Dem-CFD Study of Flow in a Random Packed Bed

Šourek, Martin Kotouč; Isoz, Martin

doi:10.14311/tpfm.2018.036

Cited by 1 publication

(1 citation statement)

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“…For fixed walls, the no-slip boundary condition is employed (noSplip in OpenFOAM), whereas the option rotatingWallVelocity is used for the rotating walls in order to specify the constant rotation rate of the impeller. The inletOutlet routine of OpenFOAM is employed with the static pressure P = 0 Pa at the outflow box set a boundary condition that enforces: (i) a Neumann-type zero-gradient boundary condition for the velocity field if the fluid flows out of the computational domain and (ii) a Dirichlet-type boundary condition if the velocity field in the domain would require a fluid inflow, which is obtained by extrapolation from the bulk 27 . Distinct mesh zones are coupled at their interfaces using the coupling condition cyclicAMI, which applies to the interfaces between: (i) inlet pipe and impeller, (ii) impeller and diffuser, and (iii) diffuser and outflow box.…”

Section: E Boundary Conditionsmentioning

confidence: 99%

Effect of inlet leakage flow on the instability in a radial vaneless diffuser

2023

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The internal flow structures in a vaneless diffuser of a radial pump are experimentally and numerically investigated. Numerical simulations are used for investigating the prominent features of the fluid flow in the vaneless diffuser upon a change of the flow rate and of the impeller-to-diffuser radial gap. Comparisons between experimental and numerical results on the overall pump and diffuser performances are presented and discussed. The influence of inlet diffuser leakages on the development of flow instabilities is specifically addressed, owing to the remarkable impact that a small impeller-to-diffuser radial gap can have on the diffuser flow. Highlights on the rotating instabilities in terms of stall cell number and propagation velocity at design and off-design conditions are the main focus of this study and will be investigated using the numerical and experimental results post-processed by fast Fourier transform (FFT) and wavelet analysis.

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Section: E Boundary Conditionsmentioning

confidence: 99%