SLIDE 1
Utilizing STAR-CCM+ to advance the South African Power Generation Industry
The advantages of incorporating Computational Fluid Dynamics (CFD) analysis in power plant management and optimization
SLIDE 2 Who is Aerotherm
- Aerotherm Computational Dynamics is a well established consulting firm
with a vast amount of experience in the application of Computational Fluid Dynamics (CFD) in industry.
- Aerotherm has been applying CFD since 1995, to solve numerous fluid
flow and heat transfer related problems to improve plant efficiency, reliability and maintainability.
- Aerotherm is unique in that it specialises only in CAE simulation and has
therefore developed a highly specialised consulting experience in a wide variety of application areas. Our Mission Statement: To assist our clients in finding cost effective practical engineering solutions through CAE simulation of components, systems and/or entire plant.
SLIDE 3 Focus on Coal Fired Power Plant
- Aerotherm has in the past 16 years placed a lot of focus on fault finding
and optimization in Coal Fired Power Plants (CFPP).
- Approximately 60% of or work experience is related to CFPP due to the
following reasons:
- Approximately 77% of the power generated in SA is via CFPP
- CFD was not used in the original design of any of the CFPP currently in
- peration in SA today (not even Majuba – commissioned 1996-2001).
- There exists large room for improvement in:
- Air flow control and measurement
- Coal combustion optimisation
- Emissions reduction
- Boiler tube leak reduction etc.
SLIDE 4 Example application areas
- Primary and secondary air flow measurement
- Calibration of flow measurement devices (venturi’s / orifice plates)
- General flow optimisation in ducting to reduce pressure drops and erosion
- PF milling & classification process
- PF distribution & transport
- Air flow distribution & control
- Gas flow in furnace and convective gas pass
- Burner optimisation / NOx Reduction
- Combustion Modelling – Coal quality variations
- SOx reduction
SLIDE 5 Holistic approach to combustion modeling
- Input Airflow : Optimisation of the secondary air windbox which supplies
combustion air to the burners in order to evenly distribute the secondary air supply to each individual burner
- Calibrate burners: Use mapped data from secondary air windbox model
- n single burner sub-model and characterise burner for different swirler
settings
- Characterise Coal: Generate a simple drop tube furnace model (DTF)
and calibrate the model to specific coal data for input to full furnace model
- Furnace Combustion: Generate of a model of the furnace area starting
at the burner mouth and ending at the outlet of the furnace and run combustion simulations
- Optimisation: Use the full boiler model, using mapped data and
calibrated input data from the single burner and DTF models, to evaluate the effect of different swirler settings, coal types etc.
- Erosion Modelling: Use mapped data at outlet of furnace model in
boiler tube erosion model
SLIDE 6 Secondary air windbox optimisation
- Secondary air windbox supplies combustion air
to the burners
- Optimise geometry to evenly distribute the
secondary air supply to each individual burner
SLIDE 7 Single burner sub-model
- Highly detailed single burner model
- Results from the secondary air windbox model
simulations mapped as inlet boundary condition to single burner sub-model
- The single burner sub-model is used to
characterise the burner for different swirler settings
- The results are exported and mapped as
boundary conditions in the full boiler model
SLIDE 8
Single burner sub-model maps
SLIDE 9 Simple drop tube furnace model
Simplified DTF CFD Model
Cell refinement towards centre of model
SLIDE 10 Simple drop tube furnace model
- The DTF model is used to calibrate the CFD model to
laboratory rate data for the specific coals and test
- conditions. (activation energy, CV, Arinius factor for
burnout rate)
- Calibration used as input data in full burner model to
accurately model specific coals
SLIDE 11 Full furnace model
- The combustion models, calibrated for specific coals
using the DTF model, is applied in the full furnace model
- The secondary air flow field, relating to specific swirler
and damper settings are extracted from the single burner sub-model solution and mapped as inlet boundary condition in the full furnace model
Input Boundary Areas Secondary Air Mapping Area Refined Burner and Furnace Section
SLIDE 12
Full furnace model
High swirl Low swirl CO contours O2 contours Temperature contours
SLIDE 13 Boiler tube erosion
- Extract the solution from the full furnace model and
apply as inlet boundary condition to the boiler tube erosion/boiler aerodynamics model
- In these analysis, all the tubes are modelled explicitly
- A Legrangian multiphase model is used to track particles
through the domain and evaluate the resultant erosion
SLIDE 14
Expanded metal screen Slotted Screens
Boiler tube erosion
SLIDE 15
Boiler tube erosion
Explicit modelling (Meshing of screens)
SLIDE 16
Boiler tube erosion
High erosion areas
SLIDE 17
PF Milling
SLIDE 18 PF Classification
- Modelling of Classifiers to optimise throughput and particle size
distribution to boilers
SLIDE 19 Other Power Plant Specific Areas
- Fan modelling and optimisation
- ACC modelling & performance
prediction
SLIDE 20 Centrifugal Flow – FD & ID fans
- Fan flow induced vibration root cause
analysis
- Fan Stress analysis & vibration modes
SLIDE 21 Hydro / Pumped Storage
- Design of intakes, outlets, spillways, surge towers etc.
- Calculation of hydrostatic and dynamic forces
- Transient predictions of water hammers and other transient responses
Closing of valve
SLIDE 22
Hydro / Pumped Storage
Stilling pond outlet Inlet structure Surge Tower
SLIDE 23
Pollution control
Fabric filter plant Detailed bags are individually modelled
SLIDE 24 Valve characterisation / Optimisation
- Single components such as valves can be characterised and/or
- ptimised
SLIDE 25 Cavitation prediction
- Many piping systems suffer
from cavitation patches which erode and eventually destroy valves and measurement equipment
SLIDE 26 Explosion modelling
- Evaluation of work site safety in the vicinity of high risk explosive storage
and/or systems.
SLIDE 27 Summary
- As can be seen there exist a multitude of applications for CFD in the
power generation industry.
- Most existing Coal Fired Power Plants have been designed before the
advent of commercial CFD. CD-adapco’s products therefore provides an understanding of where problem areas originate and it therefore offers a unique opportunity to address the root cause for problems.
- Evaluation of general flow systems also provides a birds eye view of
where losses occur and therefore CFD is opens the door to efficiency improvements in almost all areas of CFPP.
- The incredible robustness, efficiency and advanced capabilities of STAR-
CCM+ has made CFD a tool that provides extremely fast turnaround times and therefore it offers a cost effective route for problem solving, design and optimisation.
