Numerical Analysis on the Heat Transfer Characteristics of Supercritical Water in Vertically Upward Internally Ribbed Tubes
State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
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Author to whom correspondence should be addressed.
Academic Editor: Juan I. Córcoles-Tendero
Water 2021, 13(5), 621; https://doi.org/10.3390/w13050621
Received: 17 January 2021
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Revised: 17 February 2021
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Accepted: 22 February 2021
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Published: 27 February 2021
(This article belongs to the Special Issue Using Computational Fluid Dynamics Techniques Applied to Engineering Systems)
Internally ribbed tubes (IRTs) with better heat transfer capability have been widely applied in many fields. Several studies focused on the flow and heat transfer in IRTs with special structure configurations, but there is still lack of clear understanding regarding the influence of spiral ribs/grooves on the local flow structure and heat transfer capability of supercritical water. In the present paper, numerical simulation on turbulent heat transfer of supercritical water through a vertically upward IRTs is investigated. It is found at low heat fluxes, heat transfer enhancement occurs; the temperature of IRT is lower than that in the smooth tube by 6~7 °C, but at high heat fluxes; deteriorated heat transfer occurs in ST rather than in IRTs; the maximum temperature difference reaches 36 °C. The heat transfer ratio between IRT and ST is about 1.81 in the pseudocritical region, where the velocity deviation is about 20–50%. Once the deterioration heat transfer exists, a thin layer with high temperature but low density and low thermal conductivity so that (with a 20% reduction) fluids will be covered on the surfaces. Effects of rib height, width, lift angle and threads on turbulent heat transfer are analyzed, an optimum rib structure based on the performance evaluation criteria is obtained (α = 50°, e = 0.58 mm, S = 3.5 mm, m = 6), which can achieve the best performance.
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Keywords:
supercritical water; heat transfer enhancement; internally ribbed tube; heat transfer deterioration
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MDPI and ACS Style
Lei, X.; Guo, Z.; Peng, R.; Li, H. Numerical Analysis on the Heat Transfer Characteristics of Supercritical Water in Vertically Upward Internally Ribbed Tubes. Water 2021, 13, 621. https://doi.org/10.3390/w13050621
AMA Style
Lei X, Guo Z, Peng R, Li H. Numerical Analysis on the Heat Transfer Characteristics of Supercritical Water in Vertically Upward Internally Ribbed Tubes. Water. 2021; 13(5):621. https://doi.org/10.3390/w13050621
Chicago/Turabian StyleLei, Xianliang, Ziman Guo, Ruifeng Peng, and Huixiong Li. 2021. "Numerical Analysis on the Heat Transfer Characteristics of Supercritical Water in Vertically Upward Internally Ribbed Tubes" Water 13, no. 5: 621. https://doi.org/10.3390/w13050621
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