This study investigated the effects of zigzag-flow channel bending angle in printed circuit heat exchangers(PCHEs) using a computational fluid dynamics method with ANSYS-FLUENT simulation.The three-dimensional model o...This study investigated the effects of zigzag-flow channel bending angle in printed circuit heat exchangers(PCHEs) using a computational fluid dynamics method with ANSYS-FLUENT simulation.The three-dimensional model of PCHE with a 15° curved,zigzag channel was conducted for preliminary validation.The comparisons between the CFD simulation results and the experimental data showed good agreement with some discrepancies in the heat transfer and pressure drop results.In addition,different bending angle configurations(0°,3° to 30°) of zigzag channels were analyzed to obtain better thermal-hydraulic performance of the zigzag channel PCHE under different inlet mass flow rates.The criteria of heat transfer and frictional factor were applied to evaluate the thermal-hydraulic performance of the PCHE.The results showed that the 6° and 9°bending channel provided good thermal-hydraulic performance.New correlations were developed using the 6°and 9° bending channel angles in PCHE designs to predict the Nusselt number and friction factor.展开更多
One-dimensional cyanide-bridged bimetallic coordination polymer [CuL(H 2O) 2] n [(CuL)·(μ-CN) 2Fe(CN) 4] 2n ·(H 2O) 2n was synthesized and structurally characterized. The coordination polymer crystallizes i...One-dimensional cyanide-bridged bimetallic coordination polymer [CuL(H 2O) 2] n [(CuL)·(μ-CN) 2Fe(CN) 4] 2n ·(H 2O) 2n was synthesized and structurally characterized. The coordination polymer crystallizes in a monoclinic system of the space group C2/c with a=2.983 1(5) nm, b=1.527 4(3) nm, c= 1.725 3(4) nm, β=107.68(2)°, V=7.490(3) nm3, Z=8, D c=1.382 g/cm3, F(000)=3 260, R=0.059 3, wR 2=0.132 3, S=0.885. The one-dimensional zigzag chain extents through Cu—CN—Fe—CN—Cu linkages. The adjacent two polymer chains are linked by the O—H……NC hydrogen bonding between [CuL(H 2O) 2] 2+ and [Fe(CN) 6] 3- ions to form hydrophilic channels in which water molecules are included.展开更多
In this study,an experimental system was built to investigate the global performance of an 80-k W zigzag printed circuit heat exchanger(PCHE).It could meet the requirement of the pre-cooler for the supercritical carbo...In this study,an experimental system was built to investigate the global performance of an 80-k W zigzag printed circuit heat exchanger(PCHE).It could meet the requirement of the pre-cooler for the supercritical carbon dioxide(S-CO_(2))Brayton power cycle and the modified effectiveness considering the pinch point is between 61.5%and 79.3%.When the outlet S-CO_(2)temperature is near the pseudo-critical point,the thermo-physical properties have more effects on heat transfer performance compared to flow characteristics.For the local performance,the mass flow rates of both sides have crucial influences on the location where the peak of S-CO_(2)Nusselt number occurs while only the S-CO_(2)flow rate affects the variation of the peak value.In addition,the influence of the radius of curvature on the secondary-flow should not be ignored.In the end,new empirical correlations were proposed considering the drastic variations of the Prandtl number.展开更多
基金supported by the School of Mechanical,Institute of Engineering,Suranaree University of Technology (Thailand),Mechanical and Process System Engineering Program,and Vithedbundit Scholarship,Institute of Engineering,Suranaree University of Technology (Thailand)。
文摘This study investigated the effects of zigzag-flow channel bending angle in printed circuit heat exchangers(PCHEs) using a computational fluid dynamics method with ANSYS-FLUENT simulation.The three-dimensional model of PCHE with a 15° curved,zigzag channel was conducted for preliminary validation.The comparisons between the CFD simulation results and the experimental data showed good agreement with some discrepancies in the heat transfer and pressure drop results.In addition,different bending angle configurations(0°,3° to 30°) of zigzag channels were analyzed to obtain better thermal-hydraulic performance of the zigzag channel PCHE under different inlet mass flow rates.The criteria of heat transfer and frictional factor were applied to evaluate the thermal-hydraulic performance of the PCHE.The results showed that the 6° and 9°bending channel provided good thermal-hydraulic performance.New correlations were developed using the 6°and 9° bending channel angles in PCHE designs to predict the Nusselt number and friction factor.
文摘One-dimensional cyanide-bridged bimetallic coordination polymer [CuL(H 2O) 2] n [(CuL)·(μ-CN) 2Fe(CN) 4] 2n ·(H 2O) 2n was synthesized and structurally characterized. The coordination polymer crystallizes in a monoclinic system of the space group C2/c with a=2.983 1(5) nm, b=1.527 4(3) nm, c= 1.725 3(4) nm, β=107.68(2)°, V=7.490(3) nm3, Z=8, D c=1.382 g/cm3, F(000)=3 260, R=0.059 3, wR 2=0.132 3, S=0.885. The one-dimensional zigzag chain extents through Cu—CN—Fe—CN—Cu linkages. The adjacent two polymer chains are linked by the O—H……NC hydrogen bonding between [CuL(H 2O) 2] 2+ and [Fe(CN) 6] 3- ions to form hydrophilic channels in which water molecules are included.
基金supported by the National Natural Science Foundation of China(No.51606191)the National Key Research and Development Program-China(2017YFB0601803)Key deployment project of Chinese Academy of Sciences(Y7220112H1)。
文摘In this study,an experimental system was built to investigate the global performance of an 80-k W zigzag printed circuit heat exchanger(PCHE).It could meet the requirement of the pre-cooler for the supercritical carbon dioxide(S-CO_(2))Brayton power cycle and the modified effectiveness considering the pinch point is between 61.5%and 79.3%.When the outlet S-CO_(2)temperature is near the pseudo-critical point,the thermo-physical properties have more effects on heat transfer performance compared to flow characteristics.For the local performance,the mass flow rates of both sides have crucial influences on the location where the peak of S-CO_(2)Nusselt number occurs while only the S-CO_(2)flow rate affects the variation of the peak value.In addition,the influence of the radius of curvature on the secondary-flow should not be ignored.In the end,new empirical correlations were proposed considering the drastic variations of the Prandtl number.
