天然气工业2023，Vol.43Issue(12)：100-109,10.DOI:10.3787/j.issn.1000-0976.2023.12.011
不同雷诺数下的蒸发甲烷液滴阻力特性
Resistance characteristics of methane droplets at different Reynolds numbers in the process of evaporation
摘要
Abstract
There is no resistance model for the moving droplets in the process of evaporation in the same kind of vapor during spray precooling of an LNG tank.To address this problem,this paper establishes a droplet evaporation simulation model based on the theoretical model of heat and mass transfer at the gas-liquid interface using the computational fluid dynamics(CFD)method.Then,the droplet evaporation process with temperature difference of 190 K and Reynolds number(Re)ranging from 13 to 4 500 is simulated.In addition,the calculation model of droplet resistance is established,and the resistance characteristics of droplets in the process of evaporation are studied from the aspects of pressure,vapor evaporating velocity and separation point.And the following research results are obtained.First,the pressure(p)increases with the increase of Re.When Re is the same,p decreases first and then increases with the increase of the inflow included angle(φ).After the pressure reaches the minimum value(pmin),the reverse pressure causes separation.The changing trend of vapor evaporating velocity(v2)on the droplet surface is basically consistent with that of p,so correspondingly,there is a minimum vapor evaporating velocity(v2min).Second,under different conditions,the corresponding inflow included angles(φs,φv2min and φpmin)all decrease with the increase of Re.Because of the separation effect and the influence of vapor evaporation on the droplet surface,the angle(φs-d)where the tangential velocity gradient on the surface of droplet is 0 is smaller than the angle(φs-d)where the tangential velocity gradient on the surface of cryogenic sphere is 0.That is to say,the greater the Re,the higher the separation point of the droplet.Third,both the pressure drag coefficient(Cd-d)of droplet and the pressure drag coefficient(Cd-b)of cryogenic sphere decrease first and then increase with the increase of φ,and the former is larger than the latter(Ca-d＞Cd-b)under the same working condition.The velocity gradient on the surface of droplet(Lv-d)is less than that on the surface of cryogenic sphere(Lv-b),so the total resistance coefficient on the surface of droplet(Cdt-d)is less than that on the surface of cryogenic sphere(Cdt-b).In conclusion,the proposed dimensionless resistance correlations,i.e.,Cdt-d=9.8Re-05i and Cdt-b=31.4Re-0.62 are of great value for studying the droplet movement characteristics during spray precooling and for ensuring the precooling safety.关键词
LNG/液滴蒸发/强制对流/阻力特性/传热传质/蒸发速度/压力/甲烷Key words
LNG/Droplet evaporation/Forced convection/Resistance characteristics/Heat and mass transfer/Evaporating velocity/Pressure/Methane引用本文复制引用
邓佳佳,庹中兰,束露露,夏海山,卢金树,薛大文,雷利,彭辉..不同雷诺数下的蒸发甲烷液滴阻力特性[J].天然气工业,2023,43(12):100-109,10.基金项目
浙江省基础公益研究计划项目"液货舱预冷过程同种过热蒸气中液滴蒸发机理及模型研究"(编号 （）
LY18E090009). （）
