Pre-CHF boiling heat transfer performance on tube bundles with or without enhanced surfaces - a review

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Detail(s)

Original languageEnglish
Article number107278
Journal / PublicationAnnals of Nuclear Energy
Volume139
Online published31 Dec 2019
Publication statusPublished - May 2020

Abstract

Boiling heat transfer over tube bundles has been extensively applied to various industries with a high demand for efficient heat transfer. This work presents a review of recently published studies on pre-CHF boiling heat transfer across plain and enhanced tube bundles. Bundle effect and heat transfer enhancement by modified heating surfaces under various operating and geometric parameters are analyzed. Flow regime maps for boiling two-phase flow in horizontal and vertical bundles are critically described separately. The local boiling heat transfer performance is affected by the non-uniform heat flux distribution in a bundle. A decreasing heat flux distribution along the bundle height can enhance the bundle effect. The effect of the pitch to diameter ratio on bundle effect also depends on the heat flux distribution. Significant influences of the bundle inclination angle and elevation angle on the boiling heat transfer were observed by researchers. Complex bundle effect was found in special shape bundles, such as V-shape, C-shape, and U-shape bundles, which suggests applying different HTC correlations to different regions in a bundle. Moreover, the bundle boiling behaviors under sub-atmospheric and sub-critical pressures have been examined. The heat transfer performance in tube bundles with enhanced surfaces is significantly impacted by the surface characteristics and the imposed heat flux. Bundle effect is still prominent, and the surface enhancement reduces along the bundle height. A mixed bundle with enhanced tubes only in the lower part can achieve the same heat transfer performance as a fully enhanced bundle.

Research Area(s)

  • Boiling, Bundle effect, Enhanced surfaces, Heat transfer enhancement, Two-phase flow