重力对超临界甲烷绕管内冷凝换热影响  

Effect of gravity on condensation heat transfer of supercritical methane in winding tube

作　　者：赵敏 杨雨青 栾林林 韩方玲 吴学红 吕财 刘勇 ZHAO Min;YANG Yu-qing;LUAN Lin-lin;HAN Fang-ling;WU Xue-hong;LYU Cai;LIU Yong(School of Energy and Power Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,Henan Province,China)

机构地区：[1]郑州轻工业大学能源与动力工程学院,河南郑州450002

出　　处：《化学工程》2022年第5期25-29,共5页Chemical Engineering(China)

基　　金：国家自然科学基金资助项目(51476149);河南省高等学校重点科研项目(20A470016);郑州市协同创新专项(校重大重点项目培育)(2021ZDPY0107)。

摘　　要：超临界流体在绕管式换热器中发生气液相变时重力影响显著,为研究超临界甲烷在绕管内冷却至液态过程中重力对其换热的影响,采用数值模拟方法对比分析有无重力下管内超临界甲烷的温度场、速度场及换热系数变化特性。结果表明:与无重力相比,在有重力作用时,浮升力的影响大于离心力,速度、温度以及密度分布不再呈水平对称分布,密度最大值由绕管内部偏移到内底部,温度和速度最大值由绕管外部偏移到外顶部。温度高于准临界点(6.4 MPa、202 K)时,重力使换热能力增强,无重力时换热系数在准临界点附近201 K达到最大值1821.84 W/(m^(2)·K),有重力时换热系数在202 K达到最大值1924.24 W/(m^(2)·K),增大5.66%。The effect of gravity is significant when a supercritical fluid undergoes a gas-liquid phase-change in a winding tube heat exchanger.In order to investigate the effect of gravity on the heat transfer of supercritical methane during cooling to liquid state in a winding tube,numerical simulations were used to compare the temperature field,velocity field and heat transfer coefficient variation characteristics of supercritical methane in the tube with or without gravity.The results show that compared with no gravity,the effect of the buoyancy force is greater than the centrifugal force in the presence of gravity,the velocity,temperature and density distribution is no longer horizontally symmetrical,the density maximum is shifted from the inside of the winding tube to the inner bottom,and the temperature and velocity maximum is shifted from the outside of the winding tube to the outer top.When the temperature rises above the quasi-critical point(6.4 MPa,202 K),gravity strengthens the heat transfer capacity,with the heat transfer coefficient reaching a maximum value of 1821.84 W/(m^(2)·K)at 201 K near the quasi-critical point without gravity,and 1924.24 W/(m^(2)·K)at 202 K with gravity,increasing by 5.66%.

关 键 词：超临界甲烷 湍流模型 数值模拟 重力 湍流换热 

分 类 号：TK01[动力工程及工程热物理]