The study of refrigerant-based nanofluid boiling and two-phase flow phenomena is still in its infancy. This field of research provides many opportunities to study new frontiers but also poses great challenges. To summ...
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The study of refrigerant-based nanofluid boiling and two-phase flow phenomena is still in its infancy. This field of research provides many opportunities to study new frontiers but also poses great challenges. To summarize the current status of research in this newly developing interdisciplinary field and to identify the future research needs as well, this paper presents a comprehensive review of nucleate pool boiling, flow boiling, condensation and two-phase flow of refrigerant-based nanofluids. The effects of nanolubricants on boiling and two phase flow phenomena are presented as well. Furthermore, studies of applications and challenges of refrigerant-based nanofluids are presented and future research needs are identified. For the limited studies done so far, there are some controversies from one study to another. Conclusions and contradictions on the available refrigerant-based studies of physical properties, boiling and two phase flow are presented. According to this review, it has been realized that the physical properties have significant effects on the refrigerant-based nanofluid boiling and two-phase flow characteristics but the lack of the accurate knowledge of these physical properties has greatly limited the study in this interdisciplinary field. Furthermore, the limited available experiments and quite contradictive results have limited the understanding of the fundamentals of boiling and two phase flow phenomena. flow regimes are very important in understanding the phenomena but less investigated so far. Apparently it is still a long way to go to achieve systematic fundamental knowledge and theory in the relevant subject. Therefore, effort should be made to contribute to the physical property database of nanofluids as a first priority. Secondly, systematic accurate experiments and flow regime observations on boiling and two-phase flow phenomena under a wide range of test conditions and nanofluid types should be emphasized to understand the fundamentals.
The synthesis and properties of metal chalcogenides have been extensively researched because of their useful and novel properties. Most of them have been synthesized by traditional high-temperature calcination methods...
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The synthesis and properties of metal chalcogenides have been extensively researched because of their useful and novel properties. Most of them have been synthesized by traditional high-temperature calcination methods. However, other preparation methods have also been investigated such as solvothermal synthesis method. Pruss et al synthesized layered Cu 2 WS 4 materials with square primitive lattices by using Cu(CH 3 CN) 4 BF 4 and [NH 4 ] 2 WS 4 with the solvothermal method in 1993. Later Crossland group reported the synthesis and characterization of this kind of copper tetrathiometallide materials. In this paper, a new synthesis method of Cu 2 MS 4 ( M = W or Mo) polycrystal was proposed. Cu 2 MS 4 ( M = W or Mo) materials were prepared under the different reaction conditions by hydrothermal synthesis method, the structure of which has been solved from powder X-ray diffraction data, and the scanning electron microscope photographs of which were taken using an JEOL JSM-6700. [NH 4 ] 2 WS 4 crystal and CuCl 2 were used as the raw materials to produce Cu 2 WS 4 crystal. The prepared Cu 2 WS 4 semiconductor crystallizes in space group I-42m with cell parameters a = b = 5.4454 (3) , c = 10.0671(7) . [NH 4 ] 2 MoS 4 crystal, CuCl and ammonia were used as the raw materials to prepare Cu 2 MoS 4 crystal. The Cu 2 MoS 4 material crystallizes in space group I-42m with cell parameters a = b = 5.4087(7) , c = 10.0428(2) . Cu 2 MS 4 ( M = W or Mo) polycrystal contains layers of edge-sharing MS 4 and CuS 4 tetrahedra separated by a van der Waals gap.
Experiments were conducted to study pool boiling heat transfer on ultra-light porous metal foam surfaces, with deionized water as working fluid. The metal foams have pore densities from 30 to 60ppi (pores per inch) an...
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Cryogen spray cooling (CSC) can be used in laser dermatology to prevent burning injury of skin during *** uses a short spurt of (40 ~100 ms) on the skin surface before laser irradiation, leading to quick reduction in ...
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Cryogen spray cooling (CSC) can be used in laser dermatology to prevent burning injury of skin during *** uses a short spurt of (40 ~100 ms) on the skin surface before laser irradiation, leading to quick reduction in the skin *** this work, a systematic experimental study was presented to investigate the spray behavior of R134a.
The synthesis and properties of metal chalcogenides have been extensively researched because of their useful and novel *** of them have been synthesized by traditional high-temperature calcination ***, other preparati...
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The synthesis and properties of metal chalcogenides have been extensively researched because of their useful and novel *** of them have been synthesized by traditional high-temperature calcination ***, other preparation methods have also been investigated such as solvothermal synthesis method.
For high-efficiently solving the power dissipation problem of electronic components on the spacecraft, experiments were performed using micro-pin-finned structure as heater surface in subcooled nucleate pool boiling o...
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For high-efficiently solving the power dissipation problem of electronic components on the spacecraft, experiments were performed using micro-pin-finned structure as heater surface in subcooled nucleate pool boiling of FC-72 under microgravity condition utilizing the drop tower Beijing. Micro-pin-fins with the dimensions of 50 μm×120 μm (thickness × height) were fabricated on the surface of square silicon by using the dry etching technique. The micro-pin-finned silicon chip was heated by means of controlling heating voltage for the desired heat flux. At the same time, video of the bubble behavior was obtained by using high speed camera. The results showed that micro-pin-fins can increase the effective nucleate boiling sites number and the heat transfer performance efficiently, which stems from the sufficient supply of fresh liquid to the heater surface due to the capillary force independent of gravity. The steady nucleate pool boiling heat transfer on micro-pin-finned surface can be obtained at high heat fluxes and is greatly enhanced compared with smooth surface in microgravity.
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