ES410 Air Quality: smoke control
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ES410 Air Quality: smoke control
Development of an intelligent, real-time smoke control system
1
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”
2
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
Experimental Data
Fluid Theory
Simulations
Control System
3
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.
4
Work Breakdown Structure
5
Network Diagram
6
Gantt Chart
7
SMOKE
SmokeRegulationsExisting Systems
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Smoke
• Hot Gases and Particulates
• Variable Toxicities and Density
• Transmits Heat via Convection
9
Smoke Effects
• Deaths
• Non Fatal Casualties
• Reduced Visibility
Inhibit ability to escape
Increases difficulty for firefighting
• Generate Flashover Conditions
• Property Damage
10
Regulations• Building Regulations
Part B
• British Standards• Design Guidance
e.g. CIBSE Guide E• Continuing Research
11
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 12
Pressure Differential Systems
• Stairwell kept at higher pressure than floors
• Prevents smoke spreading into stairwell
13
Smoke Containment
Morgan H P, Smoke control methods in enclosed shopping complexes of one or more storeys: a design summary, BRE, 1979
Example of a Smoke Curtain
14
TEST RIG DESIGN
DesignScaling
15
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
16
Test Rig Specification•Modular to allow various configurations of floors, walls, partitions, and inlets.
4 Outlets
6 Inlets17
Test Rig Specification1. Heating Box2. Hot Plate3. Perspex Box4. Laser Sheet5. Inlet & Outlet Fans6. Fan Power Supply7. Laser Lenses
Inlet & Outlet Fans 18
Scaling Equations
Dynamic SimilarityReynold’s Number, Re
Heat Transfer SimilarityGrashof Number, Gr
LUmRe
3
2
( )Sg T T LGr
Um = Mean VelocityL = Characteristic Lengthν = Kinematic Viscosityg = Acceleration due to Gravityβ = Volumetric Thermal Expansion CoefficientTS = Source TemperatureTinf = Quiescent Temperature 19
Scaling Results
Reynold’s NumberOffice value 20x larger than test rig value1 Order of Magnitude
Grashof NumberOffice value 100x larger than test rig value2 Orders of Magnitude
Re
Gr
20
SENSOR SYSTEM
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Measurement: Sensory data used for analysis.
Control: Sensory data used to provide feedback to control system tocontrol smoke behaviour.
Sensors
Control PCControl Laws Smoke Behaviour
Closed Loop Control
Ventilation+ -
Feedback leads to a dynamic system which reacts to the smoke in real time
Control & Measurement System
22
Temperature Sensors
MCP9701A±2°C Absolute Accuracy±1°C Relative Accuracy (25°C)Can drive large capacitive loadsLinear response – direct ADC connection
Smoke Sensors
Custom madeOptical attenuation880nm wavelengthMeasures relative smoke density
1) Phototransistor (Receiver)2) IR LED (Emitter)3) Transparent windows4) Smoke slot5) Casing
Sensory Array
Smoke Sensor
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40mm Brushless DC fansComplimentary pairs
Fan Control Circuitry
Low Pass Filtered PWM2 Pole FilterDC onlyDiode protected MOSFETLow side control
Ventilation
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I2C Bus
Control PC
RS232
Microcontroller(I2C Master)
InletFan
OutletFan
TempSensor
SmokeSensor
Microcontroller(I2C Slave)
InletFan
OutletFan
TempSensor
SmokeSensor
System Block Diagram
25
Packet Formatted Communications Protocol
SmokeTalk
$ Destination{1 Byte}
Destination Port
{1 Byte}
Source{1 Byte}
Source Port{1 Byte}
Type{1 Byte}
Control{1 Byte}
Data{2 Bytes} \r\n
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CONTROL SYSTEM
PurposeDesignGeneral Operation
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The Control System
• Purpose
– What
– Why
– How
• Design
– What
– Why
– How28
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
29
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
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General Operation
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EXPERIMENTAL RESULTS
PIV Results & AnalysisSensor Results & Analysis
32
Particle Image Velocimetry
Figure 1: PIV setup. Source: Dr P Dunkley, University of Warwick.33
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) 34
Inlet Particles
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Inlet Velocity Vector
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Outlet Particles
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Outlet Velocity Vector
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Averaged Cell 1 Smoke Density Comparison with varying fan condition
0
20
40
60
80
100
120
140
-10 -8 -6 -4 -2 0 2 4 6 8Smoke Reading (Volts)
Tim
e S
tep
(s)
4 Calibrations (----) 4 Inlets (BBBB) 4 Outlets (SSSS)
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 desired39
Average Smoke Readings in rig with varying fan arrangements
0
20
40
60
80
100
120
140
160
-20 -15 -10 -5 0 5 10 15 20
Smoke Reading (Volts)
Tim
e S
tep
(s)
Av BBBB Av BBSS Av BSBB Av BSBS Av Calibration Av SBSB Av SSSS
Figure 7: Average Smoke Reading in rig with varying fan arrangements
• Pressure condition – inlets and outlets
• Relative position and arrangement to inlet 40
Average Rig Smoke Readings with Varying Setups
0
10
20
30
40
50
60
-10 -5 0 5 10 15
Smoke Reading (Volts)
Tim
e S
tep
(s)
Without Floor With Floor Floor and Partitions
Figure 8: Average Smoke Reading in rig with varying setups
• Barriers to movement
• Levels of circulation
• Smoke Screen effects
41
SIMULATIONS
CCM+Simulation ResultsAnalysis
42
Simulation Summary
• The need for CFD• Star CCM+• CFD Solvers• Results and Analysis:
– PIV vs CFD– Phase 1– Phase 2– Phase 3
• Further Work
43
The Need For CFD
• Inconsistent environment in physical rig• Stable and versatile environment• Able to visualise the Propagation• Accurate Temperature Plots• Scalable Model
44
The Simulation Testing Plan
• Systematic Approach• Broken into Phases• Create an animation
for each
45
Star CCM+
• Powerful CFD software• Allows us to use exact Solid Works CAD
drawing• Use of an unsteady Solver
46
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
47
Results And Analysis:PIV VS CFD
• Similar wall-effect
• Similar re-circulation
48
CFD Results
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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
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Fan 1 as an Inlet
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Best fan configurations
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Best fan configurations (cont)
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Phase 2
• A best fan configuration was not found due to incomplete simulations.
• Comparisons between phases 1 and 2 possible.
• Detailed look at the temperature changes in the room.
• More difficult problem than in phase 1.
54
Phases 1 and 2 Comparison
55
Scalar Temperature Animation
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Phase 3
• Shows dynamic similarity between test rig and scaled room.• Further tests need to be done on good fan configurations
from small scale simulations.
0.5m 3.0m
57
Further work
• Phase 4 – Simulations on realistic room• Introduction of partitions and screens• Multiple storeys• Seeing the effects of including the ducting
system in the simulations• Run simulations for much longer
58
ARCHITECTURAL INTEGRATION
Full Scale SystemBuilding Control
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Full Scale System
Standard Room
Supply Fan
Extract Fan
(SHEV)
Normal Balanced
Ventilation
Sensor Network Fire Rated Data Cable
Protected damper control and power supply cables
Protected fan control and power supply cables
SmokeControlSystem
Power Supply
Linked Systems
Fire Alarm & Notification
System
Other Fire Related Control Systems
Fire Data Output to Emergency Services
60
Building ControlFailsafe Smoke and Fire Rated
Control Dampers
Standard Supply Ventilation Plant
Smoke and Fire Rated
Extraction Ventilation Ductwork
Supply Ventilation Ductwork
Smoke and Fire Rated
Control Dampers
Fire Rated Ceiling Ventilation Grilles
High Temperature Smoke Heat Extraction Ventilation Unit
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CONCLUSIONS
Continued DevelopmentConclusions
62
Continued Development
• The project is useful and viable• Minimising losses to human life as well as
financial losses for companies is an important area
• Laid the Foundations• Already evidence of interest• Other Avenues
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Conclusions
• Project an overall Success• Dynamic Similarity between the test rig scale
and life size• CFD analysis provided an intelligent response• The system provides an intelligent response to
detected environmental changes
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Thank You For Your Attention
Questions Please?
65