The pressure loss of cross-flow perforated of physical modeling, simulation and data processing. muffler has been computed with the procedure Three-dimensional computational fluid dynamics （CFD） has been used to inv...The pressure loss of cross-flow perforated of physical modeling, simulation and data processing. muffler has been computed with the procedure Three-dimensional computational fluid dynamics （CFD） has been used to investigate the relations of porosities, flow velocity and diameter of the holes with the pressure loss. Accordingly, some preliminary results have been obtained that pressure loss increases with porosity descent as nearly a hyperbolic trend, rising flow velocity of the input makes the pressure loss increasing with parabola trend, diameter of holes affects little about pressure loss of the muffler. Otherwise, the holes on the perforated pipes make the air flow gently and meanly, which decreases the air impact to the wall and pipes in the muffler. A practical perforated muffler is used to illustrate the available of this method for pressure loss computation, and the comparison shows that the computation results with the method of CFD has reference value for muffler design.展开更多
The flow field in junction is complicated due to the ripple property of oil flow velocity and different frequencies of two pumps in aircraft. In this study, the flow fields of T-junction and Y-junction were analyzed u...The flow field in junction is complicated due to the ripple property of oil flow velocity and different frequencies of two pumps in aircraft. In this study, the flow fields of T-junction and Y-junction were analyzed using shear stress transport （SST） model in ANSYS/CFX software. The simulation results identified the variation rule of velocity peak in T-junction with different frequencies and phase-differences, meanwhile, the eddy and velocity shock existed in the corner of the T-junction, and the limit working state was obtained. Although the eddy disappeared in Y-junction, the velocity shock and pressure loss were still too big. To address these faults, an arc-junction was designed. Based on the flow fields of arc-junction, the eddy in the junction corner disappeared and the maximum of velocity peak declined compared to T-and Y-junction. Additionally, 8 series of arc-junction with different radiuses were tested to get the variation rule of velocity peak. Through the computation of the pressure loss of three junctions, the arc-junction had a lowest loss value, and its pressure loss reached the minimum value when the curvature radius is 35.42 mm, meanwhile, the velocity shock has decreased in a low phase.展开更多
文摘The pressure loss of cross-flow perforated of physical modeling, simulation and data processing. muffler has been computed with the procedure Three-dimensional computational fluid dynamics （CFD） has been used to investigate the relations of porosities, flow velocity and diameter of the holes with the pressure loss. Accordingly, some preliminary results have been obtained that pressure loss increases with porosity descent as nearly a hyperbolic trend, rising flow velocity of the input makes the pressure loss increasing with parabola trend, diameter of holes affects little about pressure loss of the muffler. Otherwise, the holes on the perforated pipes make the air flow gently and meanly, which decreases the air impact to the wall and pipes in the muffler. A practical perforated muffler is used to illustrate the available of this method for pressure loss computation, and the comparison shows that the computation results with the method of CFD has reference value for muffler design.
基金supported by the National Natural Science Foundation of China(No.51175014)
文摘The flow field in junction is complicated due to the ripple property of oil flow velocity and different frequencies of two pumps in aircraft. In this study, the flow fields of T-junction and Y-junction were analyzed using shear stress transport （SST） model in ANSYS/CFX software. The simulation results identified the variation rule of velocity peak in T-junction with different frequencies and phase-differences, meanwhile, the eddy and velocity shock existed in the corner of the T-junction, and the limit working state was obtained. Although the eddy disappeared in Y-junction, the velocity shock and pressure loss were still too big. To address these faults, an arc-junction was designed. Based on the flow fields of arc-junction, the eddy in the junction corner disappeared and the maximum of velocity peak declined compared to T-and Y-junction. Additionally, 8 series of arc-junction with different radiuses were tested to get the variation rule of velocity peak. Through the computation of the pressure loss of three junctions, the arc-junction had a lowest loss value, and its pressure loss reached the minimum value when the curvature radius is 35.42 mm, meanwhile, the velocity shock has decreased in a low phase.
