The Impact of Predried Lignite Cofiring With Hard Coal in an Industrial Scale Pulverized Coal Fired Boiler

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Halina Pawlak-Kruczek ◽  
Robert Lewtak ◽  
Zbigniew Plutecki ◽  
Marcin Baranowski ◽  
Michal Ostrycharczyk ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Bituminous Coal ◽  
Cfd Simulation ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Industrial Scale ◽  
Hard Coal ◽  
Cfd Simulations ◽  
Reference Case ◽  
The Impact

The paper presents the experimental and numerical study on the behavior and performance of an industrial scale boiler during combustion of pulverized bituminous coal with various shares of predried lignite. The experimental measurements were carried out on a boiler WP120 located in CHP, Opole, Poland. Tests on the boiler were performed during low load operation and the lignite share reached over to 36% by mass. The predried lignite, kept in dedicated separate bunkers, was mixed with bituminous coal just before the coal mills. Computational fluid dynamic (CFD) simulation of a cofiring scenario of lignite with hard coal was also performed. Site measurements have proven that cofiring of a predried lignite is not detrimental to the boiler in terms of its overall efficiency, when compared with a corresponding reference case, with 100% of hard coal. Experiments demonstrated an improvement in the grindability that can be achieved during co-milling of lignite and hard coal in the same mill, for both wet and dry lignite. Moreover, performed tests delivered empirical evidence of the potential of lignite to decrease NOx emissions during cofiring, for both wet and dry lignite. Results of efficiency calculations and temperature measurements in the combustion chamber confirmed the need to predry lignite before cofiring. Performed measurements of temperature distribution in the combustion chamber confirmed trend that could be seen in the results of CFD. CFD simulations were performed for predried lignite and demonstrated flow patterns in the combustion chamber of the boiler, which could prove useful in case of any further improvements in the firing system. CFD simulations reached satisfactory agreement with the site measurements in terms of the prediction of emissions.

Analysis of Temperature and Residence Time of the Exhausts in the Combustion Chamber of an Incinerator Plant

2008 ◽  
Author(s):  
M. Costa ◽  
M. Dell’Isola ◽  
N. Massarotti ◽  
A. Mauro
Keyword(s):  
Combustion Chamber ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Waste Incineration ◽  
Numerical Approach ◽  
Full Scale ◽  
Practical Applications ◽  
The Common ◽  
Semi Empirical ◽  
The Impact

The interest for energy recovery from waste incineration has increased over the years, in order to reduce the number of landfills and produce electricity and heat. At the same time, concern for the impact such processes have on the environment has also grown, and to reduce such an impact, new legislation is being enforced in Europe and Italy. In particular, important restrictions are imposed on the temperature of the exhausts in the combustion chamber, which must be kept above certain values for a given period of time, depending on the type of waste that is being incinerated. Such conditions can be rather difficult and certainly very expensive to monitor with acceptable accuracy. For this reason, in practical applications the temperature of the exhausts in the chamber is usually calculated through semi-empirical and approximate models that relate the temperatures in different sections of the chamber. In this work, the authors present a numerical approach for the analysis of such models that can be used to quantify the uncertainty on this type of measurement due to the common approximations used in full scale incineration plants. The analysis is based on the CFD simulation of the thermo-fluid-dynamic field in the combustion chamber of a full scale plant in Italy, whose results have verified based on a comparison with the data collected during an experimental campaign.

On the Role of Leading-Edge Bumps in the Control of Stall Onset in Axial Fan Blades

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Alessandro Corsini ◽  
Giovanni Delibra ◽  
Anthony G. Sheard
Keyword(s):  
Numerical Study ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Leading Edge ◽  
Suction Side ◽  
Axial Fan ◽  
Early Recovery ◽  
Viscosity Models ◽  
Flow Mechanisms ◽  
The Impact

Taking a lead from the humpback whale flukes, characterized by a series of bumps that result in a sinusoidal-like leading edge, this paper reports on a three-dimensional numerical study of sinusoidal leading edges on cambered airfoil profiles. The turbulent flow around the cambered airfoil with the sinusoidal leading edge was computed at different angles of attack with the open source solver OpenFOAM, using two different eddy viscosity models integrated to the wall. The reported research focused on the effects of the modified leading edge in terms of lift-to-drag performance and the influence of camber on such parameters. For these reasons a comparison with a symmetric airfoil is provided. The research was primarily concerned with the elucidation of the fluid flow mechanisms induced by the bumps and the impact of those mechanisms on airfoil performance, on both symmetric and cambered profiles. The bumps on the leading edge influenced the aerodynamic performance of the airfoil, and the lift curves were found to feature an early recovery in post-stall for the symmetric profile with an additional gain in lift for the cambered profile. The bumps drove the fluid dynamic on the suction side of the airfoil, which in turn resulted in the capability to control the separation at the trailing edge in coincidence with the peak of the sinusoid at the leading edge.

scholarly journals Numerical study on the fracture characteristics and failure mode of hard coal under coupled static and dynamic loads

2020 ◽  
Vol 192 ◽  
pp. 04002
Author(s):  
Lihai Tan ◽  
Ting Ren ◽  
Xiaohan Yang ◽  
Xueqiu He
Keyword(s):  
Fracture Mode ◽  
Stress Level ◽  
Coupling Effect ◽  
Numerical Study ◽  
Dynamic Loads ◽  
Hard Coal ◽  
Fracture Characteristics ◽  
Shpb Test ◽  
Static And Dynamic Loads ◽  
The Impact

It has been well accepted by mining researchers that coal tends to undergo abrupt fracture under the coupling effect of dynamic and static loads. Hence, the study of influence of coupled static and dynamic loads on coal failure behaviour is meaningful for the understanding of coal burst. In this paper, PFC modelling of SHPB test is adopted to investigate the fracture mode and energy evolution of Australian hard coal under different combinations of pre-stress levels and impact velocities. Results have shown that high dynamic load will make the fracture mode and energy release of coal samples more violent even the static load is low. Although the strain energy increases with pre-stress level, the kinetic energy remains on a low level with the increase of pre-stress level when the impact velocity is 4 m/s.

scholarly journals Numerical Analysis of Air Flow in a Modular Fan Unit Using CFD Simulation

2019 ◽  
Vol 111 ◽  
pp. 01008
Author(s):  
Petr Zelenský ◽  
Martin Barták ◽  
Vojtìch Zavøel ◽  
Vladimír Zmrhal ◽  
Radislav Krupa
Keyword(s):  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Aerodynamic Noise ◽  
Design Development ◽  
Cfd Simulations ◽  
Optimization Study ◽  
Optimum Position ◽  
New Type ◽  
Operational Program ◽  
The Individual

The current regulation of European Commission No. 1253/2014 regarding Ecodesing requirements for ventilation units, which classified them based on the Specific Fan Power (SFP), has been driving the innovation in the sector of air-handling systems. The required energy saving can be met by applying modern and energy efficient Electronically Commutated (EC) motor which, at the same time, significantly change the internal geometry of the fan unit. The paper deals with design of a new type of modular fan unit ALTEKO Alton with EC motor and unhoused backward curved impeller. The design development and optimization of the fan unit leading to the reduction of generated aerodynamic noise, lower pressure loss and better outflow characteristics is supported by the Computational Fluid Dynamic (CFD) simulations, which enables visualization of air streamlines, velocities and pressure contours within the unit. Such a design is an iterative process between CFD specialist and construction team, where, based on the simulated results, the critical spots are identified, the geometry is improved and again verified throughout the CFD simulation. The paper describes in detail the individual steps of the optimization study, starting with the import of the detailed geometry from the design CAD software and its necessary simplification for the use in the CFD study, meshing of the model and consequent simulation. The methods of the fan rotation approximation are discussed as well. Additionally, the optimum position of heat exchanger in front of the fan unit is addressed. The presented work is a part of a project supported by the EU under the Operational Program Enterprise and Innovation for Competitiveness.

Propeller Effect on 3D Flow at the Stern Hull of a LNG Carrier Using Finite Volume Method

2014 ◽  
Vol 554 ◽  
pp. 566-570
Author(s):  
Mehdi Nakisa ◽  
Adi Maimun Abdul Malik ◽  
Yasser M. Ahmed ◽  
Sverre Steen ◽  
Fatemeh Behrouzi ◽  
...  
Keyword(s):  
Viscous Flow ◽  
Finite Volume ◽  
Cfd Simulation ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Computational Domain ◽  
Two Phase ◽  
Sst Turbulence Model

Numerical study and RANS simulations have been applied to investigate the incompressible free surface flow around the stern hull of Liquefied Natural Gas (LNG) ship affected by working propeller behind of her. Experimental works are carried out using LNG ship model in Marine Teknologi Center (MTC) of Univrsiti Teknologi Malaysia (UTM) to verify the computational fluid dynamic (CFD) results. Ansys-CFX 14.0 based on viscous flow finite volume code using the two-phase Eulerian–Eulerian fluid approach and shear stress transport (SST) turbulence model have been used in this study. A tetrahedral unstructured combined with prism grid were used with the viscous flow code for meshing the computational domain of water surface around it. CFD simulation has been verified using available experimental results. Finally, the flow structure, streamlines, velocity and pressure distribution around stern hull and propeller zone are discussed and analysed.

Test and Simulation of the Effects of Surface Roughness on a Shrouded Centrifugal Impeller

2014 ◽  
Author(s):  
William T. Cousins ◽  
Lei Yu ◽  
Jacquelynn Garofano ◽  
Barbara Botros ◽  
Vishnu Sishtla ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Cfd Simulation ◽  
Centrifugal Impeller ◽  
Test Results ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
The Common ◽  
R Value ◽  
The Impact ◽  
Grain Roughness

Surface roughness is an important parameter in the operational efficiency and loss development of turbomachinery components. Many computational fluid dynamics (CFD) simulations are performed on turbomachinery, but often one of the common assumptions is that the surfaces are hydraulically smooth. In this work, examination of the surfaces of two cast impellers is performed and compared to machined impellers with smoother surfaces. Both impeller sets were run in a two-stage industrial chiller unit using R134a refrigerant. Test results are presented and the impact of surface roughness modeling on the design is reviewed. Also discussed is the theory of the impact of roughness on turbulent boundary layers. Details about providing the CFD simulation with the proper sand grain roughness is discussed when surface finish (R-value) in microinches (μin) is measured.

Numerical Investigation of the Interaction Between Gas-Turbine Engine Components With Dynamic Mode Tracking

2021 ◽  
Author(s):  
Carlos Pérez Arroyo ◽  
Jérôme Dombard ◽  
Florent Duchaine ◽  
Laurent Gicquel ◽  
Nicolas Odier
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Fluid Dynamic ◽  
Gas Turbine Engine ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Impeller Blade ◽  
Turbine Engine ◽  
The Impact ◽  
Mode Tracking

Abstract Optimizing the design of aviation propulsion systems using computational fluid dynamics is essential to increase their efficiency and reduce pollutant as well as noise emissions. Nowadays, this design process is increasingly aided by computational fluid dynamic methods for which and with the adequate modeling approach it is possible to perform meaningful unsteady computations of the various components of a gas-turbine engine. However, these simulations are often carried out independently of each other and only share averaged quantities at the component interfaces minimizing the impact and interactions between components. The present work investigates the interactions between fan, compressor and annular combustion chamber at takeoff conditions by simulating a 360 azimuthal degrees large-eddy simulation of over 2100 million cells of the DGEN-380 demonstrator. In that case, the domain includes: 14 fan blades; 42 outlet-guide vanes (OGV); the impeller with 11 main blades and 11 splitter blades; a radial and an axial diffuser with 22 and 55 vanes, respectively; and the annular combustion chamber with a contouring casing and 13 swirlers on the back of the chamber. At take-off conditions it is found that the compressor operates in transonic conditions in the rotating frame of reference of the impeller and a shock is formed at the leading edge of the main blades which propagates upstream towards the fan and it is perceived at half the impeller blade-passing frequency (BPF). Preliminary results also show that pressure fluctuations at the impeller BPF generated by the interaction of the impeller blades with the diffuser vanes are propagated through the axial diffuser and enter the combustion chamber through the dilution holes and the swirler. The objective of this paper is to provide a deeper analysis of the interactions between components through the use of the novel operator-based analysis called dynamic mode tracking method (DMT). Indeed, this method facilitates the analysis of three-dimensional results despite the billion-size mesh and the complexity of the simulation, since it extracts modes at specific frequencies on-the-fly within the code. The frequencies corresponding to the fan, impeller and half the impeller BPF are analyzed in the domain and compared against traditional and more computationally demanding methods like the well-known Dynamic Mode Decomposition or the Direct Fourier transform.

Research of 3D-CFD Simulation on a Large Sized Pit Type Carburizing Furnace

2006 ◽  
Vol 118 ◽  
pp. 337-342
Author(s):  
Wei Min Zhang ◽  
Ye Ma ◽  
Lin Lin Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Gas Flow ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Cfd Simulations ◽  
3 Dimensional ◽  
Set Up ◽  
Carburizing Process

A fluid dynamic model was set up to describe the flow field of gas in a large sized pit type carburizing furnace when large sized gears were being carburized. The commercial software Fluent was adopted to carry out 3 dimensional computational fluid dynamics (3D-CFD) simulations of the gas flow field under different, actually four kinds of , furnace designs in this article. The flow fields of the carburizing gas around the part were analyzed. According to the simulations and analysis, it was shown that the number of fans on gear’s carburizing is not a primary factor, using a air inducting tub can improve the carburizing process significantly and proper loading tray design can also be positive. The results indicate that the simulation provides a reference to the furnace’s design optimization.

scholarly journals Numerical Simulation of Oil Jet Lubrication for High Speed Gears

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Tommaso Fondelli ◽  
Antonio Andreini ◽  
Riccardo Da Soghe ◽  
Bruno Facchini ◽  
Lorenzo Cipolla
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Low Pressure ◽  
Adaptive Meshing ◽  
Viscous Effects ◽  
Cfd Simulations ◽  
Oil Jet ◽  
Oil Injection ◽  
Bypass Ratio

The Geared Turbofan technology is one of the most promising engine configurations to significantly reduce the specific fuel consumption. In this architecture, a power epicyclical gearbox is interposed between the fan and the low pressure spool. Thanks to the gearbox, fan and low pressure spool can turn at different speed, leading to higher engine bypass ratio. Therefore the gearbox efficiency becomes a key parameter for such technology. Further improvement of efficiency can be achieved developing a physical understanding of fluid dynamic losses within the transmission system. These losses are mainly related to viscous effects and they are directly connected to the lubrication method. In this work, the oil injection losses have been studied by means of CFD simulations. A numerical study of a single oil jet impinging on a single high speed gear has been carried out using the VOF method. The aim of this analysis is to evaluate the resistant torque due to the oil jet lubrication, correlating the torque data with the oil-gear interaction phases. URANS calculations have been performed using an adaptive meshing approach, as a way of significantly reducing the simulation costs. A global sensitivity analysis of adopted models has been carried out and a numerical setup has been defined.

Use of CFD Simulation to Measure the Effects of Floor Plan Shape and Building Height on Pedestrian Wind Comfort and Wind Safety

2014 ◽  
Vol 1057 ◽  
pp. 121-128
Author(s):  
Dagmara Čeheľová ◽  
Milan Janák ◽  
Boris Bielek
Keyword(s):  
Computer Technology ◽  
Cfd Simulation ◽  
Rapid Development ◽  
Wind Tunnels ◽  
Floor Plan ◽  
Cfd Simulations ◽  
Computer Performance ◽  
Building Height ◽  
Wind Comfort ◽  
The Impact

The rapid development of computer technology, especially computer performance, enabled significant development of CFD simulations. Nowadays advanced computer technology, have CFD simulations in the construction sector irreplaceable position in determining the impact of wind on buildings and people. In comparison to the measurements in wind tunnels, represent much faster and cheaper method with comparable results. Presented paper deals with identifying and assessing the impact of floor plan and building height of nine different pairs of highrise buildings on pedestrian wind comfort and safety in their immediate surroundings. For simulation was selected computer program OpenFOAM. The results of simulations for all of nine cases were compared and evaluated according to the requirements of the Dutch standard NEN 8100:2006.

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