computational analysis of water atomization in spray desuperheaters of steam boilers
DESCRIPTION
Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers. A Thesis by Paul Bovat. Outline. Background Objectives Main Equations Model Main Results Conclusions Recommendations. Background. What is a desuperheater? What are the components? - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/1.jpg)
1
Computational Analysis of Water Atomization in Spray Desuperheaters of
Steam Boilers
A Thesis by Paul Bovat
![Page 2: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/2.jpg)
2
• Background• Objectives• Main Equations• Model• Main Results• Conclusions• Recommendations
Outline
![Page 3: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/3.jpg)
3
Background• What is a desuperheater?• What are the components?• Common problem with desuperheaters• How is the problem corrected?
![Page 4: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/4.jpg)
4
Objectives
• Determine pressure drop across spray nozzles– Compare to industry standard
• Determine final steam temperature• Determine droplet life• Determine full droplet evaporation location
![Page 5: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/5.jpg)
5
Equations• Turbulent dissipation and kinetic energy equations
• Energy equation
• Equation for mass diffusion in turbulent flows
![Page 6: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/6.jpg)
6
• Particle inertia Equation (Lagrangian reference frame)
• Spherical drag law coefficients
• Equations for heat and mass exchange
• Film Formation thickness equation
![Page 7: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/7.jpg)
7
• Atomizer spray half-angle
• Secondary Break-up– Webber #
• Droplet evaporation
• Droplet lifetime
![Page 8: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/8.jpg)
8
Model
• ANSYS Fluent CFD– Realizable k-ε turbulent model– Energy equation– Species model– Discrete Phase Model• Pressure Swirl Atomizer
![Page 9: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/9.jpg)
9
Model
![Page 10: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/10.jpg)
10
Results• Pressure loss across then nozzle– 17% higher results between the empirical and
computational results
![Page 11: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/11.jpg)
11
Results
![Page 12: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/12.jpg)
12
Results
• Desuperheater spray system– Inlet temp of desuperheater 650 deg F– Outlet temp of desuperheater 645.5 deg F– 4.5 deg F reduction in temperature– Total evaporation is ≈1.48ft
![Page 13: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/13.jpg)
13
Results
13.5
![Page 14: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/14.jpg)
14
Results
2.01.81.61.41.21.00.80.60.40.20.0E+00
1.0E-06
2.0E-06
3.0E-06
4.0E-06
5.0E-06
6.0E-06
7.0E-06
8.0E-06
9.0E-06
1.0E-05
Injection - 1Injection - 2Injection - 3Injection - 4Injection - 5Injection - 6Injection - 7Injection - 8Injection - 9Injection - 10Injection - 11Injection - 12Injection - 13Injection - 14Injection - 15Injection - 16Injection - 17Injection - 18Injection - 19Injection - 20
Distance (ft)
Diameter
![Page 15: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/15.jpg)
15
Conclusion
• Pressure drop across nozzle– Limitations of elements– Second Order Up-Wind
• Desuperheater temperature– Temperature not regulated enough– Evaporated time is as designed
![Page 16: Computational Analysis of Water Atomization in Spray Desuperheaters of Steam Boilers](https://reader033.vdocuments.mx/reader033/viewer/2022061617/568163ab550346895dd4bdf9/html5/thumbnails/16.jpg)
16
Recommendations
• Re-run pressure drop analysis with more elements
• Lower spray water temperature• Increase spray half angle