The Printed Circuit Heat Exchanger(PCHE) is one of the most promising heat exchangers for Synergetic Air-breathing and Rocket Engine(SABRE). To reduce pressure drop and improve compactness, the micron-sized PCHE made ...The Printed Circuit Heat Exchanger(PCHE) is one of the most promising heat exchangers for Synergetic Air-breathing and Rocket Engine(SABRE). To reduce pressure drop and improve compactness, the micron-sized PCHE made up of rectangular channels of tens of microns in size, is used in SABRE. In present work, we focus on thermal-hydraulic-structural characteristics of micron-sized PCHE by conducting three-dimensional(3-D) numerical simulation. Helium and hydrogen are employed as the working fluids and the Stainless Steel 316(SS316) as the solid substrate. The thermal-hydraulic performance of the micron-sized PCHE is discussed by using the commercial Computational Fluid Dynamics(CFD) software of Fluent. ANSYSMechanical is also employed to simulate stress field of representative PCHE channels. The mechanical stress induced by pressure loading and the thermal stress induced by temperature gradient are found to be equally important sources of stress. To improve comprehensive performances of micron-sized PCHE, two types of channel arrangements and different channel aspect ratios are studied. The double banking is of higher thermal-hydraulic performance compared to the single banking while the stress performance is identical for the two modes. Meanwhile, the effect of channel aspect ratio is investigated by comparing thermal-hydraulic characteristics and structural stress of the model. The rectangular channel with w/h=2 achieves the most balanced stress characteristic and higher thermal-hydraulic performance.展开更多
Printed circuit heat exchangers(PCHEs)are promising candidates for recuperators in supercritical CO2 Brayton cycles.A comparative study is given in this paper on the flow and heat transfer characteristics of PCHEs wit...Printed circuit heat exchangers(PCHEs)are promising candidates for recuperators in supercritical CO2 Brayton cycles.A comparative study is given in this paper on the flow and heat transfer characteristics of PCHEs with sinusoidal and zigzag channels.With mass flow rates of 0.6–1.8 kg/h and the bend angles of 15°–30°,the thermal-hydraulic performance of the PCHEs is discussed.Results show that the sinusoidal channel is superior to the zigzag channel in its comprehensive performance.Larger bend angles result in greater reductions in pressure drop if sinusoidal channels are used instead of zigzag channels and a maximum of 48.4%reduction can be obtained in the considered working conditions.Meanwhile,the inlet sections should be carefully optimized since these sections account for up to 31%and 17%of the total pressure drop in the sinusoidal and zigzag channels,respectively.The corner shape of the zigzag channel can be specially designed to further reduce the pressure drop.The nonuniform density and heat flux distributions in both channels are found to be related to the periodic changes of flow directions and the centrifugal forces should not be ignored when optimizing the sinusoidal and zigzag channels.展开更多
基金supported by the National Key Research and Development Program of China under grant number 2017YFB0601803the National Natural Science Foundation of China under grant number 51576156the 111 Project under grant number B16038
文摘The Printed Circuit Heat Exchanger(PCHE) is one of the most promising heat exchangers for Synergetic Air-breathing and Rocket Engine(SABRE). To reduce pressure drop and improve compactness, the micron-sized PCHE made up of rectangular channels of tens of microns in size, is used in SABRE. In present work, we focus on thermal-hydraulic-structural characteristics of micron-sized PCHE by conducting three-dimensional(3-D) numerical simulation. Helium and hydrogen are employed as the working fluids and the Stainless Steel 316(SS316) as the solid substrate. The thermal-hydraulic performance of the micron-sized PCHE is discussed by using the commercial Computational Fluid Dynamics(CFD) software of Fluent. ANSYSMechanical is also employed to simulate stress field of representative PCHE channels. The mechanical stress induced by pressure loading and the thermal stress induced by temperature gradient are found to be equally important sources of stress. To improve comprehensive performances of micron-sized PCHE, two types of channel arrangements and different channel aspect ratios are studied. The double banking is of higher thermal-hydraulic performance compared to the single banking while the stress performance is identical for the two modes. Meanwhile, the effect of channel aspect ratio is investigated by comparing thermal-hydraulic characteristics and structural stress of the model. The rectangular channel with w/h=2 achieves the most balanced stress characteristic and higher thermal-hydraulic performance.
基金supported by the National Natural Science Foundation of China(Grant Nos.51822606,51806249)Hunan Provincial Natural Science Foundation of China(Grant No.2019JJ50801)。
文摘Printed circuit heat exchangers(PCHEs)are promising candidates for recuperators in supercritical CO2 Brayton cycles.A comparative study is given in this paper on the flow and heat transfer characteristics of PCHEs with sinusoidal and zigzag channels.With mass flow rates of 0.6–1.8 kg/h and the bend angles of 15°–30°,the thermal-hydraulic performance of the PCHEs is discussed.Results show that the sinusoidal channel is superior to the zigzag channel in its comprehensive performance.Larger bend angles result in greater reductions in pressure drop if sinusoidal channels are used instead of zigzag channels and a maximum of 48.4%reduction can be obtained in the considered working conditions.Meanwhile,the inlet sections should be carefully optimized since these sections account for up to 31%and 17%of the total pressure drop in the sinusoidal and zigzag channels,respectively.The corner shape of the zigzag channel can be specially designed to further reduce the pressure drop.The nonuniform density and heat flux distributions in both channels are found to be related to the periodic changes of flow directions and the centrifugal forces should not be ignored when optimizing the sinusoidal and zigzag channels.
