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© Copyright KSB Aktiengesellschaft 2015
Mechanical Analysis of a Boiler Water Circulation Pump (BWCP)
M. Haßlöcher, PU-GP513October 6th.2015
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Content
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 20152
1. Application for FEM at KSB
2. Evaluation of BWCP prior Staudinger
3. Current FEM Calculation of a BWCP
4. Outlook and Set of Problems
MPA Seminar
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1. Application for FEM at KSB
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• Design
• Optimization
• Stress Analysis and Proof of Safety (incl. Seismic Qualification) for existing Design acc. relevant Codes as ASME, KTA, RCC-M, API, DIN, AD-Merkblatt
• Feasibility Study
• Failure Analysis
• Structural Safety
• Operability
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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2. Evaluation of BWCP prior Staudinger
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• Standard: Evaluation of static load cases
=> Operating Condition + Pressure Test
=> Evaluation acc. ASME Sec. VIII Div.2
• Special: Fatigue analysis (state of the art)
=> Bexbach, Kentucky, Ivanpah, Ibbenbühren
=> Evaluation acc. ASME Sec. VIII Div.2KTA 3211.2
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3. Current FEM Calculation of a BWCP
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• Calculation to evaluate fatique strength of new bowls
• LUV Az (350bar / 380°C Design) with 1000mm bowl
• Considering of transients (Temperature + Pressure),bolt preload and nozzle loads if available (small influence!)
• Evaluation of further parts, e.g. bolts, heat barrier andupper motorflange possible
• Evaluation acc. KTA 3211.2 (very conservative in comparison to DIN)
• ANSYS 15.0 SP1
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Halfmodel
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Modeled Parts:
• Pump Housing
• Upper Motorflange
• Heat Barrier incl.Insulatingmaterial (Ceramic)
• Main Closure Studs
• Nuts
Decay Length = 2.5 (R·t)1/2
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Halfmodel
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approx. 73000 Elements
approx. 330000 Nodes
Hexaeder Mesh with Skin Layer
Solid 90 Temperature
Solid 186 Stress
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Boundary Conditions
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Film Coefficients:
alfiso = 5 W/m²K
alfpg = 21861 W/m²K (100%)
alfpg2 = 0.5 · alfpg
alfpg3 = 0.5 · alfpg2
alfds = 35555 W/m²K (100%)
alfss = 22444 W/m²K (100%)
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Boundary Conditions
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Film Coefficients:
alfluft1 = 23 W/m²K
alfluft2 = 10 W/m²K
alfmotor = 2000 W/m²K
alfws = 241 W/m²K
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Boundary Conditions
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Stress Model generated from Temperature Model
=> same Nodes!!!!
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Boundary Conditions
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Contacts were been defined axial as well as radial!
Clearance Fits have been considered!
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Boundary Conditions
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Fv = 1700 kN per Stud
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Boundary Conditions
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Considered Loads:
• System Pressure
• End Cap Loads
• Reset Force of Sealing
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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Transients
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Description TStart in °C TEnd in °C vT in K/min
PStart in bar
PEnd in bar
N
Cold Start Step 1 immediately after pump start
30 140 20 1 4 2000
Cold Start Step 2 140 350 1 4 196 2000
Shutdown 350 30 0.3 196 1 2000
Warm Start 200 350 4 50 196 1000
Load Changes fromBenson Operating
270 310 20 90 90 9400
Hot Start 250 350 20 50 196 6000
Additional 10 x Assembly
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Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Results
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Temperature Distribution
Stationary Condition
TSYS = 350°C
TMotor = 60°C
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Results
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Temperature Distribution
Stationary Condition
TSYS = 350°C
TMotor = 60°C
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Results
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Stress Distribution (SEQV) in MPa
Stationary Condition
PSYS = 196bar
FV = 1700kN per Stud
TSYS = 350°C
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Results
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Stress Distribution (SEQV) in MPa
Stationary Condition
PSYS = 196bar
FV = 1700kN per Stud
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Evaluation Points
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237 SCL
(Stress Classification Lines)
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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3D FEM Evaluation Points
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Evaluation at new increased Radius:
UF1 = 0.7
UF2 = 0.7
UF3 = 0.8
UF4 = 0.7
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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4. Outlook and Set of Problems
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• The fatigue strength of new pump housings will be determinedwith this procedure.
• The aim is a “standardization“ of the modeling and thecalculation, to save time.
• It is possible to evaluate further parts, e.g. bolts and/orheat barrier.
• Evaluation acc. DIN 12952-3 will be realized
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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4. Outlook and Set of Problems
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• The specification of the transients has to be improved. Abetter coordination is needed here.
• Current => Transfer of records of the control room and ahuge amount of data in Excel Tables for number ofoccurences and operation mode.
=> A lot of Time is needed to evaluate the data=> Expensive and defective
• “Warming during Hot Stand By“ not defined yet
=> Temperature Layer?
Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
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23Mechanical Analysis of a BWCPM. Haßlöcher I PU-GP513 I October 6th 2015
MPA Seminar
Thank you very much for your attention!
Questions?