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Journal articles on the topic 'Matrix cooling'
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1
Yang, Haiwei, Xue Liu, Yuyang Bian, and Ge Wang. "Numerical Investigation on the Mechanism of Transpiration Cooling for Porous Struts Based on Local Thermal Non-Equilibrium Model." Energies 15, no. 6 (2022): 2091. http://dx.doi.org/10.3390/en15062091.
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Struts as an important structure in the combustion chamber of hypersonic flight vehicles to inject fuel into main flow face a severe thermal environment. Transpiration cooling is considered as a potential method to provide a thermal protection for struts. This paper presents a numerical investigation on transpiration cooling for a strut based on Darcy–Forchheimer model and the local thermal non-equilibrium model and analyzes the mechanism of transpiration cooling. A coolant film and a velocity boundary layer are formed on the strut surface and the shock wave is pushed away from the strut, which can effectively reduce the heat load exerted on the strut. The temperature difference between coolant and solid matrix inside the porous strut is analyzed, a phenomenon is found that the fluid temperature is higher than solid temperature at the leading edge inside the porous strut. As flowing in the porous medium, the coolant absorbs heat from solid matrix, and the fluid temperature is higher than solid temperature at the stagnation point of the strut. The influence of coolant mass flow rate and various coolants on transpiration cooling is studied. As mass flow rate increases, the cooling efficiency becomes higher and the temperature difference between fluid and solid in the porous medium is smaller. The coolant with a lower density and a higher specific heat will form a thicker film on the strut surface and absorbs more heat from solid matrix, which brings a better cooling effect for strut.
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Sokolovs, Alvis, and Ilya Galkin. "Matrix Converter Bi-directional Switch Power Loss and Cooling Condition Estimation for Integrated Drives." Scientific Journal of Riga Technical University. Power and Electrical Engineering 27, no. 1 (2010): 138–41. http://dx.doi.org/10.2478/v10144-010-0036-9.
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Matrix Converter Bi-directional Switch Power Loss and Cooling Condition Estimation for Integrated DrivesIn this paper power loss estimation of bi-directional switch of matrix converter is done by means of calculation and experiments. For safe operation of power devices an efficient cooling system of specific device must be designed. This work is part of a greater project of integrated matrix converter AC drives and the cooling problem here is viewed in context of this task. It is necessary to develop a compact power board and cooling system to extract excessive heat from power devices.
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Barnes, Stuart, and Ian R. Pashby. "Through-Tool Coolant Drilling of Aluminum/SiC Metal Matrix Composite1." Journal of Engineering Materials and Technology 122, no. 4 (2000): 384–88. http://dx.doi.org/10.1115/1.1288925.
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Through-tool coolant was applied to the drilling of an aluminum/SiC MMC. Titanium nitride coated, solid carbide drills were used to investigate the effect of the coolant application method on the performance of the drilling operation. Holes were produced dry, with conventional coolant and with through-the tool coolant. The results provided strong evidence that the conventional application of coolant was having no beneficial effect on the cutting operation compared to dry drilling. However, through-tool cooling gave a significant improvement in performance in terms of tool wear, cutting forces, surface finish and the height of the burrs produced. [S0094-4289(00)02104-6]
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Yu, Zhi Chen, Zhen Li Mi, Qing Wu Cai, Jin Guo, and Na Gong. "Effect of Final Rapid Cooling Temperature on Ultra-Fine Carbides of Ti-Mo Ferrite Matrix Microalloyed Steel." Materials Science Forum 926 (July 2018): 3–10. http://dx.doi.org/10.4028/www.scientific.net/msf.926.3.
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The size and distribution of nanoscale precipitate particles in Ti-Mo ferrite matrix microalloyed steel under three different final rapid cooling temperatures were studied by scanning electron microscopy(SEM), transmission electron microscope(TEM) and microhardness test. The results show that the interphase precipitation could be weakened by the excessive final rapid cooling temperature. A higher supersaturated solid solubility and high-density dislocation in ferrite matrix can be obtained under a relatively lower final rapid cooling temperature, which makes it easier to precipitate in ferrite. The related thermodynamic analysis indicated that the precipitation behavior was influenced by the final rapid cooling temperature during austenite/ferrite region. It is not conducive to get a large amount of small size precipitates in Ti-Mo ferrite matrix microalloyed steel when the final rapid cooling temperature is too high or low.
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Omrani, E., Ali Shokuhfar, A. Etaati, A. Dorri M., and A. Saatian. "The Effects of Homogenization Time and Cooling Environment on Microstructure and Transformation Temperatures of Ni-42.5wt%Ti-7.5wt%Cu Alloy." Defect and Diffusion Forum 297-301 (April 2010): 344–50. http://dx.doi.org/10.4028/www.scientific.net/ddf.297-301.344.
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The present paper deals with different effects of homogenization time and cooling environment on Ni-42.5wt%Ti-7.5wt%Cu alloy. The alloy was prepared by vacuum arc melting. Afterwards, three homogenization times (half, one and two hour) and three cooling environments (water, air and furnace) at 1373 K were selected. Optical and Scanning Electron Microscopic methods, EDX, DSC and hardness tests have been used to evaluate the microstructure, transformation temperatures and hardness. Results indicate that specimens that were cooled in air are super-saturated. Also, the microstructure from furnace cooling has many disparities with the other cooling environments’ microstructure and two types of precipitates exhibit in the matrix, but in other cooling environments, only one phase can be seen. Particles of the Ti2(Ni,Cu) phase are distributed in the matrix in all of the microstructures irrespective of cooling rate. Observations show that increasing the time of homogenization results in finer precipitates and uniform distribution in the matrix. In addition, alteration of cooling rate and time of homogenization affect the martensitic transformation temperatures. On the other hand, the hardness varies slightly for different homogenization times but declines extremely with decreasing cooling rate. Moreover homogenization time and the cooling environment affect the transformation temperatures on furnace cooled samples.
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Song, Wenjun, Min Lei, Mingpan Wan, and Chaowen Huang. "Continuous Cooling Transformation Behaviour and Bainite Transformation Kinetics of 23CrNi3Mo Carburised Steel." Metals 11, no. 1 (2020): 48. http://dx.doi.org/10.3390/met11010048.
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In this study, the phase transformation behaviour of the carburised layer and the matrix of 23CrNi3Mo steel was comparatively investigated by constructing continuous cooling transformation (CCT) diagram, determining the volume fraction of retained austenite (RA) and plotting dilatometric curves. The results indicated that Austenite formation start temperature (Ac1) and Austenite formation finish temperature (Ac3) of the carburised layer decreased compared to the matrix, and the critical cooling rate (0.05 °C/s) of martensite transformation is significantly lower than that (0.8 °C/s) of the matrix. The main products of phase transformation in both the carburised layer and the matrix were martensite and bainite microstructures. Moreover, an increase in carbon content resulted in the formation of lamellar martensite in the carburised layer, whereas the martensite in the matrix was still lath. Furthermore, the volume fraction of RA in the carburised layer was higher than that in the matrix. Moreover, the bainite transformation kinetics of the 23CrNi3Mo steel matrix during the continuous cooling process indicated that the mian mechanism of bainite transformation of the 23CrNi3Mo steel matrix is two-dimensional growth and one-dimensional growth.
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Diao, Xiao Gang, Zhi Liang Ning, Fu Yang Cao, Shan Zhi Ren, and Jian Fei Sun. "Microstructure Evolution of Heavy Section Ductile Iron." Advanced Materials Research 97-101 (March 2010): 1020–23. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.1020.
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Ductile iron, Heavy section, Cooling curve, Microstructure, Cooling rate. Abstract. Two 250×250×250 mm cubic ductile iron castings solidified in sand and insulation mould were fabricated. The effect of cooling rate on graphite and matrix microstructure of heavy section ductile iron together with their cooling curves were evaluated. Results show that increasing the cooling rate leads to fine graphitization and favors spheroidal graphite formation. The matrix structure is fully ferrite structure at the edge of both castings, while pearlite can be seen near the eutectic cell boundaries at the center of two castings. Furthermore, the amount of pearlite increases with increasing solidification time. Cooling curves confirm that cooling rate affects solidification time of the eutectic transformation and characteristic temperature points on the cooling curves remain unchanged. Low cooling rate appears to significantly increase the eutectic plateau length. Besides, cooling curves show that eutectic temperature remains constant (about 1160°C), which allows for spheroidal graphite formation. Undercooling and inoculation fading during the long time eutectic solidification lead to pearlite formation in the center of cubic ductile iron castings.
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Wu, Xingwei, Niudong Li, and Feng Li. "Heat Transfer and Pressure Loss Simulations of Matrix Cooling Channels for Gas Turbine Airfoils." Journal of Physics: Conference Series 2185, no. 1 (2022): 012003. http://dx.doi.org/10.1088/1742-6596/2185/1/012003.
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Abstract The paper selected 10 geometrical parameter combinations to numerically investigate the dependencies of heat transfer enhancement, flow resistances and overall thermal performance on three geometrical factors including rib inclination angle, channel blockage ratio and subchannel number. The investigated Reynolds number starts at 5,000 and can be as high as 90,000. The turbulence model selected was Transition SST model. The results show that the matrix cooling channels of 30deg rib angle have greater heat transfer enhancement and much higher pressure loss than that of 60deg rib angle. Moreover, matrix cooling channels of higher channel blockage ratio have greater heat transfer enhancement and higher flow friction, while the relationship between the overall thermal performance and the channel blockage ratio depends on the Reynolds number. It was also concluded that the heat transfer performance factor of matrix cooling channel does not change linearly with the subchannel number and the effect of subchannel number on heat transfer performance is less significant than the other two factors. Besides, matrix cooling channels of higher subchannel number have higher pressure loss and poorer overall thermal performance.
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Nirmalan, N. V., and L. D. Hylton. "An Experimental Study of Turbine Vane Heat Transfer With Leading Edge and Downstream Film Cooling." Journal of Turbomachinery 112, no. 3 (1990): 477–87. http://dx.doi.org/10.1115/1.2927683.
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This paper presents the effects of downstream film cooling, with and without leading edge showerhead film cooling, on turbine vane external heat transfer. Steady-state experimental measurements were made in a three-vane, linear, two-dimensional cascade. The principal independent parameters—Mach number, Reynolds number, turbulence, wall-to-gas temperature ratio, coolant-to-gas temperature ratio, and coolant-to-gas pressure ratio—were maintained over ranges consistent with actual engine conditions. The test matrix was structured to provide an assessment of the independent influence of parameters of interest, namely, exit Mach number, exit Reynolds number, coolant-to-gas temperature ratio, and coolant-to-gas pressure ratio. The vane external heat transfer data obtained in this program indicate that considerable cooling benefits can be achieved by utilizing downstream film cooling. The downstream film cooling process was shown to be a complex interaction of two competing mechanisms. The thermal dilution effect, associated with the injection of relatively cold fluid, results in a decrease in the heat transfer to the airfoil. Conversely, the turbulence augmentation, produced by the injection process, results in increased heat transfer to the airfoil. The data presented in this paper illustrate the interaction of these variables and should provide the airfoil designer and computational analyst with the information required to improve heat transfer design capabilities for film-cooled turbine airfoils.
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Zhou, Chuwei, Wei Yang, and Daining Fang. "Damage of Short-Fiber-Reinforced Metal Matrix Composites Considering Cooling and Thermal Cycling." Journal of Engineering Materials and Technology 122, no. 2 (1999): 203–8. http://dx.doi.org/10.1115/1.482788.
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Mechanical properties and damage evolution of short-fiber-reinforced metal matrix composites (MMC) are studied under a micromechanics model accounting for the history of cooling and thermal cycling. A cohesive interface is formulated in conjunction with the Gurson-Tvergaard matrix damage model. Attention is focused on the residual stresses and damages by the thermal mismatch. Substantial stress drop in the uniaxial tensile response is found for a computational cell that experienced a cooling process. The stress drop is caused by debonding along the fiber ends. Subsequent thermal cycling lowers the debonding stress and the debonding strain. Micromechanics analysis reveals three failure modes. When the thermal histories are ignored, the cell fails by matrix damage outside the fiber ends. With the incorporation of cooling, the cell fails by fiber end debonding and the subsequent transverse matrix damage. When thermal cycling is also included, the cell fails by jagged debonding around the fiber tops followed by necking instability of matrix ligaments. [S0094-4289(00)01202-0]
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Lo¨f, George O. G., Gerald Cler, and Thomas Brisbane. "Performance of a Solar Desiccant Cooling System." Journal of Solar Energy Engineering 110, no. 3 (1988): 165–71. http://dx.doi.org/10.1115/1.3268252.
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A solar desiccant cooling system was operated at the Solar Energy Applications Laboratory, Colorado State University, throughout the 1986 summer. The system comprises an American Solar King fresh air heating/desiccant evaporative cooling unit, a Sunmaster evacuated tube solar collector, hot water solar storage tank, auxiliary electric boiler, controls, and accessories. The cooling unit is operated in the ventilation mode, fresh air being dried in a rotating desiccant matrix, and cooled by heat exchange and evaporative cooling. Return air is used as a cooling medium in a rotating heat exchange matrix, heated by solar energy in a heat exchange coil, and discarded through the rotating desiccant bed. The solar-driven system provided over 90 percent of the seasonal cooling requirements in an experimental, residence type building at average COP levels of 1.0 and solar collection efficiencies of 50 percent when supplied with solar heated water at temperatures of 50 to 65° C. Detailed operating results, including total and average solar cooling provided, coefficients of performance, and overall solar cooling performance ratios are presented.
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Keshav, M., Shanmukha Nagaraj, and Sangamesh Gudda. "Investigation of matrix fin based effluent cooling system." Journal of Physics: Conference Series 1473 (February 2020): 012053. http://dx.doi.org/10.1088/1742-6596/1473/1/012053.
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Rosado, Mário T. S., António J. Lopes Jesus, Igor D. Reva, Rui Fausto, and José S. Redinha. "Conformational Cooling Dynamics in Matrix-Isolated 1,3-Butanediol†." Journal of Physical Chemistry A 113, no. 26 (2009): 7499–507. http://dx.doi.org/10.1021/jp900771g.
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JATTAKUL, Prajak, Tavee MADSA, Piyawan SUNASUAN, and Niwat MOOKAM. "Influence of cooling conditions on microstructure and mechanical property of Sn-0.3Ag-0.7Cu lead-free solder." Journal of Metals, Materials and Minerals 31, no. 2 (2021): 129–36. http://dx.doi.org/10.55713/jmmm.v31i2.1085.
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This research has investigated the influence of cooling conditions on the microstructure and mechanical properties i.e., tensile strength and microhardness of Sn-0.3Ag-0.7Cu lead-free solder. In the experiments, casting was performed at 300℃ with comparison between copper and stainless steel molds under slow and fast cooled conditions. X-ray diffractometer confirmed the presence of Cu6Sn5 and Ag3Sn phases in the solder matrix. Lead-free solder solidified under slow cooled conditions exhibited -Sn matrix with larger grain growth as compared to the fast cooled solder. The eutectic area of intermetallic compound (IMC) was found to increase with cooling rate. The tensile strength of slow cooled solder was greater than fast cooled solder for both molds. In addition, the microhardness of the solder was also influenced by cooling rate. The dimples size of facture surface was decreased by higher cooling rate. A greater eutectic area of the Cu6Sn5 and Ag3Sn phases of initial -Sn matrix lead to lower values of the mechanical property from fast cooled conditions.
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Tang, L. Q., K. Pochiraju, C. Chassapis, and S. Manoochehri. "A Computer-Aided Optimization Approach for the Design of Injection Mold Cooling Systems." Journal of Mechanical Design 120, no. 2 (1998): 165–74. http://dx.doi.org/10.1115/1.2826955.
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A methodology is presented for the design of optimal cooling systems for injection mold tooling which models the mold cooling as a nonlinear constrained optimization problem. The design constraints and objective function are evaluated using Finite Element Analysis (FEA). The objective function for the constrained optimization problem is stated as minimization of both a function related to part average temperature and temperature gradients throughout the polymeric part. The goal of this minimization problem is to achieve reduction of undesired defects as sink marks, differential shrinkage, thermal residual stress built-up, and part warpage primarily due to non-uniform temperature distribution in the part. The cooling channel size, locations, and coolant flow rate are chosen as the design variables. The constrained optimal design problem is solved using Powell’s conjugate direction method using penalty function. The cooling cycle time and temperature gradients are evaluated using transient heat conduction simulation. A matrix-free algorithm of the Galerkin Finite Element Method (FEM) with the Jacobi Conjugate Gradient (JCG) scheme is utilized to perform the cooling simulation. The optimal design methodology is illustrated using a case study.
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Martyushev, Nikita. "Copper Alloys Structure Parameters." Advanced Materials Research 1040 (September 2014): 225–29. http://dx.doi.org/10.4028/www.scientific.net/amr.1040.225.
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In this research it was examined the influence of crystallisation conditions binary leaded bronze on parametres of a received microstructure. Change of crystallisation conditions was carried out by change of cooling melt speed, through preliminary heating of casting moulds. Quantitative regularities of influence of cooling rate of explored bronze on parametres dendritic cells, grain size are presented. The data about formation of lead inclusions between dendrites of a copper matrix are published as well. It is shown that high rates of cooling of an order 100-150°С/c lead to dendritic structures formation containing only axes of the first and second order. Decrease of cooling rate at the moment of crystallisation to the values less 15°C/c leads to appearance and growth of axes of 3rd order at dendrites matrix.
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Wang, Haiping, Dong Liu, Jianguo Wang та ін. "Study on the Evolution of the γ′ Phase and Grain Boundaries in Nickel-Based Superalloy during Interrupted Continuous Cooling". Crystals 11, № 12 (2021): 1464. http://dx.doi.org/10.3390/cryst11121464.
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The formation of the irregular γ′ precipitates in the nickel-based superalloy Waspaloy was investigated during the continuous cooling, which is relevant to the cooling rates and interrupted temperature. The morphology of the γ′ precipitates was observed to change from a dispersed sphere to the flower-like one with the decreasing of the cooling rates. It was found that there are three modes of transportation of the solute atoms involved in relation to the γ′ precipitates: dissolution from the small γ′ precipitates to the γ matrix, diffusion to the large γ′ precipitates from the matrix, and the short distance among γ′ precipitates close to each other. Meanwhile, the slower cooling rates tend to result in the serrated grain boundaries, and the wavelength between successive peaks (λ) and the maximum amplitude (A) are larger with the decreasing of the cooling rates. The content of the low ΣCSL boundaries increases with the decreasing of the cooling rates, which is of great benefit in improving the creep property of the Waspaloy.
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Sadik, M. Ibrahim, and Gustav Grenmyr. "Application of Different Cooling Strategies in Drilling of Metal Matrix Composite (MMC)." Materials Science Forum 836-837 (January 2016): 3–12. http://dx.doi.org/10.4028/www.scientific.net/msf.836-837.3.
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Conventional cutting fluids are known for being expensive, polluting and a non-sustainable part of modern manufacturing processes. Global industrial trends are leaning towards environmental and health friendly technologies. CO2 cooling is an innovative and sustainable method, capable of replacing conventional oil-based cutting fluids under various conditions. The current study intends to cover the indexable insert drilling of aluminium-silicon carbide (Al-SiC) metal matrix composite (MMC) using different diamond coated carbide inserts. Al-SiC composite containing 20% wt. of SiC was used as workpiece material under different cooling strategies. Response Surface Methodology (RSM) and SEM analysis were incorporated to evaluate the tool performance and to understand the wear development in drilling of MMC. Performance tests were carried out at various cutting data and cooling strategies (external CO2, external emulsion, internal CO2 and internal emulsion) in order to study the output in terms of tool life, surface finish and diameter difference of the holes. The results revealed an advantage in the favour of CO2 cooling concerning tool life, precision and surface finish. Drilling with internal supply of CO2 significantly improves the tool life. The internal supply of CO2 generated the best precision and surface finish compared to the other cooling strategies. The test results clearly indicate that the tool failure for internal CO2 is governed by the flaking of the diamond coating in contrast to a combination of flank wear and flaking for emulsion. The results from the external cooling strategy show that there is no significant difference between emulsion and CO2 while the internal cooling strategy shows that CO2 provides the best results. Since the shape and the surface of the hole are generated by the cutting edge of the periphery insert, the wear development on the periphery insert is the main factor which governs the tool life, surface finish and the diameter difference. This can be explained by the internal CO2 strategy that protects the periphery insert.
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Hu, Y., Y. Liu, and A. Du. "The effect of a cooling field on exchange bias in a nanoparticle system." Proceedings of the Institution of Mechanical Engineers, Part N: Journal of Nanoengineering and Nanosystems 222, no. 1 (2008): 17–22. http://dx.doi.org/10.1243/17403499jnn131.
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Interest in exchange bias in magnetic nanoparticles has increased in the past few years by virtue of its potential for applications in fields such as ultrahigh-density magnetic recording. A modified Monte Carlo Metropolis method is employed to simulate the effect of cooling field on exchange bias and coercivity of a granular system of ferromagnetic nanoparticles embedded in an antiferromagnetic matrix, based on the classical three-dimensional Heisenberg model. The results show that the exchange bias is constantly negative, and that its absolute value decreases to a metastable value initially, while the coercivity increases monotonically with increase in the cooling field, and they both level off as the cooling field gains sufficient strength. The phenomena can be attributed to the energy barriers arising from the high antiferromagnetic anisotropy and the frustrated core—matrix structure. However, the interfacial coupling may change the configuration of the antiferromagnetic matrix to influence the exchange bias.
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Wang, Xiao-Yan, Zhi-Xun Wen, Hao Cheng, Shu-Ning Gu, and Guang-Xian Lu. "Influences of the Heating and Cooling Rates on the Dissolution and Precipitation Behavior of a Nickel-Based Single-Crystal Superalloy." Metals 9, no. 3 (2019): 360. http://dx.doi.org/10.3390/met9030360.
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The effects of the heating rate before solution treatment, and the cooling rate after solution treatment on the morphological distribution and evolution of the precipitation phase of nickel-based single crystal superalloy were studied. The dissolution, precipitation, and growth of the precipitation phase and the matrix phase during heat treatment were analyzed by the means of high-power scanning electron microscopy. The results show that the morphology of the precipitated phase has nothing to do with the distribution of the precipitated phase and the heating rate in the heating process, but the cooling rate in the cooling process affects the shape, size, and distribution of the precipitated phase. The faster the cooling rate, the smaller the precipitated phase is, the more irregular the shape is, the smaller the equivalent edge length is, and the smaller the channel width of the matrix phase is.
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Liu, Xiaogang, Meng Zhang, Zhongyi Wang, Juhui Chen, Haiou Sun, and Haifeng Sun. "Numerical Analysis of Fluid Flow and Heat Transfer in Micro-Channel Heat Sinks with Double-Layered Complex Structure." Micromachines 11, no. 2 (2020): 146. http://dx.doi.org/10.3390/mi11020146.
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Micro-channel heat sink (MCHS) has been extensively used in various electronic cooling fields. Double-layered MCHS, or DL-MCHS, is regarded as one effective technique for high-heat-flux transfer and is expected to meet the ever-increasing heat load requirement of future electronic device generations. In order to improve the cooling capacity, two new types of the MCHS, with a double-layered matrix structure (DL-M) and double-layered interlinked matrix structure (DL-IM) are proposed and investigated numerically. The two designs are compared with the traditional double-layered rectangular structure (DL-R) and the double-layered triangular structure (DL-T). Different properties of the heat sink are investigated to assess the overall heat transfer performance, for which coolant flow and heat transfer are both evaluated. The numerical results reveal that the periodical slot subchannel in the matrix has a significant effect on fluid flow for heat transfer. In comparison to the DL-R and the DL-T, the DL-M and DL-IM realize a much lower pressure drop and temperature rise at the base surface and also have higher Nusselt number and secondary flow intensity, therefore, manifesting better overall thermal performance. In the DL-M and DL-IM, the coolant flows along the periodical subchannel in one layer and is redirected into the second layer with vortices being induced. The vortices promote the coolant mixing and enhance the mass and heat transfer. These geometric design strategies can provide references for wide heat sink applications.
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Nirmalan, N. V., J. A. Weaver, and L. D. Hylton. "An Experimental Study of Turbine Vane Heat Transfer With Water–Air Cooling." Journal of Turbomachinery 120, no. 1 (1998): 50–60. http://dx.doi.org/10.1115/1.2841387.
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This paper presents data showing the improvement in cooling effectiveness of turbine vanes through the application of water–air cooling technology in an industrial/utility engine application. The technique utilizes a finely dispersed water-in-air mixture that impinges on the internal surfaces of turbine airfoils to produce very high cooling rates. An airfoil was designed to contain a standard impingement tube, which distributes the water–air mixture over the inner surface of the airfoil. The water flash vaporizes off the airfoil inner wall. The resulting mixture of air–steam–water droplets is then routed through a pin fin array in the trailing edge region of the airfoil where additional water is vaporized. The mixture then exits the airfoil into the gas path through trailing edge slots. Experimental measurements were made in a three-vane, linear, two-dimensional cascade. The principal independent parameters—Mach number, Reynolds number, wall-to-gas temperature ratio, and coolant-to-gas mass flow ratio—were maintained over ranges consistent with typical engine conditions. Five impingement tubes were utilized to study geometry scaling, impingement tube-to-airfoil wall gap spacing, impingement tube hole diameter, and impingement tube hole patterns. The test matrix was structured to provide an assessment of the independent influence of parameters of interest, namely, exit Mach number, exit Reynolds number, gas-to-coolant temperature ratio, water-and air-coolant-to-gas mass flow ratios, and impingement tube geometry. Heat transfer effectiveness data obtained in this program demonstrated that overall cooling levels typical for air-cooled Vanes could be achieved with the water–air cooling technique with reductions of cooling air flow of significantly more than 50 percent.
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Mohamad Nor, Ahmad Azhari, Mohd Sabri Minhat, Norsuzila Ya’acob, and Murizah Kassim. "Linear regression and R-squared correlation analysis on major nuclear online plant cooling system." International Journal of Electrical and Computer Engineering (IJECE) 13, no. 4 (2023): 3998. http://dx.doi.org/10.11591/ijece.v13i4.pp3998-4008.
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The primary cooling system is an integral part of a nuclear reactor that maintains reactor operational safety. It is essential to investigate the effects of the cooling system parameter before implementing predictive maintenance techniques in the reactor monitoring system. This paper presents a linear regression and R-squared correlation analysis of the nuclear plant cooling system parameter in the TRIGA PUSPATI Reactor in Malaysia. This research examines the primary cooling system's temperature, conductivity, and flow rate in maintaining the nuclear reactor. Data collection on the primary coolant system has been analyzed, and correlation analysis has been derived using linear regression and R-squared analysis. The result displays the correlation matrix for all sensors in the primary cooling system. The R-squared value for TT5 versus TT2 is 89%, TT5 versus TT3 is 94%, and TT5 against TT4 is 66% which shows an excellent correlation to the linear regression. However, the conductivity sensor CT1 does not correlate with other sensors in the system. The flow rate sensor FT1 positively correlates with the temperature sensor but does not correlate with the conductivity sensor. This finding can help to better develop the predictive maintenance strategy for the reactor monitoring program.
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Ahmad, Azhari Mohamad Nor, Sabri Minhat Mohd, Ya'acob Norsuzila, and Kassim Murizah. "Linear regression and R-squared correlation analysis on major nuclear online plant cooling system." International Journal of Electrical and Computer Engineering (IJECE) 13, no. 4 (2023): 3998–4008. https://doi.org/10.11591/ijece.v13i4.pp3998-4008.
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The primary cooling system is an integral part of a nuclear reactor that maintains reactor operational safety. It is essential to investigate the effects of the cooling system parameter before implementing predictive maintenance techniques in the reactor monitoring system. This paper presents a linear regression and R-squared correlation analysis of the nuclear plant cooling system parameter in the TRIGA PUSPATI Reactor in Malaysia. This research examines the primary cooling system's temperature, conductivity, and flow rate in maintaining the nuclear reactor. Data collection on the primary coolant system has been analyzed, and correlation analysis has been derived using linear regression and R-squared analysis. The result displays the correlation matrix for all sensors in the primary cooling system. The R-squared value for TT5 versus TT2 is 89%, TT5 versus TT3 is 94%, and TT5 against TT4 is 66% which shows an excellent correlation to the linear regression. However, the conductivity sensor CT1 does not correlate with other sensors in the system. The flow rate sensor FT1 positively correlates with the temperature sensor but does not correlate with the conductivity sensor. This finding can help to better develop the predictive maintenance strategy for the reactor monitoring program.
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Sivaperuman Kalairaj, Manivannan, Hritwick Banerjee, Chwee Ming Lim, Po-Yen Chen, and Hongliang Ren. "Hydrogel-matrix encapsulated Nitinol actuation with self-cooling mechanism." RSC Advances 9, no. 59 (2019): 34244–55. http://dx.doi.org/10.1039/c9ra05360c.
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Wong, Choo Siew, A. Pramanik, and A. K. Basak. "Residual stress generation in metal matrix composites after cooling." Materials Science and Technology 34, no. 11 (2018): 1388–400. http://dx.doi.org/10.1080/02670836.2018.1458460.
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Sankar, M. Ravi, Janakarajan Ramkumar, and S. Aravindan. "Machining of Metal Matrix Composites with Minimum Quantity Cutting Fluid and Flood Cooling." Advanced Materials Research 299-300 (July 2011): 1052–55. http://dx.doi.org/10.4028/www.scientific.net/amr.299-300.1052.
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In the present work, minimum quantity cutting fluid (MQCF) technology was developed and applied for enhancing the machining performance by maintaining eco-friendly conditions. Machining experiments were carried on Al alloy/SiC metal matrix composite using cemented carbide tool with both MQCF and flood cooling. MQCF was effective in bringing down the forces, surface roughness, flank wear by ~17 %, ~5 %, ~12.5 % respectively compared to flood cooling. In MQCF, the consumption of cutting fluid is extremely low (10ml/min) compared to flood cooling (~ 400-600 ml/min). So, emission produced in MQCF are very less, which is eco-friendly.
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Xu, Jing, Guang Chen, Xiangjun Bao, Xin He, and Qingyue Duan. "A Study on the Heat Transfer Characteristics of Steel Plate in the Matrix Laminar Cooling Process." Materials 14, no. 19 (2021): 5680. http://dx.doi.org/10.3390/ma14195680.
Full textAbstract:
Accurate prediction and control of the steel plate temperature in the laminar cooling process are very challenging. In this research, an experimental platform was built to measure the heat transfer characteristics of the steel plate in the process of matrix laminar spray cooling when the steel plate is one millimeter away from the upper surface. The “buried couple method” was used, including the cooling temperature and cooling rate. Then, the temperature and the integrated heat transfer coefficient at the steel plate surface were calculated by the time-sequential function method (TSFM). The obtained results show that the fast cooling stage under the water cooling condition occurred in the first 1.5 s, and the measuring point temperature decreased by 8%. The “re-reddening” phenomenon of the steel plate appeared with time, and the measuring point temperature increased by 37%. Second, the maximum calculated difference between the surface temperature and the measuring point temperature was 0.75 °C, and the integrated heat transfer coefficient conformed to the periodic boundary features. The comprehensive convective heat transfer coefficient on the surface was in agreement with the periodic boundary characteristics, and its value exhibited oscillatory attenuation with the cooling process, and the oscillatory peak period was about 6 seconds. Two methods, sequential function method (SFM) and finite difference method (FDM), were used to verify the correctness of TSFM.
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Park, J. S., J. H. Yun, Young Do Park, Yong Ho Park, Kyung Mok Cho, and Ik Min Park. "Effect of Cooling Rate on Mechanical and Electrical Properties of Cu-TiB2 by Turbulent In-Situ Mixing Process." Solid State Phenomena 119 (January 2007): 135–38. http://dx.doi.org/10.4028/www.scientific.net/ssp.119.135.
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A copper matrix composite reinforced with in situ TiB2 nanoparticle was successfully fabricated by tubulent in-situ mixing process. The microstructure, mechanical and electrical properties of the in situ composite were investigated. The results showed that the in situ formed TiB2 particles, in which size varying from about 50nm to 200nm, exhibited a homogenous dispersion in the copper matrix. It is shown that the interface between the nanoscale particles and the matrix was clean without a transitional layer. Because of the reinforcement, the hardness and Young’s Modulus of the composite improved with increment of cooling rate. Moreover, the in situ Cu-TiB2 composite exhibited higher electrical conductivity with increasing of cooling rate.
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Choi, Nak Sam, Sung Choong Woo, Tae Won Kim, and Kyong Y. Rhee. "Monitoring of Failure Mechanisms in Fiber Reinforced Composites During Cryogenic Cooling by Acoustic Emission." International Journal of Modern Physics B 17, no. 08n09 (2003): 1763–69. http://dx.doi.org/10.1142/s0217979203019630.
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Microfractures in composite laminates during cryogenic cooling were monitored employing thermo-acoustic emission(AE). During the initial stage of cryogenic cooling, very strong AE signals with low and high frequency bands were dominantly detected showing a development of large cracks accompanying fiber breakages. After that, weak emissions with low frequency bands became prevalent indicating the propagation of microfractures in the matrix and/or fiber-matrix interface. It was concluded that the breakage of bridged-fibers hindering the macroscopic cracking in the initial stage might be the representative cryogenic damage of composite laminates.
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Balokhonov, Ruslan, Aleksandr Zemlianov, Diana Gatiyatullina, and Varvara Romanova. "Computational Analysis of the Influence of Residual Stress on the Strength of Composites with Different Aluminum Matrices and Carbide Particles." Metals 13, no. 4 (2023): 724. http://dx.doi.org/10.3390/met13040724.
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A numerical study of the mechanical behavior of aluminum matrix–carbide particle composites subjected to combined thermomechanical loading is carried out. The composite structure, corresponding to that observed experimentally, is explicitly taken into account in the calculations. The mechanical response of the aluminum matrix and carbide particles is described using the isotropic elastic–plastic and elastic–brittle models. A fracture criterion of the maximum equivalent stress acting in the local regions of volumetric tension is used to study the crack initiation and propagation in the particles. The dynamic plane stress boundary value problems of cooling and tension of the composites are solved by the finite element method ABAQUS/Explicit. The influence of the cooling-induced residual stress and thermomechanical properties of the matrix and particle materials on the strength of the composites is investigated. A positive or negative effect of the residual stress is found to depend on the ratio between the particle strength and the matrix yield stress. Compressive residual stress formed in the particle after the cooling increases the strength of composites with hard matrices and low-strength particles. A decrease in the matrix–particle interfacial curvature results in a change in the fracture mechanism from in-particle cracking to debonding, which increases the composite strength. Composite elongation upon the fracture onset decreases with the volume fraction of the particles.
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Kublinskiy, Maxim, Nikita Smolnikov, and Artem Naymushin. "Supervised machine learning with regression for the IRT-T reactor cooling system." ITM Web of Conferences 59 (2024): 03007. http://dx.doi.org/10.1051/itmconf/20245903007.
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The purpose of this study is to create a machine learning model for the IRT-T reactor cooling system, which can estimate and predict the temperature difference in the secondary circuit. To do this, data was downloaded from the SCADA system, then an application was developed for converting and preprocessing this data. Then regression and classification models were constructed that evaluated the efficiency of the cooling system and its ability to predict changes in the temperature drop on heat exchangers. The main technical characteristics of the IRT-T reactor include a thermal power of 6 MW, the use of UO2 nuclear fuel in an aluminum matrix with an enrichment of 90.1%, a coolant in the form of desalinated water, tubular square-section fuel rods with external cooling, the fuel element shell material is SAV-1 alloy, and the use of five 5 IRT-1000 type heat exchangers with a total area of heat exchange of 1000 m2.
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Libing, Lin, Zhang Bo, Li Jiquan, and Zhang Naru. "The Heat Transfer Characteristics in Stepped Hole of Traditional Metal Materials Induced by Stepped Film Holes." Revista de Chimie 71, no. 4 (2020): 488–99. http://dx.doi.org/10.37358/rc.20.4.8091.
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With the increase of temperature requirement, the application of metal matrix materials is gradually reduced due to its poor temperature resistance. In order to improve the application of traditional metal based materials, new cooling technology must be developed to meet the application of metal based materials. In this paper, the cooling flow field of cylindrical hole and two kinds of stepped film holes based on metal materials is simulated by large eddy method(LES), the development of vortex structure and flow characteristics in the mixing area of coolant flow and mainstream are analyzed and studied. The distribution is strongly effected by stronger thermal convection compared with the new temperature resistant material. The results show that four kinds of vortices form downstream the film hole, namely, horseshoes vortex, shear layer vortex, hairpin vortex and the counter rotate vortex pair (CVP). The CVRP formed on the stepped plane which strongly influences the flow and heat transfer of downstream, which is more evident in metal based materials, especially resulted by its isotropic features. Compared with the cylindrical film hole, the structure of step plane efficiently decreases the coolant flow velocity which results in a decrease of the CVP intensity so that the cooling film is adherent to the wall. The thermal conductivity of metal base material is strong, which has a great influence on the temperature distribution inside the wall. Velocity pulsation tightly influenced by CVP, in where the CVP intensity is strong, velocity pulsation is also strong so that the coolant flow strongly mixes with the mainstream. The flow velocity and velocity pulsation decrease with the increasing of the area ratio of stepped hole. The influence of geometric parameters on the heat transfer performance is mainly due to the high heat transfer performance of the metal matrix material.
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Ahlers, Sandra, Benjamin Bittner, and Petra Maier. "Influence of Cooling Conditions on Long-Period Stacking-Ordered Phase Evolution and Corrosion Behavior of As-Cast Resoloy®." Metals 11, no. 9 (2021): 1372. http://dx.doi.org/10.3390/met11091372.
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This study focuses on the influence of cooling conditions on the long-period stacking-ordered (LPSO) phase evolution and corrosion behavior of as-cast Resoloy®, a bioresorbable Mg-Dy-based alloy. Metallographic and corrosive tests are used to monitor the changes in the properties of this material. The corrosion behavior is investigated by potentiodynamic polarisation. Permanent mold chill casted ingots are wire-eroded to cylindrical platelets. The eroded platelets are solution heat treated over three different time periods. Cooling is performed in two different ways: quenching in water and cooling in air at ambient temperature. The as-cast condition shows a homogeneous fine-grained microstructure. Grains become larger with increasing heat treatment duration and slow cooling leads to additional grain growth. Furthermore, cooling in air leads to faint lamellar LPSO structures, which develop from bulk LPSO structures during the cooling process. The corrosion rate of the cooled platelets increases with increasing grain size. When the lamellar LPSO structures are uniformly distributed over the entire grain, the corrosion starts at the matrix between the LPSO lamellae and stops at them. Heat treatment at 500 °C reduces the normal potential difference between matrix and secondary phase and thus weakens the galvanic corrosion.
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Zhu, A. L., Z. C. Tu, J. K. Mao, and C. W. Zhao. "Investigation of the film cooling performance of ceramic matrix composites plate with different braided structures." Journal of Physics: Conference Series 2707, no. 1 (2024): 012086. http://dx.doi.org/10.1088/1742-6596/2707/1/012086.
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Abstract The ceramic matrix composite (CMC) materials have been gradually applied in the high temperature components, due to its excellent heat resistance and mechanical performance. The CMC component still need cooling to protect its safe operation in the high temperature environment of aero engine, such as film cooling structure. This study focuses on the influence of braided structure on the film cooling effect over a three-dimensional braided CMC plate. The full-size calculation model reflecting the internal mesoscale structure of CMC plate was established. The thermal properties of fibers and matrix are also introduced in mesoscale. The geometric parameter which is braided angle of braided structure is changed in different models, to analyze its impacts on the comprehensive film cooling effect. The results show that the fiber bundles inside the CMC plate are the main heat transfer channel, due to its relatively higher thermal conductivity. The different braided angles affect the anisotropic thermal conductivity of CMC on the three main directions. There exists an optimal braided angle near 40° that maximizes the heat dissipation effect in the region near the film cooling holes. While in the downstream region away from holes, the influence of braided angle is weak.
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De Cicco, Michael, Lih Sheng Turng, Xiao Chun Li, and John H. Perepezko. "Semi-Solid Casting of Metal Matrix Nanocomposites." Solid State Phenomena 116-117 (October 2006): 478–83. http://dx.doi.org/10.4028/www.scientific.net/ssp.116-117.478.
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Semi-solid casting (SSC) techniques have proven useful in the mass production of high integrity castings for the automotive and other industries. Recent research has shown metal matrix nanocomposite (MMNC) materials to have greatly improved properties in comparison to their base metals. However, current methods of MMNC production are costly and time consuming. Thus development of a process that combines the integrity and cost effectiveness of semi-solid casting with the property improvement of MMNCs would have the potential to greatly improve cast part quality available to engineers in a wide variety of industries. This paper presents a method of combining SSC with MMNC in a way that benefits from MMNCs’ tendency to naturally form the globular microstructure necessary for SSC. This method uses ultrasonically dispersed nanoparticles as nucleating agents to achieve globular primary grains such that fluidity is maintained even at high solid fractions. Once particle dispersion is achieved, the material needs no further processing to become a semi-solid slurry of globular primary grains as it cools. This quiescent method of slurry production, while still imposing some constraints on cooling rates, has a large process window making this process capable of industrial rates of throughput. It was found that the key factor to achieving globular microstructure is a sufficiently slow cooling rate at the onset of solidification such that particle-induced nucleation can occur. Once nucleation occurs, continued cooling is virtually unconstrained, with globular microstructure evident in quenched samples as well as samples cooled at rates as slow as 1 °C/min. This method was demonstrated in several material systems using zinc (Zn), aluminum (Al), and magnesium (Mg) alloys and nanoparticles of aluminum oxide (Al2O3), silicon carbide (SiC), and titanium oxide (TiO2). Additionally, several nucleation models are examined for applicability to nanoscale composites.
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Zhao, Chenwei, Zecan Tu, and Junkui Mao. "Investigation of the Film-Cooling Performance of 2.5D Braided Ceramic Matrix Composite Plates with Preformed Hole." Aerospace 8, no. 4 (2021): 116. http://dx.doi.org/10.3390/aerospace8040116.
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The film-cooling performance of a 2.5D braided ceramic matrix composite (CMC) plate with preformed holes was numerically studied. Four numerical models containing braided structures were established: one model with film-cooling holes preformed through fiber extrusion deformation (EP-Hole), one model with film-cooling holes directly woven through fibers (WP-Hole), and two models with directly drilled holes (DP-Hole1,2). Besides, the influence of the ratio between the equivalent thermal conductivities on the axial and radial directions of fiber Kr was investigated. The results show that the preformed holes have better performance in controlling the thermal gradient with the increase of Kr. The maximum thermal gradient around the DP-Hole is significantly higher than that of the WP-Hole and EP-Hole, and the maximum relative variation reaches 123.3%. With Kr increasing from 3.32 to 13.05, the overall cooling effectiveness on the hot-side wall decreases for all models, by about 10%. Compared with the traditional drill method, the new preformed film-cooling hole studied in this paper can reduce the temperature and the thermal gradient in the region around the holes.
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Shen, Xiao, Shuiqing Liu, Xin Wang, et al. "Effect of Cooling Rate on the Microstructure Evolution and Mechanical Properties of Iron-Rich Al–Si Alloy." Materials 15, no. 2 (2022): 411. http://dx.doi.org/10.3390/ma15020411.
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The mechanical properties of iron-rich Al–Si alloy is limited by the existence of plenty of the iron-rich phase (β-Al5FeSi), whose unfavorable morphology not only splits the matrix but also causes both stress concentration and interface mismatch with the Al matrix. The effect of the cooling rate on the tensile properties of Fe-rich Al–Si alloy was studied by the melt spinning method at different rotating speeds. At the traditional casting cooling rate of ~10 K/s, the size of the needle-like β-Al5FeSi phase is about 80 μm. In contrast, the size of the β-Al5FeSi phase is reduced to 500 nm and the morphology changes to a granular morphology with the high cooling rate of ~104 K/s. With the increase of the cooling rate, the morphology of the β-Al5FeSi phase is optimized, meanwhile the tensile properties of Fe-rich Al–Si alloy are greatly improved. The improved tensile properties of the Fe-rich Al-Si alloy is attributed to the combination of Fe-rich reinforced particles and the granular silicon phase provided by the high cooling rate of the melt spinning method.
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Juuti, Timo J., Timo Manninen, and David Porter. "Influence of Cooling Rate on Free Interstitial Concentration in Type 430 Ferritic Stainless Steel." Key Engineering Materials 611-612 (May 2014): 111–16. http://dx.doi.org/10.4028/www.scientific.net/kem.611-612.111.
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In ferritic steels, the amount of free C and N should be as low as possible to avoid the formation of Cottrell atmospheres and their associated discontinuous yielding and Lüders bands during forming. During the post-annealing cooling of ferritic stainless steel, carbides and nitrides of the type MX and M23C6precipitate. The volume fraction of the precipitates is determined by chemical composition, microstructure and the cooling path. In some cases, precipitation might not be sufficient to remove all free interstitials from the matrix, in which case, the process parameters or composition of the steel should be reconsidered. Here, thermodynamic and kinetic calculations using Thermo-calc and TC Prisma software have been made to investigate the precipitation of C and N as a function of total interstitial content and cooling rate. According to the calculations, decreasing the cooling rate would result in a more efficient precipitation and hence, less free C and N in the matrix, but the amount is not sufficient to remove the upper yield point. Furthermore, changing the C and N content of the steel was found to have insignificant influence. However, the free C and N could possible be bound through a more complex cooling.
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Bloch, Jacques, Jonas Glesaaen, Jacobus Verbaarschot, and Savvas Zafeiropoulos. "Progress on Complex Langevin simulations of a finite density matrix model for QCD." EPJ Web of Conferences 175 (2018): 07034. http://dx.doi.org/10.1051/epjconf/201817507034.
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We study the Stephanov model, which is an RMT model for QCD at finite density, using the Complex Langevin algorithm. Naive implementation of the algorithm shows convergence towards the phase quenched or quenched theory rather than to intended theory with dynamical quarks. A detailed analysis of this issue and a potential resolution of the failure of this algorithm are discussed. We study the effect of gauge cooling on the Dirac eigenvalue distribution and time evolution of the norm for various cooling norms, which were specifically designed to remove the pathologies of the complex Langevin evolution. The cooling is further supplemented with a shifted representation for the random matrices. Unfortunately, none of these modifications generate a substantial improvement on the complex Langevin evolution and the final results still do not agree with the analytical predictions.
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Li, Baokuo, Sheng Huang, Huaixu Yan, Xiaobo Zhang, Kun Du, and Zhanxue Wang. "Modeling and Performance Analysis of Variable Cycle Engine with Ceramic Matrix Composite Turbine Blades." Aerospace 11, no. 11 (2024): 886. http://dx.doi.org/10.3390/aerospace11110886.
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To meet the requirements of future aircraft for power systems, the turbine inlet temperatures of aero engines are gradually increasing. Ceramic matrix composite (CMC), with its higher thermal limit, has become the preferred material for the turbine blades of variable cycle engines (VCEs). However, the impact of CMC turbine blades on the performance of a VCE is still unknown. In this research project, the comprehensive cooling-efficiency characteristics of CMC are determined through a fluid–solid coupling calculation; a cooling calculation model for turbine blades is established, and cooling airflow solution and control technology (CSCT) for an air system is developed. Additionally, a VCE simulation model is established to analyze the influence of CMC turbine blades on the cooling airflow of the air system and the overall performance of the engine. The results show that, for the design condition, the CMC turbine blade can reduce the cooling airflow of the air system by approximately 10%, and the net thrust is increased by 6.07–7.98%. For the off-design conditions, with the CSCT, the specific fuel consumption can be reduced by 3.06–5.73% while ensuring that the engine net thrust remains unchanged. A comprehensive analysis of the performance for both the design point and off-design points indicates that the use of CMC for high-pressure turbine (HPT) guide vanes and rotor blades yields significant performance benefits, while the performance improvement from the use of CMC for low-pressure turbine (LPT) rotor blades is minimal.
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Zheng, Liang, Yu Feng Liu, Michael J. Gorley, et al. "The DSC Investigation on Phase Transformations of Directionally Solidified (DS) and Powder Metallurgy (PM) Ni-Base Superalloys." Materials Science Forum 941 (December 2018): 1035–40. http://dx.doi.org/10.4028/www.scientific.net/msf.941.1035.
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The phase transformations of the directionally solidified (DS) and powder metallurgy (PM) Ni-base superalloys were investigated by JMatPro, synchrotron XRD (SXRD) and differential scanning calorimetry (DSC). The minor phases, such as MC, eutectic γ′ and Ni5Hf, and γ matrix with secondary γ′ existed in as-cast microstructure of DS DZ22. However, only γ matrix was found in PM625 alloy powders. The phase change in both heating (melting) and cooling (solidification) process was investigated by DSC on DZ22 test bar and PM625 alloy powders respectively. The DSC experiment with different heating/cooling rates (5-40°C/min) was performed on DS superalloy DZ22. The results indicated that the heating/cooling rate had obvious effect on the DSC results of the phase transformation temperatures of liquidus, MC carbides, solidus, eutectic (γ+γ′) and secondary γ′. The heating and cooling DSC curves shifted to high and low temperature direction respectively, accompanied by the heating/cooling rate increased. However, the average values of specific peaks of heating and cooling curves are relatively consistent which is close to the equilibrium phase change temperatures of the alloy and makes the results comparable. Besides the average value method, the liquidus temperature of the alloy (0°C/min) can also be obtained by method of linear-fit/extrapolating from 5-40°C/min heating/cooling rates or inflection point deviate from the baseline of DSC cooling curves which could minimize the heating/cooling rate effects. The DSC experiment was carried out on PM625 superalloy powders with different particle size range (0-355μm), the results indicated that the particle size had minor effect on liquidus and solidus temperatures of DSC heating curves, the differences were less than 2°C. The change in phase transformation temperatures under different heating/cooling rate should be considered for selecting the process parameter (heat treatment, HIP or casting) for manufacturing Ni-base superalloy components.
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Zhukov, V. P., M. D. Fomichev, E. V. Barochkin, E. A. Shuina, and S. I. Shuvalov. "Combined model of heat and mass transfer in cooling towers." Vestnik IGEU, no. 5 (October 31, 2023): 90–96. http://dx.doi.org/10.17588/2072-2672.2023.5.090-096.
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The priority directions of the scientific and technological policy of the Russian Federation include issues on research in the field of energy and resource saving technologies while generating heat and electric energy. One of the possible ways to implement it at thermal and nuclear power plants is to increase the efficiency of the operation of circulating cooling systems (COO). Modeling and optimization of circulating cooling systems with tower cooling towers is of particular relevance under modern conditions of a limited amount of low-mineralized water for charging circulating cooling systems. To determine the parameters of air flow in the tower cooling tower, a three-dimensional simulation model is developed. To describe heat and mass transfer, considering the phase transitions in coolants, a matrix model is used. The model is developed based on the mass and energy balance equations. A combined model of a circulating cooling system with cooling towers has been developed. It describes air flow within the framework of a three-dimensional simulation model and the process of heat and mass transfer, considering a possible phase transition in coolants within the framework of a matrix model. Comparison of modeling results and normative data is carried out. Adequate description of the real-life process using the combined model is presented. The developed combined model allows setting and solving problems of choosing the optimal design and operating parameters of the COO equipment, as well as solving problems of diagnosing the state of the COO according to the readings of standard instruments. In the future, the proposed calculation method will allow optimizing the operating modes of combined water supply systems, which combine water cooling in a direct-flow scheme and water cooling in a reverse scheme with cooling towers.
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Fang, Naiwen, Ruisheng Huang, Kai Xu та ін. "Phase Transformation, Microstructures, and Mechanical Properties of α + β Two-Phase Titanium Alloy Deposited Metal by Surfacing Welding". Advances in Materials Science and Engineering 2022 (15 квітня 2022): 1–8. http://dx.doi.org/10.1155/2022/6415091.
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The effect of cooling rate on phase transformation, microstructures, and mechanical properties of TC4 titanium alloy deposited metal by laser surfacing welding with filler wire was investigated by in situ observation with a high-temperature laser confocal microscope, XRD, SEM, and through microhardness test. The results showed that primary α phase began to appear at grain boundaries when the deposited metal was heated to 890.5°C, and microstructures were all composed of coarse β columnar grains after the temperature was raised to 1 190.2°C; with the increase of cooling rate during the cooling process, temperature for starting new phase transformation decreased from 943.7°C to 811.1°C, and temperature for ending the transformation increased gradually from 708.0°C to 736.2°C; when cooled to room temperature at a rate of 1°C/s, microstructures consisted of α phase; at a rate of 15°C/s, acicular α′ martensite appeared in the microstructures; at 100°C/s, the microstructures were completely comprised by acicular α′ martensite; when the cooling rate was low, V element would be slightly precipitated from αgb into the matrix; when cooling turned faster, V element had no time to enter the matrix by diffusion, so it became uniformly distributed; as the cooling rate getting faster, lamellar microstructures became thinner gradually, and microhardness of the deposited metal was improved in a gradual manner.
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Kuzay, Tuncer M. "Cryogenic cooling of x‐ray crystals using a porous matrix." Review of Scientific Instruments 63, no. 1 (1992): 468–72. http://dx.doi.org/10.1063/1.1142734.
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Ghasemi, Hamid, Pierre Kerfriden, Stéphane P. A. Bordas, Jacob Muthu, Goangseup Zi, and Timon Rabczuk. "Probabilistic multiconstraints optimization of cooling channels in ceramic matrix composites." Composites Part B: Engineering 81 (November 2015): 107–19. http://dx.doi.org/10.1016/j.compositesb.2015.06.023.
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Li, Xiaolin, Jiawei Yang, Yating Li, et al. "A Systematical Evaluation of the Crystallographic Orientation Relationship between MC Precipitates and Ferrite Matrix in HSLA Steels." Materials 15, no. 11 (2022): 3967. http://dx.doi.org/10.3390/ma15113967.
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Here we systematically investigate the crystallographic orientation relationship (OR) between MC-type precipitates (M, metal; C, carbon) and ferrite matrix in the Ti-Mo microalloyed steel with different processing. In the specimens without austenite deformation, the interphase precipitation can be obtained, and the precipitates obey Baker–Nutting (BN) OR with ferrite matrix. By contrast, in the specimens with austenite deformation, the supersaturated precipitates were formed in ferrite grains, which can obey BN, Nishiyama–Wasserman (NW), Kurdjumov–Sachs (KS) and Pitsch (P) ORs simultaneously. The cooling rate after austenite deformation can influence the OR between carbides and ferrite in the MC/ferrite system. At the cooling rate of 80 °C/s, carbides and ferrite can roughly satisfy these OR with the deviation ≥10°, while at the cooling rate of 20 °C/s, carbides and ferrite can strictly obey the specific OR. The energy accumulated in the deformation process and maintained in the fast-cooling process (80 °C/s) can offset the formation energy of the carbides. Thus, the carbides formed in the specimen with the cooling rate of 80 °C/s do not strictly satisfy the specific ORs to meet the rule of lowest energy, and then deviate by a small angle based on the specific ORs.
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Li, Xiaolin, Qian Li, Haozhe Li, Xiangyu Gao, Xiangtao Deng, and Zhaodong Wang. "The Effect of Cooling Rate on the Microstructure Evolution and Mechanical Properties of Ti-Microalloyed Steel Plates." Materials 15, no. 4 (2022): 1385. http://dx.doi.org/10.3390/ma15041385.
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Ti-bearing microalloyed steel plates with a thickness of 40 mm were subjected to ultra-fast cooling (UFC) and traditional accelerate cooling after hot-rolling, aiming to investigate the effect of cooling rate on the microstructure and mechanical properties homogeneity, and thus obtain thick plates with superior and homogeneous mechanical properties. Yield strength, tensile strength, and elongation were 642 MPa, 740 MPa, 19.2% and 592 MPa, 720 MPa and 16.7%, respectively, in the surface and mid-thickness of the steel with ultra-fast cooling, while in the steel with traditional accelerate cooling, 535 MPa, 645 MPa, 23.4% and 485 MPa, 608 MPa, 16.2% were obtained in the surface and mid-thickness of the plate. The yield strength has been greatly improved after UFC, for the refinement of grain and precipitates produced by UFC. In addition, the equivalent grain size and precipitates size in the thick plate with UFC are homogeneous in the thickness direction, leading to uniform mechanical properties. The crystallographic characteristics of different precipitates have been studied. The precipitates formed in the austenite deformation stage obey Kurdjumov–Sachs orientation relationship with the ferrite matrix, while the fine precipitates formed in the ferrite obey [112]MC//[110]α and (1¯1¯1)MC//(1¯12)α orientation relationship with the ferrite matrix.
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Svetov, Sergei A., Svetlana Y. Chazhengina, and Alexandra V. Stepanova. "Paleoproterozoic Variolitic Lavas from the Onega Basin, Fennoscandian Shield: Mineralogy, Geochemistry and Origin." Minerals 13, no. 10 (2023): 1320. http://dx.doi.org/10.3390/min13101320.
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The Yalguba Ridge volcanic rocks form part of the Middle Paleoproterozoic (ca. 1.97 Ga) volcano-sedimentary sequence within the Karelian Craton in the Fennoscandian Shield. Yalguba variolitic textures are known worldwide and have been previously considered to originate from liquid immiscibility. The present study reveals two new variolite types recognized in the Yalguba sequence: (1) Variolites with unzoned varioles have distinct chemical and mineralogical compositions of varioles and matrix that support an origin by liquid immiscibility. They were recognized in quenched zones of pillows, so it might be assumed that melt separation caused by liquid immiscibility occurred before magma emplacement. The difference from the previously described variolites lies in the variole microtexture and might be caused by the various cooling conditions. (2) Spherulitic variolites have varioles composed of andesine–oligoclase spherulites embedded in the cryptocrystalline matrix with oligoclase–anorthoclase composition, thus the variole and matrix have similar chemical and mineralogical composition. The mineralogical and textural features of these variolites suggest that the spherulites have a primary magmatic origin due to the rapid cooling of superheated magma. The variety of variolitic textures in the Yalguba section might be caused by the different H2O saturation of parental magma and cooling conditions.
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Zou, Jin, Jian Yun Zhang, De Ping Lu, and Qi Jie Zhai. "The Research on Thermal Residual Stress of SiCp/Al Composites." Advanced Materials Research 852 (January 2014): 127–31. http://dx.doi.org/10.4028/www.scientific.net/amr.852.127.
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SiCp/Al composites would produce a large thermal residual stresses field during cooling process. The thermal residual stress has a greater impact to the composites dimension stability and the accuracy of application. In this paper, the thermal residual stress in SiCp/A356 composites was measured by X-ray diffraction and simulated by finite element method (FEM), the influence of particle shapes and cooling rates are considered, the stress field contour nephogram and stress-time curve during cooling was simulated. The studies present residual stress formed during cooling process because of the difference of thermal expansion coefficient (CTE) between SiC particle and aluminum alloy, the maximum stress distributes near the interface of matrix/SiCp mainly. The stress-time curves are inconsistent under different cooling rates, the higher cooling rate, the more dramatic variety in stress.