• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>International Journal of Heat and Mass Transfer >Heat transfer of aqueous salt solution layers
【24h】

Heat transfer of aqueous salt solution layers

机译：盐水溶液层的热传递

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Heat transfer and evaporation of layers of water and aqueous solutions of salts on a heated horizontal wall were studied experimentally. Aqueous solutions of salts can be divided into two characteristic groups. For the first group of salts, the evaporation rates and heat transfer coefficients increase with time. For the second group, the rate of evaporation falls sharply with increasing salt concentration and with decreasing liquid layer height. This difference in salts’ behavior is determined by the difference in equilibrium curves and in physical and chemical properties of salts. The heat transfer coefficient for water and salt solutions increases when the layer height becomes less than 1.2–1.5 mm. With increasing concentration of salt and when approaching the crystallization point the role of free convection in the liquid phase decreases sharply, and the Nusselt number approaches 1. For salt solutions (LiBr, CaCl2and LiCl), a significant excess of convection (α) over the conductive heat transfer (λ) is observed for the layer heightδover 1.8–2.0 mm. For pure water, convective and conductive components are comparable even forδ= 3 mm. This difference for salts is associated with substantial intensification of heat transfer, which is probably caused by the concentration flow of MarangoniMaC. Strong influence ofMaCon heat and mass transfer in a thin layer and at high temperatures is detected for the first time and is extremely important for accurate modeling in unsteady and non-isothermal processes. Experimental data show a surprising result. The free liquid convection for salt solutions significantly exceeds the convection in the water layer for the most part of the evaporation time.
机译：实验研究了加热的水平壁上水层和盐水溶液的热传递和蒸发。盐的水溶液可以分为两个特征组。对于第一类盐，蒸发速率和传热系数随时间增加。对于第二组，蒸发速度随着盐浓度的增加和液层高度的减小而急剧下降。盐行为的差异取决于平衡曲线以及盐的物理和化学性质的差异。当层的高度小于1.2–1.5？mm时，水和盐溶液的传热系数会增加。随着盐浓度的增加和接近结晶点时，液相中对流的作用急剧下降，Nusselt值逼近1。对于盐溶液（LiBr，CaCl2和LiCl），对流（α）相对于盐溶液明显过量。在层厚δ超过1.8-2.0 mm时观察到了导热（λ）。对于纯水，对流和导电成分即使在δ= 3 mm时也是可比的。盐的这种差异与传热的大量增强有关，这可能是由于MarangoniMaC的浓度流引起的。首次检测到MaCon在薄层和高温下传热和传质的强烈影响，这对于在不稳定和非等温过程中进行精确建模非常重要。实验数据显示出令人惊讶的结果。盐溶液的自由液体对流在大部分蒸发时间内都大大超过了水层中的对流。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号