Study of spacer effects on deteriorated heat transfer of supercritical fluid flow in an annulus. (May 2020)

• Record Type: Journal Article
• Authors: Xiao, Yao; Li, Junlong; Deng, Jian; Gao, Xinli; Gu, Hanyang; Pan, Jinsong
• Is Part Of: Progress in nuclear energy. Volume 123(2020)
• Publication Date: 2020-05
• Subjects: Deteriorated heat transfer -- Spacer -- Spacer induced heat transfer deterioration -- Boundary layer -- Turbulence kinetic energy; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 333.7924
• DOI: 10.1016/j.pnucene.2020.103306
• Languages: English
• ISSNs: 0149-1970

Abstract

Abstract: Spacer effects on deteriorated heat transfer (DHT) of supercritical R-134a flows in a vertical annular channel is numerically investigated. The results indicate that, under heat transfer deterioration condition, the spacer effects on heat transfer coefficient (HTC) are highly dependent on spacer end enthalpy. In particular, if a spacer disturbs the flow heat transfer in the HTC recovery region of a heat transfer deterioration, spacer induced heat transfer deterioration may occur in the spacer downstream. Based on the detail analysis of evolutions of axial velocity and turbulence kinetic energy (TKE) distributions, the results indicate that spacer induced oscillatory recovery of boundary layer in the spacer downstream causes the spacer induced heat transfer deterioration. In the HTC recovery region of heat transfer deterioration, the evolutions of velocity and TKE distributions in the spacer downstream is oscillatory. The oscillatory recovery process of the boundary layer and TKE in the near-wall region affects the heat transfer in the spacer downstream, which results in the oscillatory evolution of HTC and the spacer induced heat transfer deterioration.