Journal articles: 'High cooling rate'

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Drlička, R., V. Kročko, and M. Matúš. "Machinability improvement using high-pressure cooling in turning." Research in Agricultural Engineering 60, Special Issue (December 30, 2014): S70—S76. http://dx.doi.org/10.17221/38/2013-rae.

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Process fluids are used primarily for their cooling and lubricating effect in machining. Many ways to improve their performance have been proposed; the analysis of some of them is provided in the paper. The effect of high pressure cooling has been investigated with regard to chip formation and tool life. Standard and for high pressure application particularly designed indexable cutting inserts were used with fluid pressure 1.5 and 7.5 MPa. The pressure effect on tool life at different feed rates was observed as well. Not each cooling pressure value or machined material showed favourable chip formation. Tool life though has improved significantly while machining with a lower feed rate. 

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Adamovsky, S. A., A. A. Minakov, and C. Schick. "Scanning microcalorimetry at high cooling rate." Thermochimica Acta 403, no. 1 (June 2003): 55–63. http://dx.doi.org/10.1016/s0040-6031(03)00182-5.

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Imamudeen, Bello, and Shiv Singh. "HIGH-SPEED QUECHING OF HIGH CARBONSTEEL." International Journal of Research -GRANTHAALAYAH 7, no. 12 (June 8, 2020): 25–31. http://dx.doi.org/10.29121/granthaalayah.v7.i12.2019.297.

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Medium and high carbon steels are usually quenched in polymer and oil in order to avoid cracking and distortion; however, recent studies have proved that it is possible to minimize cracking using water as a coolant of these steels by promoting extremely high cooling rates. By great agitation and velocity of quench ant, the vapour blanket is reduced or prevented during water quench, allowing uniform hardening of the surface. In this study, the cooling severity of a spray quenching system and a high-speed quenching chamber are studied. Cylindrical samples of AISI 304 stainless steel (20mm in diameter and 100mm length) were employed to characterize the cooling severity. Thermal data was acquired through K-type thermocouples placed in the sample at three positions, 1mm below surface, mid-radius and at centre of the specimen, connected to a data acquisition system. High thermal gradients were observed in both systems, being the high-speed chamber the severest cooling. The maximum cooling rate obtained at the surface was 470 and 300C/s for the high-speed chamber and the spray system, respectively. In addition, 5160 spring steel samples were quenched for short times in both systems; the cooling was interrupted to avoid through transformation and to produce a case-core type microstructure. Different cooling times were used for the interrupted quenching to modify the marten site case thickness. No cracks.

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Nakata, Naoki, Takashi Kuroki, Akio Fujibayashi, and Yoshio Utaka. "Cooling Performance of High Temperature Steel Plate in Intensive Cooling with High Water Flow Rate." Tetsu-to-Hagane 99, no. 11 (2013): 635–41. http://dx.doi.org/10.2355/tetsutohagane.99.635.

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Su, Fengmin, Hongbin Ma, Xu Han, Hsiu-hung Chen, and Bohan Tian. "Ultra-high cooling rate utilizing thin film evaporation." Applied Physics Letters 101, no. 11 (September 10, 2012): 113702. http://dx.doi.org/10.1063/1.4752253.

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Wang, Chen, Chunhua Wang, and Jingzhou Zhang. "Parametric Studies of Laminated Cooling Configurations: Overall Cooling Effectiveness." International Journal of Aerospace Engineering 2021 (February 10, 2021): 1–15. http://dx.doi.org/10.1155/2021/6656804.

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Combing the advantages of film cooling, impingement cooling, and enhanced cooling by pin fins, laminated cooling is attracting more and more attention. This study investigates the effects of geometric and thermodynamic parameters on overall cooling effectiveness of laminated configuration, and model experiments were carried out to validate the numerical results. It is found that the increases in film cooling hole diameter and pin fin diameter both result in the increase in cooling effectiveness, but the increases in impingement hole diameter, impingement height, and spanwise hole pitch degrade the cooling performance. The increase of the coolant flow rate causes the increase in cooling efficiency, but this effect becomes weaker at a high coolant flow rate. The coolant-to-mainstream density ratio has no obvious effect on cooling effectiveness but affects wall temperature obviously. Moreover, based on the numerical results, an empirical correlation is developed to predict the overall cooling efficiency in a specific range, and a genetic algorithm is applied to determine the empirical parameters. Compared with the numerical results, the mean prediction error (relative value) of the correlation can reach 8.3%.

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Lu, Hai Na, Xiu Hua Gao, Zheng Yi Jiang, Dong Bin Wei, and Xiang Hua Liu. "Development of High Strength Hull Plate by Normal Hot Rolling and High Rate Cooling Process." Advanced Materials Research 148-149 (October 2010): 253–58. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.253.

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This paper investigates the effects of normal hot rolling and high rate cooling (NHR+HRC) on microstructure and mechanical properties of the rolled EH 36 hull plate. Double-hit tests were carried out to study the effect of process parameters such as the deformation temperature and soaking time on microstructures of the tested steel, and explore optimal processing parameters. Single-hit compression with various parameters was developed and the microstructures of the tested steel are analyzed to determine the cooling rate and the final cooling temperature of the normal hot rolling and high rate cooling. This study will provide experimental and theoretical base on high-temperature rolling control system. Industrial trial was performed to produce regular products. The results show that the NHR+HRC is an effective and promising method to improve the product quality of high-strength hull plate.

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De Santis, Felice, Sergey Adamovsky, Giuseppe Titomanlio, and Christoph Schick. "Scanning Nanocalorimetry at High Cooling Rate of Isotactic Polypropylene." Macromolecules 39, no. 7 (April 2006): 2562–67. http://dx.doi.org/10.1021/ma052525n.

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Bardelcik, Alexander, Christopher P. Salisbury, Sooky Winkler, Mary A. Wells, and Michael J. Worswick. "Effect of cooling rate on the high strain rate properties of boron steel." International Journal of Impact Engineering 37, no. 6 (June 2010): 694–702. http://dx.doi.org/10.1016/j.ijimpeng.2009.05.009.

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Zhang, Zhi Min, Wei Yu, and Qing Wu Cai. "Control Basis for Cooling Rate of Plates during Roller Quenching in High-Pressure Zone." Advanced Materials Research 538-541 (June 2012): 2090–94. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.2090.

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A basis based on temperature field is developed to control the cooling rate of plates during roller quenching in high-pressure zone. In order to determine the optimal cooling rate of plate during roller quenching, temperature field of SPV490 plate during quenching was calculated. Then a formula for calculating cooling rate of the center for plate at a certain cooling intensity during roller quenching in high-pressure zone was put forward and the control basis for cooling rate of plate during roller quenching in high-pressure zone was suggested. The cooling rates and corresponding heat transfer coefficients of SPV490 plates with different thickness during roller quenching in high-pressure zone were determined with the given basis.

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Gällström, Andreas, Björn Magnusson, Patrick Carlsson, Nguyen Tien Son, Anne Henry, Franziska Christine Beyer, Mikael Syväjärvi, Rositza Yakimova, and Erik Janzén. "Influence of Cooling Rate after High Temperature Annealing on Deep Levels in High-Purity Semi-Insulating 4H-SiC." Materials Science Forum 556-557 (September 2007): 371–74. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.371.

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The influence of different cooling rates on deep levels in 4H-SiC after high temperature annealing has been investigated. The samples were heated from room temperature to 2300°C, followed by a 20 minutes anneal at this temperature. Different subsequent cooling sequences down to 1100°C were used. The samples have been investigated using photoluminescence (PL) and IV characteristics. The PL intensities of the silicon vacancy (VSi) and UD-2, were found to increase with a faster cooling rate.

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Yuan, Guang Lin, Jing Wei Zhang, Jian Wen Chen, and Dan Yu Zhu. "Deterioration of Mechanical Properties of High-Strength Pumpcrete after Exposure to High Temperatures." Advanced Materials Research 168-170 (December 2010): 564–69. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.564.

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This paper makes an experimental study of mechanical properties of high-strength pumpcrete under fire, and the effects of heating rate, heating temperature and cooling mode on the residual compressive strength(RCS) of high-strength pumpcrete are investigated. The results show that under air cooling, the strength deterioration speed of high-strength concrete after high temperature increases with the increase of concrete strength grade. Also, the higher heating temperature is, the lower residual compressive strength value is. At the same heating rate (10°C/min), the residual compressive strength of C45 concrete after water cooling is a little higher than that after air cooling; but the test results are just the opposite for C55 and C65 concrete. The strength deterioration speed of high-strength concrete after high temperature increases with the increase of heating rate, but not in proportion. And when the heating temperature rises up between 200°C and 500°C, heating rate has the most remarkable effect on the residual compressive strength of concrete. These test results provide scientific proofs for further evaluation and analysis of mechanical properties of reinforced-concrete after exposure to high temperatures.

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Tsukiyama, Kuniaki, Nobuo Nakada, Toshihiro Tsuchiyama, Setsuo Takaki, and Yo Tomota. "Effect of Cooling Rate after High Temperature Nitriding on Transformation Microstructure in Low Carbon Steel." Advanced Materials Research 922 (May 2014): 773–78. http://dx.doi.org/10.4028/www.scientific.net/amr.922.773.

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High temperature nitriding was applied to a low carbon steel, and then the transformation microstructure formed from the high nitrogen austenite was observed. The microstructure was greatly influenced by cooling rate after the nitriding. The austenite transformed to martensite when the cooling rate was fast (water-cooling) though a certain amount of austenite was retained in the martensite. On the other hand, a diffusional transformation product such as (ferrite + Fe4N) eutectoid structure was formed when the cooling rate was slow (gas- or furnace-cooling). The hardness profile obtained in these specimen were related with microstructure depending on the nitrogen concentration profile and cooling rate.

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Sorrentino, A., R. Pantani, and G. Titomanlio. "Crystallization of syndiotactic polystyrene under high pressure and cooling rate." Macromolecular Research 18, no. 11 (November 2010): 1045–52. http://dx.doi.org/10.1007/s13233-010-1116-6.

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Monnot, A., P. Boldo, N. Gondrexon, and A. Bontemps. "Enhancement of Cooling Rate by Means of High Frequency Ultrasound." Heat Transfer Engineering 28, no. 1 (January 2007): 3–8. http://dx.doi.org/10.1080/01457630600985485.

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16

Guo, You Dan. "Critical Cooling Rate and Design of Mould Cooling System for Hot Forming of High-Strength Sheet." Advanced Materials Research 295-297 (July 2011): 1474–78. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.1474.

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High-strength sheet including 2MnB5 Boron and magnesium alloy sheet is the material commonly used in modern machinery, which is easy to induce problems such as excessive rebound, cracking, forming force increase, easy mould wear and the like. The heat analysis of 2MnB5 Boron and magnesium alloy sheet hot stamping forming process and experiments indicate that the transition process from Austenite to Martensite by controlling the sheet heating and cooling temperature is the foundation of heat forming. Only when the cooling rate reaches or surpasses the critical cooling rate, Austenite can be transformed to Martensite directly. Critical cooling rate of sheet is related to the elements of critical water flow rate, mould cooling system design, cooling medium, dented mould medium and the like. Under the condition that the elements of mould structure, cooling system, cooling medium and the like are defined, critical cooling rate is a constant value. As a result, through controlling critical water flow rate, hot forming transition process and hot forming requirements can be guaranteed to overcome the excessive rebound, cracking, forming force increase, easy mould wear and the like in hot forming process.

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Ping, Qi, Qi Diao, Dezhi Qi, Chen Wang, and Chuanliang Zhang. "Influence of Two Cooling Methods on Dynamic Mechanical Properties of High Temperature Sandstone." Shock and Vibration 2021 (July 17, 2021): 1–12. http://dx.doi.org/10.1155/2021/2667182.

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To study the influence of different cooling methods on dynamic mechanical properties of high temperature rock, both natural cooling and water cooling were used to cool high temperature (100°C∼1000°C) coal mine sandstone to room temperature (20°C). Basic physical parameters of sandstone were measured, and impact compression tests were carried out by using the SHPB test device. Comparative analysis shows that the volume expansion rate, mass loss rate, density reduction rate, and P-wave velocity reduction rate of sandstone specimens are positively correlated with the temperature in a quadratic function. The deteriorate rate of physical parameters of water cooling sandstone specimens is slightly larger than that of natural cooling. The variation of dynamic stress-strain curves is basically consistent. Compaction stage of water cooling is slightly larger than that of natural cooling. With the increase in temperature, dynamic compressive strength of sandstone specimens first increases, then decreases, and reaches maximum at 300°C. Subsequently, dynamic compressive strength decreases in a quadratic function with the temperature, and dynamic compressive strength of water cooling sandstone specimens is significantly lower than that of natural cooling. The dynamic elastic modulus also first increases and then decreases with the temperature and reaches maximum at 300°C. The dynamic elastic modulus of water cooling sandstone specimens is lower than that of natural cooling, but they are roughly the same at 1000°C. Dynamic strain increases in a quadratic function with the temperature, and dynamic strain of water cooling sandstone specimens is greater than that of natural cooling. The impact failure of sandstone specimens is intensified with the temperature, and the failure degree of water cooling is greater than that of natural cooling.

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Hou, Jianfeng, Kefeng Pan, and Xihan Tan. "Preparation of 6N,7N High-Purity Gallium by Crystallization: Process Optimization." Materials 12, no. 16 (August 10, 2019): 2549. http://dx.doi.org/10.3390/ma12162549.

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In this study, radial crystallization purification method under induction was proposed for preparing 6N,7N ultra-high purity gallium crystal seed. The effect of cooling temperature on the morphology of the crystal seed, as well as the cooling water temperature, flow rate, and the addition amount of crystal seed on the crystallization process was explored, and the best purification process parameters were obtained as follows: temperature of the crystal seed preparation, 278 K; temperature and flow rate of the cooling water, 293 K and 40 L·h−1, respectively; and number of added crystal seed, six. The effects of temperature and flow rate of the cooling water on the crystallization rate were investigated. The crystallization rate decreased linearly with increasing cooling water temperature, but increased exponentially with increasing cooling water flow. The governing equation of the crystallization rate was experimentally determined, and three purification schemes were proposed. When 4N crude gallium was purified by Scheme I, 6N high-purity gallium was obtained, and 7N high-purity gallium was obtained by Schemes II and III. The purity of high-purity gallium prepared by the three Schemes I, II, and III was 99.999987%, 99.9999958%, and 99.9999958%, respectively.

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Greetham, Gregory M., Ian P. Clark, Benjamin Young, Robby Fritsch, Lucy Minnes, Neil T. Hunt, and Mike Towrie. "Time-Resolved Temperature-Jump Infrared Spectroscopy at a High Repetition Rate." Applied Spectroscopy 74, no. 6 (March 30, 2020): 720–27. http://dx.doi.org/10.1177/0003702820913636.

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Time-resolved temperature-jump infrared absorption spectroscopy at a 0.5 to 1 kHz repetition rate is presented. A 1 kHz neodymium-doped yttrium aluminum garnet (Nd:YAG) laser pumping an optical parametric oscillator provided >70 µJ, 3.75 µm pump pulses, which delivered a temperature jump via excitation of the O–D stretch of a D2O solution. A 10 kHz train of mid-infrared probe pulses was used to monitor spectral changes following the temperature jump. Calibration with trifluoroacetic acid solution showed that a temperature jump of 10 K lasting for tens of microseconds was achieved, sufficient to observe fast processes in functionally relevant biomolecular mechanisms. Modeling of heating profiles across ≤10 µm path length cells and subsequent cooling dynamics are used to describe the initial <100 ns cooling at the window surface and subsequent, >10 µs cooling dynamics of the bulk solution.

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Xia, Pei Pei, Liu Qing Yang, Xiao Jiang Guo, and Ye Zheng Li. "Continuous Cooling Phase Transformation Rules of High Nb X80 Pipeline Steel." Materials Science Forum 850 (March 2016): 916–21. http://dx.doi.org/10.4028/www.scientific.net/msf.850.916.

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The microstructural evolution of the high Nb X80 pipeline steel in Continuous Cooling Transformation (CCT) by Gleeble-3500HS thermal mechanical simulation testing system was studied, the corresponding CCT curves were drawn and the influence of some parameters such as deformation and cooling rate on microstructure of high Nb X80 pipeline steel was analyzed. The results show that as cooling rate increased, the phase transformation temperature of high Nb X80 steel decreased, with the microstructure transformation from ferrite-pearlite to acicular ferrite and bainite-ferrite. When cooling rate was between 20°C/s and 30°C/s, the microstructure was comparatively ideal acicular ferrite, thermal deformation accelerates phase transformation notably and made the dynamic CCT curves move upward and the initial temperature of phase transformation increase obviously. Meanwhile the thermal deformation refined acicular ferrite and extended the range of cooling rate accessible to acicular ferrite.

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Guo and Ye. "Numerical and Experimental Study on a High-Power Cold Achieving Process of a Coil-Plate Ice-Storage System." Energies 12, no. 21 (October 25, 2019): 4085. http://dx.doi.org/10.3390/en12214085.

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Heat dissipation of high-power lasers needs a cold storage and supply system to provide sufficient cooling power. A compact coil-plate heat exchange device has been proposed and applied in the phase-change cold storage system with ice as the cold-storage medium and glycol aqueous solution as the coolant. The heat exchanger consists of several stacked coil-plate units and each unit is constructed with a flat plate and serpentine coils welded on the plate. A simulation model on the cold achieving process of a coil-plate unit was built and verified by the corresponding experiment. The influences of the structural parameters (tube diameter, tube pitch, and plate spacing) of the unit and the inlet temperature and volume flow rate of the coolant on the heat exchange power density were analyzed to obtain the maximal cooling effect in a limited time period. It was found that the heat exchange power density is limited when the tube pitch and plate spacing are large, otherwise, the effective cooling time period is limited. A small plate spacing can make the power density decrease rapidly in the later stage. The inlet coolant temperature can significantly affect the heat exchange power density while the coolant volume flow rate in tube has a small effect on the power density when the coolant is in turbulent state. In a time period of 900 s, for a coil-plate heat exchanger with a plate size of 940 mm ×770 mm and a tube pitch of 78 mm, when the plate spacing is 20 mm, the average heat exchange power density is 5.1 kW/m2 when the inlet temperature and volume flow rate of the coolant are 20 °C and 0.5 m3/h, respectively. The total cooling power of several stacked coil-plate units in the limited time period can match the high requirement of laser heat dissipation.

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Stanic, Davor, and Zdenka Zovko-Brodarac. "Influence of cooling rate on microstructure development of AlSi9MgMn alloy." Journal of Mining and Metallurgy, Section B: Metallurgy, no. 00 (2020): 36. http://dx.doi.org/10.2298/jmmb200503036s.

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Aluminum alloys are widely applied in automotive, aircraft, food and building industries. Multicomponent technical AlSi9MgMn alloy is primarily intended for high cooling rate technology. Controlled addition of alloying elements such as iron and manganese as well as magnesium can improve mechanical and technological properties of final casting in dependence from cooling conditions during solidification. The aim of this investigation is characterization of AlSi9MgMn alloy microstructure and mechanical properties at lower cooling rates than those for which this alloy was primarily developed. Thermodynamic calculation and thermal analyses revealed solidification sequence in correlation to microstructure investigation as follows: development of primary dendrite network, precipitation of high temperature Al15(Mn,Fe)3Si2 and Al5FeSi phases, main eutectic reaction, precipitation of intermetallic Al8Mg3FeSi6 phase and Mg2Si as a final solidifying phase. Influence of microstructure features investigation and cooling rate reveals significant Al15(Mn,Fe)3Si2 morphology change from Chinese script morphology at low, irregular broken Chinese script morphology at medium and globular morphology at high cooling rate. High manganese content in AlSi9MgMn alloy together with high cooling rate enables increase of Fe+Mn total amount in intermetallic Al15(Mn,Fe)3Si2 phase and encourage favourable morphology development, all resulting in enhanced mechanical properties in as-cast state.

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Xin, Rui Shan, Hui Long An, Shuai Ren, Ji Tan Yao, and Jin Pan. "Behaviors of Continuous Cooling Transformation and Microstructure Evolution of a High Strength Weathering Prefabricated Building Steel." Solid State Phenomena 279 (August 2018): 21–25. http://dx.doi.org/10.4028/www.scientific.net/ssp.279.21.

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Continuous cooling transformation (CCT) diagram of a high strength weathering prefabricated building steel was determined using a DIL805L thermal dilatometer by means of the expansion method combined with metallography hardness method. Effect of cooling rate on microstructure and hardness of the steel was also studied. The results show that the austenite transformation products of the steel are ferrite and pearlite when cooling rate is lower than 3°C/s. In the cooling rate range of 3 to 20°C/s, the mixed microstructure of ferrite, pearlite and bainite can be obtained. When cooling rate is higher than 20°C/s but lower than 100°C/s, the microstructure is composed of ferrite, bainite and martensite. When cooling rate is above 100°C/s, ferrite disappeared completely, and transformation products are bainite and martensite.

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Huang, Chang Shan, Hui Wu Xu, Yu Shan Cheng, Jin Ying Wu, and Mian Xue. "Metal Corrosion Problems and Countermeasures in High Conductivity of Circulating Water." Applied Mechanics and Materials 333-335 (July 2013): 1841–46. http://dx.doi.org/10.4028/www.scientific.net/amm.333-335.1841.

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Objective: Through the test of air conditioning cooling water circulation system and the electrical conductivity of iron corrosion velocity, find out the method of corrosion control measures; Methods: Rotating hanging plate method and conductivity meter and other cooling water test air conditioning system in different conductivity of metal iron corrosion rate; Conductivity results: Air-conditioning cooling water circulation system of more than 1900 μs/cm, metal corrosion rate less than 0.05mm/a, shall meet the relevant standards. Conclusion: Through the addition of corrosion inhibitor, scientific emission and control of circulating cooling water pH, conductivity decreased circulating water cooling, can reduce the corrosion of iron, to ensure the safe and stable operation of cooling water pipe and equipment.

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Klocke, Fritz, Dieter Lung, Alexander Krämer, Tolga Cayli, and Hubertus Sangermann. "Potential of Modern Lubricoolant Strategies on Cutting Performance." Key Engineering Materials 554-557 (June 2013): 2062–71. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.2062.

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Besides developments in the area of dry machining and minimum quantity lubrication, the use of coolant lubricants is still essential when machining high alloyed steels or heat resistant materials like titanium and nickel based alloys. Experts agree that this fact will not change in the next decade. For this reason it is necessary to use coolant lubricants as effectively as possible to maximise their positive effect on productivity and process stability. High-performance cooling strategies like high-pressure cooling and cooling with cold gases (cryogenic cooling) have received increased attention in the last years. Through the targeted supply of coolant lubricants to the cutting site it is possible to decrease tool wear, increase cutting speeds, guarantee defined chip breakage and chip transport and – in terms of cryogenic cooling – waive part cleaning. This paper shows current research results in the above mentioned field. Since the performance of a high-pressure coolant lubricant supply in turning difficult to cut materials has been shown in many previous papers, this paper focuses on the quantification of the potential in turning different steels, namely quenched and tempered but also stainless steel in comparison to the conventional flood cooling. Since energy efficiency is very crucial, pressure and flow rate have to be adjusted carefully and in accordance with the cutting parameters to guarantee best results with less energy. Moreover the effects of cryogenic cooling will be evaluated in comparison to high-pressure cooling and conventional flood cooling. In latter field, cutting tests were carried out under variation of the flow rate in order to find the minimum required value for a certain machining task with the overall aim to prevent waste of the media used. Especially in cryogenic cooling technologies, many fundamental research regarding the working mechanisms but also further developments in cutting tool and machine tool technology are still necessary to make this technology ready for industrial use.

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Glover, Simon, and Daniel Wolf Savin. "cooling in primordial gas." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, no. 1848 (September 20, 2006): 3107–12. http://dx.doi.org/10.1098/rsta.2006.1867.

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Simulations of the thermal and dynamical evolution of primordial gas typically focus on the role played by H 2 cooling. H 2 is the dominant coolant in low-density primordial gas and it is usually assumed that it remains dominant at high densities. However, H 2 is not an effective coolant at high densities, owing to the low critical density at which it reaches local thermodynamic equilibrium and to the large opacities that develop in its emission lines. It is therefore important to quantify the contribution made to the cooling rate by emission from the other molecules and ions present in the gas. A particularly interesting candidate is the ion, which is known to be an effective coolant at high densities in planetary atmospheres. In this paper, we present results from simulations of the thermal and chemical evolution of gravitationally collapsing primordial gas, which include a detailed treatment of chemistry and an approximate treatment of cooling. We show that in most cases, the contribution from is too small to be important, but if a sufficiently strong ionizing background is present, then cooling may become significant.

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Zhao, Dong Wei, Jian Chun Cao, Wei Chen, Lei Deng, Zhe Shi, and Xin Qi. "Effect of Cooling Rate after Deformation on Microstructure of V-N Microalloying High Strength Aseismic Rebar." Advanced Materials Research 482-484 (February 2012): 1600–1604. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.1600.

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Thermo-simulated test was conducted to study the effect of cooling rate from 1 °C/s to 15 °C/s on microstructure of V-N microalloying high strength aseismic rebar. Microstructure investigation was done using both optical and scanning electron microscopes. Microstructures in center of the rebar mainly consist of ferrite, pearlite, and bainite. The percentage of bainite increases below 5 °C/s cooling rate and decreases between 5 °C/s and 15 °C/s with the increase in cooling rate. At the cooling rate of 15 °C/s the fraction of bainite is about 7.7%, and the finest ferrite with 5.3 μm was obtained. Higher strength value obtained at the cooling rate 8~10 °C/s is due to the combination of smaller ferrite and about 10 % bainite.

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Torbidoni, Leonardo, and J. H. Horlock. "A New Method to Calculate the Coolant Requirements of a High-Temperature Gas Turbine Blade." Journal of Turbomachinery 127, no. 1 (January 1, 2005): 191–99. http://dx.doi.org/10.1115/1.1811100.

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Earlier papers by the first author have described a computational method of estimating the cooling flow requirements of blade rows in a high-temperature gas turbine, for convective cooling alone and for convective plus film cooling. This method of analysis and computation, when applied to the whole blade chord was compared to a well-known semi-empirical method. In the current paper, a more sophisticated method is developed from the earlier work and is used to calculate the cooling flow required for a nozzle guide vane (the first blade row) of a high-temperature gas turbine, with given inlet gas temperature and coolant inlet temperature. Now the heat flux through an elementary cross-sectional area of the blade, at given spanwise (y) and chordwise (s) locations, is considered, with a guessed value of the elementary coolant flow [as a fraction dΨs of the external gas flow]. At the given s, integration along the blade length gives the blade metal temperatures at the outer and inner walls, Tbgy and Tbcly. If the value of Tbg at the blade tip y=H is assumed to be limited by material considerations to Tbg,max then the elementary coolant flow rate may be obtained by iteration. Summation along the chord then gives the total coolant flow, for the whole blade. Results using the method are then compared to a simpler calculation applied to the whole blade, which assumes chordwise constant temperatures and constant selected values of cooling efficiency and film-cooling effectiveness.

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Studer, D., M. Michel, E. B. Hunziker, and M. Buschmann. "A new high-pressure freezing apparatus: The importance of improving cooling rates during high-pressure freezing." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 138–39. http://dx.doi.org/10.1017/s0424820100168426.

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High pressure freezing is the only approach shown so far to adequately cryoimmobilise bulk biological samples. Based on freeze-fractured and freeze-substituted samples, some studies suggested that a 600(μm thick specimen could be completely vitrified. Recently electron diffraction, allowing experimental proof of vitrification, demonstrated that only samples less than 200μm thick can be vitrified. This discrepancy of the depth of vitrification (600μm vs. 200μm) led us re evaluate high pressure freezing theoretically and experimentally. We calculated the cooling rate profiles through samples of different thicknesses and surface cooling rates. We also determined the depth to which bovine articular cartilage specimens could be vitrified using an improved high pressure freezing machine.The calculations of the cooling rates are based on Fourier’s law of heat conduction. When thermal conductivity is assumed to be constant, the cooling rate can be expressed as δT/δt=α·∇2T, where α is the thermal diffusivity (α=k/ρ·C; k=thermal conductivity; ρ=density; C=heat capacity).

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Zhang, Minglei, Runde Qiu, Lei Yang, and Yuting Su. "Experimental Research on Mechanical Properties of High-Temperature Sandstone with Different Cooling Methods." Advances in Civil Engineering 2020 (September 15, 2020): 1–9. http://dx.doi.org/10.1155/2020/8879760.

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Various tests including the longitudinal wave velocity tests and uniaxial compression tests have been conducted to evaluate the impact of cooling methods (including natural cooling, water cooling, and cooling by liquid carbon dioxide) on mechanical properties of sandstone under the natural status and high temperature. The acoustic emission signals were also monitored during the tests. According to the tests conducted, the sandstone sample density attenuation rate and the longitudinal wave velocity attenuation rate are higher than those of the specimen under natural status while the uniaxial compressive strength and Young’s modulus are lower. Comparing with the sandstone under the natural status, the compression sections of the stress-strain curves of the high-temperature sandstone samples treated by three cooling methods are longer with lower strain peak values. The order of the acoustic emission is revealed as follows: the sample cooled by liquid carbon dioxide < the sample cooled by water < sample cooled naturally < the sample under natural status, which suggests that the rapid cooling (cooled by liquid carbon dioxide) produces the severest damage on the sample, followed by the water cooling and natural cooling methods. In addition, the relationship between the sample strength weakening coefficient and the cooling rate is defined based on the statistical data of the cooling time of the high-temperature specimen under the three cooling methods.

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Nishi, Yoshitake, Yuichiro Kita, Akira Igarashi, and Shigeki Tokunaga. "Cooling rate dependence ofJ c in high-T c YBa2Cu3O6?y." Journal of Materials Science Letters 8, no. 5 (May 1989): 503–4. http://dx.doi.org/10.1007/bf00720276.

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Fielding, J. P., and M. A. F. Vaziry-Z. "Avionics cooling-rate trade-off modelling for ultra-high capacity aircraft." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 211, no. 6 (June 1, 1997): 403–12. http://dx.doi.org/10.1243/0954410971532767.

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A computer aided conceptual aircraft design methodology (CACAD) has been developed to size ultra-high capacity jet transport aircraft. Modules were also developed for predicting maintenance costs of each airframe and avionics system and these were incorporated into CACAD. A methodology was developed to enhance the reliability of avionics systems, based on experimentally-proven engineering design solutions. A number of avionics cooling techniques were investigated, and reliability and maintainability models of thermal management were developed and linked to an avionics maintenance cost module. Further models were produced to investigate the impact of proposed changes on the environmental control systems, engine-provided bleeds and power off-takes. It was found that increased flowrates above the normally recommended values for the avionics bay, and to the flight deck instruments, may increase the reliability of the avionics systems, and also increase aircraft dispatch reliability. They may not, however, greatly improve direct operating costs (DOC), due to significant fuel penalties. A separate refrigeration unit was investigated and found to be a feasible cost-effective measure, even allowing for increased engine fuel consumption caused by the effect of the engine power off-take required to drive the refrigeration unit.

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Shan, Yao, Gong Xuena, Dai Lixin, Ma Chunying, Jin Junze, and Abuliti Abudula. "The mathematical model of solidification latent heat under high cooling rate." Heat Transfer—Asian Research 35, no. 2 (2006): 115–21. http://dx.doi.org/10.1002/htj.20104.

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Gulyaev, A. P. "Problem of cooling rate during the quenching of high-speed steel." Metal Science and Heat Treatment 33, no. 8 (August 1991): 602–3. http://dx.doi.org/10.1007/bf00774842.

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Jowkar, S., M. Jafari, and M. R. Morad. "Heat transfer characteristics of high flow rate electrospray and droplet cooling." Applied Thermal Engineering 162 (November 2019): 114239. http://dx.doi.org/10.1016/j.applthermaleng.2019.114239.

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Pei, Yu, Zhe Gao, Yi Liu, Shi Qian Zhao, Chang Yu Xu, Li Yong Ren, and Xing Liang Li. "Continuous Cooling Transformation Behavior and the Phase Transformation Model in Low Carbon High Strength Sheet Steel." Advanced Materials Research 1035 (October 2014): 27–35. http://dx.doi.org/10.4028/www.scientific.net/amr.1035.27.

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Phase transformation of austenite continuous cooling process in low carbon high strength sheet steel has been researched by DIL805 thermal mechanical simulate. The Austenite continuous cooling transformation (CCT) diagram of steel has been determined by dilatometry and metallography. With the increase of cooling rate, ferritic transformation, perlitic transformation, bainite transformation and martensitic transformation have produced in the organization. Mathematical equations of phase transformation point-cooling rate and phase variable-cooling rate have been established and phase transformation model of high fit degree has been gained by regression calculation. The results show that calculated value and experimental value are nearly similar, so the phase transformation model is feasible.

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Pan, Libo, Wen Tan, Wenqiang Zhou, and Junlin Wang. "Development of a DP980 steel with low cooling rate requirement." E3S Web of Conferences 245 (2021): 01003. http://dx.doi.org/10.1051/e3sconf/202124501003.

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DP980 is a promising light-weightening material in car body. To avoid high investment of strong cooling system, a new DP980 steel with low cooling rate requirement was developed. The mechanical properties and microstructure were analyzed under different manufacturing process. It could be concluded that the chemical composition design should be reasonable and of low cost to achieve both high strength and also austenite to martensite transformation at low cooling rate. Strength increased with coiling temperature decreasing during hot rolling, and higher annealing temperature and lower over aging temperature were favourable to higher strength. The austenite-martensite transforming could be completed at even lower rapid cooling rate of 20°C/s. Through optimized manufacturing process parameters, the new DP steel product with good mechanical properties could be obtained successfully, which provided a new option for normal production line to produce ultra high strength steel.

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Chvykov, Vladimir. "Ti:Sa Crystals in Ultra-High Peak and Average Power Laser Systems." Crystals 11, no. 7 (July 20, 2021): 841. http://dx.doi.org/10.3390/cryst11070841.

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In this paper, Ti:Sa amplifiers with crystals of the different geometries are discussed. Benefits of using this active medium for a thin disk (TD) and slab amplifiers are evaluated numerically and tested experimentally. Thermal management for amplifiers with multi-kW average power and multi-J pulse energy has been demonstrated. The presented numerical simulations revealed the existing limitations for heat extraction in TD geometry in the sub-joule energy regime for higher repetition rate operation. Geometry conversion from TD to thin-slab (TS) and cross-thin-slab (XTS) configurations significantly increases the cooling efficiency with an acceptable crystal temperature for pump average power values up to few kW with room temperature cooling, and up to tens of kW with cryogenic cooling. The abilities to attain 0.3 J output energy and a greater than 50% extraction efficiency were demonstrated with a repetition rate exceeding 10 kHz with room temperature cooling and one order more of a repetition rate with cryogenic conditions with pulsed pumping. Direct diode pumping simulated for CW regimes demonstrated 1.4 kW output power with 34% extraction efficiency using room temperature cooling and more than 10 kW and ~40% efficiency with cryogenic cooling.

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Feng, Yong, and Wei Hua Sun. "Phase Transformation Rule, Microstructure and Properties of JG590 High Strength Steel." Materials Science Forum 561-565 (October 2007): 29–32. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.29.

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The phase transformation rule, microstructures and properties of JG590 high strength steel produced in Jinan Iron and Steel Co. ltd. have been investigated in this paper. When the chemical composition of steel are given, the cooling rates after finished rolling affect on the properties of steel greatly. The yield strength and tensile strength increasing, the elongation and reduction of area decreasing as increasing of cooling rates after rolling. The main cause is due to appearance and increasing of Bainite and Martensite other than Ferrite and Pearlite in room temperature. The finished rolling temperature have distinct effects upon the mechanical properties of steel plates. Finished rolling at different temperature with the 0.5°C/s cooling rate, the tensile strength vary in 599-698MPa, the yield strength changed from 412 MPa to 536MPa. The elongation is between 30.4-40.5%. But when finished rolling at different temperature with the 2.0°C/s cooling rate, the tensile strength vary in 747-784MPa, the yield strength changed from 441 MPa to 601MPa. The strength index can both meet the requirements of employ. But the elongation is only 18.7-24.5%. This is related with production of lots of Bainite microstructure more than 2°C/s cooling rate. In the procedure of manufacture of JG590 high steel, the quickly cooling rate should be avoided to keep suitable microstructure and good elongation and toughness.

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Fujii, Hidetoshi, Ling Cui, and Kiyoshi Nogi. "Welding of High Carbon Steel without Transformation." Key Engineering Materials 345-346 (August 2007): 1411–15. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.1411.

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A high carbon steel joint, S70C (0.72wt%C) was successfully friction stir welded without any postheat treatments. There are two methods for obtaining proper joint properties. The first method is to decrease the peak temperature to below A1, and the other method to decrease the cooling rate to less than the lower critical cooling rate. As a result, the ultimate tensile strength of 1214 MPa, 0.2 % proof strength of 700 MPa and elongation of 40% were obtained for a joint.

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Tang, Da Pei. "Thermo-Mechanical Coupled and Fracture in Diamond Film under High Strain Rate." Advanced Materials Research 548 (July 2012): 160–64. http://dx.doi.org/10.4028/www.scientific.net/amr.548.160.

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According to the special case of high strain rate for diamond film produced by DC plasma jet method, a transient thermo-mechanical coupled model for the cooling process of diamond film and Mo substrate was developed. The direct coupled finite element method was used to simulate the transient thermal stresses in diamond film during the cooling period after the film deposition. The residual thermal stresses of diamond film were calculated and compared respectively under two conditions of real uneven temperature fields and unreal even temperature fields. Based on the simulated results of stresses, the moment and cause of diamond film cracking were analyzed. The conclusions are as the follows: (1) the thermal stresses in diamond film increase with the increase of cooling time, but the maximum first principal tensile stress may reach the fracture strength of common diamond film before the film cools to room temperature; (2) the excessive tensile stress at the film edge causes the film cracking; (3) in order to reduce the thermal (residual ) stresses and increase the finished product ratio of diamond film, it is essential to further improve the temperature uniformity.

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Li, Fan, Hai Long Yi, Zhen Yu Liu, and Guo Dong Wang. "Influence of Cooling Rate on the Microstructures and Properties of Q550." Applied Mechanics and Materials 117-119 (October 2011): 1705–7. http://dx.doi.org/10.4028/www.scientific.net/amm.117-119.1705.

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A Q550 high strength steel was selected at two different cooling rates through ultra-fast cooling process, and its microstructures and strengthening mechanisms were analyzed. The results show the bainite transformation temperature of the steel decreased with the increasing of cooling rate.The ultra-fast cooling process can improve the performance of Q550 compared with the conventional cooling process, and the yield strength, tensile strength and elongation are 600MPa, 755MPa and 19%, and - 20 °Cimpact energy is 253J, and good strength and toughness are obtained under ultra-fast cooling process. The microstructure of this steel is bainite and good strength and toughness are caused by the refinement of bainite and fine precipitates. Ultra-fast cooling technology improves the strength and toughness of this steel effectively.

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Panchal, Satyam, Krishna Gudlanarva, Manh-Kien Tran, Roydon Fraser, and Michael Fowler. "High Reynold’s Number Turbulent Model for Micro-Channel Cold Plate Using Reverse Engineering Approach for Water-Cooled Battery in Electric Vehicles." Energies 13, no. 7 (April 2, 2020): 1638. http://dx.doi.org/10.3390/en13071638.

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The investigation and improvement of the cooling process of lithium-ion batteries (LIBs) used in battery electric vehicles (BEVs) and hybrid electric vehicles (HEVs) are required in order to achieve better performance and longer lifespan. In this manuscript, the temperature and velocity profiles of cooling plates used to cool down the large prismatic Graphite/LiFePO4 battery are presented using both laboratory testing and modeling techniques. Computed tomography (CT) scanning was utilized for the cooling plate, Detroit Engineering Products (DEP) MeshWorks 8.0 was used for meshing of the cooling plate, and STAR CCM+ was used for simulation. The numerical investigation was conducted for higher C-rates of 3C and 4C with different ambient temperatures. For the experimental work, three heat flux sensors were attached to the battery surface. Water was used as a coolant inside the cooling plate to cool down the battery. The mass flow rate at each channel was 0.000277677 kg/s. The k-ε model was then utilized to simulate the turbulent behaviour of the fluid in the cooling plate, and the thermal behaviour under constant current (CC) discharge was studied and validated with the experimental data. This study provides insight into thermal and flow characteristics of the coolant inside a cooing plate, which can be used for designing more efficient cooling plates.

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Fu, Yu Can, Hong Jun Xu, and Fang Hong Sun. "Studies on Exploiting Further the Potential of High Efficiency Grinding." Materials Science Forum 471-472 (December 2004): 405–8. http://dx.doi.org/10.4028/www.scientific.net/msf.471-472.405.

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Aiming at the existent problems in the application of high efficiency grinding, some countermeasures are put forward to further exploit its potential, including the topography optimization design for high efficiency grinding wheel and cooling enhancement technology with jet impingement in grinding zone. The optimization model advanced here can be used to optimize the grinding wheel topography for different grinding processes with the minimum specific grinding energy. The cooling enhancement technology employed in creep feed deep grinding experiment of titanium alloy shows remarkable cooling capability. It is able to steadily control the temperature on workpiece surface at an extremely low lever under 100°C,when the workpiece is seriously burn with the conventional coolant supply. Further studies on the combination of these two countermeasures will not only enable us to increase the available material removal rate to a new lever but also solve the workpiece burn problem for those difficult-to-machining materials in high efficiency grinding.

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Zhu, Zi-Jue, Jing Zhai, Jian-Lin Hu, Yi-Zhou Wang, Wei Chen, Feng Liu, Yong-Hua Huang, and Zheng Li. "Cryopiece, a novel carrier with faster cooling rate, high recovery rate and retrieval rate, for individual sperm cryopreservation." Translational Andrology and Urology 10, no. 3 (March 2021): 1121–32. http://dx.doi.org/10.21037/tau-20-1080.

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Zhuravlev, Evgeny, Jing Jiang, Dongshan Zhou, René Androsch, and Christoph Schick. "Extending Cooling Rate Performance of Fast Scanning Chip Calorimetry by Liquid Droplet Cooling." Applied Sciences 11, no. 9 (April 23, 2021): 3813. http://dx.doi.org/10.3390/app11093813.

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The liquid droplet cooling technique for fast scanning chip calorimetry (FSC) is introduced, increasing the cooling rate for large samples on a given sensor. Reaching higher cooling rates and using a gas as the cooling medium, the common standard for ultra-fast temperature control in cooling requires reducing the lateral dimensions of the sample and sensor. The maximum cooling rate is limited by the heat capacity of the sample and the heat exchange between the gas and the sample. The enhanced cooling performance of the new liquid droplet cooling technique is demonstrated for both metals and polymers, on examples of solidification of large samples of indium, high-density polyethylene (HDPE) and poly (butylene 2,6-naphthalate) (PBN). It was found that the maximum cooling rate can be increased up to 5 MK/s in room temperature environment, that is, by two orders of magnitude, compared to standard gas cooling. Furthermore, modifying the droplet size and using coolants at different temperatures provide options to adjust the cooling rate in the temperature ranges of interest.

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Ma, Ning, Yu Jie Ma, Ye Xuan Wang, Jian Yi Ji, Yi Chun Ji, Chao Hui Yang, Chang Cheng Ma, Zhen Dong Han, and Xiao Feng Zhang. "Research on Hot Stamping Technology of High Strength Medium and Heavy Steel Plate." Key Engineering Materials 837 (April 2020): 81–86. http://dx.doi.org/10.4028/www.scientific.net/kem.837.81.

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An innovative study on the high strength of U shaped steel plate was carried out. Through the two different cooling systems of hot stamping die obtained the two U shaped steel plates, founding that the cooling rate of U shaped steel plate obtained by bath water cooling system in the die was significantly higher than the steel plate obtained by cooling pipe in the die system, and had a smaller temperature difference, Which is a good solution to the problem the cooling rate of blank decreases with the thickness of blank increasing and the blank had a large temperature difference for badly uniform temperature quenching. This system is also greatly shorten the quenching time and improve the production efficiency in hot forming process.

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Barman, N., and P. Dutta. "Rheological Behavior of Semi-Solid Slurry of A356 Alloy at High Shear and Cooling Rates." Solid State Phenomena 141-143 (July 2008): 409–14. http://dx.doi.org/10.4028/www.scientific.net/ssp.141-143.409.

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The rheological behavior of semisolid aluminium alloy (A356) slurry is investigated by using a concentric cylinder viscometer under high cooling rate (30 to 50°C/min) and high shear rate (650 to 1500s-1) conditions. Two different series of experiments are carried out. In all of these experiments, the pellets of A356 alloy are poured into the outer cylinder where they melt completely by resistance heating. When the inner cylinder is placed concentrically, the molten metal resides in the annular space between the cylinders. As the inner cylinder rotates, the alloy is sheared continuously during cooling from a temperature of 630°C, and a slurry forms. In the first series of experiments, for different cooling rates, shearing continues under a constant shear rate until rotation of the inner cylinder stops. During experiments, the temperature of the slurry is measured continuously using a K-type thermocouple, from which the solid fraction is calculated. In the second series of experiments, the molten alloy is cooled and sheared continuously at different shear rates for a given cooling rate. The apparent viscosity of the slurry is calculated by measuring the torque applied to the inner cylinder and its rotational speed. The results show that the slurry viscosity increases with increasing fraction of solid and increasing cooling rate, and it decreases with increasing shear rate. At high values of shear and cooling rates, the viscosity varies gradually up to a solid fraction of about 0.5.

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Ma, Zhong Fei, Li Chen, and Fu Qin Wang. "Tests on High-Pressure Water Rotational Jetting Ventilation Cooling Characteristic." Advanced Materials Research 594-597 (November 2012): 2073–76. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.2073.

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In order to improve the cooling effect and practical applicability of falling temperature technique on high-temperature workplaces, the aeration and cooling principle of the high pressure water rotational jetting ventilation were analysed, and the experimental study was carried out. The results show that water pressure and cooling rate are an approximation of parabolic growth relationship, different structure of jet tube and temperature difference on water and gas also have an obvious effect on the cooling amplitude and air quantity. the guide vanes installed may improve effect of ventilation and cooling the capacity on high pressure water rotational jetting.

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Lv, Wei, Di Wu, and Zhuang Li. "Thermo-Mechanical Simulation of Ultra-High Strength Ferrite-Bainite Dual Phase Steel." Applied Mechanics and Materials 184-185 (June 2012): 1367–70. http://dx.doi.org/10.4028/www.scientific.net/amm.184-185.1367.

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In the present paper, thermo-mechanical simulation of ultra-high strength ferrite-bainite dual phase (DP) steel was performed using a thermomechanical simulator. Continuous cooling transformation (CCT) diagram was constructed for DP steel. The effects of composition and cooling rate on the kinetics and products of phase transformation and the form of the CCT diagram were investigated. The results have shown that the α→γ transformation in DP steel was found to be more sluggish due to the addition of alloying elements. The segregation of manganese and niobium at austenite grain boundaries is expected to cause a solute drag effect, thereby reducing the rate of γ→α transformation in DP steel. The pearlite transformation region disappeared for cooling rates from 0.1 to 20°C/s. The microstructure comprises of bainite and martenite was obtained at fast cooling rate. The present steel is expected to have a higher hardenability.

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Journal articles on the topic 'High cooling rate'

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