This overview intends to provide a comprehensive assessment of the novel fluids and the current techniques for surface modification for pool boiling enhancement. The surface modification at macro-, micro-, and nanoscales is assessed concerning the underlying fluid routing and capability to eliminate the incipient boiling hysteresis and ameliorate the pool boiling heat-transfer ability, particularly when employed together with self-rewetting fluids and nanofluids with enriched thermophysical properties. Considering the nanofluids, it is viable to take the profit of their high thermal conductivity and their specific heat simultaneously and to produce a film of deposited nanoparticles onto the heating surface, which possesses enhanced surface roughness and an increased density of nucleation sites. Whilst the diverse improvement scales are found to achieve distinct levels of success regarding the nucleate boiling heat-transfer capability enhancement, it is also shown that the micro-nanoscale boiling surface features are susceptible to blockage, leading to the degradation of the improvement with time. Furthermore, topics relating to the heat transfer thermal behavior, ease of manufacture, cost-effectiveness, reliability, and durability are reviewed whenever available and challenges and recommendations for further research are highlighted.
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http://dx.doi.org/10.3390/mi15030302 | DOI Listing |
Adv Sci (Weinh)
December 2024
Institute of Thermal Science and Power Systems, School of Energy Engineering, Zhejiang University, Hangzhou, 310027, China.
High-performance boiling surfaces are in great demand for efficient cooling of high-heat-flux devices. Although various micro-/nano-structured surfaces have been engineered toward higher surface wettability and wickability for enhanced boiling, the design and fabrication of surface structures for realizing both high critical heat flux (CHF) and high heat transfer coefficient (HTC) remain a key challenge. Here, a novel "electrode-transpose" all-electrochemical strategy is proposed to create superhydrophilic microporous surfaces with higher dendrites and larger pores by simply adding an electrochemical etching step prior to the multiple electrochemical deposition steps.
View Article and Find Full Text PDFEnviron Sci Technol
December 2024
Institute of Thermal Science and Power Systems, School of Energy Engineering, Zhejiang University, Hangzhou 310027, China.
Materials (Basel)
October 2024
School of Physics and Astronomy, Sun Yat-sen University, Zhuhai 519082, China.
Deionized water is replacing fluorinated liquids as the preferred choice for two-phase immersion cooling in data centers. Yet, insufficient bubble removal capability at low saturated pressure is a key challenge hindering the widespread application. To solve this issue, this study employs non-ionic surfactant (Tween 20) and asymmetric structures (expanding microchannel) to enhance the boiling performances of deionized water under sub-atmospheric pressure.
View Article and Find Full Text PDFInterface Focus
August 2024
Clean Energy Processes (CEP) Laboratory and the Sargent Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
The Royal Society and UK Department for International Development supported a consortium of three universities across sub-Saharan Africa and Imperial College London with the aim of developing new knowledge on direct-steam-generation concentrated solar power (CSP) plants and supporting relevant capacity building across the Universities of Lagos, Mauritius and Pretoria. Key research findings from the programme include an improved flow-classification scheme for two-phase, liquid-liquid flows; testing of advanced surfaces with much-improved steady-state heat transfer performance-the commercial nanoFLUX surface showed up to 200% higher heat-transfer coefficients (HTCs) in pool boiling compared with other surfaces with R-134a/R-245fa; first-of-a-kind measurements of transient flow boiling HTCs, which were up to 30% lower in step perturbations than quasi-steady-state expectations in horizontal pipes with R-245fa; error estimation and corrections for laser-induced fluorescence (LIF) measurements, leading to the development of an adapted planar LIF technique with uncertainty <10% for local, instantaneous film thickness measurements in annular flows, and the application of such diagnostic methods to pool, falling-film and flow boiling in pipes; and predictions of an ~80% increase in the net present value of a case-study CSP plant when integrated with solid storage media.
View Article and Find Full Text PDFData Brief
August 2024
Department of Mechanical Engineering, University of Arkansas, Fayetteville, AR 72701, USA.
Boiling is a high-performance heat dissipation process that is central to electronics cooling and power generation. However, there exists a practical limit of boiling heat transfer known as the critical heat flux (CHF), beyond which significant performance degradation is observed. Understanding the physical mechanism that triggers CHF is essential to meet the increasing cooling demands driven by power densification and device miniaturization.
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