1. Interactive System for Pulverized Coal Combustion Visualization with Fluid Simulator Marek Gayer, Pavel Slavík and František Hrdlička Department of Computer Science and Engineering Faculty of Electrical Engineering of CTU in Prague Czech Republic Visualization, Imaging and Image Processing (VIIP) Malaga – Spain - September 9-12, 2002

2. 2VIIP '2002 Outline of the presentation Introduction and motivation Fluid flow modeling - CFD Our Fluid simulator Virtual coal particle system Simplified combustion and heat transfer Implementation and visualization Our results and their reliability Conclusion and future work

3. 3VIIP '2002 Introduction and motivation to coal combustion visualization Both for the ecological and economical reasons) Finding optimal boiler configurations. –To reduce pollution –To find a way for optimal fuel preparation How can visualization help

4. 4VIIP '2002 The modeling of fluid flow - CFD Most often: solving complex differential equations (e.g. Navier-Stokes) Fluid simulators for computer graphics Coal combustion as an CFD application Current solutions and systems: Precise, robust, well-known Slow, no real-time + -

5. 5VIIP '2002 Our fluid simulator Dividing the boiler area to “voxel” arrays Mass fluxes and velocity changes per time dt based on Newton’s second law and continuity equation Principle of local simulation Is fast, easy to implement, reusable but “unstable” For more information, see our paper

6. 6VIIP '2002 Virtual coal particle system Used both for simulation and visualization of the combustion process Virtual particle system approach Movement determination: –Aerodynamic resistance –Gravity force

7. 7VIIP '2002 Simplified combustion and heat transfer The temperature array Statistical view of combustion process Basic coal properties Some of the combustion issues: –Various combustion phase steps –Heat distribution to the particles and air –Heat radiation and to voxels and walls

8. 8VIIP '2002 t = 0 seconds: T = 303 o C (above ignition) O 2 concentration = 60% Coal particle Partially burned particle C C C t = 0.01 seconds: T = 305 o C (increased) O2 concentration = 57% Partially burned coal particles Coal particle transformed to burned ash particle C B C C C Interaction of virtual coal particles

9. 9VIIP '2002 Our interactive combustion system

10. 10VIIP '2002 Our interactive combustion system

11. 11VIIP '2002 Sample visualization of our system using particle systems and linear interpolation Visualization of coal particles flowing from jets. Detail of coal particles flowing from jets.

12. 12VIIP '2002 Results comparison - visual appearance Velocities magnitude Our system | FLUENT 5.5 Temperatures Our system | FLUENT 5.5

13. 13VIIP '2002 Results comparison – global parameters ParameterOur systemFLUENT 5.5 Average Temperature890 o C1002 o C Outlet Temperature814 o C1068 o C Max Temperature2546 o C2488 o C Average stream velocity14 m/s11 m/s Average outlet velocity56 m/s48 m/s Wattage187 W/m 3 232 W/m 3 Mass total21.1 kg21.3 kg Solution converge timeBelow 1 min7 hours Real-time simulation / visualization Enabled, 10 FPS Not available

14. 14VIIP '2002 Results comparison – numerical approach Built-in numerical comparison code Statistically compares the results between our system and FLUENT From 60% to 80% voxels are less than 20% different from FLUENT values (temperature, flow directions,... )

15. 15VIIP '2002 Conclusion and future research Interactive 2D coal combustion system with: –Fast & simple real-time fluid simulator (reusable) –Simplified combustion engine –Real-time visualization using OpenGL –Results reliability tested with FLUENT –Designated for education and “preview” design Future research: –Precision improvements – further to reality –Further testing on real boiler tasks –The real-time 3D combustion system experiment

16. 16VIIP '2002 Thank you for your attention. ?????? Do you have any questions ?