CFD Modelling of Ventilation, Dust and Gas Flow Dispersion Patterns on a Longwall Face

2018 ◽  
pp. 198-208
Author(s):  
Ting Ren ◽  
Zhongwei Wang
Keyword(s):  
Gas Flow ◽  
Longwall Face ◽  
Cfd Modelling ◽  
Dispersion Patterns

Characterisation of Static Strip Seal Flow

2007 ◽  
Author(s):  
Arash Farahani ◽  
Peter Childs
Keyword(s):  
Gas Flow ◽  
Pressure Ratio ◽  
Flow Characteristics ◽  
Main Stream ◽  
Cfd Modelling ◽  
Height Range ◽  
And Performance ◽  
Nozzle Guide ◽  
The Cost ◽  
Cooling Air

Strip seals are used in gas turbine engines between two static elements or between components which do not move relative to each other, such as Nozzle Guide Vanes (NGVs). The key role of a strip seal between NGV segments is sealing between the flow through the main stream annulus and the internal air system, a further purpose is to limit the inter-segmental movements. In general the shape of the strip seal is a rectangular strip that fits into two slots in adjacent components. The minimum clearance required for static strip seals must be found by accounting for thermal expansion, misalignment, and application, to allow correct fitment of the strip seals. Any increase in leakage raises the cost due to an increase in the cooling air use, which is linked to specific fuel consumption, and it can also alter gas flow paths and performance. The narrow path within the seal assembly, especially the height has the most significant affect on leakage. The height range of the narrow path studied in this paper is 0.01–0.06 mm. The behaviour of the flow passing through the narrow path has been studied using CFD modelling and measurements in a bespoke rig. The CFD and experimental results show that normalized leakage flow increases with pressure ratio before reaching a maximum. The main aim of this paper is to provide new experimental data to verify the CFD modelling for static strip seals. The typical flow characteristics validated by CFD modelling and experiments can be used to predict the flow behaviour for future static strip seal designs.

scholarly journals Explosion Characteristics of Hydrogen for CFD Modelling and Simulation of Turbulent Gas Flow

2018 ◽  
Vol 168 ◽  
pp. 07013 ◽  
Author(s):  
Jan Skřínský ◽  
Jan Koloničný ◽  
Tadeáš Ochodek
Keyword(s):  
Energy Demand ◽  
Gas Flow ◽  
Hydrogen Gas ◽  
Absolute Pressure ◽  
Gas Explosion ◽  
Cfd Modelling ◽  
Gas Dispersion ◽  
Turbulent Gas Flow ◽  
Gas Cloud ◽  
Chamber Gas

Renewable energies became more and more important in the last years. Hydrogen as a promising energy carrier is a perfect candidate to supply the energy demand of the world. The state of the hydrogen gas (turbulences and point concentrations) has a significant impact on the gas explosion indices. A gas cloud is formed by a partial-pressure method in gas explosion experiments in the spherical 20.0∙10-3 m3 chamber. Gas in the chamber reaches an uniform state beyond in hundreds of ms. The absolute pressure for gas dispersion should be higher than 0.01 MPa for the H2 of concentration larger than 30 vol. % of fuel. The initial temperature also influences turbulent gas flow before ignition, especially in the case of the gases lighter-than-air.

Multiphase Flow Induced Vibrations at High Pressure: CFD Analysis of Multiphase Forces

2021 ◽  
Author(s):  
Paul Emmerson ◽  
Mike Lewis ◽  
Neil Barton ◽  
Steinar Orre ◽  
Knud Lunde ◽  
...  
Keyword(s):  
High Pressure ◽  
Multiphase Flow ◽  
Gas Flow ◽  
Production Systems ◽  
Pressure Fluctuations ◽  
High Amplitude ◽  
Operating Pressure ◽  
Cfd Analysis ◽  
Cfd Modelling ◽  
Test Loop

Abstract CFD analysis of a high pressure 2” pipe test loop with water-gas flow was undertaken using three different solvers. Multiphase flow induced forces were predicted on the bends at a range of operating pressures between 10 and 80 barg and compared with forces reconstructed from vibration measurements. Overall the three different CFD solvers predicted consistent results. The fluid forces predicted on the bends of the double U-loop test rig have a good range of values compared to the test reconstructed forces. The forces predicted at low pressure were in line with the experimental reconstructed values, whilst at high pressure all three CFD solvers predicted higher forces. The trend of the forces reducing with increased operating pressure, evident in test, was matched by one of the CFD methods, but less well by the other two. At low operating pressure the forces are dominated by the momentum of the liquid in the multiphase flow, whilst at high pressure the pressure fluctuations and turbulent effects will be more important. All three CFD solvers use VOF methods and above about 40 barg it is possible that they struggle to fully resolve the flow behaviour, which will be more influenced by bubble and droplet entrainment and turbulence. Multiphase flow can induce high amplitude vibrations in piping systems, potentially leading to fatigue failures. CFD modelling offers a potentially powerful tool to provide the flow induced forces required for assessing and diagnosing multiphase flow induced pipework vibration problems in hydrocarbon production systems.

Influence of bed conditions on gas flow in the COREX shaft furnace by DEM–CFD modelling

2016 ◽  
Vol 44 (9) ◽  
pp. 685-691 ◽  
Author(s):  
M. H. Bai ◽  
S. F. Han ◽  
W. Y. Zhang ◽  
K. Xu ◽  
H. Long
Keyword(s):  
Gas Flow ◽  
Shaft Furnace ◽  
Cfd Modelling ◽  
Corex Shaft Furnace

Effect of pressure and salinity on the performance of a gas-liquid separator—a preliminary study

2011 ◽  
Vol 51 (1) ◽  
pp. 603 ◽  
Author(s):  
Shakil Ahmed ◽  
Gerardo Sanchez-Soto ◽  
Chong Wong ◽  
Edson Nakagawa ◽  
Jamal Naser
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Water Flow Rate ◽  
Water Mixture ◽  
Gas Flow Rate ◽  
Cfd Modelling ◽  
Effect Of Pressure ◽  
Compact Design ◽  
Operational Range ◽  
Liquid Separator

The separation of liquid from gas during the initial stages of the separation process is very important in increasing well productivity. This is why the design of an efficient and compact gas-liquid separator has received much attention from academic researchers as well as field operators. They all state the necessity of compact design in deploying separators offshore (and potentially subsea) to enhance the recovery of gas wells. This investigation describes an experimental and computational fluid dynamics (CFD) modelling of a laboratory-scale compact gas-liquid separator designed by CSIRO. The separator consists of two concentric pipes with a swirl tube in the annular space between the pipes. The gas-liquid mixture comes from the tangential side inlet, and the system works with a combination of gravity and centrifugal forces to achieve a highly efficient gas-liquid separation. The effect of pressure and salinity on the performance of the gas-liquid CSIRO’s separation technology (CS-T) separator is investigated in this paper. The performance of the separator is visually established by observing the liquid carry over (LCO) regime in which liquid is carried out in the gas stream. The liquid and gas-flow rate at which the LCO is observed defines the upper operational range of the separator. Air-water mixture is used for both experimental and CFD investigations. The performance is evaluated at 1, 2, 5, 10 and 12 barg pressure. The upper operational range decreases with increases in pressure. For higher pressure (10 and 12 barg), the LCO curve was nearly vertical, which indicates no change in gas-flow rate with the increase in water flow rate. Salinity does not affect the performance of the CS-T separator. The CFD results are used to visualise the continuous LCO and to understand the physics and mechanism of LCO.

Optimization of Secondary Air Distribution in Biomass Boiler by CFD Analysis

2016 ◽  
Vol 832 ◽  
pp. 231-237 ◽  
Author(s):  
Martin Lisý ◽  
Jiří Pospíšil ◽  
Otakar Štelcl ◽  
Michal Špilaček
Keyword(s):  
Combustion Chamber ◽  
Flue Gas ◽  
Gas Flow ◽  
Air Distribution ◽  
Cfd Modelling ◽  
Biomass Boiler ◽  
Air Supply ◽  
Secondary Air ◽  
Emission Limits ◽  
The Impact

This paper deals with a use of CFD modelling for optimization of supply of secondary combustion air in the two-chamber biomass boiler combusting very wet biomass (capacity ca. 200 kW). Objective of the analyse is to observe the impact of diameter of a secondary air supply pipe and air flow velocity on mixing of the secondary air with flue gas in the combustion chamber. The numerical model of the experimental boiler was build up for subsequent utilizing of CFD computation based on finite element method. The commercial code STAR-CD was used for carried out parametrical studies. Series of calculations were carried out for four different diameters of air distribution pipes and for 3 different air velocities in distribution orifice. Quality of air dispersion in flue gas flow was assessed in the vertical cross section lead in the end of the combustion chamber. The results of calculation were verified on the experimental installation of the boiler. Influence of secondary air mixing on emission production was measured and analysed. Emissions of pollutants for recommended air distribution comply with emission limits stipulated in the most stringent class 5 according to ČSN-EN 303-5 as well as with emission limits under Regulation No. 405/2012 Sb.

scholarly journals A CFD strategy to retrofit an anaerobic digester to improve mixing performance in wastewater treatment

2020 ◽  
Vol 81 (8) ◽  
pp. 1646-1657 ◽  
Author(s):  
D. Dapelo ◽  
J. Bridgeman
Keyword(s):  
Wastewater Treatment ◽  
Gas Flow ◽  
Biogas Production ◽  
Continuous Phase ◽  
Mixing Efficiency ◽  
Mixing Times ◽  
Cfd Modelling ◽  
Mixing Performance ◽  
Quantitative Results ◽  
Computational Fluid Dynamics Cfd

Abstract To date, mixing design practice in anaerobic digestion has focussed on biogas production, but no adequate consideration has been given to energy efficiency. A coherent, comprehensive and generalized strategy based on computational fluid dynamics (CFD) modelling is proposed to improve mixing efficiency of a full-scale, unconfined gas-mixed digester for wastewater treatment. The model consists of an Euler–Lagrange (EL) model where biogas bubbles are modelled as the Eulerian dispersed phase, and non-Newtonian sludge as the Lagrangian continuous phase. Robustness tests show that mixing predictions are independent of bubble size. The CFD strategy comprises the assessment of different mixing geometries and a range of input gas flow rates. Quantitative results show that simple retrofitting measures are able to achieve a significant improvement in the degree of mixing with reduced mixing times, and consequently recommendations for best mixing geometry and gas flow rate are given. A generalization to a generic digester is discussed in a form that is readily usable by professionals and consultants.

Sign in / Sign up

Export Citation Format

Share Document