute to enhance the process mentioned above.