The flow between a grooved and a flat plate was presented to investigate the effects of groove on the behavior of hydro-viscous drive. The flow was solved by using computational fluid dynamics (CFD) code, Fluent. Para...The flow between a grooved and a flat plate was presented to investigate the effects of groove on the behavior of hydro-viscous drive. The flow was solved by using computational fluid dynamics (CFD) code, Fluent. Parameters related to the flow, such as velocity, pressure, temperature, axial force and viscous torque, are obtained. The results show that pressure at the upstream notch is negative, pressure at the downstream notch is positive and pressure along the film thickness is almost the same. Dynamic pressure peak decreases as groove depth or groove number increases, but increases as output rotary speed increases. Consequently, the groove depth is suggested to be around 0.4 mm. Both the groove itself and groove parameters (i.e. groove depth, groove number) have little effect on the flow temperature. Circumferential pressure gradient induced by the groove weakens the viscous torque on the grooved plate (driven plate) greatly. It has little change as the groove depth increases. However, it decreases dramatically as the groove number increases. The experiment results show that the trend of experimental temperature and pressure are the same with numerical results. And the output rotary speed also has relationship with input flow rate and flow temperature.展开更多
Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water whe...Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water when the low temperature was 20 ℃. The following results were obtained: the highest temperature at the condenser outlet reached about 85 ℃; when the difference between the water temperatures at the condenser outlet and the evaporator inlet was less than 40 ℃, the coefficient of performance (COP) was larger than 4; when the difference reached 55 ℃, the COP still kept 3; the discharge temperature of BY-3 was lower than 100 ℃, and the refrigerant vapor pressure kept lower than 1.8 MPa. When the water temperature at the condenser outlet reached over 85 ℃, nearly a 5 ℃ superheating temperature was maintained.展开更多
The solubilities of nizatidine in methanol + water, ethanol + water and i-propanol + water mixtures were determined in the temperature range from 273.15 K to 303.15 K at atmospheric pressure by a static analytical met...The solubilities of nizatidine in methanol + water, ethanol + water and i-propanol + water mixtures were determined in the temperature range from 273.15 K to 303.15 K at atmospheric pressure by a static analytical method. The general single model was used to correlate the experimental data, which fits the data very well.展开更多
The comers with small radii on cross sections are crucial for forming hydroformed components with polygonal sections. In this paper, warm hydroforming experiments of AZ61A magnesium alloy tubes were cartied out to stu...The comers with small radii on cross sections are crucial for forming hydroformed components with polygonal sections. In this paper, warm hydroforming experiments of AZ61A magnesium alloy tubes were cartied out to study the forming regularity of round comers by using a demonstration part with square sections. Effects of temperature on radius forming, thinning ratio distribution and microstructure were revealed and a component with relative outer corner radius of 3.0 was obtained by warm hydroforming at 240℃. The minimum thickness of the formed square section was located in the transition position between the corner and the straight wall. The thinning ratio of the round corner increased with the increase of forming temperature. Fotmability of the magnesium tube was improved by raising temperature under the effect of dynamic recrystallization at 240℃.展开更多
As an experimental technique, it’s desired that the temperature in specimen is uniform in high temperature split Hopkinson pressure bar (SHPB) experiments. However, the temperature in specimen decreases and the tempe...As an experimental technique, it’s desired that the temperature in specimen is uniform in high temperature split Hopkinson pressure bar (SHPB) experiments. However, the temperature in specimen decreases and the temperature of bars increases when specimen starts to contact with bars, which induces the nonuniform temperature distribution in specimen, and may result in inac-curacy of experimental results. In this paper, the temperature distributions of specimen and bars in high temperature SHPB experiments were investigated while the specimen was heated alone. Firstly, the temperature history of specimen was measured at different initial temperatures by ex-periments, then simulation was carried out. Simulation results were consistent with experimental results by adjusting the thermal contact coefficient between specimen and bars. By this way, the thermal contact coefficient and simulation results were validated, and the proper cold contact times of specimen and bars in high temperature SHPB experiments were discussed. Finally, the results were compared with those in references.展开更多
Most economically important tungsten(W)deposits are of magmatic-hydrothermal origin.The species and partitioning of W during fluid exsolution,considered to be the controlling factors for the formation of ore deposits,...Most economically important tungsten(W)deposits are of magmatic-hydrothermal origin.The species and partitioning of W during fluid exsolution,considered to be the controlling factors for the formation of ore deposits,are thus of great significance to investigate.However,this issue has not been well addressed mainly due to the significant difference in reported partition coefficients(e.g.,from strongly incompatible to strongly compatible)between fluid and melt(D_(W)^(fluid/melt)).Here,we used an in situ Raman spectroscopic approach to describe the W speciation,and to quantitatively determine the Dfluid/melt of individual and total W species in granite melts and coexisting Na2WO4 solutions at elevated temperatures(T;700–800C)and pressures(P;0.35–1.08 GPa).Results show that WO_(4)^(2-)and HWO4are predominant W species,and the fractions of these two species are similar in melt and coexisting fluid.The partitioning behaviors of WO_(4)^(2-)and HWO4are comparable,exhibiting strong enrichment in the fluid.The total DW fluid/melt ranges from 8.6 to 37.1.Specifically,DW fluid/melt decreases with rising T–P,indicating that shallow exsolution favors enrichment of W in evolved fluids.Furthermore,Rayleigh fractionation modeling based on the obtained D_(W)^(fluid/melt)data was used to describe the fluid exsolution processes.Our results strongly support that fluid exsolution can serve as an important mechanism to generate W-rich oreforming fluids.This study also indicates that in situ approach can be used to further investigate the geochemical behavior of ore-forming elements during the magmatic-hydrothermal transition,especially for rare metals associated with granite and pegmatite.展开更多
Recent studies have shown that major nominally anhydrous minerals in the Earth's mantle, such as olivine, pyroxene and garnet, can incorporate considerable amounts of water as structurally bound hydroxyl. Even a s...Recent studies have shown that major nominally anhydrous minerals in the Earth's mantle, such as olivine, pyroxene and garnet, can incorporate considerable amounts of water as structurally bound hydroxyl. Even a small amount of water is present in mantle minerals, it can strongly affect a number of physical properties, including density, sound velocity, melting temperature, and electrical conductivities. The presence of water can also influence the dynamic behavior, lead to lateral velocity heterogeneities, and affect the material circulation of the Earth's deep interior. In particular, seismic studies have reported the existence of low-velocity zones in various locations of the Earth's upper mantle and transition zone, which has been expected to be associated with the presence of water in the region. In the past two decades, the effect of water on the elasticity and sound velocities of minerals at relevant pressure-temperature(P-T) conditions of the Earth's mantle attracted extensive interests. Combining the high P-T experimental and theoretical mineralogical results with seismic observations provides crucial constraints on the distribution of water in the Earth's mantle. In this study, we summarize recent experimental and theoretical mineral physics results on how water affects the elasticity and sound velocity of nominally anhydrous minerals in the Earth's mantle, which aims to provide new insights into the effect of hydration on the density and velocity profile of the Earth's mantle, which are of particular importance in understanding of water distribution in the region.展开更多
Tuite has been suggested as a potential reservoir for trace elements in the deep mantle,but no evidence confirms this supposition.By using a natural apatite as starting material,the trace-element-bearing tuite large c...Tuite has been suggested as a potential reservoir for trace elements in the deep mantle,but no evidence confirms this supposition.By using a natural apatite as starting material,the trace-element-bearing tuite large crystals were obtained under highpressure and high-temperature conditions(15 GPa and 1800 K).X-ray diffraction pattern and Micro-Raman spectrum of the run product confirm that tuite was synthesized.The concentrations of trace elements in tuite crystals were analyzed by laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS).The rare earth element patterns of tuite show enrichment of light rare earth elements relative to heavy rare earth elements.Tuite shows high concentrations of Th and Sr,and negative anomalies of Rb,Nb,and Hf.The results show that tuite can accommodate a large amount of trace elements.Tuite might be an important host to accommodate trace elements if there is much apatite subducted into the deep mantle.展开更多
In order to clarify the structure of the cold flow discharged from the counter-flow vortex tube(VT), the temperature and pressure of the cold flow were measured, and the existence and behavior of the reversed flow at ...In order to clarify the structure of the cold flow discharged from the counter-flow vortex tube(VT), the temperature and pressure of the cold flow were measured, and the existence and behavior of the reversed flow at the cold exit was studied using a simple flow visualization technique consisting of a 0.75mm-diameter needle, and an oil paint droplet. It is observed through this experiment that the Pitot pressure at the cold exit center can either be lower or higher than atmospheric pressure, depending on the inlet pressure and the cold fraction, and that a reversed flow is observed when the Pitot pressure at the cold exit center is lower than atmospheric pressure. In addition, it is observed that when reducing the cold fraction from unity at any arbitrary inlet pressure, the region of reversed and colder flow in the central part of cold exit extends in the downstream direction.展开更多
基金Project(50475106)supported by the National Natural Science Foundation of China
文摘The flow between a grooved and a flat plate was presented to investigate the effects of groove on the behavior of hydro-viscous drive. The flow was solved by using computational fluid dynamics (CFD) code, Fluent. Parameters related to the flow, such as velocity, pressure, temperature, axial force and viscous torque, are obtained. The results show that pressure at the upstream notch is negative, pressure at the downstream notch is positive and pressure along the film thickness is almost the same. Dynamic pressure peak decreases as groove depth or groove number increases, but increases as output rotary speed increases. Consequently, the groove depth is suggested to be around 0.4 mm. Both the groove itself and groove parameters (i.e. groove depth, groove number) have little effect on the flow temperature. Circumferential pressure gradient induced by the groove weakens the viscous torque on the grooved plate (driven plate) greatly. It has little change as the groove depth increases. However, it decreases dramatically as the groove number increases. The experiment results show that the trend of experimental temperature and pressure are the same with numerical results. And the output rotary speed also has relationship with input flow rate and flow temperature.
基金Supported by Major State Basic Research Development Program of China ("973" Program, No. 2009CB219907)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT0936)
文摘Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water when the low temperature was 20 ℃. The following results were obtained: the highest temperature at the condenser outlet reached about 85 ℃; when the difference between the water temperatures at the condenser outlet and the evaporator inlet was less than 40 ℃, the coefficient of performance (COP) was larger than 4; when the difference reached 55 ℃, the COP still kept 3; the discharge temperature of BY-3 was lower than 100 ℃, and the refrigerant vapor pressure kept lower than 1.8 MPa. When the water temperature at the condenser outlet reached over 85 ℃, nearly a 5 ℃ superheating temperature was maintained.
基金Supported by the National Natural Science Foundation of China (20976160)the Research Fund for the Doctoral Program of Higher Education of China (20090101110134)
文摘The solubilities of nizatidine in methanol + water, ethanol + water and i-propanol + water mixtures were determined in the temperature range from 273.15 K to 303.15 K at atmospheric pressure by a static analytical method. The general single model was used to correlate the experimental data, which fits the data very well.
基金Sponsored by the National Natural Science Foundation of China for Distinguished Young Scholars(Grant No. 50525516)the National Key Technology R&D Program (Grant No. 2006BAE04B03)Program for New Century Excellent Talents in University
文摘The comers with small radii on cross sections are crucial for forming hydroformed components with polygonal sections. In this paper, warm hydroforming experiments of AZ61A magnesium alloy tubes were cartied out to study the forming regularity of round comers by using a demonstration part with square sections. Effects of temperature on radius forming, thinning ratio distribution and microstructure were revealed and a component with relative outer corner radius of 3.0 was obtained by warm hydroforming at 240℃. The minimum thickness of the formed square section was located in the transition position between the corner and the straight wall. The thinning ratio of the round corner increased with the increase of forming temperature. Fotmability of the magnesium tube was improved by raising temperature under the effect of dynamic recrystallization at 240℃.
文摘As an experimental technique, it’s desired that the temperature in specimen is uniform in high temperature split Hopkinson pressure bar (SHPB) experiments. However, the temperature in specimen decreases and the temperature of bars increases when specimen starts to contact with bars, which induces the nonuniform temperature distribution in specimen, and may result in inac-curacy of experimental results. In this paper, the temperature distributions of specimen and bars in high temperature SHPB experiments were investigated while the specimen was heated alone. Firstly, the temperature history of specimen was measured at different initial temperatures by ex-periments, then simulation was carried out. Simulation results were consistent with experimental results by adjusting the thermal contact coefficient between specimen and bars. By this way, the thermal contact coefficient and simulation results were validated, and the proper cold contact times of specimen and bars in high temperature SHPB experiments were discussed. Finally, the results were compared with those in references.
基金supported by the National Natural Science Foundation of China(41922023,41830428,42173038,41973055,and 42130109)the Research Funds for the Frontiers Science Center for Critical Earth Material Cycling(Nanjing University,China)the Fundamental Research Funds for the Central Universities,China(2022300192).
文摘Most economically important tungsten(W)deposits are of magmatic-hydrothermal origin.The species and partitioning of W during fluid exsolution,considered to be the controlling factors for the formation of ore deposits,are thus of great significance to investigate.However,this issue has not been well addressed mainly due to the significant difference in reported partition coefficients(e.g.,from strongly incompatible to strongly compatible)between fluid and melt(D_(W)^(fluid/melt)).Here,we used an in situ Raman spectroscopic approach to describe the W speciation,and to quantitatively determine the Dfluid/melt of individual and total W species in granite melts and coexisting Na2WO4 solutions at elevated temperatures(T;700–800C)and pressures(P;0.35–1.08 GPa).Results show that WO_(4)^(2-)and HWO4are predominant W species,and the fractions of these two species are similar in melt and coexisting fluid.The partitioning behaviors of WO_(4)^(2-)and HWO4are comparable,exhibiting strong enrichment in the fluid.The total DW fluid/melt ranges from 8.6 to 37.1.Specifically,DW fluid/melt decreases with rising T–P,indicating that shallow exsolution favors enrichment of W in evolved fluids.Furthermore,Rayleigh fractionation modeling based on the obtained D_(W)^(fluid/melt)data was used to describe the fluid exsolution processes.Our results strongly support that fluid exsolution can serve as an important mechanism to generate W-rich oreforming fluids.This study also indicates that in situ approach can be used to further investigate the geochemical behavior of ore-forming elements during the magmatic-hydrothermal transition,especially for rare metals associated with granite and pegmatite.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41590621 & 41473058)the Fundamental Research Funds for the Central Universities of China (Grant No. WK2080000097)
文摘Recent studies have shown that major nominally anhydrous minerals in the Earth's mantle, such as olivine, pyroxene and garnet, can incorporate considerable amounts of water as structurally bound hydroxyl. Even a small amount of water is present in mantle minerals, it can strongly affect a number of physical properties, including density, sound velocity, melting temperature, and electrical conductivities. The presence of water can also influence the dynamic behavior, lead to lateral velocity heterogeneities, and affect the material circulation of the Earth's deep interior. In particular, seismic studies have reported the existence of low-velocity zones in various locations of the Earth's upper mantle and transition zone, which has been expected to be associated with the presence of water in the region. In the past two decades, the effect of water on the elasticity and sound velocities of minerals at relevant pressure-temperature(P-T) conditions of the Earth's mantle attracted extensive interests. Combining the high P-T experimental and theoretical mineralogical results with seismic observations provides crucial constraints on the distribution of water in the Earth's mantle. In this study, we summarize recent experimental and theoretical mineral physics results on how water affects the elasticity and sound velocity of nominally anhydrous minerals in the Earth's mantle, which aims to provide new insights into the effect of hydration on the density and velocity profile of the Earth's mantle, which are of particular importance in understanding of water distribution in the region.
基金financially supported by National Natural Science Foundation of China(Grant No.40973045)
文摘Tuite has been suggested as a potential reservoir for trace elements in the deep mantle,but no evidence confirms this supposition.By using a natural apatite as starting material,the trace-element-bearing tuite large crystals were obtained under highpressure and high-temperature conditions(15 GPa and 1800 K).X-ray diffraction pattern and Micro-Raman spectrum of the run product confirm that tuite was synthesized.The concentrations of trace elements in tuite crystals were analyzed by laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS).The rare earth element patterns of tuite show enrichment of light rare earth elements relative to heavy rare earth elements.Tuite shows high concentrations of Th and Sr,and negative anomalies of Rb,Nb,and Hf.The results show that tuite can accommodate a large amount of trace elements.Tuite might be an important host to accommodate trace elements if there is much apatite subducted into the deep mantle.
文摘In order to clarify the structure of the cold flow discharged from the counter-flow vortex tube(VT), the temperature and pressure of the cold flow were measured, and the existence and behavior of the reversed flow at the cold exit was studied using a simple flow visualization technique consisting of a 0.75mm-diameter needle, and an oil paint droplet. It is observed through this experiment that the Pitot pressure at the cold exit center can either be lower or higher than atmospheric pressure, depending on the inlet pressure and the cold fraction, and that a reversed flow is observed when the Pitot pressure at the cold exit center is lower than atmospheric pressure. In addition, it is observed that when reducing the cold fraction from unity at any arbitrary inlet pressure, the region of reversed and colder flow in the central part of cold exit extends in the downstream direction.