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3 Current solutions – CFD Based on solving complex differential equations (such as the Navier Stokes) Advantages: Precise, robust, well-known Combustion processes in FLUENT Main drawback : SLOW
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Dynamic visualisation of the combustion processes in
boilersMarek [email protected]
Computer Graphics GroupDepartment of Computer Science and Engineering
Faculty of Electrical Engineering of CTU Prague
2
Simulation of combustion processes
To find an optimal boiler configurations and optimal mode of boiler exploitation.
(both for the ecological and economical reasons)– To lower pollution– To find a way for
optimal fuel preparation (particle sizes and quantity, speed etc.)
3
Current solutions – CFD Based on solving complex differential
equations (such as the Navier Stokes) Advantages: Precise, robust, well-known Combustion processes in FLUENT
Main drawback : SLOW
4
Our methodology Based on an different approach Fast enough to enable real-time
visualisation / simulation Allows on-line change of some parameters Enables view of process of combustion Usable as a fast tool for boiler designers Suitable for education
5
Particle system Used for BOTH the simulation
of the technological problem and visualisation
Concept of virtual particles Quality & speed of
visualisation could be enhanced by increasing number of particles
Movement of particles strongly determinated by the Flow array
6
Flow array Precalculated array of
vectors of the speed Divides the area of the
boiler to the voxelized space
Computed only once at the beginning of simulation
FAST computation using isotherm free stream – see the paper
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Flow array – sample visualisation
8
Simplified Combustion and heat transfer
The temperature array Combustion issues:
– Temperature above ignition– Part of the coal to burn depends on the
temperature and mass of the coal and air– The released heat is distributed to the
particles– Heat radiation between the walls
T = 303K(above ignition)
t = 0 seconds
Coal particle
Air particle
Partially burned coal particle
A
C
C
CA
A A
T = 305K(increased)
t = 0.01 seconds
Coal particle (partially burned)
Air particle (decreased m)
Coal particle transformed to burned gas particle
A
C
B
CAA
BEFORE
AFTER
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Visualisation OpenGL graphics system Particle system visualisation Visualisation of the Flow Array and
temperature array
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Particle system, temperature vizualization
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ResultsPararameter Our system FLUENT 5Average Temperature 1029 oC 1158 oC Outlet Temperature 1151 oC 1384 oC Max Temperature 3010 oC 2753 oC Stream velocity 23 m/s 17 m/sAverage outlet velocity 28 m/s 21 m/sWattage 192 W/m3 232 W/m3
Mass total 21.1 kg 21.3 kgConverge time Below 1 min 7 hoursReal-time visualisation/simulation
Enabled, 10 FPS
Not available
13
Conclusion Results comparable with standard methods Very fast simulation and visualisation speed Future plans
– more accurate heat distribution– Simulate and monitor additional
characteristics– Improved Flow Array