1. Dynamic visualisation of the combustion processes in boilers Marek Gayer xgayer@fel.cvut.cz Computer Graphics Group Department of Computer Science and Engineering Faculty of Electrical Engineering of CTU Prague

2. 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. 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. 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. 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. 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

7. 7 Flow array – sample visualisation

8. 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

9. T = 303K (above ignition) t = 0 seconds Coal particle Air particle Partially burned coal particle A C C C A 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 C A A BEFOREBEFORE AFTERAFTER

10. 10 Visualisation OpenGL graphics system Particle system visualisation Visualisation of the Flow Array and temperature array

11. 11 Particle system, temperature vizualization

12. 12 Results PararameterOur systemFLUENT 5 Average Temperature1029 o C1158 o C Outlet Temperature1151 o C1384 o C Max Temperature3010 o C2753 o C Stream velocity23 m/s17 m/s Average outlet velocity28 m/s21 m/s Wattage192 W/m 3 232 W/m 3 Mass total21.1 kg21.3 kg Converge timeBelow 1 min7 hours Real-time visualisation/simulation Enabled, 10 FPS Not available

13. 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