Rotating Drum Half-Filled With Large Beads in Liquid: Fictitous-Domain Simulation and Experiment

Author(s):  
Hung V. Truong ◽  
John C. Wells ◽  
Anh Nguyen

To numerically simulate “bedload transport” of sediment by a turbulent flow over an erodible bed, our group has been developing “fictitious domain” methods to handle dense-phase particulate flow in turbulent flow of liquid. We report on efforts to check our simulation method against experiment for a dense-phase particulate flow in liquid, namely a rotating drum half-filled with spherical particles. Overall agreement between experimental and simulated values of static and dynamic angle of repose is found to be quite satisfactory, both in air and in oil.

Author(s):  
Yan Jin

Abstract The turbulent flow in a compressor cascade is calculated by using a new simulation method, i.e., parameter extension simulation (PES). It is defined as the calculation of a turbulent flow with the help of a reference solution. A special large-eddy simulation (LES) method is developed to calculate the reference solution for PES. Then, the reference solution is extended to approximate the exact solution for the Navier-Stokes equations. The Richardson extrapolation is used to estimate the model error. The compressor cascade is made of NACA0065-009 airfoils. The Reynolds number 3.82 × 105 and the attack angles −2° to 7° are accounted for in the study. The effects of the end-walls, attack angle, and tripping bands on the flow are analyzed. The PES results are compared with the experimental data as well as the LES results using the Smagorinsky, k-equation and WALE subgrid models. The numerical results show that the PES requires a lower mesh resolution than the other LES methods. The details of the flow field including the laminar-turbulence transition can be directly captured from the PES results without introducing any additional model. These characteristics make the PES a potential method for simulating flows in turbomachinery with high Reynolds numbers.


2021 ◽  
Vol 2097 (1) ◽  
pp. 012028
Author(s):  
Mingming Liu ◽  
Haifei Zhuang ◽  
Lei Cao

Abstract In order to reveal the dredge pump flow instability characteristics, the cavitation and pressure fluctuation in experimental study are carried out, the pressure fluctuation frequency domain and time domain characteristics of three different position inside the volute are analyzed. The results showed that, before cavitation, the main frequency at different positions at different flow rates is 1 times the main frequency of the blade. The fluctuation amplitude near the volute tongue and diffusion section is slightly larger than that at other positions. Before cavitation, the fluctuation amplitude at the same position off design flow is slightly higher than that near the design flow. Cavitation has little influence on the main frequency of the pressure fluctuation. After cavitation, the pressure fluctuation amplitude in the low flow point and the position of the volute tongue under each condition has little change, but cavitation aggravates the pressure fluctuation in the other conditions. Besides, the comparison between simulation and experiment results shows the dredge pump performance curve is in good agreement with the simulation curve, and the simulation results of pressure amplitude at different positions are basically consistent with the experiment results, which verifies the reliability of the numerical simulation method.


2010 ◽  
Vol 44-47 ◽  
pp. 1724-1728
Author(s):  
Hong Ge Tao ◽  
Huan Xin Chen ◽  
Jun Long Xie ◽  
Jun Zhi Jiang

CFD technique is often employed to simulate and optimize air duct design, but the corresponding experiment validation in metro vehicle is rare. By taking an independent metro vehicle duct as research object in this paper, supply air through air duct is simulated and compared with the actual test results from the angle of supply air velocity at each outlet and supply air volume through several outlets of air duct. The results show that the relative deviation of simulation and test value of air velocity at most of the outlets are within or near ±20%, which is acceptable for the engineering applications. Moreover, the ratio of supply air volume through several outlets to the corresponding total supply air volume through main air duct or flat duct in the case of simulation is consistent with that in the case of experiment. It can be concluded that numerical simulation method is effective and reliable in air duct optimization design of metro vehicle.


2012 ◽  
Vol 60 (6) ◽  
pp. 1502-1546 ◽  
Author(s):  
Athanasios N. Papanicolaou ◽  
Casey M. Kramer ◽  
Achilleas G. Tsakiris ◽  
Thorsten Stoesser ◽  
Sandeep Bomminayuni ◽  
...  

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