Articles de revues : « Flash-heat »

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Rong, Yan, Linyuan Guo, Yunyan Peng, Jianhua Yang et Dong Jin. « Uncertainty Measurement of Closed Flash Point of Organic Heat Carrier ». E3S Web of Conferences 267 (2021) : 02039. http://dx.doi.org/10.1051/e3sconf/202126702039.

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The closed flash point is an important indicator in the detection of organic heat carrier. In this paper, based on the Pensky-Martin flash point (closed) measurement method, the closed flash point of the organic heat carrier is measured with an automatic closed cup flash point meter. The factors that may affect the accuracy of the measurement result during the measurement process are analyzed, and the uncertainty is determined. Through the analysis of the established uncertainty component sources, the repeatability measurement of the organic heat carrier, the temperature sensor, the pressure sensor, and the numerical rounding based on the standard, the results of the closed flash point determination of the organic heat carrier are obtained. The synthetic uncertainty and the relative expanded uncertainty are evaluated to improve the reliability of the measurement results of the closed flash point of the organic heat carrier and provide a reference for the quality control of the organic heat carrier.

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Mo, Kingtse C., et Dennis P. Lettenmaier. « Precipitation Deficit Flash Droughts over the United States ». Journal of Hydrometeorology 17, n^o 4 (1 avril 2016) : 1169–84. http://dx.doi.org/10.1175/jhm-d-15-0158.1.

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Abstract Flash drought refers to relatively short periods of warm surface temperature and anomalously low and rapid decreasing soil moisture (SM). Based on the physical mechanisms associated with flash droughts, these events are classified into two categories: heat wave and precipitation P deficit flash droughts. In previous work, the authors have defined heat wave flash droughts as resulting from the confluence of severe warm air temperature Tair, which increases evapotranspiration (ET), and anomalously low and decreasing SM. Here, a second type of flash drought caused by precipitation deficits is explored. The authors term these events P-deficit flash droughts, which they associate with lack of P. Precipitation deficits cause ET to decrease and temperature to increase. The P-deficit flash droughts are analyzed based on observations of P, Tair, and SM and ET reconstructed using land surface models for the period 1916–2013. The authors find that P-deficit flash droughts are more common than heat wave flash droughts. They are about twice as likely to occur as heat wave flash droughts over the conterminous United States. They are most prevalent over the southern United States with maxima over the southern Great Plains and the Southwest, in contrast to heat wave flash droughts that are mostly likely to occur over the Midwest and the Pacific Northwest, where the vegetation cover is dense.

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Mo, Kingtse C., et Dennis P. Lettenmaier. « Heat wave flash droughts in decline ». Geophysical Research Letters 42, n^o 8 (24 avril 2015) : 2823–29. http://dx.doi.org/10.1002/2015gl064018.

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Huang, Guidong, Songyuan Zhang, Zhong Ge, Zhiyong Xie, Zhipeng Yuan, Chong Tang, Jianbin Xie et Jian Xu. « Thermal performance analysis of organic flash cycle using R600A/R601A mixtures with internal heat exchanger ». Thermal Science, n^o 00 (2020) : 296. http://dx.doi.org/10.2298/tsci200507296h.

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In this study, the thermal performance of an internal heat exchanger-organic flash cycle system driven by geothermal water was investigated.R600a/R601a mixtures were selected as the working fluid. The effects of the mole fraction of mixtures on the heat absorption capacity of the heater, the temperature rise of cold working fluid in the internal heat exchanger, net power output, thermal efficiency, and electricity generation costs were analyzed. The net power outputs, electricity generation costs, and thermal efficiency of the internal heat exchanger-organic flash cycle and simple organic flash cycle systems were compared. Results showed that the system using theR600a/R601a mixtures (0.7/0.3mole fraction) has the largest net power output, which increased the net power output by 3.68% and 42.23% over the R601a and R600a systems, respectively. WhentheR600a mole fraction was 0.4, the electricity generation costs reduction of the internal heat exchanger-organic flash cycle system was the largest (1.77% compared with the simple organic flash cycle system).The internal heat exchanger can increase the thermal efficiency of organic flash cycle, but the net power output does not necessarily increase.

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Chou, Qiao Li, Cong Zhuo Jin et Peng Cheng Shu. « Vapor Compress Flash : Synthesis and Progress on Seawater Desalination Methods ». Advanced Materials Research 322 (août 2011) : 134–38. http://dx.doi.org/10.4028/www.scientific.net/amr.322.134.

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Among the modern seawater desalination methods, this article analyzes and induces the question of the second vapor condensing latent heat loss of the open heat process in multi-stage flash. Then this article synthesizes its merits and proposes for the first time the newest and the best and integrated vapor compress flash seawater desalination method, in witch a flash with the best product water quality is driven by a vapor compress with the highest heat-power efficiency, with technical superiorities such as the lowest investment cost and independent flash operation and modularization combination production and so on.

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Mo, Kingtse C., et Dennis P. Lettenmaier. « Prediction of Flash Droughts over the United States ». Journal of Hydrometeorology 21, n^o 8 (1 août 2020) : 1793–810. http://dx.doi.org/10.1175/jhm-d-19-0221.1.

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AbstractWe examine reforecasts of flash droughts over the United States for the late spring (April–May), midsummer (June–July), and late summer/early autumn (August–September) with lead times up to 3 pentads based on the NOAA second-generation Global Ensemble Forecast System reforecasts version 2 (GEFSv2). We consider forecasts of both heat wave and precipitation deficit (P deficit) flash droughts, where heat wave flash droughts are characterized by high temperature and depletion of soil moisture and P deficit flash droughts are caused by lack of precipitation that leads to (rather than being the cause of) high temperature. We find that the GEFSv2 reforecasts generally capture the frequency of occurrence (FOC) patterns. The equitable threat score (ETS) of heat wave flash drought forecasts for late spring in the regions where heat wave flash droughts are most likely to occur over the north-central and Pacific Northwest regions is statistically significant up to 2 pentads. The GEFSv2 reforecasts capture the basic pattern of the FOC of P-deficit flash droughts and also are skillful up to lead about 2 pentads. However, the reforecasts overestimate the P-deficit flash drought FOC over parts of the Southwest in late spring, leading to large false alarm rates. For autumn, the reforecasts underestimate P-deficit flash drought occurrence over California and Nevada. The GEFSv2 reforecasts are able to capture the approximately linear relationship between evaporation and soil moisture, but the lack of skill in precipitation forecasts limits the skill of P-deficit flash drought forecasts.

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Habuka, Hitoshi, Akiko Hara, Takeshi Karasawa et Masaki Yoshioka. « Heat Transport Analysis for Flash Lamp Annealing ». Japanese Journal of Applied Physics 46, n^o 3A (8 mars 2007) : 937–42. http://dx.doi.org/10.1143/jjap.46.937.

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Hunt, Eric. « The flash drought of 1936 ». Journal of Applied and Service Climatology 2020, n^o 4 (20 novembre 2020) : 1–15. http://dx.doi.org/10.46275/joasc.2020.11.001.

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An exceptional flash drought during the spring and summer of 1936 led to extreme heat waves, large losses of human life and significant reductions of crop production. An analysis of historic precipitation and temperature records shows that the flash drought originated over the southeastern United States (U.S.) in April 1936. The flash drought then spread north and westward through the early summer of 1936 and possibly merged with a flash drought that had developed in the spring over the northern Plains. The timing of the flash drought was particularly ill-timed as most locations were at or entering their climatological peak for precipitation at the onset of flash drought, thus maximizing the deficits of precipitation. Thus, by early July most locations in the central and eastern U.S. were either in drought or rapidly cascading toward drought. The weeks that followed the 1st of July were some of the hottest on record in the U.S., with two major heat waves: first over the Midwest and eastern U.S. in the first half of July and then across the south-central U.S in the month of August. The combination of the flash drought and heat wave led to an agricultural disaster in the north central U.S. and one of the deadliest events in U.S. history.

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Luo, Chao, Jun Zhao, Yongzhen Wang, Hongmei Yin, Qingsong An et Yulie Gong. « Design and experimental research on the combined flash-binary geothermal power generation system driven by low-medium temperature geothermal system ». Thermal Science 24, n^o 2 Part A (2020) : 831–42. http://dx.doi.org/10.2298/tsci181112013l.

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To match for the different temperature of the geothermal resource and strengthen the flexibility of organic Rankine cycle, a variable capacity power generation superstructure based on flash and organic Rankine cycle for geothermal energy was proposed. A combined flash-binary experimental prototype is newly established to investigate thermodynamic performance both on system and equipment in this paper. Pressured hot water is adopted as the extensive worldwide existed hydrothermal geothermal resource, eliminating the influence of the used heat transfer oil on evaporating process. The experimental results show that there is an optimal mass-flow rate of R245fa under the condition of different heat source temperature. Flash and binary power subsystem dominate the flash-binary power system, respectively, when the heat source temperature is 120? and 130?. The isotropic efficiency of modified compressor just between 0.2 and 0.25. The power output of per ton geofluid are 0.78 kWh/t and 1.31 kWh/t, respectively, when the heat source temperature are 120? and 130?. These results will predict the operation data of flash-binary power plant driven by the low-medium temperature geothermal water for construction in western of China.

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Banks, H. T., D. Cioranescu, A. K. Criner et W. P. Winfree. « Modeling the flash-heat experiment on porous domains ». Quarterly of Applied Mathematics 70, n^o 1 (1 janvier 2012) : 53–67. http://dx.doi.org/10.1090/s0033-569x-2011-01230-8.

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Pertsev, L. P., P. E. Novikov, E. P. Novikov et P. A. Kapustenko. « Intensification of heat transfer in flash film evaporators ». Chemical and Petroleum Engineering 28, n^o 8 (août 1992) : 467–70. http://dx.doi.org/10.1007/bf01152263.

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Kim, Kyoung Hoon, Hyung Jong Ko et Chul Ho Han. « Exergy Analysis of Kalina and Kalina Flash Cycles Driven by Renewable Energy ». Applied Sciences 10, n^o 5 (6 mars 2020) : 1813. http://dx.doi.org/10.3390/app10051813.

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The Kalina cycle (KC) has been recognized as one of the most efficient conversion systems of low-grade heat sources. The Kalina flash cycle (KFC) is a recently proposed novel cycle which is equipped with an additional flash process to the KC. In this study, the exergy performance of KC and KFC driven by a low-grade heat source are investigated comparatively. The dependence of the exergy destruction at each component as well as the system’s exergy efficiency on ammonia concentration, separator pressure and, additionally, flash pressure for KFC, are systematically investigated. Results showed that KFC can be optimized with respect to flash pressure on the base of exergy efficiency, and the component where largest exergy destruction occurs varies for different separator pressure and ammonia fraction in both systems. It is also shown that the maxima of net power production and exergy efficiency in KFC with optimal flash pressure are superior to those in KC.

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Chen, Kuo Wei. « The Key-Factor Modulation of Waste Tire Pyrolysis in Resource Chemical Plant for Recovered Fuel Production ». Advanced Materials Research 852 (janvier 2014) : 772–75. http://dx.doi.org/10.4028/www.scientific.net/amr.852.772.

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The study was to investigate the pyrolysis technology of the Recovered Fuel produced from waste tire. Waste tire block was disposed of the pyrolysis in resource chemical plant to produce the Recovered Fuel. The pyrolysis operation was controlled by a Catalyst, pyrolysis temperature and reaction time. In general, the set flash point, sulfur content and heat value of the Recovered Fuel ameliorate with the reaction time for significant impact. The set flash point and heat value of the Recovered Fuel ameliorate with the pyrolysis temperature for significant impact. The set flash point, sulfur content and heat value of the Recovered Fuel ameliorate with the pyrolysis processing Catalyst B13A.The results also show the production techniques and commercialization of marketing orientation in accordance with appropriate operating conditions in this study.

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Chen, Kuo Wei. « The Applicant Feasibility Study of Recovered Fuel after Waste Tire Pyrolysis ». Advanced Materials Research 852 (janvier 2014) : 776–79. http://dx.doi.org/10.4028/www.scientific.net/amr.852.776.

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The present research was involved in forming Pyrolysis condition of Catalysis, Pyrolysis Temperature and Reaction Time etc. In addition to ameliorate Flash Point, Sulfur content and Heat Value of the Recovered Fuel from Waste Tire after pyrolysis process in resource chemical plant. This study explored optimal pyrolysis condition of Recovered Fuel production based to improve its Flash point, sulfur content and heat value. The results can serve as a reference to the Recovered Fuel production process design. Improve Recovered Fuel quality, reduce energy consumption and sulfur content, flash point and heat value of Recovered Fuel can meet the national standards. Besides finding a suitable pyrolysis condition, this study also conducted analysis on product property and developed technique to improve process and product property, as an important reference for future studies.

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Zhang, Yuqing, Qinglong You, Changchun Chen, Jing Ge et Muhammad Adnan. « Evaluation of Downscaled CMIP5 Coupled with VIC Model for Flash Drought Simulation in a Humid Subtropical Basin, China ». Journal of Climate 31, n^o 3 (18 janvier 2018) : 1075–90. http://dx.doi.org/10.1175/jcli-d-17-0378.1.

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Abstract Compared to traditional drought events, flash droughts evolve rapidly during short-term extreme atmospheric conditions, with a lasting period of one pentad to several weeks. There are two main categories of flash droughts: the heat wave flash drought (HWFD), which is mainly caused by persistent high temperatures (heat waves), and the precipitation deficit flash drought (PDFD), which is mainly triggered by precipitation deficits. The authors’ previous research focused on the characteristics and causes of flash drought based on meteorological observations and Variable Infiltration Capacity (VIC) model simulations in a humid subtropical basin (Gan River basin, China). In this study, the authors evaluated the downscaled phase 5 of the Coupled Model Intercomparison Project (CMIP5) models’ simulations, coupled with the VIC model (CMIP5–VIC) in reproducing flash droughts in a humid subtropical basin in China. Most downscaled CMIP5–VIC simulations can reproduce the spatial patterns of flash droughts with respect to the benchmarks. The coupled models fail to readily replicate interannual variation (interannual pentad change), but most models can reflect the interannual variability (temporal standard deviation) and long-term average pentads of flash droughts. It is difficult to simultaneously depict both the spatial and temporal features of flash droughts within only one coupled model. The climatological patterns of the best multimodel ensemble mean are close to those of the all-model ensemble mean, but the best multimodel ensemble mean has a minimal bias range and relatively low computational burden.

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Wang, Jing Fu, Yong Zhang, Wei Wang et Yong Zhi Zhang. « Comparative Analysis of Electric Power and Steam Loss Rate between Single Flash and Binary Geothermal Power System with Single Screw Expander ». Advanced Materials Research 354-355 (octobre 2011) : 325–28. http://dx.doi.org/10.4028/www.scientific.net/amr.354-355.325.

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In this paper, cycle efficiency, net electric power and steam lose rate are calculated between the single flash and binary geothermal power system. The prime mover is 10kW single screw expander. These parameters of the single flash system are calculated by rated inlet volume flow rate of the single screw expander. The heat absorption capacity of both systems is determined to be equivalent. The working fluids of binary system are R134a, R245fa, and R600a. Those parameters of binary system are calculated with the condition that the saturated temperature of the working fluid before pump is 22°C. Engineering Equation Solver (EES) software is used for analysis. The results show that electric power of the single flash system is on the rise and steam loss rate of the single flash system is on the decrease with an increase of the inlet temperature between 100°C and 155°C. From the same heat absorption capacity, the binary system has apparent improvement in electric power and efficiency. The efficiency of binary system can increase by 2.1% compared with single flash system.

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Wang, Zhi Yu, Song Zhou, Bang Long Zhang, Cai Ling Li et He Fu Zhang. « Study on Marine Diesel Engine Waste Heat Recovery System with Multi-Stage Flash ». Advanced Materials Research 709 (juin 2013) : 297–300. http://dx.doi.org/10.4028/www.scientific.net/amr.709.297.

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As international oil price rise rapidly, the proportion of the fuel cost share of the transport cost has become increasingly high. At the same time, in order to reduce CO2 emission, the meeting of MPEC formulated and adopted the resolution on EEDI, so saving energy and reducing emission has become a marine industry benchmark. In this paper, through the study on marine diesel engine waste heat recovery system with multi-stage flash, establishing the universal model of multi-stage flash unit, and optimizing the parameters of the low-temperature waste heat recovery system with multi-stage flash. This paper constructs the power equation in matrix model, and each matrix of the model has a simple rule to be filled in, which make it versatile, and suitable for computerization, through estimating the power generation and CO2 emission reduction of the system on main diesel engine different loads, analyzing the waste heat recovery system with economic method finally.

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Černe, Borut, Jože Duhovnik et Jože Tavčar. « Semi-analytical flash temperature model for thermoplastic polymer spur gears with consideration of linear thermo-mechanical material characteristics ». Journal of Computational Design and Engineering 6, n^o 4 (18 mars 2019) : 617–28. http://dx.doi.org/10.1016/j.jcde.2019.03.001.

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Abstract The temperature increase that occurs during running of a polymer gear pair can be divided into two components: the nominal and flash temperatures. The latter denotes the short-term temperature increase that takes place during a gear meshing cycle. A thorough analysis of the flash temperature yields an insight into the heat dissipation process, which also determines the nominal temperature increase. We focus here on the flash component using numerical and analytical computation tools, with which we can obtain realistic predictions of the temperature increase during a gear meshing cycle. The analysis is performed using a decoupled procedure that involves a mechanical finite element analysis, followed by a semi-analytical temperature evaluation method based on the computed mechanical response of the system. With it, we obtain an improved flash temperature model that offers an accurate representation of the real life thermo-mechanical processes taking place at the gear teeth contact interfaces. Highlights Sliding friction during polymer gear meshing generates dominant part of heat losses. The developed flash temperature model is based on numerical and analytical tools. Meshing kinematics influence considerably the frictional losses and temperature rise. Flash temperature model applicable to any type of spur gear geometry. The model provides necessary groundwork for long term nominal temperature analysis.

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Kim, Kyoung, Chul Han et Hyung Ko. « Comparative Thermodynamic Analysis of Kalina and Kalina Flash Cycles for Utilizing Low-Grade Heat Sources ». Energies 11, n^o 12 (27 novembre 2018) : 3311. http://dx.doi.org/10.3390/en11123311.

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The Kalina flash cycle (KFC) is a novel, recently proposed modification of the Kalina cycle (KC) equipped with a flash vessel. This study performs a comparative analysis of the thermodynamic performance of KC and KFC utilizing low-grade heat sources. How separator pressure, flash pressure, and ammonia mass fraction affect the system performance is systematically and parametrically investigated. Dependences of net power and cycle efficiencies on these parameters as well as the mass flow rate, heat transfer rate and power production at the cycle components are analyzed. For a given set of separator pressure and ammonia mass fraction, there exists an optimum flash pressure making exergy efficiency locally maximal. For these pressures, which are higher for higher separator pressure and lower ammonia mass fraction, KFC shows better performance than KC both in net power and cycle efficiencies. At higher ammonia mass fraction, however, the difference is smaller. While the maximum power production increases with separator pressure, the dependence is quite weak for the maximum values of both efficiencies.

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Kim, Seog-Kwang, et Yong-Jin Kim. « Improvement of specific heat measurement by the flash method ». Thermochimica Acta 455, n^o 1-2 (avril 2007) : 30–33. http://dx.doi.org/10.1016/j.tca.2006.11.028.

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Kövér, Michal, Mária Behúlová, Marián Drienovský et Petr Motyčka. « Determination of the specific heat using laser flash apparatus ». Journal of Thermal Analysis and Calorimetry 122, n^o 1 (16 mai 2015) : 151–56. http://dx.doi.org/10.1007/s10973-015-4748-0.

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Arabaci, Uğur, et Şafhak Turan. « Weldability of austempered rail steel using the flash-butt process ». Materials Testing 63, n^o 7 (1 juillet 2021) : 662–67. http://dx.doi.org/10.1515/mt-2020-0105.

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Abstract In this study, bainitic microstructure was formed via heat treatmenton R260 rail steel, which is generally used in railways. Bainitic steel, which is considered more advantageous than current rail steel, waswelded by flash butt welding, which is often used for joining rails andthe mechanical and microstructure of the samples were thenexamined and compared. Bainitic structural steel obtained by austempering heattreatment with normal rail steel was welded by flash butt welding. Flash-butt welding parameters were kept constant during the experiment. The welding capabilities of the joints were compared and the results wereevaluated. It was determined that the bainite structure obtained as a result of austempering heat treatment changes the microstructuralproperties of the samples and affects the mechanical values of the joints.

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Haibao, WANG, YANG Zisen, LV Yanchun, MA Changwen et WANG Weihua. « The Analysis of Heat Affected Zone Width of Vehicle Wheel Rim Flash Butt Welding ». MATEC Web of Conferences 175 (2018) : 02016. http://dx.doi.org/10.1051/matecconf/201817502016.

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The FEM model of temperature field was built using FEM soft of ANSYS according to flash butt welding parameters: the amount of burnt the time of burnt and the velocity of burnt which come from four manufacturing vehicle wheels factories. Then the heat affected zone width of four factories was analyzed, as a result that the higher of the velocity of burnt, the narrower of the heat affected zone width, consequently, the guidance of flash butt welding parametres can be offered to manufacturing vehicle wheels factories.

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Hou, Zhen-Bing, et R. Komanduri. « Magnetic Field Assisted Finishing of Ceramics—Part III : On the Thermal Aspects of Magnetic Abrasive Finishing (MAF) of Ceramic Rollers ». Journal of Tribology 120, n^o 4 (1 octobre 1998) : 660–67. http://dx.doi.org/10.1115/1.2833763.

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Conditions during finishing of advanced ceramics by magnetic abrasive finishing (MAF) processes are found to be, by and large, transient. Consequently, the available quasi-steady-state solutions for the moving heat sources are not directly applicable for this case. Hence, the general solution for a moving disk heat source, developed in Part I of this three-part series, is applied to determine the minimum flash temperatures and flash times generated at the contact points between the workmaterial (Si3N4 roller) and the abrasive (Cr2O3)). Since chemo-mechanical action between the abrasive—the workmaterial—the environment depends on both the thermodynamics and kinetics of the process, it is important to determine the flash temperatures as well as flash times during polishing. These were determined as a function of the polishing pressure and the rotational speed of the work material in this investigation. Thermodynamic considerations (not covered in this paper) indicate that even the minimum flash temperatures generated under the conditions of lower pressure, lower sliding velocity, and transient state would be adequate to initiate chemo-mechanical action, and experimental results confirmed the formation of chemo-mechanical reaction products during polishing (Bhagavatula and Komanduri, 1996).

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Kuhlmann-Wilsdorf, D. « Temperatures at Interfacial Contact Spots : Dependence on Velocity and on Role Reversal of Two Materials in Sliding Contact ». Journal of Tribology 109, n^o 2 (1 avril 1987) : 321–29. http://dx.doi.org/10.1115/1.3261361.

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Based on the theory by Blok and Jaeger, simple equations have been obtained for the theoretical evaluation of flash temperatures, i.e., the temperatures of circular or elliptical contact spots between two homogeneous materials, when friction heat and/or Joule heat is evolved at the interface. The parameters appearing in the equations have been expressed in terms of experimental data, the coefficient of friction, known materials properties, and the ellipticity and number of contact spots. The equations are especially simple in the limiting cases of very high and of very low speeds, and were indeed known in these limits for circular, albeit not for elliptical contact spots. As an example, the flash temperatures of plastic contact spots on account of friction heat have been computed for (i) an electrical brush material sliding on copper, and (ii) a carbon steel sliding on itself. In these examples the dependence of the flash temperature on the velocity of the contact spots relative to either or both of the two sides has been investigated, wherein the effect of sliding rate on the flash temperature via the strain rate dependence of local hardness has been taken into consideration,- it is believed for the first time in any theoretical investigation of flash temperatures. In the high-speed case, in agreement with intuitive expectation, the numerical examples show that under otherwise same conditions and same macroscopic velocity, minimum flash temperature is attained when the spot moves relative to both sides. Typically, that minimum does not occur when the contact spot speed is one half of the relative speed on each of the two sides, however. Moreover, and somewhat unexpectedly, the results show that the previously neglected strain rate dependence of the hardness has a considerable effect.

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Gao, Jianqun, Si C. Lee, Xiaolan Ai et Harvey Nixon. « An FFT-Based Transient Flash Temperature Model for General Three-Dimensional Rough Surface Contacts ». Journal of Tribology 122, n^o 3 (21 septembre 1999) : 519–23. http://dx.doi.org/10.1115/1.555395.

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A transient flash temperature model was developed based on a Fast Fourier Transform method. An analytical expression for the heat partition function was obtained. Together, these substantially increase the speed of flash temperature calculations. The effect of surface topography on the flash temperature was examined. According to the simulation results, the surface with a longitudinal roughness produced a noticeably higher flash temperature than the surface with a transverse roughness. The simulation results also indicate that there is a significant cross-heating activity between the asperities; the temperature profiles appeared surprisingly gradual although their contact pressures had extremely sharp peaks. [S0742-4787(00)04002-9]

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Chvertko, P. N., L. A. Semyonov et K. V. Gushchin. « Flash-butt welding of thin-walled profiles of heat-hardened aluminium alloysflash-butt welding of thin-walled profiles of heat-hardened aluminium alloys ». Paton Welding Journal 2014, n^o 12 (28 décembre 2014) : 32–35. http://dx.doi.org/10.15407/tpwj2014.12.07.

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Tian, Xuefeng, et Francis E. Kennedy. « Maximum and Average Flash Temperatures in Sliding Contacts ». Journal of Tribology 116, n^o 1 (1 janvier 1994) : 167–74. http://dx.doi.org/10.1115/1.2927035.

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The surface temperature rise for a semi-infinite body due to different moving heat sources is analyzed for the entire range of Peclet number using a Green’s function method. Analytical and approximate solutions of maximum and average surface temperatures are obtained for the cases of square uniform, circular uniform, and parabolic heat sources. Considering the heat partition between the two contacting bodies, solutions of interface flash temperature are presented for the general sliding contact case as well as for the case of sliding contact between two moving asperities.

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Bucă, Anca M., Mihai Oane, Ion N. Mihăilescu, Muhammad Arif Mahmood, Bogdan A. Sava et Carmen Ristoscu. « An Analytical Multiple-Temperature Model for Flash Laser Irradiation on Single-Layer Graphene ». Nanomaterials 10, n^o 7 (5 juillet 2020) : 1319. http://dx.doi.org/10.3390/nano10071319.

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A Multiple-Temperature Model is proposed to describe the flash laser irradiation of a single layer of graphene. Zhukovsky’s mathematical approach is applied to solve the Fourier heat equations based upon quantum concepts, including heat operators. Easy solutions were inferred with respect to classical mathematics. Thus, simple equations were set for the electrons and phonon temperatures in the case of flash laser treatment of a single layer of graphene. Our method avoids the difficulties and extensive time-consuming nonequilibrium green function method or quantum field theories when applied in a condensed matter. Simple expressions were deduced that could prove useful for researchers.

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Zhang, Dan, Daotong Chong, Junjie Yan et Bingchao Zhao. « Experimental study on static flash evaporation of aqueous NaCl solution at different flash speed : Heat transfer characteristics ». International Journal of Heat and Mass Transfer 65 (octobre 2013) : 584–91. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2013.06.042.

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Chantry, Caroline J., Kiersten Israel-Ballard, Zina Moldoveanu, Jan Peerson, Anna Coutsoudis, Lindiwe Sibeko et Barbara Abrams. « Effect of Flash-Heat Treatment on Immunoglobulins in Breast Milk ». JAIDS Journal of Acquired Immune Deficiency Syndromes 51, n^o 3 (juillet 2009) : 264–67. http://dx.doi.org/10.1097/qai.0b013e3181aa12f2.

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SHINGU, Kazuma, Sadami YOSHIYAMA et Hisashi WADAHAMA. « 4C3 A Study of a Flash Boiling Powered Heat Engine ». Proceedings of Conference of Kyushu Branch 2014 (2014) : _4C3–1_—_4C3–2_. http://dx.doi.org/10.1299/jsmekyushu.2014._4c3-1_.

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Chantry, Caroline J., Jean Wiedeman, Gertrude Buehring, Janet M. Peerson, Kweku Hayfron, Okumu K'Aluoch, Bo Lonnerdal, Kiersten Israel-Ballard, Anna Coutsoudis et Barbara Abrams. « Effect of Flash-Heat Treatment on Antimicrobial Activity of Breastmilk ». Breastfeeding Medicine 6, n^o 3 (juin 2011) : 111–16. http://dx.doi.org/10.1089/bfm.2010.0078.

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Zhang, Yousen, Jinshi Wang, Jiping Liu, Daotong Chong, Wei Zhang et Junjie Yan. « Experimental study on heat transfer characteristics of circulatory flash evaporation ». International Journal of Heat and Mass Transfer 67 (décembre 2013) : 836–42. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2013.08.088.

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Iqbal, Md Arbab, Mahdi Ahmadi, Farah Melhem, Sohel Rana, Aliakbar Akbarzadeh et Abhijit Date. « Power Generation from Low Grade Heat Using Trilateral Flash Cycle ». Energy Procedia 110 (mars 2017) : 492–97. http://dx.doi.org/10.1016/j.egypro.2017.03.174.

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Guo, Guangyu, et Chao Zhu. « A modified lumped heat capacity model for droplet flash cooling ». International Communications in Heat and Mass Transfer 127 (octobre 2021) : 105557. http://dx.doi.org/10.1016/j.icheatmasstransfer.2021.105557.

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Hwang, Changhun, et Jondo Yun. « Effect of Processing Conditions on the Flash Onset Temperature in Hydroxyapatite ». Materials 14, n^o 18 (11 septembre 2021) : 5229. http://dx.doi.org/10.3390/ma14185229.

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When heat and electric field are applied to the sample, sintering takes place within a short time of a few seconds by the flash phenomenon that occurs. In what condition flash does occur is a main issue for the flash sintering technique. In this study, the effect of processing conditions such as sintering atmosphere, sample size, density and grain size on the flash onset of hydroxyapatite was investigated. In a vacuum atmosphere, a flash occurred at a lower temperature by 50–100 °C than in air. The smaller the thickness of the sample, the higher the flash onset temperature due to the larger specific surface area. Flash was also observed in samples which were presintered, having a density of 86–100% and a grain size of 0.2–0.9 μm. When the density and grain size of the sample were higher and larger, the flash onset temperature was higher. It was because the diffusion and conduction path through the grain boundary and the inner surface of the pores with high defect concentration are blocked with an increase of density or grain size. When an electric field was applied during flash sintering, a color change of the sample was observed and the reason was discussed.

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Lin, Yu-Jeng, Eric Chen et Gary T. Rochelle. « Pilot plant test of the advanced flash stripper for CO2 capture ». Faraday Discussions 192 (2016) : 37–58. http://dx.doi.org/10.1039/c6fd00029k.

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Alternative stripping processes have been proposed to reduce energy use for CO₂ capture, but only a few have been applied to pilot-scale experiments. This paper presents the first pilot plant test results of one of the most promising stripper configurations, the advanced flash stripper with cold and warm rich solvent bypass. The campaign using aqueous piperazine was carried out at UT Austin in 2015. The advanced flash stripper improves the heat duty by over 25% compared to previous campaigns using the two-stage flash, achieving 2.1 GJ per tonne CO₂ of heat duty and 32 kJ mol⁻¹ CO₂ of total equivalent work. The bypass control strategy proposed minimized the heat duty. The test successfully demonstrated the remarkable energy performance and the operability of this advanced system. An Aspen Plus® model was validated using the pilot plant data and used to explore optimum operating and design conditions. The irreversibility analysis showed that the pilot plant performance has attained 50% thermodynamic efficiency and further energy improvement should focus on the absorber and the cross exchanger by increasing absorption rate and solvent capacity.

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Koster, R. D., S. D. Schubert, H. Wang, S. P. Mahanama et Anthony M. DeAngelis. « Flash Drought as Captured by Reanalysis Data : Disentangling the Contributions of Precipitation Deficit and Excess Evapotranspiration ». Journal of Hydrometeorology 20, n^o 6 (1 juin 2019) : 1241–58. http://dx.doi.org/10.1175/jhm-d-18-0242.1.

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Abstract Flash droughts—uncharacteristically rapid dryings of the land system—are naturally associated with extreme precipitation deficits. Such precipitation deficits, however, do not tell the whole story, for land surface drying can be exacerbated by anomalously high evapotranspiration (ET) rates driven by anomalously high temperatures (e.g., during heat waves), anomalously high incoming radiation (e.g., from reduced cloudiness), and other meteorological anomalies. In this study, the relative contributions of precipitation and ET anomalies to flash drought generation in the Northern Hemisphere are quantified through the analysis of diagnostic fields contained within the MERRA-2 reanalysis product. Unique to the approach is the explicit treatment of soil moisture impacts on ET through relationships diagnosed from the reanalysis data; under this treatment, an ET anomaly that is negative relative to the local long-term climatological mean is still considered positive in terms of its contribution to a flash drought if it is high for the concurrent value of soil moisture. Maps produced in the analysis show the fraction of flash drought production stemming specifically from ET anomalies and illustrate how ET anomalies for some droughts are related to temperature and radiation anomalies. While ET is found to have an important impact on flash drought production in the central United States and in parts of Russia known from past studies to be prone to heat wave–related drought, and while this impact does appear stronger during the onset (first several days) of flash droughts, overall the contribution of ET to these droughts is small relative to the contribution of precipitation deficit.

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Md Arbab, Iqbal, Rana Sohel, Ahmadi Mahdi, Close Thomas, Date Abhijit et Akbarzadeh Aliakbar. « Prospects of Trilateral Flash Cycle (TFC) for Power Generation from Low Grade Heat Sources ». E3S Web of Conferences 64 (2018) : 06004. http://dx.doi.org/10.1051/e3sconf/20186406004.

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Despite the current energy crisis, a large amount of low grade heat (below 100oC) is being wasted for the lack of cost effective energy conversion technology. In the case of the conventional Organic Rankine Cycle (ORC) based geothermal power stations, only about 20% of available heat can be utilised due to a technological limitation as there is a phase change in the working fluid involved during the addition of heat which decreases utilisation effectiveness of the system. Therefore, in this paper, a trilateral flash cycle (TFC) based system has been studied to find out its prospect for utilizing more power from the same heat resources as the ORC. The TFC is a thermodynamic cycle that heats the working fluid as a saturated liquid from which it starts its expansion stage. The flash expansion is achieved by feeding the saturated high-pressured liquid working fluid through a convergent-divergent nozzle at which point it undergoes a flash expansion in the low-pressure environment of the generator housing. The momentum of the working fluid is extracted via a Pelton wheel and the cycle is completed with working fluid condensation and pressurisation. The analytical comparative study between the ORC and TFC based system shows that the TFC has about 50% more power generation capability and almost zero contribution on global warming.

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Kim, Kyoung. « Thermodynamic Performance and Optimization Analysis of a Modified Organic Flash Cycle for the Recovery of Low-Grade Heat ». Energies 12, n^o 3 (30 janvier 2019) : 442. http://dx.doi.org/10.3390/en12030442.

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The recently proposed organic flash cycle (OFC) has the potential for the efficient recovery of low-grade heat, mainly due to the reduction of irreversibilities in the heat input unit. In the present study, a modified OFC (OFCM) employing a two-phase expander (TPE) and regeneration is proposed and thermodynamic and optimization analysis on this cycle is conducted compared with the basic OFC (OFCB). Six substances are considered as the working fluids. Influences of flash temperature, source temperature, and working fluid are systemically investigated on the system performance. Results showed that OFCM is superior to OFCB in the aspects of power production, thermal, and second-law efficiencies.

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Martinka, Jozef, Peter Rantuch et Igor Wachter. « Impact of Water Content on Energy Potential and Combustion Characteristics of Methanol and Ethanol Fuels ». Energies 12, n^o 18 (10 septembre 2019) : 3491. http://dx.doi.org/10.3390/en12183491.

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Methanol and ethanol are among the most important biofuels and raw materials used to produce biorenewable fuels. These fuels are used with varying water contents. Nevertheless, the exact impact of the water content of these fuels on the energy potential and combustion characteristics is still unknown. Besides that, there are two noticeable risks (environmental impact of combustion and fire risk) associated with their production, processing, and utilization. Likewise, impact of the water content of these fuels on fire risk and the impact of their combustion on the environment is also unknown. The best indicator of energy potential is the effective heat of combustion, and the best combustion characteristic and indicator of the impact of the combustion of alcohols on the environment is the carbon monoxide (CO) yield, whereas the fire risk of liquid fuels is quantified by the flash point and maximum heat release rate (mHRR). The dependency of flash point on the water content was determined via the Pensky-Martens apparatus and the dependencies of the effective heat of combustion, CO yield, and mHRR on the water content were determined via the cone calorimeter. With increased water content, the flash points of both methanol and ethanol exponentially increased and the both effective heat of combustion and mHRR almost linearly decreased. In the range of water content from 0 to 60%, the CO yield of both methanol and ethanol was practically independent of the water content.

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Lim, Da-In, So-Jeong Lee, Seung-Boo Jung et Jun-Ki Kim. « Thermal Conductivity Measurement Method for the Thin Epoxy Adhesive Joint Layer ». Journal of Welding and Joining 39, n^o 4 (30 août 2021) : 402–8. http://dx.doi.org/10.5781/jwj.2021.39.4.8.

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Epoxy adhesives, particularly for non-conductive pastes, are used in 3D chip-stack flip-chip packages to reinforce the mechanical strength of joints. Although the thickness of the adhesive layer is relatively small, its thermal conductivity is known to have a major effect on the heat dissipation behavior of chipstack packages. Because conventional thermal conductivity measurement methods such as the laser flash method are based on the bulk specimens having thicknesses greater than several mm, they are limited in their ability to measure the thermal conductivity of thin adhesive layers between silicon dies. In this study, a modified guarded hot-plate method is proposed using standard joint layer samples of known thermal conductivity, and the measurement results are compared with those of the laser flash method. Results showed that, based on a constant heat flux from heat source to heat sink, the temperature difference at both sides of the joint layers was proportional to the thermal resistivity of the joint layer materials. The thermal conductivity of the under-test joint layer could therefore be determined from the thermal conductivity spectrum of the known samples using a graphical method. Although the measured values by the modified guarded hot-plate method were slightly higher than those derived from the laser flash method due to the thickness effect, it was concluded that the modified guarded hot-plate method could be a practical method in measuring the thermal conductivity of thin adhesive joint layers.

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Baptista, C. A. R. P., H. V. Ribeiro, M. S. F. Lima, Marcelo A. S. Torres et D. H. S. Costa. « Fracture Resistance of Flash Welded and Laser Welded Butt Joints in a Microalloyed HSLA Steel ». Key Engineering Materials 754 (septembre 2017) : 248–51. http://dx.doi.org/10.4028/www.scientific.net/kem.754.248.

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High-strength, low-alloy (HSLA) steels are widely used in the automotive and oil industries due to their good mechanical properties and weldability. The selection of the welding process depends on several factors, including the quality of the weld bead and the production capacity. The knowledge of the mechanical performance of the welded joint is essential to ensure structural reliability. In the present work, butt joints were produced from 5 mm thick plates of a microalloyed HSLA steel by flash welding and by laser welding processes, the latter using two different heat input conditions. The microsctructure and hardness of the weld beads were evaluated. The fracture toughness of the welded joints was assessed by means of CTOD tests. The higher heat input laser welded joint presented critical CTOD comparable to that of the flash welded joint, whereas the lower heat input martensitic-bainitic laser welded joint tended to a brittle behavior.

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Erlingis, Jessica M., Jonathan J. Gourley et Jeffrey B. Basara. « Diagnosing Moisture Sources for Flash Floods in the United States. Part II : Terrestrial and Oceanic Sources of Moisture ». Journal of Hydrometeorology 20, n^o 8 (25 juillet 2019) : 1511–31. http://dx.doi.org/10.1175/jhm-d-18-0120.1.

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Abstract Backward trajectories were derived from North American Regional Reanalysis data for 19 253 flash flood reports published by the National Weather Service to determine the along-path contribution of the land surface to the moisture budget for flash flood events in the conterminous United States. The impact of land surface interactions was evaluated seasonally and for six regions: the West Coast, Arizona, the Front Range, Flash Flood Alley, the Missouri Valley, and the Appalachians. Parcels were released from locations that were impacted by flash floods and traced backward in time for 120 h. The boundary layer height was used to determine whether moisture increases occurred within the boundary layer or above it. Moisture increases occurring within the boundary layer were attributed to evapotranspiration from the land surface, and surface properties were recorded from an offline run of the Noah land surface model. In general, moisture increases attributed to the land surface were associated with anomalously high surface latent heat fluxes and anomalously low sensible heat fluxes (resulting in a positive anomaly of evaporative fraction) as well as positive anomalies in top-layer soil moisture. Over the ocean, uptakes were associated with positive anomalies in sea surface temperatures, the magnitude of which varies both regionally and seasonally. Major oceanic surface-based source regions of moisture for flash floods in the United States include the Gulf of Mexico and the Gulf of California, while boundary layer moisture increases in the southern plains are attributable in part to interactions between the land surface and the atmosphere.

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Chen, Wen, Ya Li Jin, Shao Wen Liu et Zhou Hua Zeng. « Simulation and Experimental Study on Methanol Recovery in Continuous Production of Biodiesel via Supercritical Transesterification ». Advanced Materials Research 550-553 (juillet 2012) : 452–57. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.452.

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Recycling excessive methanol is simulated and experimentalized by adiabatic flash evaporation. The simulated results show that: methanol recovery and methanol purity in gas phase for one-stage flash process are almost same with two-stage flash process and one-stage flash process is more beneficial by thinking of equipment and operation cost. The experimental results show that flash pressure has a significant influence on methanol recovery and methanol purity in gas phase which can be effectively improved when flashing pressure is reduced. Meanwhile, reaction temperature and reaction pressure also have important effects on methanol recovery and methanol purity in gas phase. For continuous producing biodiesel in supercritical methanol, when the reaction temperature, the reaction pressure and the molar ratio of methanol/oil are kept at 300°C, 15 MPa and 25:1, respectively, methanol recovery and methanol purity in gas phase can reach 90% and 98.8% respectively if the flashing pressure is kept at 0.2MPa. Therefore, the flash evaporation device coupled with tubular reactor for high purity separation of methanol is very effective which can realize comprehensive utilization of heat energy and separation and recycle of methanol.

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Sinclair, G. B. « On Multiple Moving Sources of Heat and Implications for Flash Temperatures ». Journal of Heat Transfer 116, n^o 1 (1 février 1994) : 230–33. http://dx.doi.org/10.1115/1.2910862.

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Stankus, S. V., et I. V. Savchenko. « Laser flash method for measurement of liquid metals heat transfer coefficients ». Thermophysics and Aeromechanics 16, n^o 4 (décembre 2009) : 585–92. http://dx.doi.org/10.1134/s0869864309040076.

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Engerer, J. D., et T. S. Fisher. « Flash boiling from carbon foams for high-heat-flux transient cooling ». Applied Physics Letters 109, n^o 2 (11 juillet 2016) : 024102. http://dx.doi.org/10.1063/1.4958117.

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Zhang, Zhiwei, Qiang Li et Dinghua Hu. « Experimental investigation on heat transfer characteristics of R1336mzz flash spray cooling ». Applied Thermal Engineering 174 (juin 2020) : 115277. http://dx.doi.org/10.1016/j.applthermaleng.2020.115277.

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