Flow field and heat transfer properties in turbulent convection with local heating condition at the bottom wall 底面局部加热条件下热湍流的流场变化及传热规律

Hu，Jin1,2,3; Zhang，Shengqi4; Xia，Zhenhua1,2,3

2022-04-01

10.7638/kqdlxxb-2022.0008

空气动力学学报   影响因子和分区

0258-1825

In Rayleigh-Bénard convection (RBC), the flow is confined in an enclosed box heated from below and cooled from above. However, in many natural and engineering problems, the flow is not always heated on the whole bottom wall. In this paper, turbulent convection with local heating at the bottom wall in a two-dimensional square box is studied through direct numerical simulations. Here, the local heating is realized by setting a constant temperature at a local wall region of the bottom wall, and leaving the rest of the bottom wall to be adiabatic. The non-dimensional length of local heating region l = 0.5 is fixed. Three cases with X = 0, 0.125 and 0.25, where X is the non-dimensional location of the far-left point of the local heating region, as well as the RBC case are simulated at Rayleigh number Ra = 1×10 and Prandtl number Pr = 2. The results show that the local heating conditions can restrain the growth of corner flow near the bottom wall, which leads to the suppression of large-scale circulation (LSC) reversal. Meanwhile, the closer the heating position is to the center of the wall, the greater the absolute values of angular momentum and the total kinetic energy, and the smaller the fluctuation amplitude of them. It is found that the total kinetic energy and the heat transfer efficiency of the three local heating cases reach 62.5%~72.5% and 68.1%~73.2%, respectively, of those of the RBC system, though the heating length is only half of the latter. In addition, the heat transfer efficiency can be maximized by properly adjusting the heating position, and it is increased by 7.4% for the case with X = 0.25 as compared with the X = 0 case. The temperature contours also show that the behavior of the raising hot plumes is quite different in the three cases.

Flow structure Heat transfer Local heating Total kinetic energy Turbulent convection

中文

通讯

2-s2.0-85129535818

Scopus

1.State Key Laboratory of Fluid Power and Mechatronic Systems,Zhejiang University,Hangzhou,310027,China
2.School of Aeronautics and Astronautics,Zhejiang University,Hangzhou,310027,China
3.Guangdong Provincial Key Laboratory of Turbulence Research and Applications,Southern University of Science and Technology,Shenzhen,518055,China
4.State Key Laboratory for Turbulence and Complex Systems,Peking University,Beijing,100871,China

Hu，Jin,Zhang，Shengqi,Xia，Zhenhua. Flow field and heat transfer properties in turbulent convection with local heating condition at the bottom wall 底面局部加热条件下热湍流的流场变化及传热规律[J]. 空气动力学学报,2022,40(2):208-214.

Hu，Jin,Zhang，Shengqi,&Xia，Zhenhua.(2022).Flow field and heat transfer properties in turbulent convection with local heating condition at the bottom wall 底面局部加热条件下热湍流的流场变化及传热规律.空气动力学学报,40(2),208-214.

Hu，Jin,et al."Flow field and heat transfer properties in turbulent convection with local heating condition at the bottom wall 底面局部加热条件下热湍流的流场变化及传热规律".空气动力学学报 40.2(2022):208-214.