Analysis on Inlet Nozzle Design Geometry of Tesla Turbine

Tesla turbine is a bladeless turbine that uses a set of discs arranged at a certain distance to rotate and one of the parameters controlling turbine performance is the inlet parameter. The purpose of this study is to optimize the design of the inlet nozzle and analyse its effects on the flow of the fluid. A total of four nozzle designs have been proposed using CATIA while the Solidworks Flow Simulator is used to analyse the fluid flow at various inlet velocities. Then, the most efficient design is then fabricated via 3D printing and put to test by connecting it with the actual Tesla turbine model. Through the results obtained from the analysis, it is observed that Design 4 is the most efficient of all tested nozzles and the highest RPM and output voltage achieved from the nozzle is 7940 RPM and 13.56 V. The difference in velocity and pressure increases as the area of the nozzle outlet reduces, whereas nozzle efficiency decreases as the inlet velocity increases. The result of this study is a source material for increasing the effectiveness of an alternative power turbine in generating electricity by manipulating the inlet design geometry.

Experimental study of the flow in the elastic model of the abdominal aortic bifurcation

This paper reflected preliminary results of physical modeling of pulsating flow in a model of abdominal aortic bifurcation with taking into account the physiological elasticity of the vessel walls. Elastic vessel models were made via molding from a silicone mixture based on Lasil-T4 silicone rubber. The auxiliary study was performed to assess the elastic properties of the silicone mixture and select a necessary composition. The experiment on the pulsating flow in the rigid and elastic models of the abdominal aortic bifurcation was carried out using a blood flow simulator with circulation of blood-emulating fluid. It was revealed that interaction between the elastic model and closed rigid circuit of the blood flow simulator resulted in generation of intense parasite flow oscillations and prevented from getting similar flow conditions for rigid and elastic models. A way to solve the problem is to include dampers with liquid in the hydraulic circuit of the blood flow simulator at the inlet and the outlets of the elastic model.

An Inexpensive Cardiovascular Flow Simulator for Cardiac Catheterization Procedure Using a Pulmonary Artery Catheter

Cardiac catheterization associated with central vein cannulation can involve potential thrombotic and infectious complications due to multiple cannulation trials or improper placement. To minimize the risks, medical simulators are used for training. Simulators are also employed to test medical devices such as catheters before performing animal tests because they are more cost-effective and still reveal necessary improvements. However, commercial simulators are expensive, simplified for their purpose, and provide limited access sites. Inexpensive and anatomical cardiovascular simulators with central venous access for cannulation are sparse. Here, we developed an anatomically and physiologically accurate cardiovascular flow simulator to help train medical professionals and test medical devices. Our simulator includes an anatomical right atrium/ventricle, femoral and radial access sites, and considers the variability of arm position. It simulates physiological pulsatile blood flow with a setting for constant flow from 3 to 6 L/min and mimics physiological temperature (37°C). We demonstrated simulation by inserting a catheter into the system at radial/femoral access sites, passing it through the vasculature, and advancing it into the heart. We expect that our simulator can be used as an educational tool for cardiac catheterization as well as a testing tool that will allow for design iteration before moving to animal trials.

Adaptation of Capillary String for the Surfactants Delivery into a Gas Condensate Well and Optimization of its Operation Using Dynamic Multiphase Flow Simulator

The studied productive formation of gas condensate field is at the stage of declining production. The inflow of bottom water due to the rise of the GWC and the design features of horizontal wells (large tubing and liner diameters) create the prerequisites for the development of a liquid loading of wells. This necessitate the optimization of the existing method of liquid unloading by dosing surfactants into the annulus. In order to increase the efficiency of well treatment with a foaming agent, the use of a surfactant injection system through a capillary string suspended inside a tubing is considered. The use of this system allows to increase the speed and depth of surfactant delivery, use the potential of the well by simultaneous work in tubing and annulus during significant watering period (water flow rate: 50 and more m3 / day), reduce reagent losses associated with retention on the casing walls, and reduce the required consumption of surfactant. The capillary string for the pumping surfactant is applicated to ensuring the stable operation of gas condensate wells during liquid loading. But today there are not ready-made applied solutions for correctly accounting surfactant action in unsteady flows conditions in the well. The paper presents the substantiation and analysis of the capillary string introduction into the well for the pumping surfactant using specialized software. In the course of work, the main analysis tool is the dynamic modeling of multiphase flows in the conditions of steady and unsteady processes in wells. This approach use is aimed at determining the optimal depth and diameter of capillary, the required consumption and concentration of surfactant, the rate of its delivery to the bottomhole, and the liquid removal efficiency from the horizontal wellbore.

Efficiency Survey of a Drainage Wellbore and Well Placement in Gas Fields

The paper describes the assessment process of methods for the construction and operation of gas wells with a large water-gas ratio. One of the ways to tackle the issue of poor performance of high WGR wells is to drill a drainage wellbore with an ESP to lift accumulating water. In addition, various configurations of well placement through gas-bearing and water-bearing reservoirs have been considered. To evaluate the efficiency of a drainage wellbore with an ESP installed for lifting water that comes from the main, productive, wellbore, industry-recognized non-stationary dynamic multiphase flow simulator was used, as well as a more refined tool, such as the physical simulator based on the finite volume method (computational fluid dynamics, CFD). A non-stationary dynamic simulator was also used to assess the impact of well placement through gas- and water-bearings reservoirs. Well data, fluid data, physical parameters were entered into the models and, by varying the input parameters, dependencies and results were obtained, allowing to draw a conclusion about the efficiency of each method, as well as about the software capabilities and limitations. The applicability and technical efficiency of an additional drainage borehole with an ESP tto ensure stable operation / high productivity of the well strongly depend on the value of the water-gas ratio, the higher it is, the lower the efficiency of the method. In addition, efficiency also decreases with increasing gas rate. To assess the correctness of the calculation made with dynamic multiphase flow simulator, which is the industry standard, a verification calculation was also carried out on a physical simulator using the finite volume method, which shows the same trends, but with different absolute values. It also made it possible to assess the influence of the geometry factor on the distribution of flows, which could not be done by the non-stationary multiphase flow simulator. Apart from this, it was concluded that the location of a water-bearing reservoir in the last lower part of the wellbore is preferable, since then the impact on production is less than when it is located above the gas-bearing interval. Changing the well layout to a U-shaped one affects the dynamics of its operation insignificantly. The study helps to answer the question about the efficiency of using a borehole with an ESP and about the degree of influence of drilling through gas- and water-bearing reservoirs using the example of a real field, as well as it presents the method of conducting such an assessment for other fields.

Dual-phase flow in two-layer porous media: a radial composite Laplace domain approximation

The main purpose of this work is to present an interpretation method for injectivity test in a two-layer reservoir that can be extended to a multilayer approach, based on new analytical solutions to the well pressure response. The developed formulation uses a radially composite reservoir approach and considers that the water front propagation may be approximated by a piston-like flow displacement. The reservoir is assumed to be laterally infinite and properties such as permeability and porosity may be different in each layer. The solutions were developed in the Laplace domain and then inverted to real domain using the Stehfest Algorithm. The proposed formulation was then validated by comparison with a numerical flow simulator. Results showed a good agreement between the numerical simulator and the analytical model. Also, a sensitivity study was done by comparing the results of different scenarios varying oil viscosities and injection flow rate to assess how these properties affect the pressure and pressure derivative profiles.

Assessment of Chemical Injection to Mitigate Wax Deposition in Unconventional Wells

This work presents a numerical assessment of chemical inhibitor injection to mitigate wax deposition in unconventional wells. The goal of this study is to simulate the deposition of wax under several operational conditions and later optimize the chemical inhibitor injection position, using two different types of numerical simulations. A transient one-dimensional multiphase flow simulator - ALFAsim, with a dedicated wax model, was used to predict flow conditions such pressure, temperature, holdup and flow pattern profiles, as well the position and rates that wax accumulates. The results from the 1D simulation were then used as boundary conditions in a 3D CFD simulator, which aimed to assess how long it would take to a satisfactory homogenization of the inhibitor with the flow and what would be the minimum depth for the injector should be installed. In this work, a 1D multiphase flow simulator with wax deposition model was used to identify on which operational conditions (flow rates and environmental temperatures) an unconventional well would start to present wax deposition on its tubing walls. After defining the susceptible region where the paraffin could deposit, it was important to verify if the inhibitor would be well homogenized with the stream when reaching this region. For that, a 3D CFD simulation was performed, using information obtained directly from the 1D simulator as boundary conditions. The CFD model was capable to show the mixing evolution of the inhibitor with the stream and it was possible to determine the minimum distance where the injector should be placed to guarantee such homogeneity. A real well was selected to provide comparisons between field observations and simulated data, in order to validate the model assumptions and accuracy.

Mitigating Scale Deposition by Optimization of Completion Valves Geometry

The harsh conditions presented in Brazilian presalt, summed up with the complexity of its reservoir, generate a series of challenges to improve reservoir recovery. Routinely, we have used intelligent completion systems to address the major part of the challenges; however, with the new production rates new problems have arrived and the usual ones have turned more aggressive, generating risks even to the intelligent completion systems. Inorganic scale is a critical challenge in presalt reservoirs production. Future plans for presalt production include more robust flow conditions and the use of an all-electrical completion system. Higher flow rates are likely to increase the risk of scale deposition and an optimum design is required. To address the new challenges arising from the new perspective of exploration in the presalt fields, we developed the presented workflow to mitigate the scale deposition on completion valves. The method enables the optimization of choke geometry to reduce scale deposition on inflow control valves. The proposed workflow generates a criticalness parameter for geometry classification according to a scenario of mechanical failure (due to sleeve incapacity to move) or deviation of production design point. A computational fluid dynamics (CFD) simulation was developed and benchmarked by experimental data, thus CFD results for different scenarios and various choke geometries were used to build a risk analysis matrix, which allows the definition of the optimal choke design to mitigate scale on ICVs. The extracted criticalness parameter may be used as an evaluator to estimate the time to valve stuck due to scale deposition in a commercial 1D transient flow simulator, optimizing then valve cycling time.

Porting OpenMP to GPGPU to accelerate Krylov space computations in coupled geodynamics simulator

Understanding the causality between the events leading upto and post fault slipand the earthquake recording is important for seismic design and monitoring ofunderground structures, bridges and reinforced concrete buildings as well as climatemitigation projects like carbon sequestration and energy technologies like enhancedgeothermal systems or oilfield wastewater disposal. While the events leading uptofault slip are typically governed by poroelastostatics, the events post fault slip caneasily transition into poroelastodynamics territory due to runaway fault slip velocities.An understanding of expected fault slip velocities is critical apriori, as an algorithmwhich can seamlessly transition from time marching in poroelastostatics realm toporoelastodynamics realm and vice-versa is extremely difficult to achieve. That beingsaid, every effort in the direction of accelerating the computations on the flow sideare a necessary step forward in rendering a fast coupled geodynamics simulator.In this document, we present a framework in which we study the porting of theOpenMP parallelism of the flow simulator to a GPGPU