Three-Dimensional Multiphase Flow Simulation in Petroleum Reservoirs using the Mass Fractions as Dependent Variables

Shear stress is often present in the blood flow within blood-contacting devices, which is the leading cause of hemolysis. However, the simulation method for blood flow with shear stress is still not perfect, especially the multiphase flow model and experimental verification. In this regard, this study proposes an enhanced discrete phase model for multiphase flow simulation of blood flow with shear stress. This simulation is based on the discrete phase model (DPM). According to the multiphase flow characteristics of blood, a virtual mass force model and a pressure gradient influence model are added to the calculation of cell particle motion. In the experimental verification, nozzle models were designed to simulate the flow with shear stress, varying the degree of shear stress through different nozzle sizes. The microscopic flow was measured by the Particle Image Velocimetry (PIV) experimental method. The comparison of the turbulence models and the verification of the simulation accuracy were carried out based on the experimental results. The result demonstrates that the simulation effect of the SST k- ω model is better than other standard turbulence models. Accuracy analysis proves that the simulation results are accurate and can capture the movement of cell-level particles in the flow with shear stress. The results of the research are conducive to obtaining accurate and comprehensive analysis results in the equipment development phase.

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Development and Validation of a Three-Dimensional Multiphase Flow CFD Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

Volume 7: Structures and Dynamics, Parts A and B ◽

10.1115/gt2012-68201 ◽

2012 ◽

Cited By ~ 2

Author(s):

Stephan Uhkoetter ◽

Stefan aus der Wiesche ◽

Michael Kursch ◽

Christian Beck

Keyword(s):

Experimental Data ◽

Multiphase Flow ◽

Gas Turbines ◽

High Speed ◽

Three Dimensional ◽

Air Entrainment ◽

Journal Bearings ◽

Heavy Duty ◽

Present Contribution ◽

Two Phase

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach including cavitation and air entrainment for high-speed turbo-machinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty type gas turbine journal bearings.

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Assessment of Unsteady Flows in Turbines

Journal of Turbomachinery ◽

10.1115/1.2928001 ◽

1992 ◽

Vol 114 (1) ◽

pp. 79-90 ◽

Cited By ~ 57

Author(s):

O. P. Sharma ◽

G. F. Pickett ◽

R. H. Ni

Keyword(s):

Unsteady Flow ◽

Three Dimensional ◽

Flow Simulation ◽

Experimental Investigations ◽

Flow Parameters ◽

Research Activities ◽

Flow Features ◽

Computational Fluid Dynamics Cfd ◽

Turbine Design ◽

The Impact

The impacts of unsteady flow research activities on flow simulation methods used in the turbine design process are assessed. Results from experimental investigations that identify the impact of periodic unsteadiness on the time-averaged flows in turbines and results from numerical simulations obtained by using three-dimensional unsteady Computational Fluid Dynamics (CFD) codes indicate that some of the unsteady flow features can be fairly accurately predicted. Flow parameters that can be modeled with existing steady CFD codes are distinguished from those that require unsteady codes.

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