scholarly journals Comparison between Single-Phase Flow Simulation and Multiphase Flow Simulation of Patient-Specific Total Cavopulmonary Connection Structures Assisted by a Rotationally Symmetric Blood Pump

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 912
Author(s):  
Tong Chen ◽  
Xudong Liu ◽  
Biao Si ◽  
Yong Feng ◽  
Huifeng Zhang ◽  
...  
Keyword(s):  
Multiphase Flow ◽  
Single Phase ◽  
Damage Index ◽  
Flow Simulation ◽  
Patient Specific ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Blood Damage ◽  
Cell Destruction ◽  
Flow Particle

To accurately assess the hemolysis risk of the ventricular assist device, this paper proposed a cell destruction model and the corresponding evaluation parameters based on multiphase flow. The single-phase flow and multiphase flow in two patient-specific total cavopulmonary connection structures assisted by a rotationally symmetric blood pump (pump-TCPC) were simulated. Then, single-phase and multiphase cell destruction models were used to evaluate the hemolysis risk. The results of both cell destruction models indicated that the hemolysis risk in the straight pump-TCPC model was lower than that in the curved pump-TCPC model. However, the average and maximum values of the multiphase flow blood damage index (mBDI) were smaller than those of the single-phase flow blood damage index (BDI), but the average and maximum values of the multiphase flow particle residence time (mPRT) were larger than those of the single-phase flow particle residence time (PRT). This study proved that the multiphase flow method can be used to simulate the mechanical behavior of red blood cells (RBCs) and white blood cells (WBCs) in a complex flow field and the multiphase flow cell destruction model had smaller estimates of the impact shear stress.

Prediction of Solid Particle Erosive Wear of Elbows in Multiphase Annular Flow-Model Development and Experimental Validations

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Quamrul H. Mazumder ◽  
Siamack A. Shirazi ◽  
Brenton S. McLaury
Keyword(s):  
Multiphase Flow ◽  
Solid Particle ◽  
Single Phase ◽  
Solid Particles ◽  
Phase Flow ◽  
Operating Pressure ◽  
Single Phase Flow ◽  
Repeated Impact ◽  
Gas Phases ◽  
Erosion Rates

Erosion damage in the pipe wall due to solid particle impact can cause severe problems in fluid handling industries. Repeated impact of the suspended small solid particles to the inner wall of process equipment and piping removes material from the metal surface. The reduced wall thickness of high pressure equipment and piping can no longer withstand the operating pressure that they were originally designed for and may cause premature failure of the system components. This results in production downtime, safety, and environmental hazards with significant loss to the industry and economy. Prediction of erosion in single-phase flow with sand is a difficult problem due to the effect of different parameters and their interactions that cause erosion. The complexity of the problem increases significantly in multiphase flow where the spatial distribution of the liquid and gas phases and their corresponding velocities change continuously. Most of the currently available erosion prediction models are developed for single-phase flow using empirical data with limited accuracy. A mechanistic model has been developed for predicting erosion in elbows in annular multiphase flow (gas-liquid-solid) considering the effects of particle velocities in gas and liquid phases of the flow. Local fluid phase velocities in multiphase flow are used to calculate erosion rates. The effects of erosion due to impacts of solid particles entrained in the liquid and gas phases are computed separately to determine the total erosion rate. Erosion experiments were conducted to evaluate the model predictions. Comparing the model predicted erosion rates with experimental erosion data showed reasonably good agreement validating the model.

Capabilities and Challenges of CFD in Multiphase Simulation of Hydraulic Tanks

2014 ◽  
Author(s):  
Thees Vollmer ◽  
Johannes Untch
Keyword(s):  
Multiphase Flow ◽  
Single Phase ◽  
Test Bench ◽  
Cfd Simulation ◽  
Air Flow ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Major Purpose ◽  
Flow Models ◽  
Multiphase Models

A major purpose of hydraulic tanks is the segregation of air, which can be supported by different design measures. To improve these measures CFD multiphase simulation can be used, as it is capable to assess the air flow within the oil. The different possibilities of CFD simulation are presented. Here single-phase flow models, simplified multiphase models as well as full multiphase flow models are discussed and evaluated. An example of each presented method is given and the results are compared. Last the capabilities of validating the simulations on a test bench are briefly discussed.

Single-phase flow in a rock fracture: micro-model experiments and network flow simulation

2004 ◽  
Vol 41 (4) ◽  
pp. 687-693 ◽  
Author(s):  
J.-T. Cheng ◽  
J.P. Morris ◽  
J. Tran ◽  
A. Lumsdaine ◽  
N.J. Giordano ◽  
...  
Keyword(s):  
Network Flow ◽  
Single Phase ◽  
Rock Fracture ◽  
Flow Simulation ◽  
Phase Flow ◽  
Micro Model ◽  
Single Phase Flow ◽  
Model Experiments

Investigation of Paraffin Deposition During Multiphase Flow in Pipelines and Wellbores—Part 1: Experiments

2002 ◽  
Vol 124 (3) ◽  
pp. 180-186 ◽  
Author(s):  
Ahmadbazlee Matzain ◽  
Mandar S. Apte ◽  
Hong-Quan Zhang ◽  
Michael Volk ◽  
James P. Brill ◽  
...  
Keyword(s):  
Multiphase Flow ◽  
Single Phase ◽  
Liquid Velocity ◽  
Test Facility ◽  
Intermittent Flow ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Wax Deposition ◽  
Two Phase ◽  
Superficial Liquid Velocity

Results are presented from two-phase flow wax deposition tests using a state-of-the-art, high-pressure, multiphase flow test facility. Wax deposition was found to be flow pattern specific and dependent on the flow velocities of the two-phase fluids. Wax deposition occurs only along the pipe wall in contact with a waxy crude oil. An increase in mixture velocity results in harder deposits, but with a lower deposit thickness. The wax buildup trend at low mixture velocities is similar to that observed in laminar single-phase flow tests. The wax buildup trend at high mixture velocities is similar to that observed in turbulent single-phase flow tests. Thinner and harder deposits at the bottom than at the top of the pipe were observed in horizontal and near-horizontal intermittent flow tests. For annular flow tests, thicker and harder deposits were observed at low superficial liquid velocity than at high superficial liquid velocity. In stratified flow tests, no wax deposition was observed along the upper portion of the pipe.

Acoustical Characteristics of Single and Two-Phase Horizontal Pipe Flow Through an Orifice

2017 ◽  
Author(s):  
S. P. C. Belfroid
Keyword(s):  
Multiphase Flow ◽  
Single Phase ◽  
Two Phase Flow ◽  
Jet Noise ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Choked Flow ◽  
Flow Through

In this work, the acoustic effects of horizontal air-water flow through an orifice are investigated experimentally. Single phase flow (air) and two-phase flow (air and water) tests are performed for two sets of orifices. One set of straight edged and one set of upstream rounded orifices. For each set, the diameters of the orifices were 2, 5, and 10mm, with a thickness of 5 mm. The two-phase flow is generated by injecting water at a rate of 0 to 40 g/s to air in a pipe with diameter of 25 mm. The air rate is fixed in the range from 5.8 to 14 g/s, where the upstream pressure varies from 1.5 to 4 bar at ambient temperature. Unsteady pressure fluctuations are recorded at two upstream and two downstream position. The valve noise standard NEN-EN-IEC (60534-8-3, 2011) for dry gas is assessed by means of experimental data in dry conditions at fixed air mass flow rate. Predictions of sound power spectra by means of the standard are found to be more accurate compared to those obtained following Reethof & Ward (1986), also in conditions of a choked orifice. In case of multiphase flow already at very low liquid fractions of much less than 1%, the standard is no longer valid. The frequency spectrum is no longer determined by the jet noise but starts to be dominated by low frequency general multiphase flow. The Strouhal number based on the jet conditions is an order lower than Sr = 0.2 indicating process variations rather than jet noise. Furthermore, at choking conditions the further expansion which occurs in single phase flow is likely different at multiphase flow. For non-choked flow, the standard can be adapted using multiphase mixture properties. This does lead to a good prediction. However at choked conditions, this method fails.

Multiphase Flow Wax Deposition Modeling

2001 ◽  
Author(s):  
Ahmadbazlee Matzain ◽  
Mandar S. Apte ◽  
Hong-Quan Zhang ◽  
Michael Volk ◽  
Clifford L. Redus ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Multiphase Flow ◽  
Single Phase ◽  
Superficial Velocity ◽  
Test Facility ◽  
Intermittent Flow ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Wax Deposition ◽  
Semi Empirical

Abstract Results are presented from two-phase flow wax deposition tests using a state-of-the-art, high pressure, multiphase flow test facility. Wax deposition was found to be flow pattern dependent and occurs only along the pipe wall in contact with the waxy crude oil. The deposition buildup trend at low mixture velocities is similar to that observed in laminar single-phase flow tests. The buildup trend at high mixture velocities is similar to that observed in turbulent single-phase flow tests. Thinner and harder deposits at the bottom than at the top of the pipe were observed in horizontal intermittent flow tests. Thicker and harder deposits were observed at low liquid superficial velocity than at high liquid superficial velocity annular flow tests. No wax deposition was observed along the upper portion of the pipe in stratified flow tests. A semi-empirical kinetic model tailored for the wax deposition tests predicted wax thickness with an acceptable accuracy, especially at high oil superficial velocity. Deposition rate reduction due to shear stripping and rate enhancement due to entrapment of oil and other mechanisms not accounted for by the classical Fick’s mass diffusion theory were incorporated through the use of dimensionless variables and empirical constants derived from the wax deposition data. The kinetic model, although semi-empirical, provides an insight for future model development.

A Comprehensive Procedure to Estimate Erosion in Elbows for Gas/Liquid/Sand Multiphase Flow

2005 ◽  
Vol 128 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Xianghui Chen ◽  
Brenton S. McLaury ◽  
Siamack A. Shirazi
Keyword(s):  
Experimental Data ◽  
Multiphase Flow ◽  
Reasonable Agreement ◽  
Single Phase ◽  
Sand Particle ◽  
Phase Flow ◽  
Mass Ratio ◽  
Single Phase Flow ◽  
Erosion Prediction ◽  
Mechanistic Analysis

A comprehensive procedure that combines mechanistic analysis and numerical simulation approaches is proposed to estimate the erosion in elbows for gas/liquid/sand particle multiphase flow systems. The erosion problem in multiphase flow is approximately transferred to one in single-phase flow by introducing the effective sand mass ratio and a representative single-phase flow to which a single-phase computational-fluid-dynamics-based erosion-prediction model can be applied. Erosion in elbows is calculated for various multiphase flow patterns and compared to experimental data in the literature. Reasonable agreement between the simulations and the literature data is observed. The proposed approach is an effective tool to estimate the erosion in multiphase flow.

A Comprehensive Erosion Prediction Method for Gas/Liquid/Sand Multiphase Flow

2005 ◽  
Author(s):  
Xianghui Chen ◽  
Brenton S. McLaury ◽  
Siamack A. Shirazi
Keyword(s):  
Multiphase Flow ◽  
Prediction Model ◽  
Liquid Flow ◽  
Single Phase ◽  
Phase Flow ◽  
Mass Ratio ◽  
Single Phase Flow ◽  
Erosion Prediction ◽  
Flow Systems ◽  
Sand Particles

Sand particles induced erosion of the piping system and fittings is a concern for many industrial practices. The local flow behavior is one of the primary factors that determine the severity of erosion as well as the location where the erosion occurs. Extensive research has been conducted experimentally and numerically to study the erosion phenomena in single-phase (i.e. gas or liquid) flow systems and a variety of erosion prediction models have been developed. Nevertheless, very limited work has been done to investigate the erosion in multiphase (i.e. gas/liquid) flow systems, which is mainly due to the extreme complexity of the phenomena. A comprehensive procedure is proposed to estimate the erosion for sand particles entrained in gas/liquid multiphase flow systems. This procedure combines the mechanistic analysis approach and numerical simulation approach. In this procedure, the dominant flow characteristics of a given flow pattern are analyzed and the corresponding representative single-phase flow is proposed. Such that the erosion problem in this multiphase flow is simplified as one in the representative single-phase to which a single-phase Computational Fluid Dynamics (CFD) based erosion prediction model is applied. Meanwhile, the effective sand mass ratio is introduced to reflect the influence of individual flow patterns on the erosion process by applying a unified mechanistic multiphase flow prediction model. The calculated erosion from the single-phase flow weighted by the effective sand mass ratio yields the estimated erosion for the multiphase flow. Applying this approach, the erosion in elbows is calculated for bubbly flow, annular and annular-mist flow and slug flow and compared with the experimental data in literature. Agreement between the simulations and the data is reasonable, which indicates that the proposed method is an effective tool to estimate the erosion in multiphase flow.

Sign in / Sign up

Export Citation Format

Share Document