Water Hammer Analysis for Heated Liquid Transmission Pipeline with Entrapped Gas Based on Homogeneous Flow Model and Fractional Flow Model

The fractional flow reserve (FFR) provides an efficient quantitative assessment of the severity of a coronary lesion. Our aim is to address the problem of computing non-invasive virtual fractional flow reserve (VFFR). In this paper, we present a preliminary study of the main features of flow over a stenosed coronary arterial portion, in order to enumerate the different factors affecting the VFFR. We adopt a non-Newtonian flow model and we assume that the two-dimensional (2D) domain is rigid in a first place. In a second place, we consider a simplified weakly coupled FSI model in order to take into account the infinitesimal displacements of the upper wall. A 2D finite element solver was implemented using Freefem++. We computed the VFFR profiles with respect to different lesion parameters and compared the results given by the rigid wall model to those obtained for the elastic wall one.

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Virtual FFR Quantified with a Generalized Flow Model Using Windkessel Boundary Conditions

Computational and Mathematical Methods in Medicine ◽

10.1155/2020/3942152 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Keltoum Chahour ◽

Rajae Aboulaich ◽

Abderrahmane Habbal ◽

Nejib Zemzemi ◽

Chérif Abdelkhirane

Keyword(s):

Boundary Conditions ◽

Flow Model ◽

Fluid Model ◽

Invasive Procedure ◽

Navier Stokes ◽

Fractional Flow ◽

Flow Reserve ◽

Arbitrary Position ◽

Model Versus ◽

Good Agreement

Fractional flow reserve (FFR) has proved its efficiency in improving patient diagnosis. In this paper, we consider a 2D reconstructed left coronary tree with two artificial lesions of different degrees. We use a generalized fluid model with a Carreau law and use a coupled multidomain method to implement Windkessel boundary conditions at the outlets. We introduce our methodology to quantify the virtual FFR and conduct several numerical experiments. We compare FFR results from the Navier–Stokes model versus generalized flow model and for Windkessel versus traction-free outlet boundary conditions or mixed outlet boundary conditions. We also investigate some sources of uncertainty that the FFR index might encounter during the invasive procedure, in particular, the arbitrary position of the distal sensor. The computational FFR results show that the degree of stenosis is not enough to classify a lesion, while there is a good agreement between the Navier–Stokes model and the non-Newtonian flow model adopted in classifying coronary lesions. Furthermore, we highlight that the lack of standardization while making FFR measurement might be misleading regarding the significance of stenosis.

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Prediction of mobile water in a tight gas sandstone reservoir using NMR and fractional flow model

The APPEA Journal ◽

10.1071/aj13005 ◽

2014 ◽

Vol 54 (2) ◽

pp. 1

Author(s):

Maria Anantawati ◽

Suryakant Bulgauda

Keyword(s):

Steady State ◽

Relative Permeability ◽

Flow Model ◽

Bound Water ◽

Free Water ◽

Development Project ◽

Asia Pacific ◽

Fractional Flow ◽

Reservoir Properties ◽

Mobile Water

One of the objectives of petrophysical interpretation is the estimation of the respective volumes of formation fluids. With traditional interpretation using conventional openhole logs it is only possible to determine the total amount of water. The challenge is to determine the volumes of bound water (clay-bound and capillary-bound) and free water. At the moment, NMR is the only measurement that can help distinguish the volumes of each water component (clay-bound, capillary-bound and mobile), using cut-offs on T2 (transverse relaxation time). However NMR interpretation also requires information on reservoir properties. Alternatively, steady-state relative permeability and fractional flow of water can be used to determine the potential of mobile water. The study area, located in the Cooper Basin, South Australia, is the target of a planned gas development project in the Patchawarra formation. It comprises multiple stacked fluvial sands which are heterogeneous, tight and of low deliverability. The sands are completed with multi-stage pin-point fracturing as a key enabling technology for the area. A comprehensive set of data, including conventional logs, cores and NMR logs, were acquired. Routine and special core analysis were performed, including NMR, electrical properties, centrifuge capillary pressure, high-pressure mercury injection, and full curve steady state relative permeability. A fractional flow model was built based on core and NMR data to determine potential mobile water and the results compared with production logs. This paper (SPE 165766) was prepared for presentation at the SPE Asia Pacific Oil & Gas Conference and Exhibition, held in Jakarta, Indonesia, from 22–24 October 2013.

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Evaluation of Two-Phase Frictional Pressure Drop Correlations Against Experimental Data

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4044533 ◽

2019 ◽

Vol 12 (3) ◽

Author(s):

Wei Li ◽

Kunrong Shen ◽

Boren Zheng ◽

Xiang Ma ◽

S. A. Sherif ◽

...

Keyword(s):

Experimental Data ◽

Pressure Drop ◽

Mass Flow ◽

Flow Model ◽

Saturation Temperature ◽

Separated Flow ◽

Outer Diameter ◽

Two Phase ◽

Homogeneous Flow ◽

Frictional Pressure Drop

Abstract Results are presented here from an experimental investigation on tube side two-phase characteristics that took place in four tested tubes—the 1EHT-1, 1EHT-2, 4LB, and smooth tubes. The equivalent outer diameter of the tube was 9.52 mm and the inner diameter was 8.32 mm. Condensation tests were conducted using refrigerant R410A at a saturation temperature of 318 K, over a mass flow range of 150–450 kg m−2 s−1, with inlet and outlet vapor qualities of 0.8 and 0.2, respectively. Evaporation tests were performed at a saturation temperature of 279 K, over a mass flow range of 150–380 kg m−2 s−1, with inlet and outlet vapor qualities of 0.2 and 0.8, respectively. Pressure drop data of the four tested tubes were collected to evaluate five identified prediction correlations based on the separated flow model and the homogeneous flow model. The separated flow approaches presented predictions with average MAEs of 24.9% and 16.4% for condensation and evaporation data, respectively, while the average MAEs of the homogeneous flow model were 31.6% and 43.4%, respectively. Almost all the identified correlations underestimated the frictional pressure drop of the 4LB tube with MAEs exceeding 30%. An earlier transition of different flow patterns was expected to occur in the EHT tubes while developing a new diabatic flow pattern map is needed for the 4LB tube. A new correlation was presented based on the two-phase multiplier Φ and the Martinelli parameter Xtt, which exhibited excellent predictive results for the experimental data.

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Evaluation of Existing Frictional Pressure Drop Correlations During Condensation of R410A in Four Horizontal Tubes

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer ◽

10.1115/mnhmt2019-4038 ◽

2019 ◽

Author(s):

Kunrong Shen ◽

Zhichuan Sun ◽

Wei Li ◽

Xiang Ma ◽

Yan He ◽

...

Keyword(s):

Experimental Data ◽

Pressure Drop ◽

Flow Model ◽

Saturation Temperature ◽

Separated Flow ◽

Smooth Tube ◽

Outer Diameter ◽

Homogeneous Flow ◽

Frictional Pressure Drop ◽

Horizontal Tubes

Abstract Results are presented here from an experimental investigation on tube side condensation characteristics that took place in four tested tubes — 1EHT-1, 1EHT-2, 4LB and a smooth tube. The equivalent outer diameter of the tubes was 9.52 mm and the inner diameter was 8.32 mm. Condensation tests were conducted using refrigerant R410A at a saturation temperature of 318K, over a mass flow range of 150–450 kgm−2s−1, with inlet and outlet vapor quality of 0.8 and 0.2, respectively. Pressure drop data of the four tested tubes were collected to evaluate five identified prediction correlations based on the separated flow model and the homogeneous flow model. For 1EHT-2 and the smooth tube, all the listed correlations manage to present predictions with the Mean Absolute Relative Deviation (MARD) less than 30%, while they underestimate the frictional pressure drop of the 4LB tube with MARD exceeding 40% averagely. Regarding the experimental data, it is found that the Muller-Steinhagen and Heck correlation presents the most accurate and stable prediction for the 4 tested tubes. The listed homogeneous flow correlations can provide acceptable predictions with MARD ranging from 25% to 40% under a few conditions, but their average predictive accuracies are inferior to that of the separated flow correlations. Consequently, the separated flow approach performs better than the homogeneous flow model in the prediction of frictional pressure drop for our experimental data.

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