NUMERICAL STUDY OF THE MECHANISM OF TURBULENT HEAT TRANSFER ENHANCEMENT IN TUBE UNDER SUPERCRITICAL PRESSURE
A numerical modeling of the characteristics and mechanism of turbulent heat transfer enhancement of water at low heat flux under supercritical pressure in a vertical smooth tube was performed in this work. The renormalization group (RNG) k-ε model was used to account for the turbulent flow and heat transfer at a constant heat flux with buoyancy force effect. A control volume finite element method (CVFEM) was used to solve numerically the two-dimensional full elliptic governing equations for the problem. A near-wall modeling approach enhanced wall treatment was adopted. The effects of large variations of fluid properties including density, specific heat capacity, thermal conductivity and viscosity were considered. In order to verify the accuracy of the computed model, a preparatory simulation on the flow and heat transfer of water was conducted under the same experimental conditions as done by Yamagata et al. (1972), and the numerical results were compared with the Yamagata’s experimental data. We obtained the radial profiles of velocity, temperature, properties and turbulent parameters. Based on theory of heat transfer in turbulent boundary layer, the influence on heat transfer enhancement of every parameter variation between far and near the pseudo-critical point was compared and analyzed. According to the distribution of thermal conductivity, turbulent conductivity and total conductivity in the boundary layer, the mechanism of heat transfer enhancement could be explained turbulent heat transfer ability increased in the buffer layer and turbulent core due to the specific heat capacity extremely increased.
M. Guo L.J. Guo Y.F. Mao X.F. Peng
State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an,Shaanxi, 710049, CHINA
国际会议
首届亚洲计算传热与计算流体国际会议(2007 Asian Symposium on Computational Heat Transfer and Fluid Flow)
西安
英文
2007-10-08（万方平台首次上网日期，不代表论文的发表时间）