UGM 2016 PRAGUE Complete saloon + air duct + HVAC unit modeling with Star- ccm+ Huu-Thi DO 08/03/2016

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 2 1. Presentation of Alstom p 3 2. Introductionp 5 3. Step 1: Saloon thermal comfort and air duct designp 7 4. Step 2: Hvac unit fan MRF modeling calibrationp Step 3: Complete modelp Step 4: Testing preparation by CFD p Conclusionp 20

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 3 Presentation of Alstom  Trains  Infrastructures  Signalling  Services  Turnkey systems

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 4 Presentation of Alstom / Rolling Stock from Tramways to Very High Speed Trains DISTANCE Very High Speed High Speed SPEED Tramwa y

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 5 Introduction Main lines European Normes criteria for climatic comfort air temperature in a saloon are severe ( thermal gradient < 3K in an section of the saloon volume) Requirements to achieve the performance Good HVAC behaviour (at nominal point) Good air ventilation in the saloon Context: a new saloon interior design on an existing train

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 6 Challenge and Approach Challenge New interior for the « bar » saloon But same HVAC unit and air duct architecture The current HVAC unit has reached at its pressure drop limit The air duct shapes must be optimised to respect the pressure drop limit No mock-up => no mistake is allowed Approach Step 1: thermal comfort design and standard air duct design to reduce pressure drop Step 2: Hvac unit Moving Reference Frame modeling Step 3: Complete model for a more accurate air flow volume rate Step 4: Preparation of testing by CFD assistance

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 7 Step 1: thermal comfort and air duct design Saloon geometry Large 3D saloon model (length > 10m) Only saloon and air duct network study xm side Air duct network Hvac unit position yp side Air duct network > 10 m

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 8 Step 1 Saloon thermal comfort design After iterations on air diffusion The thermal gradient is quite good Cooling mode: Text=40°C 1K Good mixing behaviour 2 nd order discretisation Ideal gas Steady-state K-Epsilon Realizable

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 9 Step 1 Air duct design Example of air duct optimisation Pressure drop 40 Pa improvement Initial design Improved design Pressure drop optimisation performed but uncertainties remain on the air flow volume rate delivered by the Hvac unit the future train => a more accurate modeling: Moving Reference Frame modeling of the Hvac unit fan

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 10 Step 2 HVAC unit by Moving Reference Frame (MRF) calibration of the hvac unit fan modeling New Air 2: AN_xp Diffusion xm : AS_xm Diffusion xp : AS_xp Recycling : AR Heat exchanger Thermal resistances Fan New Air 1: AN_xp

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 11 Step 2 HVAC unit by Moving Reference Frame (MRF) calibration of the hvac unit fan modeling / mesh views About 13M cells polyedral Trimmed cells

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 12 Step 2 HVAC unit by Moving Reference Frame (MRF) calibration of the hvac unit fan modeling / testing Moving Reference Frame CFD approach is enough accurate in this case The air flow volume rate / pressure drop curve is well reproduced (regarding testing uncertainties) The HVAC unit fan modeling is representative 2 nd order discretisation Incompressible Steady-state K-Epsilon Realizable MRF ∆P(Pa) Qv(m3/h)

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 13 Step 2 HVAC unit modeling / mesh cell number reduction heat exchanger by porous media Light polyedral mesh for an exchanger about 3 M cells 0,2 mm thins !!! Trimmed cell mesh with porous media < 0,5 M cells

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 14 Step 2: HVAC unit modeling / mesh cell number reduction heat exchanger by porous media Estimation of Pi and Pv porous media coefficients with several pressure drop points The porous media modeling reproduces well the equivalent pressure drop for the exchanger V(m/s) Pi, Pv porous media Y= A x 2 + B x + C V(m/s) ∆P(Pa)

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 15 Step 2 Hvac unit by CFD MRF modeling Final optimized modeling The Hvac unit air flow volume dispatching is the same when the pressure drop changes The MRF hvac unit model can be integrated into the saloon + air duct network model Qv (m3/h)

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 16 Step 3: Complete saloon + air duct + hvac unit Geometry & mesh HVAC unit Air duct network Recycling air 44 M cells

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 17 Step 3: Complete saloon + air duct + hvac unit Separation at the interface between air HVAC and the duct Quite stabilized flow 2 nd order discretisation Incompressible Steady-state K-Epsilon Realizable MRF

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 18 Step 3: Complete saloon + air duct + hvac unit Air duct network / flow dispatching Yp_Qv_x2 Ym_Qv_x1 Qv_Ls Yp_Qv_x1 Ym_Qv_x2 Qm_duct_xm Qm_duct_xp = AS_xp Ym_Qv_x3 Qv_AN_xm Qv_AN_xp Slight difference between branches on side xm and xp side regarding to the initial HVAC distribution hypothesis (50% / 50%) Qv (m3/h) The complete model results are quite similar to the model without HVAC => the previous air flow volume rate balancing hypothesis in air duct design phase were quite realistic xm side xp side

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 19 Step 4: Testing preparation by deflector position tunning Deflector has been turned of -10° Only slight tunning capabilities on the testing (confirmed in real life) Deftector at angle 0° Deflector at angle -10°

© ALSTOM SA, All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authorisation, is strictly prohibited ALSTOM – Global Conference 2016 Prague - Huu-Thi DO – 08/03/2016– P 20 Conclusion All the design has been performed by CFD with Star-ccm+ Almost performances and limitations have been identified at very early project stage Final testing on real train has confirmed the CFD results Thanks to CFD approach that permitted to reach globally the thermal comfort performances without the expensive cost of a real saloon mock-up