To enhance the computational efficiency of spatio-temporally discretized phase-field models,we present a high-speed solver specifically designed for the Poisson equations,a component frequently used in the numerical c...To enhance the computational efficiency of spatio-temporally discretized phase-field models,we present a high-speed solver specifically designed for the Poisson equations,a component frequently used in the numerical computation of such models.This efficient solver employs algorithms based on discrete cosine transformations(DCT)or discrete sine transformations(DST)and is not restricted by any spatio-temporal schemes.Our proposed methodology is appropriate for a variety of phase-field models and is especially efficient when combined with flow field systems.Meanwhile,this study has conducted an extensive numerical comparison and found that employing DCT and DST techniques not only yields results comparable to those obtained via the Multigrid(MG)method,a conventional approach used in the resolution of the Poisson equations,but also enhances computational efficiency by over 90%.展开更多
以甲醇为工质,在不同进口温度、质量流率、热流密度和倾角下,对低高宽比矩形微通道中流动沸腾压降特性进行了研究,并分别采用均相模型和分相模型对通道压降进行了计算。通过对比实验结果与计算结果发现,均相模型中两相平均粘度的计算应...以甲醇为工质,在不同进口温度、质量流率、热流密度和倾角下,对低高宽比矩形微通道中流动沸腾压降特性进行了研究,并分别采用均相模型和分相模型对通道压降进行了计算。通过对比实验结果与计算结果发现,均相模型中两相平均粘度的计算应当采用Dukler公式,用其他计算式时误差较大;利用Lockhart- Martinelli关系式进行的分相模型计算发现,现有C值计算公式,如Chisholm,Lee and Lee,Mishima及Qu and Mudawar等,都不能用于预测该实验中低高宽比微通道的两相压降。实验发现当通道中含气率相对较高时,汽液两相间相互作用随x升高而减小,需采用一随质量流率减小而减小的C值计算式。通过实验提出了基于Mishima公式的C值计算式,用该公式得到的计算值与实验结果符合较好,平均相对误差仅为16.9%。展开更多
According to the interaction of three shallow tunnels with large section, the analytical solution to rock pressure has been derived and discussed. The load model is given when the bilateral tunnels are excavated. Acco...According to the interaction of three shallow tunnels with large section, the analytical solution to rock pressure has been derived and discussed. The load model is given when the bilateral tunnels are excavated. According to the model, the stresses of three tunnels and single tunnel are calculated and compared to analyze the distribution characteristics, where the stresses are influenced by controlling factors of clear distance, covering depth and inclination angle of ground surface. The results show that, in general, the bias distribution is more serious. Therefore, it is significant to settle down the load model of three shallow tunnels so as to determine the measure of reinforcement and design the structure of support. The model and results can be used as a theoretical basis in designation and further research of the three shallow tunnels.展开更多
The fact that outburst traffic in industrial Ethemet was focused on that would bring self-similar phenomenon leading to the delay increase of the cyclical data, and a hybrid priority queue schedule model was proposed ...The fact that outburst traffic in industrial Ethemet was focused on that would bring self-similar phenomenon leading to the delay increase of the cyclical data, and a hybrid priority queue schedule model was proposed in which the outburst data was given the highest priority. Some properties of the self-similar outburst data were proved by network calculus, and its service curve scheduled by the switch was gained. And then the performance of the scheduling algorithm was obtained. The simulation results are close to those calculated by using network calculus model. Some results are of actual significance to the construction of switched industrial Ethernet.展开更多
The current work is an extension of the nonlocal elasticity theory to fractional order thermo-elasticity in semiconducting nanostructure medium with voids.The analysis is made on the reflection phenomena in context of...The current work is an extension of the nonlocal elasticity theory to fractional order thermo-elasticity in semiconducting nanostructure medium with voids.The analysis is made on the reflection phenomena in context of three-phase-lag thermo-elastic model.It is observed that,four-coupled longitudinal waves and an independent shear vertical wave exist in the medium which is dispersive in nature.It is seen that longitudinal waves are damped,and shear wave is un-damped when angular frequency is less than the cut-off frequency.The voids,thermal and non-local parameter affect the dilatational waves whereas shear wave is only depending upon non-local parameter.It is found that reflection coefficients are affected by nonlocal and fractional order parameters.Reflection coefficients are calculated analytically and computed numerically for a material,silicon and discussed graphically in details.The results for local(classical)theory are obtained as a special case.The study may be useful in semiconductor nanostructure,geology and seismology in addition to semiconductor nanostructure devices.展开更多
Fluid invasion through fractures is frequently observed in subsurface engineering. To elucidate the microkinetic behavior of fracture fluids, the microfracture structure of coal from the Surat Basin was reconstructed ...Fluid invasion through fractures is frequently observed in subsurface engineering. To elucidate the microkinetic behavior of fracture fluids, the microfracture structure of coal from the Surat Basin was reconstructed using a 3D morphometric system and stitching algorithm, then the transparent models characterizing the fracture structure were produced using microfluidics, and water invasion in the microfracture model was measured via visualization experiments under various conditions. High flow rate facilitated the invasion of the water phase into the closed channel, improving the efficiency of water invasion in the neutral wetting system. Wettability reversal changed the dominant channel for water invasion in the hydrophobic system. The invasion efficiency in closed and small aperture bypass channels was low.The reduction of effective seepage channels led to the fastest breakthrough time. Higher surface tension and interfacial curvature promoted the hysteresis effect. The reduction of effective seepage channels led to the fastest breakthrough time. The larger surface tension and interfacial curvature make the hysteresis effect more significant. These results will enable a better understanding of the rock-gas-liquid multiphase interaction mechanisms under unsaturated conditions of rocks.展开更多
In order to investigate the temperature distribution, a three-dimensional finite element model （FEM） was developed to simulate the temperature regime in the channels of double-loop inductor, and the simulated result...In order to investigate the temperature distribution, a three-dimensional finite element model （FEM） was developed to simulate the temperature regime in the channels of double-loop inductor, and the simulated results were compared with experimental data from low load trials of a 400 kW inductor. The results of numerical simulations, such as the temperature and Joule heating rate, show reasonable correlation with experimental data. The results indicate that Joule heating rate and the temperature reach the maximum at the comers and the minimum at the centre of the cross-section area. The temperature difference between the inlet and outlet is in an inverse proportion to mass transport. Joule heating rate and the temperature are directly proportional to power frequency. It is concluded that mass transport and power frequency play a critical role in determining the temperature regime and Joule heating rate, the relative permeability of the magnetic core shows no significant influence on temperature regime and Joule heating rate, when the relative permeability varies from 5 000 to 10 000.展开更多
基金Supported by Shanxi Province Natural Science Research(202203021212249)Special/Youth Foundation of Taiyuan University of Technology(2022QN101)+3 种基金National Natural Science Foundation of China(12301556)Research Project Supported by Shanxi Scholarship Council of China(2021-029)International Cooperation Base and Platform Project of Shanxi Province(202104041101019)Basic Research Plan of Shanxi Province(202203021211129)。
文摘To enhance the computational efficiency of spatio-temporally discretized phase-field models,we present a high-speed solver specifically designed for the Poisson equations,a component frequently used in the numerical computation of such models.This efficient solver employs algorithms based on discrete cosine transformations(DCT)or discrete sine transformations(DST)and is not restricted by any spatio-temporal schemes.Our proposed methodology is appropriate for a variety of phase-field models and is especially efficient when combined with flow field systems.Meanwhile,this study has conducted an extensive numerical comparison and found that employing DCT and DST techniques not only yields results comparable to those obtained via the Multigrid(MG)method,a conventional approach used in the resolution of the Poisson equations,but also enhances computational efficiency by over 90%.
文摘以甲醇为工质,在不同进口温度、质量流率、热流密度和倾角下,对低高宽比矩形微通道中流动沸腾压降特性进行了研究,并分别采用均相模型和分相模型对通道压降进行了计算。通过对比实验结果与计算结果发现,均相模型中两相平均粘度的计算应当采用Dukler公式,用其他计算式时误差较大;利用Lockhart- Martinelli关系式进行的分相模型计算发现,现有C值计算公式,如Chisholm,Lee and Lee,Mishima及Qu and Mudawar等,都不能用于预测该实验中低高宽比微通道的两相压降。实验发现当通道中含气率相对较高时,汽液两相间相互作用随x升高而减小,需采用一随质量流率减小而减小的C值计算式。通过实验提出了基于Mishima公式的C值计算式,用该公式得到的计算值与实验结果符合较好,平均相对误差仅为16.9%。
基金Projects(2013CB036004, 2011CB013800) supported by the National Basic Research Program of ChinaProject(51178468, 50908234) supported by the National Natural Science Foundation of ChinaProject(2011G103-B) supported by the Science and Technology Development of Railway in China
文摘According to the interaction of three shallow tunnels with large section, the analytical solution to rock pressure has been derived and discussed. The load model is given when the bilateral tunnels are excavated. According to the model, the stresses of three tunnels and single tunnel are calculated and compared to analyze the distribution characteristics, where the stresses are influenced by controlling factors of clear distance, covering depth and inclination angle of ground surface. The results show that, in general, the bias distribution is more serious. Therefore, it is significant to settle down the load model of three shallow tunnels so as to determine the measure of reinforcement and design the structure of support. The model and results can be used as a theoretical basis in designation and further research of the three shallow tunnels.
基金Project( 60425310) supported by the National Science Fund for Distinguished Young Scholars of ChinaProject(05JJ40118) supported by the Natural Science Foundation of Hunan Province, China
文摘The fact that outburst traffic in industrial Ethemet was focused on that would bring self-similar phenomenon leading to the delay increase of the cyclical data, and a hybrid priority queue schedule model was proposed in which the outburst data was given the highest priority. Some properties of the self-similar outburst data were proved by network calculus, and its service curve scheduled by the switch was gained. And then the performance of the scheduling algorithm was obtained. The simulation results are close to those calculated by using network calculus model. Some results are of actual significance to the construction of switched industrial Ethernet.
文摘The current work is an extension of the nonlocal elasticity theory to fractional order thermo-elasticity in semiconducting nanostructure medium with voids.The analysis is made on the reflection phenomena in context of three-phase-lag thermo-elastic model.It is observed that,four-coupled longitudinal waves and an independent shear vertical wave exist in the medium which is dispersive in nature.It is seen that longitudinal waves are damped,and shear wave is un-damped when angular frequency is less than the cut-off frequency.The voids,thermal and non-local parameter affect the dilatational waves whereas shear wave is only depending upon non-local parameter.It is found that reflection coefficients are affected by nonlocal and fractional order parameters.Reflection coefficients are calculated analytically and computed numerically for a material,silicon and discussed graphically in details.The results for local(classical)theory are obtained as a special case.The study may be useful in semiconductor nanostructure,geology and seismology in addition to semiconductor nanostructure devices.
基金Projects(52174159, 52074169, 52174026, 51904167, 52004146) supported by the National Nature Science Foundation of ChinaProject(ZR2020QE102) supported by the Natural Science Foundation Youth Branch of Shandong Province,ChinaProject(SKLMRDPC21KF06) supported by the Open Fund for State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines,China。
文摘Fluid invasion through fractures is frequently observed in subsurface engineering. To elucidate the microkinetic behavior of fracture fluids, the microfracture structure of coal from the Surat Basin was reconstructed using a 3D morphometric system and stitching algorithm, then the transparent models characterizing the fracture structure were produced using microfluidics, and water invasion in the microfracture model was measured via visualization experiments under various conditions. High flow rate facilitated the invasion of the water phase into the closed channel, improving the efficiency of water invasion in the neutral wetting system. Wettability reversal changed the dominant channel for water invasion in the hydrophobic system. The invasion efficiency in closed and small aperture bypass channels was low.The reduction of effective seepage channels led to the fastest breakthrough time. Higher surface tension and interfacial curvature promoted the hysteresis effect. The reduction of effective seepage channels led to the fastest breakthrough time. The larger surface tension and interfacial curvature make the hysteresis effect more significant. These results will enable a better understanding of the rock-gas-liquid multiphase interaction mechanisms under unsaturated conditions of rocks.
基金Project(50876116) supported by the National Natural Science Foundation of ChinaProject(2007CK3077) supported by the Innovative Program of Hunan Science and Technology Agency, ChinaProject(1343-77225) supported by the Graduate School of Central South University, China
文摘In order to investigate the temperature distribution, a three-dimensional finite element model （FEM） was developed to simulate the temperature regime in the channels of double-loop inductor, and the simulated results were compared with experimental data from low load trials of a 400 kW inductor. The results of numerical simulations, such as the temperature and Joule heating rate, show reasonable correlation with experimental data. The results indicate that Joule heating rate and the temperature reach the maximum at the comers and the minimum at the centre of the cross-section area. The temperature difference between the inlet and outlet is in an inverse proportion to mass transport. Joule heating rate and the temperature are directly proportional to power frequency. It is concluded that mass transport and power frequency play a critical role in determining the temperature regime and Joule heating rate, the relative permeability of the magnetic core shows no significant influence on temperature regime and Joule heating rate, when the relative permeability varies from 5 000 to 10 000.
