scholarly journals Numerical Modelling of Gaseous Fuel Combustion Process with the Stepwise Redistribution of Enriched Combustion Air

2020 ◽  
Vol 328 ◽  
pp. 02001
Author(s):  
Miroslav Rimár ◽  
Ján Kizek ◽  
Andrii Kulikov
Keyword(s):  
Numerical Modelling ◽  
System Design ◽  
Combustion Process ◽  
Flame Length ◽  
Simulation Software ◽  
Gaseous Fuel ◽  
Design Changes ◽  
Gaseous Media ◽  
Aluminium Smelting ◽  
Burner Design

The authors of this paper present the results of simulations for burner system design changes in the smelting aggregate. Based on the analysis of the existing burner system in the experimental aluminium smelting equipment, changes in the burner design were proposed. The obtained results are presented in tables and figures. The properties of the proposed changes were investigated using the simulation software ANSYS. The simulations confirmed the suitability of the proposed system for shortening the flame length and intensification of the mixing of gaseous media.

scholarly journals A Numerical Study on the Combustion Process and Emission Characteristics of a Natural Gas-Diesel Dual-Fuel Marine Engine at Full Load

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1342
Author(s):  
Van Chien Pham ◽  
Jae-Hyuk Choi ◽  
Beom-Seok Rho ◽  
Jun-Soo Kim ◽  
Kyunam Park ◽  
...  
Keyword(s):  
Natural Gas ◽  
Combustion Process ◽  
Simulation Software ◽  
Dual Fuel ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Cylinder Pressure ◽  
Marine Engine ◽  
Full Load ◽  
Simulation Results

This paper presents research on the combustion and emission characteristics of a four-stroke Natural gas–Diesel dual-fuel marine engine at full load. The AVL FIRE R2018a (AVL List GmbH, Graz, Austria) simulation software was used to conduct three-dimensional simulations of the combustion process and emission formations inside the engine cylinder in both diesel and dual-fuel mode to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results were then compared and showed a good agreement with the measured values reported in the engine’s shop test technical data. The simulation results showed reductions in the in-cylinder pressure and temperature peaks by 1.7% and 6.75%, while NO, soot, CO, and CO2 emissions were reduced up to 96%, 96%, 86%, and 15.9%, respectively, in the dual-fuel mode in comparison with the diesel mode. The results also show better and more uniform combustion at the late stage of the combustions inside the cylinder when operating the engine in the dual-fuel mode. Analyzing the emission characteristics and the engine performance when the injection timing varies shows that, operating the engine in the dual-fuel mode with an injection timing of 12 crank angle degrees before the top dead center is the best solution to reduce emissions while keeping the optimal engine power.

Towards self-predicting systems: What if you could ask ‘what-if’?

2006 ◽  
Vol 21 (3) ◽  
pp. 261-267 ◽  
Author(s):  
ENO THERESKA ◽  
DUSHYANTH NARAYANAN ◽  
GREGORY R. GANGER
Keyword(s):  
System Design ◽  
Large System ◽  
System Management ◽  
System Behavior ◽  
Search Problems ◽  
Interactive Exploration ◽  
Design Changes ◽  
Rules Of Thumb ◽  
System Changes ◽  
Management Problems

Today, management and tuning questions are approached using if… then… rules of thumb. This reactive approach requires expertise regarding system behavior, making it difficult to deal with unforeseen uses of a system’s resources and leading to system unpredictability and large system management overheads. We propose a What…if… approach that allows interactive exploration of the effects of system changes, thus converting complex tuning problem into simpler search problems. Through two concrete management problems, automating system upgrades and deciding on service migrations, we identify system design changes that enable a system to answer What…if… questions about itself.

Plant-Limited Co-Design of an Energy-Efficient Counterbalanced Robotic Manipulator

2012 ◽  
Author(s):  
James T. Allison
Keyword(s):  
System Design ◽  
Physical System ◽  
Control Design ◽  
Robotic Manipulator ◽  
Plant Design ◽  
Design Modification ◽  
Baseline Design ◽  
Design Changes ◽  
Pick And Place ◽  
Place Task

Modifying the design of an existing system to meet the needs of a new task is a common activity in mechatronic system development. Often engineers seek to meet requirements for the new task via control design changes alone, but in many cases new requirements are impossible to meet using control design only; physical system design modifications must be considered. Plant-Limited Co-Design (PLCD) is a design methodology for meeting new requirements at minimum cost through limited physical system (plant) design changes in concert with control system redesign. The most influential plant changes are identified to narrow the set of candidate plant changes. PLCD provides quantitative evidence to support strategic plant design modification decisions, including tradeoff analyses of redesign cost and requirement violation. In this article the design of a counterbalanced robotic manipulator is used to illustrate successful PLCD application. A baseline system design is obtained that exploits synergy between manipulator passive dynamics and control to minimize energy consumption for a specific pick-and-place task. The baseline design cannot meet requirements for a second pick-and-place task through control design changes alone. A limited set of plant design changes is identified using sensitivity analysis, and the PLCD result meets the new requirements at a cost significantly less than complete system redesign.

Modeling Air Traffic Controller Performance in Highly Automated Environments

1989 ◽  
Vol 33 (2) ◽  
pp. 47-51 ◽  
Author(s):  
Elizabeth D. Murphy ◽  
Ray A. Reaux ◽  
Lisa J. Stewart ◽  
William D. Coleman ◽  
Kelly Harwood
Keyword(s):  
System Design ◽  
Traffic Control ◽  
Human Performance ◽  
The United States ◽  
Air Traffic ◽  
Automated System ◽  
Performance Variables ◽  
Design Changes ◽  
Controller Performance ◽  
Performance Dimensions

As increasing levels of automation are planned for the United States' air traffic control system, there is a need to assess planned system design changes for their potential effects on human performance. The model of controller performance developed by this work permits the comparison of prior and planned system transition states on several performance dimensions: perceptual, analytic, response, and resource management. Systematic predictions of performance provide a basis for identifying potential trouble spots in a planned system. The model can be employed to determine whether system design changes will improve controller performance without placing unreasonable demands on the controller's resources. It can be tailored to represent human performance variables and sources of resource demand in any complex automated system.

Controlling Gravity Impact on Diffusion Flames by Magnetic Field

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Fouad Khaldi
Keyword(s):  
Magnetic Field ◽  
Scaling Laws ◽  
Diffusion Flames ◽  
Combustion Process ◽  
Flame Length ◽  
Dimensionless Number ◽  
Length Variation ◽  
Zero Gravity ◽  
Blue Color ◽  
Gravity Level

The ability to use a magnetic field as a means for controlling the role of gravity buoyancy on the combustion process is demonstrated by applying a strong vertical magnetic field gradient on a laminar gas jet diffusion flame. The confirmation is based on a comparison of flame appearance; in particular, length variation, to both elevated gravity (higher than earth’s gravity) and zero-gravity combustion experimental data. The comparison parameter is the dimensionless number G, defined as the ratio of gravity level generated by magneto-gravity buoyancy to earth’s gravity. The more important results are as follows. First, for G > 1, good agreement between magnetic and centrifuge length scaling laws reveals that the slight decrease of flame length according to L ∼ G−1/8 is the result of increasing artificial magnetically induced gravity strength. It ensues that flame thinning, bluing, lifting, and extinction are produced by similar mechanisms previously identified in centrifuge diffusion flames. Thereafter, at G ≅ 0, the flame assumes a nearly hemispheric shape and a blue color in perfect similarity to nonbuoyant flames under zero-gravity conditions generated in drop towers. Another important fact is that the magnetic field offers the ability to observe the flame behavior at low gravity levels 0 < G < 1. A primary interesting result is that flame length varies strongly, following the scaling law L ∼ G−1/2.

Plant-Limited Co-Design of an Energy-Efficient Counterbalanced Robotic Manipulator

2013 ◽  
Vol 135 (10) ◽  
Author(s):  
James T. Allison
Keyword(s):  
System Design ◽  
Physical System ◽  
Control Design ◽  
Robotic Manipulator ◽  
Plant Design ◽  
Design Modification ◽  
Baseline Design ◽  
Design Changes ◽  
Pick And Place ◽  
Place Task

Modifying the design of an existing system to meet the needs of a new task is a common activity in mechatronic system development. Often, engineers seek to meet requirements for the new task via control design changes alone, but in many cases new requirements are impossible to meet using control design only; physical system design modifications must be considered. Plant-limited co-design (PLCD) is a design methodology for meeting new requirements at minimum cost through limited physical system (plant) design changes in concert with control system redesign. The most influential plant changes are identified to narrow the set of candidate plant changes. PLCD provides quantitative evidence to support strategic plant design modification decisions, including tradeoff analyses of redesign cost and requirement violation. In this article the design of a counterbalanced robotic manipulator is used to illustrate successful PLCD application. A baseline system design is obtained that exploits synergy between manipulator passive dynamics and control to minimize energy consumption for a specific pick-and-place task. The baseline design cannot meet requirements for a second pick-and-place task through control design changes alone. A limited set of plant design changes is identified using sensitivity analysis, and the PLCD result meets the new requirements at a cost significantly less than complete system redesign.

Numerical Simulation of Dimethyl Ether/Air Laminar Diffusion Combustion Characteristic with the Different Fuel Inlet Velocity and Rotate Speed

2011 ◽  
Vol 383-390 ◽  
pp. 2984-2990
Author(s):  
Rong Chen ◽  
Hua Wang ◽  
Hui Tao Wang
Keyword(s):  
Flow Velocity ◽  
Combustion Temperature ◽  
Combustion Process ◽  
Simulation Software ◽  
Combustion Characteristic ◽  
Diffusion Combustion ◽  
Fuel Flow ◽  
Laminar Diffusion ◽  
Simulation Results ◽  
Jet Characteristics

The paper establishes physical and mathematical model to study the laminar diffusion combustion, which is formed by concentric jet characteristics of DME/air. It uses commercial simulation software fluent to simulation laminar diffusion combustion process to get the temperature field distribution in different conditions and analyze the simulation results. Simulation results indicates that the faster fuel flow velocity, the higher combustion temperature and higher efficiency without rotate speed conditions, But with the rotate speed, the combustion temperature and the combustion efficiency decrease to half of their original. However, increasing fuel flow velocity on the basis kind of circumstance can make the combustion temperature and efficiency increased.

scholarly journals TINJAUAN PEMANFAATAN SLUDGE CAKE PABRIK PULP KRAFT SEBAGAI ENERGI ALTERNATIF MELALUI PROSES GASIFIKASI

2015 ◽  
Vol 5 (01) ◽  
Author(s):  
Syamsudin Syamsudin
Keyword(s):  
Moisture Content ◽  
Alternative Energy ◽  
Combustion Process ◽  
Pulp Mill ◽  
Calorific Value ◽  
Steam Gasification ◽  
Gaseous Fuel ◽  
Biomass Waste ◽  
Lime Kiln ◽  
Sludge Cake

Kraft pulp mills generate large amounts of sludge cake with typical calorific value of 24 MJ/kg (dry and ash-free basis). Sludge cake could be utilized as an alternative energy through gasification to produce medium gaseous fuel. Sludge cake has a high moisture content and low dewaterability, probably due to biomass from the microbial growth in the wastewater treatment by activated sludge. These problems could be overcome by the addition of filtration aid utilizing biomass waste from pulp mill and dewatering processes by TAMD method. Drying was continued by utilizing hot flue gas from the boiler or lime kiln. Steam gasification of sludge cake by allothermal model could produce a gaseous fuel with a calorific value of 11 MJ/Nm3. Allothermal gasification model of two reactors was able for handling sludge cake with a moisture content of <55%, but produce gas with a high tar content.Gasification or combustion of sludge cake on this model should be performed at temperatures >1200°C to prevent slagging and fouling problem. In contrast, allothermal gasification model of three reactors could produce gas with a low tar content. Heat of gasification reaction might be supplied from thecombustion of volatile gas. Pyrolysis could be performed at temperatures <500oC to permit adequateheat supply for gasification and high char yield. Substitution of natural gas with producer gas need topay attention to the redesign of the combustion process associated with the lower heat of combustion.Keywords: sludge cake, dewatering, gasification, steam, CO2, medium gaseous fuelABSTRAK Pabrik pulp kraft menghasilkan sludge cake dalam jumlah besar dengan nilai kalor tipikal 20 MJ/kg (dasar kering dan bebas abu). Sludge cake dapat dimanfaatkan sebagai energi alternatif melalui gasifikasi untuk menghasilkan bahan bakar gas medium. Sludge cake memiliki kadar air tinggi dan dewaterability rendah, disebabkan adanya biomassa hasil pertumbuhan mikroba pengolahan air limbahsecara lumpur aktif. Kendala ini diatasi dengan penambahan media bantu  filtrasi memanfaatkan limbah biomassa pabrik pulp dan proses dewatering dengan metode TAMD. Pengeringan dilanjutkan dengan memanfaatkan gas panas dari boiler atau lime kiln. Proses gasifikasi-kukus allothermal terhadap sludge cake dapat menghasilkan gas bakar dengan nilai kalor 11 MJ/Nm3. Gasifikasi allothermal model dua reaktor mampu menangani sludge cake dengan kadar air <55%, namun menghasilkan gas dengan kadar tar yang tinggi. Gasifikasi atau pembakaran sludge cake pada model ini sebaiknya dilakukan pada suhu di bawah 1200oC untuk menghindari terjadinya slagging dan fouling. Sebaliknya, gasifikasi allothermal model tiga reaktor dapat menghasilkan gas dengan kadar tar rendah. Panas reaksi gasifikasi mungkin dapat dipenuhi dari pembakaran gas volatil hasil pirolisis. Pirolisis dapat dilakukan pada suhu <500ºC dengan mempertimbangkan kecukupan suplai panas gasifikasi dan yield arang tinggi. Penggantian gas bumi dengan gas produser perlu memperhatikan redesign proses pembakaran terkait dengan panas pembakaran yang lebih rendah.Kata kunci: sludge cake, dewatering, gasifikasi, kukus, CO2, bahan bakar gas kalor medium

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