ES410 Air Quality: smoke control

1. ES410 Air Quality: smoke control Development of an intelligent, real-time smoke control system

2. Project Goal “To develop an intelligent, real-time sensor control framework that will detect, monitor and control the development of smoke propagation throughout an office environment”

3. Project Objectives • Create a physical test rig to perform testing on • Simulate propagation of flow using CFD • Draw Conclusions from CFD • Use to develop responsive sensor control system

4. Management Structure • Project Manager throughout the project for stability. • Project Leader changing every few weeks to give everyone experience. • Specific dynamics of individuals within the team allowed it to work.

5. Work Breakdown Structure

6. Network Diagram

7. Gantt Chart

8. Smoke Regulations Existing Systems Smoke

9. Smoke • Hot Gases and Particulates • Variable Toxicities and Density • Transmits Heat via Convection

10. Smoke Effects • Deaths • Non Fatal Casualties • Reduced Visibility • Inhibit ability to escape • Increases difficulty for firefighting • Generate Flashover Conditions • Property Damage

11. Regulations • Building Regulations Part B • British Standards • Design Guidance e.g. CIBSE Guide E • Continuing Research

12. Smoke & Heat Extraction Ventilation - SHEV Morgan H P, Smoke control methods in enclosed shopping complexes of one or more storeys: a design summary, BRE, 1979

13. Pressure Differential Systems • Stairwell kept at higher pressure than floors • Prevents smoke spreading into stairwell

14. Smoke Containment Example of a Smoke Curtain Morgan H P, Smoke control methods in enclosed shopping complexes of one or more storeys: a design summary, BRE, 1979

15. Design Scaling Test rig design

16. Reason for use of Test Rig Simulation models needed to be validated by experimental data. “For many phenomena [such as turbulence] the exact equations are either not available or [a] numerical solution is not feasible.” Ferziger and Perić , Computational Methods for Fluid Dynamics

17. Test Rig Specification • Modular to allow various configurations of floors, walls, partitions, and inlets. 4 Outlets 6 Inlets

18. Test Rig Specification Heating Box Hot Plate Perspex Box Laser Sheet Inlet & Outlet Fans Fan Power Supply Laser Lenses Inlet & Outlet Fans

19. Scaling Equations Dynamic Similarity Reynold’s Number, Re Heat Transfer Similarity Grashof Number, Gr Um = Mean Velocity L = Characteristic Length ν = Kinematic Viscosity g = Acceleration due to Gravity β = Volumetric Thermal Expansion Coefficient TS = Source Temperature Tinf = Quiescent Temperature

20. Scaling Results Reynold’s Number Office value 20x larger than test rig value 1 Order of Magnitude Grashof Number Office value 100x larger than test rig value 2 Orders of Magnitude Re Gr

21. Sensor system

22. Control & Measurement System + - Ventilation Smoke Behaviour Control Laws Control PC Measurement: Sensory data used for analysis. Control: Sensory data used to provide feedback to control system to control smoke behaviour. Sensors Closed Loop Control Feedback leads to a dynamic system which reacts to the smoke in real time

23. Sensory Array Temperature Sensors MCP9701A ±2°C Absolute Accuracy ±1°C Relative Accuracy (25°C) Can drive large capacitive loads Linear response – direct ADC connection Smoke Sensors Custom made Optical attenuation 880nm wavelength Measures relative smoke density 1) Phototransistor (Receiver) 2) IR LED (Emitter) 3) Transparent windows 4) Smoke slot 5) Casing Smoke Sensor

24. Ventilation Low Pass Filtered PWM 2 Pole Filter DC only Diode protected MOSFET Low side control 40mm Brushless DC fans Complimentary pairs Fan Control Circuitry

25. Microcontroller (I2C Master) Microcontroller (I2C Slave) Smoke Sensor Smoke Sensor Inlet Fan Inlet Fan Temp Sensor Temp Sensor Outlet Fan Outlet Fan System Block Diagram Control PC RS232 I2C Bus

26. SmokeTalk Packet Formatted Communications Protocol

27. Purpose Design General Operation Control system

28. The Control System • Purpose • What • Why • How • Design • What • Why • How

29. Purpose • What – A PC client that sends and receives data through a serial port • Why – To more effectively control smoke • How – By taking measurements and following a set of control laws

30. Design • What – A Java application interfacing with the Master micro-controller via SmokeTalk • Why – Fast development, great flexibility • How – A scalable, modular, responsive Java application

31. General Operation

32. PIV Results & Analysis Sensor Results & Analysis Experimental Results

33. Figure 1: PIV setup. Source: Dr P Dunkley, University of Warwick. Particle Image Velocimetry

34. Figure 4 - Inlet PIV Vector Plot • Inlet and wall positions • Velocities • Wall interactions • Vortex shedding (video) • Figure 5 - Outlet PIV Vector Plot • Outlet and wall positions • Lower velocities • Recirculation (video)

35. Inlet Particles

36. Inlet Velocity Vector

37. Outlet Particles

38. Outlet Velocity Vector

39. Figure 6: Averaged cell 1 smoke density comparisons with varying fan conditions • Calibration Condition = all fans off • Smoke movement through individual cells through turbulence and pressure differences • Relative positioning of fans and sensors • Both fans and sensors work as desired

40. Figure 7: Average Smoke Reading in rig with varying fan arrangements • Pressure condition – inlets and outlets • Relative position and arrangement to inlet

41. Figure 8: Average Smoke Reading in rig with varying setups • Barriers to movement • Levels of circulation • Smoke Screen effects

42. CCM+ Simulation Results Analysis Simulations

43. Simulation Summary • The need for CFD • Star CCM+ • CFD Solvers • Results and Analysis: • PIV vs CFD • Phase 1 • Phase 2 • Phase 3 • Further Work

44. The Need For CFD • Inconsistent environment in physical rig • Stable and versatile environment • Able to visualise the Propagation • Accurate Temperature Plots • Scalable Model

45. The Simulation Testing Plan • Systematic Approach • Broken into Phases • Create an animation for each

46. Star CCM+ • Powerful CFD software • Allows us to use exact Solid Works CAD drawing • Use of an unsteady Solver

47. CFD Solvers • Implicit Unsteady allows us to: • Observe a time-step solution • High Accuracy over Explicit • Spalart-Allmaras turbulence model allows us to: • Observe detailed Detached Eddy formations • Create accurate at-wall viscous effects

48. Results And Analysis:PIV VS CFD • Similar wall-effect • Similar re-circulation

49. CFD Results

50. Phase 1 • Aim – choose the ideal fan configuration when a fire starts in the corner of a room. • Method – Run simulations on possible fan configurations