Heat transfer enhancement of turbulent duct flow by vortex generators attached to a large eddy break-up manipulator

1999 ◽  
Vol 28 (3) ◽  
pp. 189-200 ◽  
Author(s):  
Kyoji Inaoka ◽  
Hitoshi Uezu ◽  
Kenjiro Suzuki
Author(s):  
Juan Wen ◽  
Li Yang ◽  
Cheng Ying Qi

The flow structures and heat transfer characteristics of rectangle channel with the new type of vortex generators are obtained using large eddy simulation (LES) and by the application of the hydromechanics software FLUENT6.3. The bevel-cut half-elliptical column vortex generators, which is one model of the passive heat transfer enhancement, are laid on the three-dimensional rectangle channel. The instantaneous characteristic and the variational law of various parameters, such as the velocity, the temperature, the pressure and the vorticity magnitude, is analyzed to find out the temperature stripe structure that is similar with the velocity stripe in the temperature field. A turbulent boundary layer interacting with the disturbance of the vortex generators, is investigated using a “coherent structure” type of approach. The coherent structure and the streak structure of turbulent boundary layer flow are showed and the characteristic of vortex induced by vortex generator and its influence on turbulent coherent structure are analyzed. The control of the coherent structure induced by vortex generator plays more important role in heat transfer enhancement and drag reduction. And this fow configuration is of interest in terms of both heat transfer and skin friction control. The result of simulation indicates that the turbulence coherent structure directly affects the temperature gradient at the wall and the heat transfer enhancement mechanism of vortex generator is explained. Then we can seek suitable form of vortex generator and structure parameters, in order to achieve enhanced heat transfer and flow of drag reduction.


2002 ◽  
Vol 16 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Seong-Yeon Yoo ◽  
Dong-Seong Park ◽  
Min-Ho Chung ◽  
Sang-Yun Lee

Author(s):  
M. V. Pham ◽  
F. Plourde ◽  
S. K. Doan

Heat transfer enhancement is a subject of major concern in numerous fields of industry and research. Having received undivided attention over the years, it is still studied worldwide. Given the exponential growth of computing power, large-scale numerical simulations are growing steadily more realistic, and it is now possible to obtain accurate time-dependent solutions with far fewer preliminary assumptions about the problems. As a result, an increasingly wide range of physics is now open for exploration. More specifically, it is time to take full advantage of large eddy simulation technique so as to describe heat transfer in staggered parallel-plate flows. In fact, from simple theory through experimental results, it has been demonstrated that surface interruption enhances heat transfer. Staggered parallel-plate geometries are of great potential interest, and yet many numerical works dedicated to them have been tarnished by excessively simple assumptions. That is to say, numerical simulations have generally hypothesized lengthwise periodicity, even though flows are not periodic; moreover, the LES technique has not been employed with sufficient frequency. Actually, our primary objective is to analyze turbulent influence with regard to heat transfers in staggered parallel-plate fin geometries. In order to do so, we have developed a LES code, and numerical results are compared with regard to several grid mesh resolutions. We have focused mainly upon identification of turbulent structures and their role in heat transfer enhancement. Another key point involves the distinct roles of boundary restart and the vortex shedding mechanism on heat transfer and friction factor.


Sign in / Sign up

Export Citation Format

Share Document