The Oxford Cold Driven Shock Tube a new facility for spray research

Transcription

1 The Oxford Cold Driven Shock Tube a new facility for spray research Martin Davy, Joe Camm, Luke Doherty, Matthew McGilvray, Xiaohang Fang, Felix Förster University of Oxford 4th Sprays SIG 18-19th September 2018 University of Oxford

2 Presentation Outline Why build a high temperature, high pressure research vessel? Why build a reflected shock tube? Theory of operation CDST design and capability Set up for ECN Spray A Preliminary results Future experimental plans Conclusions

3 Why build a high temperature, high pressure research vessel? Generally Unsolved problems in combustion science Non-premixed turbulent sprays Fuel atomization Autoignition Droplet evaporation vs diffusive mixing Soot and NOx formation High quality data for model validation Understanding newly recognized behaviour / combustion strategies Exploit new optical techniques to measure quantities such as temperature Developing truly predictive models Fundamental studies under engine relevant conditions Exact matching of conditions required

4 Why build a high temperature, high pressure research vessel? In the specific context of sprays Unsolved problems in combustion science Non-premixed turbulent sprays Fuel atomization Autoignition Droplet evaporation vs diffusive mixing Soot and NOx formation Behaviour of biofuels / new fuels for new combustion strategies High quality data for model validation Understanding newly recognized behaviour / combustion strategies Exploit new optical techniques to measure quantities such as temperature Developing truly predictive models Sub-models used out of region of validity Fundamental studies under future engine relevant conditions Exact matching of conditions required Supercritical behaviour

5 Facility Wishlist Flexible, current & future engine relevant conditions (ρ, p, T, YO2, etc.) Long test duration Ease and affordability of operation Optically accessible Internationally competitive (add value to community)

6 Review of Existing Facilities Facility Mode Typical peak pressure (bar) Typical peak temp. (K) Size Sandia Pre-burn constant volume mm cube CMT Constant flow vessel mm dia. Brighton RCM RCM mm dia. IFP Pre-burn constant volume mm cube ETH Pre-burn constant volume NUI Galway High Pressure Shock Tube Heated mm dia. RPI Shock Tube Heated mm dia. Aachen Constant flow vessel mm dia. ITLR Shock Tube Double diaphragm mm sq. NUI Galway RCM RCM UBC Shock Tube Double diaphragm mm dia. Stanford Aerosol Shock Tube Heated mm sq.

7 Facility Wishlist Flexible, current & future engine relevant conditions (ρ, p, T, YO2, etc.) Long test duration Ease and affordability of operation Optically accessible Internationally competitive (add value to community) Shock Tube: Creates high temperature, high pressure quiescent charge, of chosen composixon Can be Cold Driven and compressed air operated Simple manual procedure Alternate boundary condixons due to rapid heaxng

8 Where does the Oxford CDST sit? Facility Mode Typical peak pressure (bar) Typical peak temp. (K) Size Sandia Pre-burn constant volume mm cube Oxford CDST Double diaphragm mm dia. CMT Constant flow vessel mm dia. Brighton RCM RCM mm dia. IFP Pre-burn constant volume mm cube ETH Pre-burn constant volume NUI Galway High Pressure Shock Tube Heated mm dia. RPI Shock Tube Heated mm dia. Aachen Constant flow vessel mm dia. ITLR Shock Tube Double diaphragm mm sq. NUI Galway RCM RCM UBC Shock Tube Double diaphragm mm dia.

9 Theory of Operation (1) Driven section Driver section Diaphragm P1 Adapted from, Huang, J., Experimental Shock Tube Study of Ignition Promotion for Methane under Engine Relevant Conditions, MSc Thesis, Department of Mechanical Engineering, University of British Columbia, P4

10 Theory of Operation (2) Driven section Driver section Shock P1 Rarefaction wave P2 P3 Contact surface Adapted from, Huang, J., Experimental Shock Tube Study of Ignition Promotion for Methane under Engine Relevant Conditions, MSc Thesis, Department of Mechanical Engineering, University of British Columbia, P4

11 Theory of Operation (3) Driven section Shock Driver section Rarefaction wave P2 = P3 P5 Contact surface Adapted from, Huang, J., Experimental Shock Tube Study of Ignition Promotion for Methane under Engine Relevant Conditions, MSc Thesis, Department of Mechanical Engineering, University of British Columbia, 2002.

12 Theory of Operation (4) Driven section Shock P5 P6 Driver section Rarefaction wave P2 Contact surface Adapted from, Huang, J., Experimental Shock Tube Study of Ignition Promotion for Methane under Engine Relevant Conditions, MSc Thesis, Department of Mechanical Engineering, University of British Columbia, 2002.

13 The Devil is in the Details Sound speeds not matched Either shock or expansion wave reflects off interface Test time interrupted (1) (2) (3) (4) (5) Initial Driven Gas Shocked Driven Gas (incident) Expanded Driver Gas Initial Driver Gas Shocked Driven Gas (reflected)

14 Driver Options (L1d3 predictions UQ) Cold Air Driver Area change Relatively cheap to operate Cold Helium/Argon Driver Constant Area Longer test duration - Tailored (1) (2) (3) (4) (5) Initial Driven Gas Shocked Driven Gas (incident) Expanded Driver Gas Initial Driver Gas Shocked Driven Gas (reflected) 4 1

15 Design Conditions ECN Spray A Property Low Nominal (Spray A) High (p5, bar) Reflected Shock Temperature Test durapon cold air driver (T5, K) (ms) N/A Test durapon cold He/Ar driver (ms) Reflected Shock Pressure Spray A Driver pressure (p4, bar) Driven pressure (p1, bar) Air (or N2) % He / 8% Ar

16 Oxford CDST Design Optical test section and injector mount Modular shock tubes Clamp and hub connectors Diaphragm station Driver tube Steel frame Tube cradles 11 metres 3.4 tonnes 100 mm bore

17 Oxford CDST Optical Test Section Windows virtually flush with end wall Fuel injector mounting (currently ECN Spray A single-hole diesel) Three fused silica tapered windows: 0, 90 and x 70 mm, 48 mm thick, made by Crystran. Three Ø8 mm pressure transducer holes (PCB 113B04), for gas pressure and speed (and hence temperature) calculation Ø100 mm bore

18 Oxford CDST Double Diaphragm Station Controlled triggering Repeatable set pressures Better defined experimental conditions Incident Shock 1 bar 100 bar bar bar 100 bar

19 Preliminary Results ECN Spray A Setup Low pressure initial tests Currently installed old ECN Injector with nozzle # (previously characterized by Malbec et al.) ECN Common Rail (GM Part number ) USUI 24 cm long, 2.4 mm bore pipe Air driven Maximator 2200 bar pump NI Direct Injector Driver System (DIDS) Kistler 4067 Transducer for dynamic fuel pressure KIT Electroheat nozzle heater to maintain 90 C fuel temperature Malbec, L.-M., Esquiza, J., Bruneaux, G. and Meijer, M., CharacterizaXon of a set of ECN Spray A injectors: Nozzle to nozzle variaxons and effect on spray characterisxcs. SAE Int. J. Engines, 6: ,

20 Preliminary Results ECN Spray A Low pressure initial tests Measured pressure: 12.5 bar Calculated temperature: 658 K 70 mm Run 10 Injector Pp Measured pressure: 11.2 bar Calculated temperature: 496 K Run 11 Diffuse Backlit Imaging (DBI), 1.5 µs shujer duraxon, overdriven LED illuminaxon Diesel fuel, 1500 bar injecxon pressure

21 Preliminary Results Test Duration For the tests so far achieved we see a stable pressure during the test time Run 10: 11.2 bar 11.6 bar Over 5 ms test time before disruption due to arriving secondary shock wave In agreement with L1d3 predictions InjecXon Trigger (different transducer)

22 Planned and Potential Experiments Potential ECN Contribution Mie Scattering (non-reacting) liquid length, high spatial and temporal resolution, transcritical initial conditions Schlieren vapour length, characterization of test section flow structure Natural luminosity / chemiluminescence flame lift off length and structure, combustion recession identification LIGS high accuracy point temperature measurement, characterization of test section temperature field, LIGS in the spray for local speed-of-sound measurement High temperature, non-oxidizing, long duration conditions soot pyrolysis extinction imaging Co-combustion with hydrogen and novel future fuels ignition delay

23 Conclusions The Oxford CDST is a world leading facility for sprays research Significant interest in future collaborative works Existing project partners, JLR / UCL / University of Brighton ECN / Sandia National Laboratories for extended range of single hole spray conditions, including high temperature, non-combusting studies on soot formation BP for fuel auto-ignition studies University of Southampton for fuel and gaseous dual-fuel auto-ignition studies Substantial legacy of EPSRC funding and support

24 This work was funded by the EPSRC under the grant: Ultra Efficient Engines and Fuels, Grant no. EP/M009424/1. The authors would also like to acknowledge the assistance provided in designing, building and commissioning the CDST and infrastructure by: Bill Godfrey, Hal Surtell, Jason McCluskey, Aston Tyrrell, Phil Bower, Gerald Walker, Duncan Blake, Paul Cox, Richard Stone, Felix Leach and Louis Nicholson. These slides were adapted from a SAE WCX2018 presentation given by Dr Joe Camm (now of Loughborough University) SAE Technical Paper Thank you for your attention