摘要
为探究水平螺旋管结构参数对超临界CO_2管内对流换热性能的影响,采用基于Fluent的数值模拟方法,研究了超临界CO_2在水平螺旋管内的对流换热特性以及重力对其影响,并针对水平螺旋管研究了节距及管径对换热系数的影响。模拟结果表明,水平螺旋管相对于水平直管具有更佳的换热性能,离心力和浮升力是造成换热系数增大的原因;重力对螺旋管中的对流换热影响不大,对直管中流体准临界点附近影响较为明显;随着管径的增加,浮升力和离心力引起的二次流减弱,换热系数逐渐减小;当节距较小时,节距的变化并不会对换热效果产生影响,当节距增大到一定程度时,随着节距的增加,离心力引起的湍流度降低,导致管内换热系数减小。
In order to explore the effect of structural parameters of horizontal spiral tube on the convective heat transfer performance of supercritical CO2 in the tube,the convective heat transfer performance of supercritical CO2 in horizontal spiral tube and influence of gravity on it were researched based on Fluent numerical simulation method. And the effect of pitch and tube diameter on heat transfer coefficient was also studied for horizontal spiral tubes. Simulation results show that,horizontal spiral tube has better heat transfer performance than horizontal straight pipe. Centrifugal force and buoyancy force are the causes for the increase of heat transfer coefficient;Gravity has little effect on convective heat transfer in a spiral tube,but has substantial influence on the vicinity of quasi-critical point of fluid in straight pipe;With the increase of the diameter of the tube,the secondary flow caused by the buoyancy force and centrifugal force becomes weak,the heat transfer coefficient decreases gradually,but when the pitch is relatively small,the change of pitch does not affect the heat transfer effect;When the pitch increases to a certain degree,with the increase of pitch,the turbulence intensity caused by centrifugal force decreases,resulting in decrease of heat transfer coefficient in the tube.
作者
崔海亭
刘思文
王少政
Cui Haiting;Liu Siwen;Wang Shaozheng(School of Mechanical Engineering,Hebei University of Science and Technology,Shijiazhuang 050018,China)
出处
《压力容器》
北大核心
2019年第2期22-29,共8页
Pressure Vessel Technology
基金
河北省自然科学基金项目(E2014208005)
河北省教育厅科学研究计划重点项目(ZH2018079)
关键词
超临界CO2
水平螺旋管
换热特性
数值模拟
supercritical CO2
horizontal spiral tube
heat transfer performance
numerical simulation
