An experimental investigation on jamming and critical orifice size in the discharge of a two-dimensional silo with curved hopper

Author(s):  
Hanru Liu ◽  
Yanlong Han ◽  
Fuguo Jia ◽  
Yawen Xiao ◽  
Heqin Chen ◽  
...  
1992 ◽  
Vol 241 ◽  
pp. 587-614 ◽  
Author(s):  
T. Dracos ◽  
M. Giger ◽  
G. H. Jirka

An experimental investigation of plane turbulent jets in bounded fluid layers is presented. The development of the jet is regular up to a distance from the orifice of approximately twice the depth of the fluid layer. From there on to a distance of about ten times the depth, the flow is dominated by secondary currents. The velocity distribution over a cross-section of the jet becomes three-dimensional and the jet undergoes a constriction in the midplane and a widening near the bounding surfaces. Beyond a distance of approximately ten times the depth of the bounded fluid layer the secondary currents disappear and the jet starts to meander around its centreplane. Large vortical structures develop with axes perpendicular to the bounding surfaces of the fluid layer. With increasing distance the size of these structures increases by pairing. These features of the jet are associated with the development of quasi two-dimensional turbulence. It is shown that the secondary currents and the meandering do not significantly affect the spreading of the jet. The quasi-two-dimensional turbulence, however, developing in the meandering jet, significantly influences the mixing of entrained fluid.


2016 ◽  
Vol 139 (1) ◽  
Author(s):  
A. Hildebrandt ◽  
F. Schilling

The present paper deals with the numerical and experimental investigation of the effect of return channel (RCH) dimensions of a centrifugal compressor stage on the aerodynamic performance. Three different return channel stages were investigated, two stages comprising three-dimensional (3D) return channel blades and one stage comprising two-dimensional (2D) RCH vanes. The analysis was performed regarding both the investigation of overall performance (stage efficiency, RCH total pressure loss coefficient) and detailed flow-field performance. For detailed experimental flow-field investigation at the stage exit, six circumferentially traversed three-hole probes were positioned downstream the return channel exit in order to get two-dimensional flow-field information. Additionally, static pressure wall measurements were taken at the hub and shroud pressure and suction side (SS) of the 2D and 3D return channel blades. The return channel system overall performance was calculated by measurements of the circumferentially averaged 1D flow field downstream the diffuser exit and downstream the stage exit. Dependent on the type of return channel blade, the numerical and experimental results show a significant effect on the flow field overall and detail performance. In general, satisfactory agreement between computational fluid dynamics (CFD)-prediction and test-rig measurements was achieved regarding overall and flow-field performance. In comparison with the measurements, the CFD-calculated stage performance (efficiency and pressure rise coefficient) of all the 3D-RCH stages was slightly overpredicted. Very good agreement between CFD and measurement results was found for the static pressure distribution on the RCH wall surfaces while small CFD-deviations occur in the measured flow angle at the stage exit, dependent on the turbulence model selected.


2018 ◽  
Vol 203 ◽  
pp. 152-171 ◽  
Author(s):  
Aida Cameselle-Molares ◽  
Anastasios P. Vassilopoulos ◽  
Thomas Keller

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
David Demel ◽  
Mohsen Ferchichi ◽  
William D. E. Allan ◽  
Marouen Dghim

This work details an experimental investigation on the effects of the variation of flap gap and overlap sizes on the flow field in the wake of a wing-section equipped with a trailing edge Fowler flap. The airfoil was based on the NACA 0014-1.10 40/1.051 profile, and the flap was deployed with 40 deg deflection angle. Two-dimensional (2D) particle image velocimetry (PIV) measurements of the flow field in the vicinity of the main wing trailing edge and the flap region were performed for the optimal flap gap and overlap, as well as for flap gap and overlap increases of 2% and 4% chord beyond optimal, at angles of attack of 0 deg, 10 deg, and 12 deg. For all the configurations investigated, the flow over the flap was found to be fully stalled. At zero angle of attack, increasing the flap gap size was found to have minor effects on the flow field but increased flap overlap resulted in misalignment between the main wing boundary layer (BL) flow and the slot flow that forced the flow in the trailing edge region of the main wing to separate. When the angle of attack was increased to near stall conditions (at angle of attack of 12 deg), increasing the flap gap was found to energize and improve the flow in the trailing edge region of the main wing, whereas increased flap overlap further promoted flow separation on the main wing suction surface possibly steering the wing into stall.


JETP Letters ◽  
2010 ◽  
Vol 92 (7) ◽  
pp. 466-469
Author(s):  
V. M. Muravev ◽  
A. A. Fortunatov ◽  
A. A. Dremin ◽  
I. V. Kukushkin

2017 ◽  
Vol 609 ◽  
pp. 1075-1084 ◽  
Author(s):  
Qing'an Li ◽  
Takao Maeda ◽  
Yasunari Kamada ◽  
Keisuke Yamada

Author(s):  
A. Hildebrandt ◽  
F. Schilling

The present paper deals with the numerical and experimental investigation of the effect of return channel dimensions of a centrifugal compressor stage on the aerodynamic performance. Three different return channel stages were investigated, two stages comprising 3D (three-dimensional) return channel blades and one stage comprising (2D) two-dimensional RCH (Return Channel) vanes. The analysis was performed regarding both the investigation of overall performance (stage efficiency, RCH total pressure loss coefficient) and detailed flow field performance. For detailed experimental flow field investigation at the stage exit, six circumferentially traversed three-hole probes were positioned downstream the return channel exit in order to get two-dimensional flow field information. Additionally, static pressure wall measurements were taken at the hub and shroud pressure and suction side of the 2D and 3D return channel blades. The return channel system overall performance was calculated by measurements of the circumferentially averaged 1D flow field downstream the diffuser exit and downstream the stage exit. Dependent on the type of return channel blade, the numerical and experimental results show a significant effect on the flow field overall and detail performance. In general, satisfactory agreement between CFD-prediction and test-rig measurements was achieved regarding overall and flow field performance. In comparison with the measurements, the CFD calculated stage performance (efficiency and pressure rise coefficient) of all 3D-RCH stages was slightly over-predicted. Very good agreement between CFD and measurement results was found for the static pressure distribution on the RCH wall surfaces while small CFD-deviations occur in the measured flow angle at the stage exit, dependent on the turbulence model selected.


1974 ◽  
Vol 96 (1) ◽  
pp. 11-15 ◽  
Author(s):  
C. R. Smith ◽  
S. J. Kline

A study of flow behavior of transitory stall in two-dimensional diffusers at low Mach numbers is reported. The changes in flow patterns from stall inception to full-stall are described; the geometries for maximum fluctuations are located. The mean times and distribution of stall build-up and wash-out periods are given for a series of units of varying total angle. The mean times are found to scale on total stall volume, and a nondimensional correlation of stall period is given. The distribution of stall periods, for random inlet fluctuations, is found to be broad and strongly skewed toward lower periods. Comparable results are found in water for R∼104 and in air at R∼105. A further series of tests with periodic inlet disturbances indicates that the stall behavior is modified strongly when the pulsing period is 0.5 to 1.0 times the natuarl mean period, but not otherwise. Details of flow patterns and blockage are summarized.


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