Youzhou Jiao , Yu Zeng , Xinxin Liu , Gang Li , Chao He , Liang Liu , Pengfei Li , Junfeng Guo , Shijie Zhang
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引用次数: 0
Abstract
The heat transfer characteristics of supercritical CO2 heated in vertical smooth tube are experimentally and numerically investigated. The results show that the M-shaped velocity corresponds to heat transfer enhancement (HTE) at G = 100 kg/m2s, q = 20 kW/m2, and the heat transfer coefficient (HTC) is 15% higher than that of normal heat transfer (NHT). While, the M-shaped velocity causes significant heat transfer deterioration (HTD) before the Tpc at G = 278 kg/m2s, q = 35 kW/m2, and the HTC of HTD is 28%–42% of that in NHT. According to the numerical analysis on the M-shaped flow structure, it reveals that the zero-velocity gradient point of abNHT (HTE and HTD) always falls into the buffer layer (5 < y+ < 30). While, the zero-velocity gradient point of the heat transfer recovery (HTR) is in the log-law region (30 < y+ < 60). The u/u0 of the zero-velocity gradient point of HTE are larger than 1.35. The cross-section turbulent kinetic energy structure shows that smaller TKE in the near-wall region is the dominant factor for HTD and larger TKE in the core region is the dominant factor for HTE.
期刊介绍:
International Communications in Heat and Mass Transfer serves as a world forum for the rapid dissemination of new ideas, new measurement techniques, preliminary findings of ongoing investigations, discussions, and criticisms in the field of heat and mass transfer. Two types of manuscript will be considered for publication: communications (short reports of new work or discussions of work which has already been published) and summaries (abstracts of reports, theses or manuscripts which are too long for publication in full). Together with its companion publication, International Journal of Heat and Mass Transfer, with which it shares the same Board of Editors, this journal is read by research workers and engineers throughout the world.