摘要
对壁面阵列双端倒角长方状梯形凸起时矩形通道的传热和流动特性以及强化传热综合性能进行了数值研究.分析了雷诺数在6000~16000范围内通道的摩擦阻力因数、努塞尔数、综合传热因子的变化情况.结果表明:阵列双端倒角长方状梯形凸起组成的通道具有强化传热效果,且在雷诺数较低的情况下,强化传热效果更好.当肋攻角30°、倾斜角60°时,相对凸起间距0.741所对应的矩形通道的换热性能最好.倾斜角过大或过小都会对强化传热效果减弱,强化传热的同时阻力也随之增大;不同凸起间距对于流动与传热有着一定的影响,过大或过小的凸起间距都会降低传热性能;等泵功综合传热因子随着雷诺数的增大而减小,在倾斜角或凸起间距相同时,在雷诺数较低的情况下,壁面阵列长方状梯形凸起的矩形通道的综合性能更好;等泵功综合传热因子值介于1.6至1.9之间,不同倾斜角对综合传热能力差别不大;凸起间距过大或过小都会对综合传热能力减弱.
A numerical investigation is carried out on the heat transfer,flow characteristics of a rectangular duct with array of trapezoidal protrusions on the walls and comprehensive performance of enhanced heat transfer.The variation of friction coefficient,Nusselt number and comprehensive heat transfer performance factor in the range of Reynolds number from 6000 to 16000 are analyzed.The results show that the rectangular duct with array of trapezoidal protrusions in end rounded oblong shape on the top and bottom walls has the effect of heat transfer enhancement,especially the effect is better at low Reynolds number.When attack angle is 30°and inclination angle is 60°,the heat transfer performance of the rectangular duct corresponding to relative protrusion spacing of 0.741 is the best.If the inclination angle is too large or too small,the effect of enhanced heat transfer will be weakened,and the resistance will increase at the same time.Different protrusion spacing has a certain impact on flow and heat transfer.Too large or too small protrusion spacing will reduce the heat transfer performance.The comprehensive heat transfer factor of equal pump power decreases with the increase of Reynolds number.When inclination angle or protrusions spacing are the same,the comprehensive performance of the rectangular duct with trapezoidal protrusions on the walls is better at low Reynolds number.The comprehensive heat transfer factor of equal pump power is between 1.6 and 1.9,and different inclination angles have little effect on it,while too large or too small protrusion spacing will weaken it.
作者
何璟
王良璧
杨成
HE Jing;WANG Liang-Bi;YANG Cheng(School of Chemistry and Chemical Engineering,Lanzhou Jiaotong University,Lanzhou730070,China;Key Laboratory of thermal engineering of Ministry of Education,Lanzhou Jiaotong University,Lanzhou730070,China;School of Mechanical Engineering,Lanzhou Jiaotong University,Lanzhou730070,China)
出处
《兰州交通大学学报》
CAS
2022年第3期100-107,122,共9页
Journal of Lanzhou Jiaotong University
基金
甘肃省青年科技基金计划(1506RJYA080)
兰州交通大学青年基金(2015010)
兰州交通大学-天津大学创新基金(2018066)。
关键词
梯形凸起
矩形通道
肋攻角
倾斜角
凸起间距
综合传热因子
Trapezoidal protrusions
Rectangular duct
Attack angle
Inclination angle
Protrusion spacing
Comprehensive heat transfer performance factor
