Industrial fan design and investigation by means of URANS and LES based numerical methods
Alessandro CORSINI, Giovanni DELIBRA
FMGroup @ DIMA-SUR
www.dima.uniroma1.it
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
WHO’S WHO @ FluidMachinery Group, DIMA-SUR
Marco Bassetti
Domenico Borello
Lucio Cardillo
Alessandro Corsini
Giovanni Delibra
Andrea Marchegiani
Franco Rispoli
Giuseppe Riccucci
Rafael Saavedra @ UDEP Piura, Peru
Fabrizio Sciulli
Esmeralda Tuccimei
Paolo Venturini
Previous CFD team members (… now in industry)
Carlo Iossa
Filippo Menichini
Stefano Minotti
Andrea Santoriello
FMGroup @ DIMA-SUR
CFD software
FEM f90 & C++ Xenios
FVM f90 T-Flows
FVM OpenFOAM
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
WHAT ARE WE DOING w.r.t. CFD
URANS, LES and hybrid LES/RANS for heat and mass transfer & combustion
Particle Tracking, Fouling and Deposition
development and assessment of new models & numerical technologies
computations of industrial flows, mainly for turbomachinery applications
Partner Industries
Faggiolati Pumps
FlaktWoods Group
Fieni Srl
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Outline
Industrial flows computed with OpenFOAM
• Axial flow fans:
• control of separation
• operations under strong pressure fluctuations
New projects
• Large centrifugal fans: rotor-stator interaction
• LES of onshore caisson for Wells Turbine with Actuator Line Methodology
Most of these projects were run on CINECA or CASPUR[*] HPC grids
[*]CASPUR
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
is now part of CINECA
CINECA - Bologna, 27 Nov. 2012
Up‐front logic for CFD oriented design,
where is to be located?
at conceptual stage to provide hints of the basic governing flow physics
e.g. biomimesis
at preliminary stage to explore possbile flow configuration to exploit the selected physical mechanisms
at the detailed design stage to elaborate the range of virtual proto‐types
cost reduction in the R&D process
less “real” proto‐types and test‐rigs
larger set of explored design solutions available since the early stage of the process
from D. Jakipse, 2001
design solution oriented by a deeper knowledge of the underlying flow physics
not just empiricism
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
AXIAL FLOW FAN FOR TUNNEL AND METRO UNITS
with
FlaktWoods Group
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Problem to solve
Industrial fans for tunnels in metropolitan mass-transfer systems:
•need to comply with new EU legal requirements that pose strict efficiency and
acoustic emission limits;
•need to be able to adapt to complex operating conditions such as:
• smoke and hot (400°C) gas extraction in case of fire
• the destabilising effects of compression and expansion pressure waves
generated by the passage of the trains inside the tunnels
•need to increase pressure rise and blade loading because of market request
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Problem to solve
Industrial fans for tunnels in metropolitan mass-transfer systems:
•need to comply with new EU legal requirements that pose strict efficiency and
acoustic emission limits;
•need to be able to adapt to complex operating conditions such as:
• smoke and hot (400°C) gas extraction in case of fire
• the destabilising effects of compression and expansion pressure waves
generated by the passage of the trains inside the tunnels
•need to increase pressure rise and blade loading because of market request
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Problem to solve
Industrial fans for tunnels in metropolitan mass-transfer systems:
•need to comply with new EU legal requirements that pose strict efficiency and
acoustic emission limits;
•need to be able to adapt to complex operating conditions such as:
• smoke and hot (400°C) gas extraction in case of fire
• the destabilising effects of compression and expansion pressure waves
generated by the passage of the trains inside the tunnels
•need to increase pressure rise and blade loading because of market request
• stall control is a key technology for axial fan operations
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Problem to solve: possible ways to solve it
•
need to increase pressure rise and blade loading because of market request
• stall control is a key technology for axial fan operations
• one of the possible source of inspiration for new stall resistant solutions
comes from biomimesis
•
Biomimesis is the examination of nature, its models, systems, processes, and
elements to emulate or take inspiration from in order to solve human problems.
•
Possible solution to design stall resistant fan blades: exploiting the peculiar shape
of the leading edge of the flippers of the humpback whale
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
How flipper tubercles make a mercyless hunter
exploiting the shape of the leading edge of the flippers of the humpback whale
Corsini, A., Delibra, G., Sheard, A.G., “On the role of leading-edge bumps in the control of stall on-set in axial fan blades”, Proceedings of the FAN 2012 Conference, Senlis, France, 2012.
main objective of the work was to scrutinise the performance of a sinusoidal leading
edge on a cambered airfoil (NACA4415); comparison with symmetric profile
(NACA0015) was provided
influence of the leading edge geometry at different operating conditions was studied
assessment of a modified sinusoidal-shaped leading edge in terms of lift and drag
performance
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
How flipper tubercles make a mercyless hunter
lift coefficient shows that the introduction of a sinusoidal-shaped leading
edge modifies the aerofoil performance during stall:
• early recovering in the aerodynamic work capability
• 30% gain in lift after stall for the WHALE4415 cambered airfoil
Corsini, A., Delibra, G., Sheard, A.G., “On the role of leading-edge bumps in the control of stall on-set in axial fan blades”, Proceedings of the FAN 2012 Conference, Senlis, France, 2012.
Lift coefficient vs Angle of Attack
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
How flipper tubercles make a mercyless hunter
the leading edge geometry directly impacted on the aerofoil velocity and
vorticity fields:
• leading edge sinusoid peak > stabilising effect at the trailing edge
• leading edge sinusoid through > separation
separation
Pressure isolines on the suction surface
NACA4415
Corsini, A., Delibra, G., Sheard, A.G., “On the role of leading-edge bumps in the control of stall on-set in axial fan blades”, Proceedings of the FAN 2012 Conference, Senlis, France, 2012.
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
JFM 224
Blade section
Diameter at the tip
Blade count
Hub-to-tip ratio
Chord (mm)
Solidity (-)
Pitch angle (deg)
Volume Flow Rate
Total Pressure Rise
Rotation speed
Energy consumption
ARA-D
2240 mm
16
0.5
hub
tip
143
92.5
0.64
0.21
48
24
150 m3/s
2800 Pa
1500 rpm
0.5 MW
Reynolds number, based on Dtip and Vtip exceeds 26M
A stator is present downstream the rotor but it is not
accounted for in the simulations.
Equations are always solved in the relative frame of
reference, accounting for Coriolis and centrifugal forces
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Numerical methodology
solver
SRFSimpleFOAM
(more or less)
approach
RANS
model
non-linear (cubic) low-Re k- (Lien et al.)
cell count
4.1M (2M hexa + 2.1M tetra)
average y+
1.2 (blade), 1.9 (hub & casing)
domain
1 blade vane, extending 1c upstream and
2c downstream the rotor
numerical
schemes
CDS (momentum)
QUICK (turbulent variables)
solver
GAMG (pressure)
CG (other eqns)
tolerance: 10-10
operating
points
110, 130 and 150 m3/s
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
When the whale hits the fan
Design of a “whale fan” based on literature and data from
isolated airfoil
Sinusoidal profile limited to the tip of the blade
Hub was not “whaled”
• The sinusoid amplitude was chosen as 3% of the chord at tip
• The wavelength as 5% of the blade span
• 5.5 sinusoids were used, starting with a peak at the tip
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Validation of results
Q [m3/s]
Total pressure rise [Pa]
Exp

110
2858
130
150
FMGroup @ DIMA-SUR

+1%
JFM224
(datum)
2831
JWFM224
(whale fan)
2748
-3%
2752
+2%
2798
2714
-3%
2511
+2%
2565
2502
-2%
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Inner working of the bumps
Corsini, A., Delibra, G., Sheard, A.G., “LEADING EDGE BUMPS IN VENTILATION FANS”, GT2013-94853 submitted to ASME Turbo Expo 2013, San Antonio (US)
Pressure isolines on the suction surface of the blade for the investigated cases
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Inner working of the bumps
Corsini, A., Delibra, G., Sheard, A.G., “LEADING EDGE BUMPS IN VENTILATION FANS”, GT2013-94853 submitted to ASME Turbo Expo 2013, San Antonio (US)
whale
For JFM224 isolines are aligned with the leading edge of
the blade and the only distortion comes from the tip, due
to leakage from the pressure surface.
In JWFM224 low pressure cores are generated at the
trough of the sinusoid, as already occurred with an
isolated profile.
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Inner working of the bumps
Corsini, A., Delibra, G., Sheard, A.G., “LEADING EDGE BUMPS IN VENTILATION FANS”, GT2013-94853 submitted to ASME Turbo Expo 2013, San Antonio (US)
The low-pressure cores are responsible for the release
from the leading edge of counter-rotating turbulent
structures
The straight blade of JFM224 does not generate any
large-scale structure apart from the tip-leakage vortex.
Such vortex in J1 case interacts with a large separation
zone at the tip of the blade.
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Inner working of the bumps
streamlines at 95% of the blade span
In W1 the structure originates at the leading edge is
counter-rotating with respect to the leakage vortex and
partially blocks its evolution. This lead to a complete
reattachment of the flow on the suction surface
streamlines at 95% of the blade span
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Inner working of the bumps
turbulent structures, visualised with an iso-surface of the vorticity
Corsini, A., Delibra, G., Sheard, A.G., “LEADING EDGE BUMPS IN VENTILATION FANS”, GT2013-94853 submitted to ASME Turbo Expo 2013, San Antonio (US)
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Problem to solve
Industrial fans for tunnels in metropolitan mass-transfer systems:
•need to comply with new EU legal requirements that pose strict efficiency and
acoustic emission limits;
•need to be able to adapt to complex operating conditions such as:
• smoke and hot (400°C) gas extraction in case of fire
• the destabilising effects of compression and expansion pressure waves
generated by the passage of the trains inside the tunnels
•need to increase pressure rise and blade loading because of market request
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Numerical methodology
solver
modified version of pisoFOAM
(to account for Coriolis and centrifugal effects)
approach
LES
model
one equation (k) for SGS (Davidson)
cell count
9M hexa
average y+
1.2 (blade), 1.9 (hub&casing)
domain
1 blade vane, extending 1c upstream and 1c
downstream the rotor
numerical
schemes
CDS (momentum)
QUICK (turbulent variables)
solver
GAMG (pressure) and CG (other eqns)
tolerance: 10-10
operating
point
150 m3/s
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Simulation of pressure pulses
Inflow average velocity components
p
Ubulk
tramp
tpulse
±1000 Pa
±4.8%
1.3x10-5 s
4 ms
Pressure increase/drop characterisation
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Evolution of cp for compression wave
• sudden change of the pressure
distribution during the pulse (B)
A: beginning of compression
B: middle
C: end of compression
A
B
tip
• capability of the rotor to adapt to
quickly the new mass flow rate
(C)
C
mid
hub
D. Borello - A. Corsini – G. Delibra – F. Rispoli – A. G. Sheard., “Numerical Investigation On The
Aerodynamics Of A Tunnel Ventilation Fan During Pressure Pulses”, submitted to ETC 2013
FMGroup @ DIMA-SUR
• pressure isolines on the suction
surface show a clear 90 deg
turning (B)
• during pressure pulse (B) isolines
are more radial and give
evidence of a stall from the hub
to 2/3 of the span, while the tip
section is still capable of
contributing to the rotor pressure
developing capability.
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Evolution of cp for expansion wave
A: beginning of expansion
B: middle
C: end of compression
A
B
C
tip
• As the pulse hits the blade (B) the
rotor adjust to the drop of mass
flow increasing the work and so
the lift over the blade
mid
• In this case the distribution of
pressure
isolines
remains
“vertical”, yet a strong load of the
tip of the blade is recognisable
hub
• Distributions of the pressure
coefficient show that midspan and
tip sections are over-loaded
D. Borello - A. Corsini – G. Delibra – F. Rispoli – A. G. Sheard., “Numerical Investigation On The
Aerodynamics Of A Tunnel Ventilation Fan During Pressure Pulses”, submitted to ETC 2013
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Evolution of blade loading during pressure pulse
time evolution of the integral values of forces
on the blade during the increase (top) or
drop (bottom) of mass flow rate
Compression wave:
as the blade stalls, the peripheral component
of force is almost null, whereas the axial
component shows a sudden change of sign
Expansion wave:
overall overload of the blade, as the value of
both axial and peripheral forces doubles
D. Borello - A. Corsini – G. Delibra – F. Rispoli – A. G. Sheard., “Numerical
Investigation On The Aerodynamics Of A Tunnel Ventilation Fan During
Pressure Pulses”, submitted to ETC 2013
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
Next
more snow
more whales
more fans (lot of fun)
and something new…
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012
A glimpse of the future (i)
LES of a Oscillating Water Column device coupled with Wells turbine for
Mediterranean operations simulated with Actuator Line Methodology (CINECA,
IscraB)
Numerical tools: hasNotANameYetFoam
Blade profile (rotor)
Dtip
Dhub
OWC chamber
Solidity
Blade count

Ubulk (axial):
FMGroup @ DIMA-SUR
NACA0015
500 mm
375 mm
0.64
7 + 2x
3600 rpm
9.1 m/s
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
Wells turbine
CINECA - Bologna, 27 Nov. 2012
A glimpse of the future (ii)
Numerical computations of the performance of Technopal centrifugal fan (FlaktWoods
Group), with particle dispersion, deposit and erosion
Numerical tools: pimpleDyMFoam (for URANS, possibly hybrid LES/RANS)
pTrack (in-house FEM code for particle tracking, erosion and fouling)
Technopal fan assembly
FMGroup @ DIMA-SUR
Impeller inlet diameter
Impeller outlet diameter
Volute outlet diameter
Impeller blade width
Volute width
Impeller blade count
Rotational frequency
1804 mm
3440 mm
5600 mm
400 mm
200 mm
11
900 rpm
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
Technopal impeller rendering
CINECA - Bologna, 27 Nov. 2012
Thanks
FMGroup @ DIMA-SUR
Industrial fan design and investigation by means of
URANS and LES based numerical methods
giovanni.delibra@uniroma1.it
CINECA - Bologna, 27 Nov. 2012