scholarly journals A Method to Increase the Leaching Progress of Salt Caverns with the Use of the Hydro-Jet Technique

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5833
Author(s):  
Mariusz Chromik ◽  
Waldemar Korzeniowski
Keyword(s):  
High Pressure ◽  
Numerical Simulations ◽  
Classical Method ◽  
Underground Caverns ◽  
Innovative Solution ◽  
Hydro Jet ◽  
Salt Deposits ◽  
Salt Caverns ◽  
Leaching Efficiency ◽  
Brine Concentration

For the storage of hydrocarbons, hydrogen, or other products, underground caverns left over from the exploitation of salt deposits, or made specifically for this purpose, are successfully used. This article analyses the effectiveness of currently used well-leaching technologies in terms of the possibility of increasing the speed of obtaining industrial brine, better control of the shape of the created cavern, and, as a result, a shorter production time. An innovative solution was proposed, which consisted of creating appropriate niches in the walls of the leach well using the high-pressure hydrojet technique, just before the start of the sump leaching. A series of numerical simulations of the technologies were performed for various combinations of niche locations along the well, determining the successive phases of the formation of the cavern space at individual stages and the brine concentration increments for the two assumed technology scenarios. As a result of the modified technology, the possibility of creating a sump with a volume greater than 17%, compared to the classical method carried out at the same time, was indicated. The resulting sump also had a better shape to partially eliminate the reduction in leaching efficiency due to the accumulation of insoluble matter at the bottom. In addition, the brine obtained according to the modified technology had a 15% higher concentration than in the classical method.

Experimental and Numerical Study on Pressure Losses and Flow Fluctuations in a High-Pressure Valve Assembly of Steam Turbine Governing System

2020 ◽  
Author(s):  
Vaclav Slama ◽  
Lukas Mrozek ◽  
Bartolomej Rudas ◽  
David Simurda ◽  
Jindrich Hala ◽  
...  
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Numerical Simulations ◽  
Pressure Loss ◽  
Operational Reliability ◽  
Operating Conditions ◽  
The Real ◽  
Pressure Losses ◽  
Flow Fluctuations ◽  
Valve Assembly

Abstract Aerodynamic measurements and numerical simulations carried out on a model of a high-pressure valve assembly used for nozzle governing of a turbine with 135MW output are described in this paper. Aim of the study is to investigate effects of control valve’s strainers on pressure losses and unsteadiness in the flow field. It is an important task since undesirable flow fluctuations can lead to operational reliability issues. Measurements were carried out in the Aerodynamic laboratory of the Institute of Thermomechanics of the Czech Academy of Sciences (IT) where an aerodynamic tunnel is installed. Numerical simulations were carried out in the Doosan Skoda Power (DSP) Company using ANSYS software tools. The experimental model consists of one of two identical parts of the real valve assembly. It means it consists of an inlet pipeline, a stop valve, a valve chamber with two independent control valves, its diffusers and outlet pipelines. The numerical model consists of both assembly parts and includes also an A-wheel control stage in order to simulate the real turbine operating points. The different lifts of the main cone in each control valve for its useful combinations were investigated. Results were evaluated on the model with control valve’s strainers, which were historically used in order to stabilize the flow, and without them. The results of the experimental measurement were compared with the numerical results in the form of pressure losses prediction. From measured pressure fluctuations, it was found out where and for which conditions a danger of flow instabilities occurs. It can be concluded that there is a border, in terms of operating conditions, where the flow field starts to be unstable and this border is different dependent of the fact whether the control valve’s strainers are used or not. Therefore, the areas of safe and danger operational reliability can be predicted. The influence of the control valve’s strainers on the maximal amplitude of periodic fluctuations appears only for the cases when valves are highly overloaded. For normal operating conditions, there is no difference. As a result, the control valve’s strainers do not have to be used in standard applications of valve assemblies. Furthermore, a loss model for valve pressure loss estimation could be updated. Therefore, a pressure loss should be predicted with a sufficient accuracy for each new turbine bid with similar valve assemblies.

Some Numerical Simulations and an Experimental Investigation of a Finger Seal

2005 ◽  
Author(s):  
Minel J. Braun ◽  
Hazel M. Pierson ◽  
Hongmin Li
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
Pressure Drop ◽  
Numerical Simulations ◽  
Mechanical Performance ◽  
Low Pressure ◽  
Pressure Differential ◽  
Experimental Results ◽  
Axial Pressure ◽  
Brush Seals

Finger seals (FS) are compliant seal configurations. Unlike brush seals, they exhibit hydrodynamic lifting capabilities which allow non-contact sealing between stationary and rotating members. The compliance combined with the non-contacting feature allows both axial and radial adjustment of the seal to the rotor excursions without endangering the integrity of the former. The embodiment of a two-layer finger seal with high pressure (1c) and low pressure (1b) laminates is shown in Figure1. In this paper we shall analyze the thermo-hydraulic and mechanical performance (axial and radial deformations and displacements) of a representative repetitive cell that contains four high pressure and four low-pressure fingers arranged axially in a staggered configuration, and subject to rotation and an axial pressure drop. We shall also present experimental results pertaining to the seal deformation under axial pressure differential and rotation.

Sloshing in LNG Tanks: Assessment of High and Low Pressures

2008 ◽  
Author(s):  
Sebastian Schreier ◽  
Mathias Paschen
Keyword(s):  
High Pressure ◽  
Numerical Simulations ◽  
Liquid Sloshing ◽  
Pressure Impact ◽  
Membrane Type ◽  
Low Pressures

In the assessment of 2D numerical simulations of liquid sloshing in partially filled membrane-type cargo tanks of LNG Carriers high pressure impacts and also particularly low pressures have been identified. One high pressure impact at low filling levels and one sloshing impact leading to particularly low pressures at high filling levels are studied in greater detail. The results of these investigations are presented and conclusions are drawn with respect to the underlying physics of the two phenomena.

scholarly journals On the Existence, Uniqueness and Application of the Finite Difference Method for Solving Robin Elliptic Boundary Value Problem

2019 ◽  
Vol 11 (1) ◽  
pp. 26
Author(s):  
Germain Nguimbi ◽  
Diogène Vianney Pongui Ngoma ◽  
Vital Delmas Mabonzo ◽  
Bienaime Bervi Bamvi Madzou ◽  
Melchior Josièrne Jupy Kokolo
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Numerical Simulations ◽  
Difference Method ◽  
Numerical Solutions ◽  
Classical Method ◽  
Elliptic Boundary ◽  
Boundary Condi Tions ◽  
Elliptic Boundary Value ◽  
Uniqueness Of The Solution

This paper refers to mathematical modelling and numerical analysis. The analysis to be presented through this paper deals with Robin’s problem which boundary equation is a linear combination of Dirichlet and Neumann-type boundary condi-tions. For this purpose we proved the existence and uniqueness of the solution. It is worth noting that the implementation of numerical simulations depends on the type of problem since it requires a search for explicit solution. Consequently, the motivation exists in this paper for choosing a classical method of variation of constants and employing a finite difference method to find the exact and numerical solutions, respectively so that numerical simulations were implemented in Scilab.

scholarly journals Experimental and Numerical Investigation of Phase Separation due to Multi-Component Mixing at High-Pressure Conditions

2017 ◽  
Author(s):  
Christoph Traxinger ◽  
Hagen Müller ◽  
Michael Pfitzner ◽  
Steffen Baab ◽  
Grazia Lamanna ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Separation ◽  
Numerical Simulations ◽  
A Priori ◽  
Two Phase ◽  
Separation Processes ◽  
Pure Nitrogen ◽  
Elastic Light Scattering ◽  
Large Eddy ◽  
High Pressure Injection

Experiments and numerical simulations were carried out in order to contribute to a better understanding and predic-tion of high-pressure injection into a gaseous environment. Specifically, the focus was put on the phase separation processes of an initially supercritical fluid due to the interaction with its surrounding. N-hexane was injected into a chamber filled with pure nitrogen at 5 MPa and 293 K and three different test cases were selected such that they cover regimes in which the thermodynamic non-idealities, in particular the effects that stem from the potential phase separation, are significant. Simultaneous shadowgraphy and elastic light scattering experiments were conducted to capture both the flow structure as well as the phase separation. In addition, large-eddy simulations with a vapor- liquid equilibrium model were performed. Both experimental and numerical results show phase formation for the cases, where the a-priori calculation predicts two-phase flow. Moreover, qualitative characteristics of the formation process agree well between experiments and numerical simulations and the transition behaviour from a dense-gasto a spray-like jet was captured by both.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4756

Investigation of species-mass diffusion in binary-species boundary layers at high pressure using direct numerical simulations

2021 ◽  
Vol 928 ◽  
Author(s):  
Takahiko Toki ◽  
Josette Bellan
Keyword(s):  
High Pressure ◽  
Numerical Simulations ◽  
Boundary Layers ◽  
Mass Flux ◽  
Mass Fraction ◽  
Soret Effect ◽  
Streamwise Velocity ◽  
Mass Diffusion ◽  
Direct Numerical Simulations ◽  
Temperature Fields

Direct numerical simulations of single-species and binary-species temporal boundary layers at high pressure are performed with special attention to species-mass diffusion. The working fluids are nitrogen or a mixture of nitrogen and methane. Mean profiles and turbulent fluctuations of mass fraction show that their qualitative characteristics are different from those of streamwise velocity and temperature, due to the different boundary conditions. In a wall-parallel plane near the wall, the streamwise velocity and temperature have streaky patterns and the fields are similar. However, the mass fraction field at the same location is different from the streamwise velocity and temperature fields indicating that species-mass diffusion is not similar to the momentum and thermal diffusion. In contrast, at the centre and near the edge of the boundary layer, the mass fraction and temperature fields have almost the same pattern, indicating that the similarity between thermal and species-mass diffusion holds away from the wall. The lack of similarity near the wall is traced to the Soret effect that induces a temperature-gradient-dependent species-mass flux. As a result, a new phenomenon has been identified for a non-isothermal binary-species system – uphill diffusion, which in its classical isothermal definition can only occur for three or more species. A quadrant analysis for the turbulent mass flux reveals that near the wall the Soret effect enhances the negative contributions of the quadrants. Due to the enhancement of the negative contributions, small species-concentration fluid tends to be trapped near the wall.

scholarly journals Surface Deformations Caused by the Convergence of Large Underground Gas Storage Facilities

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 402
Author(s):  
Krzysztof Tajduś ◽  
Anton Sroka ◽  
Rafał Misa ◽  
Antoni Tajduś ◽  
Stefan Meyer
Keyword(s):  
Land Surface ◽  
Depth Distribution ◽  
Gas Storage ◽  
Surface Subsidence ◽  
Underground Gas Storage ◽  
Applied Method ◽  
Surface Deformations ◽  
Underground Caverns ◽  
Salt Caverns ◽  
Storage Facilities

The article presents a method of forecasting the deformation of the land surface over large fields of underground gas storage facilities located in salt caverns. The solution allows for taking into account many parameters characterising the operation of underground gas storage facilities, such as cavern processes (leaching, enlargement, operational, etc.), their depth, distribution, diameter, shape, and many others. The advantage of the applied method over other available options is the possibility of using it for large fields of caverns while keeping the calculations simple. The effectiveness of the method has been proven for predicted surface subsidence for the EPE field with 114 underground caverns. The hypothesis was compared with the measurement outcomes.

Acoustic Sound Source Identification in a Gasoline DI Pump for High Pressure Fuel Flows

2014 ◽  
Author(s):  
Prashanth Avireddi ◽  
Nikhil Seera ◽  
Harsha Badarinarayan
Keyword(s):  
High Pressure ◽  
Simulation Model ◽  
Numerical Simulations ◽  
Combustion Chamber ◽  
Sound Pressure Level ◽  
Fuel Economy ◽  
Sound Pressure ◽  
Pressure Level ◽  
Liquid Domain ◽  
Jet Impact

The passenger class automobiles operating with gasoline direct injection (DI) pump have a better fuel economy than the automobiles operating with gasoline port fuel injection (PFI) pump. The fuel economy is higher because DI pump injects fuel directly into combustion chamber at pressures over 150 bar compared to a PFI pump which injects fuel into combustion chamber through inlet port at pressures over 50 bar. By injecting fuel directly into the combustion chamber, DI system prevents condensation of fuel, pressure leakage and improves atomization of fuel for internal combustion process. However, the disadvantage of high pressure operation is that the DI pump is noisier than a PFI pump. The loud sound in a DI pump is generated due to phenomenon such as high pressure pulsations, liquid jet impact and high velocity flows. To investigate the sound production in a DI pump, High fidelity hybrid numerical simulations were developed using CFD and Acoustic tools to simulate the operational effects and identify the behavior of internal components of DI pump. The fidelity of the numerical simulations depends on the transient boundary conditions and the fluid structure interactions in the DI pump. The CFD simulation model of DI pump has 8 million mesh elements and the simulation model is computed using 256 cores of super computer operating at a rate of 2 TFLOPS. The results derived from the CFD simulations were processed using a commercial acoustics tool for computing sound pressure level in liquid domain. Sound pressure level in liquid domain is used as a relative parameter for distinguishing the behavior of liquid-acoustic sources. The results from the numerical simulations provide a good account of the behavior of internal components in DI pump and the simulation results are in good agreement with the experiments performed on DI pump.

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