摘要
翅片管的传热特性决定着液化天然气(LNG)空温式气化器的气化性能,且管外表面结霜对传热特性的影响不可忽略。以空温式深冷翅片管为研究对象,建立翅片管空气侧传热模型,引入霜层物性参数经验公式,探究霜阻随风温与气化时间的变化规律,采用流体体积函数(VOF)多相流模型捕捉翅片管内气液两相区的流型,模拟分析结霜结露工况下翅片管内流动沸腾传热过程,研究单根翅片管管内外流固耦合传热机理。结果表明:强制通风下,当送风温度为273 K时,翅片管持续气化运行15 000 s,霜层厚度为10.8 mm,天然气出口温度为267.2 K;提高送风温度,有利于翅片管持续稳定运行;管内气相区长度随着送风温度的降低而降低,其占总管长的比例从303 K时的75%降低到了273 K时的35%;随着LNG入口流速的增大,管内流体传热系数提高且提前达到峰值,但达到0.8 m/s时管内出现传热恶化,导致液态天然气气化不完全,需选取合理的入口流速值。
The heat transfer characteristics of single finned tube determines the vaporization performance of the liquefied natural gas(LNG) ambient air vaporizer. The single cryogenic air-based finned tube was investigated. The air-side heat transfer model of the finned tube was established and the empirical formulas for frost physical parameters were introduced in order to explore the variation of frost resistances. The flow patterns of vapor-liquid phase zone in the tube were tracked by the VOF multiphase flow model, and the flow boiling heat transfer processes in the finned tube under frost or condensation conditions were simulated. Then the coupled heat transfer mechanism inside and outside the single cryogenic finned tube was studied using the fluid-structure coupled simulation. The results show that under forced convection condition, when the air supply temperature is 273 K, the finned tube continued to vaporize LNG for 15 000 s, the thickness of the frost layer is 10.8 mm and the natural gas outlet temperature is 267.2 K. The air supply temperature can be conducive to the continuous vaporization stability of the finned tube. The length of vapor-phase zone in the pipe decreases with the decrease of supply air temperature, and its proportion in the length of pipe decreases from 75% at 303 K to 35% at 273 K. The heat transfer coefficient of the fluid in the tube increases with the increase in the inlet flow rate of LNG, and the fluid in the tube will not be completely vaporized at the inlet flow rate of 0.8 m/s. Therefore, an appropriate inlet velocity of LNG should be considered to obtain a good vaporization performance of finned tube.
作者
时国华
蒋可
周文博
赵岳天
SHI Guo-hua;JIANG Ke;ZHOU Wen-bo;ZHAO Yue-tian(School of Energy Power and Mechanical Engineering;Hebei Key Laboratory of Low Carbon and High Efficiency Power Generation Technology,North China Electric Power University,Baoding 071003,Hebei Province,China)
出处
《化学工程》
CAS
CSCD
北大核心
2023年第2期35-40,共6页
Chemical Engineering(China)
基金
河北省重点研发计划项目(21374501D)
河北省自然科学基金面上项目(E2016502027)。
关键词
流固耦合
流型
结霜
LNG
传热恶化
fluid-structure coupling
flow pattern
frost formation
LNG
heat transfer deterioration
