As a system using a conventional unidirectional air turbine in oscillating water column (OWC) based on a wave energy plant, a twin unidirectional impulse turbine topology has been suggested in previous studies. Howeve...As a system using a conventional unidirectional air turbine in oscillating water column (OWC) based on a wave energy plant, a twin unidirectional impulse turbine topology has been suggested in previous studies. However, the average efficiency of the suggested twin turbine is considerably lower than that of a conventional unidirectional turbine in this topology because reciprocating air flow can’t be rectified adequately by a unidirectional turbine. In order to improve the efficiency, using fluidic diode is discussed. In this study, two different fluidic diodes were discussed by computational fluid dynamics (CFD) and a wind tunnel test. Further, its usefulness is discussed from a view point of the turbine efficiency. The fluidic diode was shown to improve rectification of the topology. However, it needs more improvement in regards to its energy loss in order to enhance the turbine efficiency.展开更多
Chaotic mixing in eight different types of micro T-mixer flow has been studied experimentally and numerically. The present experimental study was performed to visualize two-liquid flows in a micro T-mixer with baffles...Chaotic mixing in eight different types of micro T-mixer flow has been studied experimentally and numerically. The present experimental study was performed to visualize two-liquid flows in a micro T-mixer with baffles. The Reynolds number, baffle height and setting angle were varied to investigate their effect on the mixing performance. Three micro T-mixer models were produced, which are several centimeters long and have a rectangular cross-section of few millimeters a side. The mixing of two-liquid was measured using the laser induced fluorescence (LIF) technique. Moreover, three-dimensional numerical simulations were conducted with the open-source CFD solver, OpenFOAM, for the same configuration as used in the experiments to investigate the detailed mechanism of the chaotic mixing. As a result, it was found that the mixing of two-liquid is greatly improved in the micro T-mixer with baffle. The baffle height and setting angle show a significant influence on the mixing performance.展开更多
文摘As a system using a conventional unidirectional air turbine in oscillating water column (OWC) based on a wave energy plant, a twin unidirectional impulse turbine topology has been suggested in previous studies. However, the average efficiency of the suggested twin turbine is considerably lower than that of a conventional unidirectional turbine in this topology because reciprocating air flow can’t be rectified adequately by a unidirectional turbine. In order to improve the efficiency, using fluidic diode is discussed. In this study, two different fluidic diodes were discussed by computational fluid dynamics (CFD) and a wind tunnel test. Further, its usefulness is discussed from a view point of the turbine efficiency. The fluidic diode was shown to improve rectification of the topology. However, it needs more improvement in regards to its energy loss in order to enhance the turbine efficiency.
文摘Chaotic mixing in eight different types of micro T-mixer flow has been studied experimentally and numerically. The present experimental study was performed to visualize two-liquid flows in a micro T-mixer with baffles. The Reynolds number, baffle height and setting angle were varied to investigate their effect on the mixing performance. Three micro T-mixer models were produced, which are several centimeters long and have a rectangular cross-section of few millimeters a side. The mixing of two-liquid was measured using the laser induced fluorescence (LIF) technique. Moreover, three-dimensional numerical simulations were conducted with the open-source CFD solver, OpenFOAM, for the same configuration as used in the experiments to investigate the detailed mechanism of the chaotic mixing. As a result, it was found that the mixing of two-liquid is greatly improved in the micro T-mixer with baffle. The baffle height and setting angle show a significant influence on the mixing performance.
