HPC enabling of OpenFOAM for CFD applications. Diego Angeli Ph.D

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2 HPC enabling of OpenFOAM for CFD applications Diego Angeli Ph.D

3 Acknowledgements Members of mimesis involved Paolo Levoni (CEO) Marco Cavazzuti Collaborators of mimesis Elia Agnani Stefano Martella (once were) undergraduate Ruggero Verzulli Federico Rossi

4 Outline mimesis introduction OpenFOAM-based industrial research: 3 examples a road vehicle application an agricultural vehicle application a fire protection engineering application Master Thesis OpenFOAM vs. Fluent aerodynamics of a Formula Student car Education and training

5 mimesis is an engineering company working in the fields of thermofluids and energy mimesis means imitation of nature, a nature which always evolves, improves and refines itself... if the goal is to optimize, for sure there is no better muse. mimesis was born as a spinoff company of DIEF (Dipartimento di Ingegneria Enzo Ferrari ) from the Applied Phisics Research Group of the University of Modena and Reggio Emilia The company was then expanded in order to incorporate specific knowledge in the fields of energy and sustainable mobility, that represent main challenges for modern human society

6 thermofluids energy

7 thermofluids services

8 thermofluids services design & 3D modelling

9 thermofluids services design & 3D modelling CFD thermofluid analyses

10 thermofluids services design & 3D modelling CFD thermofluid analyses standard experimental analysis

11 thermofluids services design & 3D modelling CFD thermofluid analyses standard experimental analysis advanced experimental analysis

12 thermofluids services design & 3D modelling CFD thermofluid analyses standard experimental analysis advanced experimental analysis prototype development

13 thermofluids services design & 3D modelling CFD thermofluid standard experimental analysis advanced experimental analysis prototype development optimization processes

14 thermofluids services design & 3D modelling CFD thermofluid analyses standard experimental analysis advanced experimental analysis prototype development optimization processes

15 energy services

16 energy services stationary applications

17 energy services stationary applications energy management and planning

18 energy services stationary applications energy management and planning renewable energy plants

19 energy services stationary applications energy management and planning renewable energy plants plants and component testing

20 energy services stationary applications energy management and planning renewable energy plants plants and component testing development of advanced energy processes and products

21 energy services stationary applications energy management and planning renewable energy plants plants and component testing development of advanced energy processes and products buildings energy diagnosis and plants optimization

22 energy services stationary applications energy management and planning renewable energy plants plants and component testing development of advanced energy processes and products buildings energy diagnosis and plants optimization

23 energy services mobility

24 energy services mobility electric prototype development

25 energy services mobility electric prototype development power supply transformation kits

26 energy services mobility electric prototype development power supply transformation kits smart mobility & social pooling

27 energy services mobility electric prototype development power supply transformation kits smart mobility & social pooling

28 Outline mimesis introduction OpenFOAM-based industrial research: 3 examples a road vehicle application an agricultural vehicle application a fire protection engineering application Master Thesis OpenFOAM vs. Fluent aerodynamics of a Formula Student car Education and training

29 Road vehicle application Self-ventilated brake disk for a HP road car

30 Road vehicle application Computational mesh and numerical details 36 slice, rotational symmetry flow induced by rotation ~1.6 million cells hybrid tet-prism mesh SRFSimpleFoam RANS (k-ω SST) I order schemes 2 days on an i7 CPU

31 Road vehicle application A snapshot of the results

32 Outline mimesis introduction OpenFOAM-based industrial research: 3 examples a road vehicle application an agricultural vehicle application a fire protection engineering application Master Thesis OpenFOAM vs. Fluent aerodynamics of a Formula Student car Education and training

33 Agricultural vehicle application Lubrication circuit of a tractor clutch Main idea: 0D approach Subparts are represented by their flow rate/head loss curve (obtained by OpenFOAM) experimental tuning/verification Cross-section of the whole clutch group Reverse gear group Detail of the reverse gear group

34 Agricultural vehicle application Subsystem modeling: the friction plates the friction plates are made up of a permeable material with many microchannels, whose full modeling is out of scope adoption of a (rotating) porous medium model Metallic disk Friction material

35 Agricultural vehicle application A small fix of OpenFOAM development poroussimplefoam + SRFSimpleFoam = poroussrfsimplefoam Porosity Model: power-law: Two coefficients to be tuned i 0 u i based on experimental data (non-rotating system) Extrapolation of the characteristic curve under rotation S C (C1 1) / 2

36 Outline mimesis introduction OpenFOAM-based industrial research: 3 examples a road vehicle application an agricultural vehicle application a fire protection engineering application Master Thesis OpenFOAM vs. Fluent aerodynamics of a Formula Student car Education and training

37 Fire Safety Engineering Application Numerical validation of the OpenFOAM-based CFD solver firefoam Experiments were performed for the case of a heptane pool fire in a fullscale under-ventilated environment (a closed garage), measuring the temperature at several locations by the use of thermocouples The experimental layout has been numerically reproduced and simulated using firefoam This is a preliminary study in order to validate the CFD solver and understand the critical issues in fire modelling The work is still in progress and the numerical model still has to be calibrated properly, just a quick overwiev on the problem and the results obtained so far will be given

38 Fire Safety Engineering Application Experimental room and thermocouples layout: front view and top view

39 Fire Safety Engineering Application Experimental room and thermocouples layout: front view and top view

40 Fire Safety Engineering Application Experimental room and thermocouples layout: front view and top view A steel panel is located 1m above the pool fire Thermocouples were mainly located on the central x-z plane at different heights, at the wall, at the room centre, and on the right of the steel panel Temperatures were recorded every 11s

41 Fire Safety Engineering Application Numerical setup: BCs and critical issues Inlet BC: the fuel burning rate of a pool fire is not known a priori and must be set according to experimental results Wall BC: a 3rd type (wallheattransfer) condition is applied, however a global wall heat transfer coefficient is not known from experiments Outlet BC: two thin outlet sections are added to the numerical model in correspondence to the garage door in order to avoid the pressurization of the room In strongly under-ventilated conditions such as the one we are addressing fuel combustion is incomplete and a lot of soot is produced, thus the actual Heat Release Rate of the fuel is not known a priori; as a first guess it is assumed a combustion efficiency of 75% both in terms of fully burnt fuel mass and HRR: the following combustion reaction is adopted C 7 H O N 2 5CO 2 + 2CO + 8H 2 O N MJ/kg

42 Fire Safety Engineering Application Fire evolution: experiment vs simulation

43 Fire Safety Engineering Application Temperature history at various locations

44 Fire Safety Engineering Application Temperature history at various locations

45 Fire Safety Engineering Application Temperature history at various locations

46 Outline mimesis introduction OpenFOAM-based industrial research: 3 examples a road vehicle application an agricultural vehicle application a fire protection engineering application Master Thesis OpenFOAM vs. Fluent aerodynamics of a Formula Student car Education and training

47 MS Projects OpenFOAM vs. Fluent Test case n.1 hydrodynamics of appendages Simulation types: simplefoam RANS II order schemes* 3 turbulence models: Spalart-Allmaras SST k-ω RSM *(I order)

48 MS Projects OpenFOAM vs. Fluent Test case n.1 hydrodynamics of appendages k-ω SST model: qualitative comparison OpenFOAM Fluent

49 MS Projects OpenFOAM vs. Fluent Test case n.1 hydrodynamics of appendages Spalart-allmaras model: qualitative comparison OpenFOAM Fluent

50 MS Projects OpenFOAM vs. Fluent Test case n.1 hydrodynamics of appendages RSM model: quantitative comparison

51 MS Projects OpenFOAM vs. Fluent Test case n.2 Wigley-Hull Simulation types: interfoam RANS (k-ω SST) II order schemes

52 MS Projects OpenFOAM vs. Fluent Test case n.2 Wigley-Hull pressure distribution on the free surface free surface relative height OpenFOAM Fluent OpenFOAM Fluent

53 Outline mimesis introduction OpenFOAM-based industrial research: 3 examples a road vehicle application an agricultural vehicle application a fire protection engineering application Master Thesis OpenFOAM vs. Fluent aerodynamics of a Formula Student car Education and training

54 MS Projects Formula Student External aerodynamics study of the UNIMORE 2012 IMechE Formula Student single-seater

55 MS Projects Formula Student External aerodynamics study of the UNIMORE 2012 IMechE Formula Student single-seater

56 MS Projects Formula Student External aerodynamics study of the UNIMORE 2012 IMechE Formula Student single-seater

57 Outline mimesis introduction OpenFOAM-based industrial research: 3 examples a road vehicle application an agricultural vehicle application a fire protection engineering application Master Thesis OpenFOAM vs. Fluent aerodynamics of a Formula Student car Education and training

58 Education and training DIEF - UNIMORE Since 2010, we teach an introductory course on OpenFOAM (20 hrs. + project work) to the Undergraduate Master Students of Mechanical Engineering and Vehicle Engineering, in the frame of the Numerical Thermofluid-dynamics course Training We held a small crash course on OpenFOAM at the 12th U.I.T. Summer School (organized by the Italian Union of Thermofluid-dynamics, Sep. 2012) We are looking forward to organizing on-demand courses for industry researchers and/or to partnering existing training events (no community, no OF!)

59 HPC enabling of OpenFOAM for CFD applications CFD analysis of the Mont Blanc Tunnel Diego Angeli, Ph.D mimesis s.r.l. - c/o DIEF Dipartimento Ingegneria Enzo Ferrari - via Vignolese 905, Modena

60 Overview The project Collaboration among DIEF, Mimesis s.r.l. and GEIE-TMB started in 2009, on the study and optimization of the Mont Blanc tunnel ventilation system. The research is carried out by both modeling and experiments, combined in an integrated approach for the analysis of this class of problems. Experiments allowed to collect accurate in situ air velocity data for model development and validation, and for the verification of airflow control infrastructures. Numerical work: 3D full-scale CFD with OpenFOAM development of 1D codes for simplified modeling

61 Experimental work Like moles in a wormhole

62 Full-scale simulation Critical aspects Length Height Width m 6 m 9 m Huge domain

63 Full-scale simulation Critical aspects Huge domain Jet fans Fresh air intake Smoke extraction outlet Ventilation elements

64 Full-scale simulation Critical aspects Huge domain Ventilation elements Complex modularity

65 TMB Modeling Geometrical simplifications No garages No sidewalk No road signs Equivalent wall roughness (tuned with experimental data) Typical tunnel section

66 TMB Modeling Geometrical simplifications Typical tunnel section Modeling of small air vents (one each 10 m) avoided Continuous boundary patch Fresh air intake

67 TMB Modeling Geometrical simplifications Typical tunnel section Fresh air intake Internal machinery unmodeled Hollow cylinders with ad-hoc BCs Jet fans

68 TMB Modeling Meshing Mesh convergence assessed by means of Richardson analysis Optimal section grid

69 TMB Modeling Meshing Optimal section grid Near high-gradient zones Smoke extraction Jet fans Fresh air intake Axial refinement

70 Jet fans modeling Modeling procedure Hot-wire anemometry Measurement if U r, U ϑ, U z and k Experimental characterization

71 Jet fans modeling Modeling procedure Experimental characterization Ensure mass conservation Swirl taken into account Curve fits of experimental data

72 Jet fans modeling Modeling procedure Experimental characterization Curve fits of experimental data Available fanpressurebc No mass conservation No swirl Customized BC

73 TMB Modeling Customized BC for jet fans At the fan suction inlet (an outlet of the CFD model), pressure is imposed as equal to the average pressure at the discharge section, minus the nominal pressure jump given by the fan; a zero gradient condition is imposed for the velocity p S = p D - Δp FAN u n S = 0 At the fan discharge (an inlet of the CFD model), velocity is imposed as equal to the average velocity at the suction, multiplied by the reconstructed dimensionless velocity profile (ensuring mass conservation); a zero gradient condition is imposed on pressure u D = U S ~ u D p n D = 0

74 Jet fans modeling Application of customized BC Swirl

75 Jet fans modeling Application of customized BC Swirl Coanda effect

76 Jet fans modeling Application of customized BC Swirl Coanda effect n. fans U exp [m/s] Validation vs. experimental data U OF [m/s] E %

77 Full-scale simulation Towards the complete TMB simulation ~2 million cells k- realizable model, standard wall functions All ventilation elements in a 300 m long tunnel segment Trouble-free calculation Qualitative analysis of a tunnel segment

78 Full-scale simulation Towards the complete TMB simulation Qualitative analysis of a tunnel segment Decomposition in elemental blocks Arbitrary Mesh Interface (AMI) Control scripts How to build the whole model?

79 Full-scale simulation Towards the complete TMB simulation Qualitative analysis of a tunnel segment How to build the whole model? Full-scale CINECA Multiscale coupling with 1D models Perspectives

80 o c/o DIEF - Dipartimento di Ingegneria Enzo Ferrari Via Vignolese 905, Modena - IT o spanish office Calle Ortigosa 14, Barcelona - ES