Boiling and quenching heat transfer advancement by nanoscale surface modification (original) (raw)
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Advances in Boiling Heat Transfer Enhancement using Micro/Nano Structured Surfaces
European Journal of Engineering Research and Science
In this article we present an inclusive review of research carried out in the field of phase change heat transfer enhancement. First, we discuss about different kinds of conventional heat transfer enhancement techniques performed in convection heat transfer related heat exchangers. Next, we present the advantages of implementing phase change heat transfer and report a brief introduction to the physics behind the phase change (boiling) heat transfer phenomenon. We present a well explained data about different kinds of enhancement techniques using micro and nano scale structures on heat transfer surface/device to increase the limit of boiling heat transfer. The entire review article is broadly divided into two categories: first the investigation related to fluid flow or transport mechanism over the micro/nano structured surface which is of crucial importance, second is the actual computational and experimental methods to achieve higher heat transfer capability in terms of critical hea...
Enhancement of pool-boiling heat transfer using nanostructured surfaces on aluminum and copper
International Journal of Heat and Mass Transfer, 2010
Enhanced pool boiling critical heat fluxes (CHF) at reduced wall superheat on nanostructured substrates are reported. Nanostructured surfaces were realized using a low temperature process, microreactor-assisted-nanomaterial-deposition. Using this technique we deposited ZnO nanostructures on Al and Cu substrates. We observed pool boiling CHF of 82.5 W/cm 2 with water as fluid for ZnO on Al versus a CHF of 23.2 W/cm 2 on bare Al surface with a wall superheat reduction of 25-38 C. These CHF values on ZnO surfaces correspond to a heat transfer coefficient of ~ 23000 W/m 2 K. We discuss our data and compare the behavior with conventional boiling theory.
Nanoengineered materials for liquid–vapour phase-change heat transfer
Nature Reviews Materials, 2016
Liquid-vapour phase change is a useful and efficient process to transfer energy in nature, as well as in numerous domestic and industrial applications. Relatively recent advances in altering surface chemistry, and in the formation of micro-and nanoscale features on surfaces, have led to exciting improvements in liquid-vapour phase-change performance and better understanding of the underlying science. In this Review, we present an overview of the surface, thermal and material science to illustrate how new materials and designs can improve boiling and condensation. There are many parallels between boiling and condensation, such as nucleation of a phase and its departure from a surface; however, the particular set of challenges associated with each phenomenon results in different material designs used in different manners. We also discuss alternative techniques, such as introducing heterogeneous surface chemistry or direct real-time manipulation of the phase-change process, which can offer further control of heat-transfer processes. Finally, long-term robustness is essential to ensure reliability and feasibility but remains a key challenge.
Surface engineering for phase change heat transfer: A review
MRS Energy & Sustainability, 2014
Among numerous challenges to meet the rising global energy demand in a sustainable manner, improving phase change heat transfer has been at the forefront of engineering research for decades. The high heat transfer rates associated with phase change heat transfer are essential to energy and industry applications; but phase change is also inherently associated with poor thermodynamic efficiencies at low heat flux, and violent instabilities at high heat flux. Engineers have tried since the 1930's to fabricate solid surfaces that improve phase change heat transfer. The development of micro and nanotechnologies has made feasible the high-resolution control of surface texture and chemistry over length scales ranging from molecular levels to centimeters. This paper reviews the fabrication techniques available for metallic and siliconbased surfaces, considering sintered and polymeric coatings. The influence of such surfaces in multiphase processes of high practical interest, e.g. boiling, condensation, freezing, and the associated physical phenomena are reviewed. The case is made that while engineers are in principle able to manufacture surfaces with optimum nucleation or thermofluid transport characteristics, more theoretical and experimental efforts are needed to guide the design and cost-effective fabrication of surfaces that not only satisfy the existing technological needs, but also catalyze new discoveries.
Pool boiling heat transfer of N-pentane on micro/nanostructured surfaces
International Journal of Thermal Sciences, 2018
In the present study, one type of uniformly nanostructured surface (NPDS) was modified by electrophoretic deposition. Two kinds of micro/nanostructured surfaces (FLS1 and FLS2) were fabricated on copper surfaces by femtosecond laser processing. The micro/nanostructured surfaces were further modified by electrophoretic deposition. Afterwards, composite micro/nanostructured surfaces (CS1 and CS2) were developed. Saturated pool boiling heat transfer of the modified surfaces was investigated experimentally. An organic fluid, n-pentane was chosen as the working liquid. Heat transfer coefficient and critical heat flux (CHF) of smooth and micro/nanostructured surfaces were studied. The results showed that the heat transfer coefficient (HTC) of all structured surfaces increased obviously with a notable decrease of wall superheat at CHF compared to the smooth surface, which was attributed to increments in nucleation site density and heat transfer area. The CHF of femtosecond laser processed surfaces was also increased compared with the smooth surface due to a much higher liquid spreading ability, while a uniformly nanostructured surface has no augmentation in CHF. Composite micro/ nanostructured surfaces show the best heat transfer performance among all tested surfaces, and the critical heat flux and heat transfer coefficient were increased by more than 60% and 300% over the smooth surface, respectively. The liquid spreading ability of n-pentane on the tested surfaces was measured. For the well wetting liquid, the liquid spreading ability of the heated surface, instead of the wettability, is the main factor for CHF enhancement. It is suggested that a surface with multiscale structures can be an efficient way for boiling heat transfer enhancement.
Micro-Nano Scale Surface Coating for Nucleate Boiling Heat Transfer: A Critical Review
Energies
Nucleate boiling is a phase change heat transfer process with a wide range of applications i.e., steam power plants, thermal desalination, heat pipes, domestic heating and cooling, refrigeration and air-conditioning, electronic cooling, cooling of turbo-machinery, waste heat recovery and much more. Due to its quite broad range of applications, any improvement in this area leads to significant economic, environmental and energy efficiency outcomes. This paper presents a comprehensive review and critical analysis on the recent developments in the area of micro-nano scale coating technologies, materials, and their applications for modification of surface geometry and chemistry, which play an important role in the enhancement of nucleate boiling heat transfer. In many industrial applications boiling is a surface phenomenon, which depends upon its variables such as surface area, thermal conductivity, wettability, porosity, and roughness. Compared to subtractive methods, the surface coati...
Boiling Heat Transfer on the Micro-Textured Interfaces
Heat Transfer - Fundamentals, Enhancement and Applications
Higher heat flux than its normal criticality from high-power transistors, LIDAR (Laser Imaging Detection and Ranging), stacked CPUs, high-power transistors, and lasers must be efficiently transferred to cooling media through the metallic interface. The micro-/nano-textured aluminum and copper devices were highlighted among several approaches and fabricated to enhance the boiling heat transfer process to the subcooled water. The plasma printing was proposed to fabricate a pure aluminum device with concave micro-textures and to describe the boiling heat transfer behavior with comparison to the bare aluminum plate. A copper device was wet-plated to have convex micro-textures and to discuss the effect of micro-textures on the heat transfer characteristics under the forced water cooling by varying the Reynolds number. The boiling curve on the micro-textured interfaces was newly constructed by improving the boiling heat transfer process by micro-/nano-texturing.
Iranian Journal of Science and Technology, Transactions of Mechanical Engineering, 2019
The higher-thermal conductive Cu-Al 2 O 3 nanoparticles are deposited on the copper surface by using single-step electrodeposition technique. The developed Cu-Al 2 O 3 nanocomposite-coated surfaces attained excellent adhesiveness with copper substrate. Again, the surface morphology parameters like wettability, roughness, porosity, and porous layer thickness, as per the necessity in structured surfaces, can be easily managed by managing the electrodeposition parameters like potential difference, deposition time, current density, and electrolyte concentration. The surface morphology characterization is carried out with respect to the wettability, roughness, coating thickness, porosity, and average pore diameter. The flow boiling heat transfer experiments at different mass flow rates with deionized (DI) water are carried out in a minichannel of developed experimental setup. The Cu-Al 2 O 3 coating offers lower thermal resistance due to its higher thermal conductivity and lower coating thickness. Again, the percentage enhancement in critical heat flux (CHF) and boiling heat transfer coefficient (BHTC) of the Cu-Al 2 O 3-coated surfaces is decreased with the increase in mass flow rate, which is owing to the partial wetting of the pores at higher mass flow rate. The maximum augmentations in BHTC and CHF for the coated surfaces are achieved up to 84% and 86% as compared to the bare surface, respectively, which are due to the improvement in surface wettability and formation of huge number of cavities/pores on coated surfaces. Thus, the porous surface with minichannel is the potential candidate for the microelectronics cooling devices due to its compact size, lower heating surface temperature, higher CHF, and higher BHTC.
Journal of physics, 2019
The present paper is based on experimental studies on nucleate pool boiling heat transfer enhancement of different surfaces using water as a base fluid at atmospheric pressure. The test surfaces for the experiments include untreated, treated, and treated with Aluminumsilver oxide composite thin film surfaces having nano-layer thickness of 180 nm and 260 nm. The thin films are prepared on copper substrate by electron beam evaporation technique. The characterization of the heated surfaces is done by using optical surface profilometer for surface roughness and sessile drop method for contact angle measurement. The experiment is conducted in a closed boiling chamber and the heat flux is varied from 141.524-1244.101 kW/m 2 in time steps. The enhancement of heat transfer coefficient is found as 22.8%, 17.27% and 11.81% from the 260 nm, 180 nm composite nanostructured coated and treated surfaces respectively compared to plain surface. Enhancement in nanostructured coated surfaces is found higher due to the capillary effect, increased wettability and high active nucleate site density and the increased rate of bubble frequency.