Effects of water addition on the combustion of iso-octane investigated in laminar flames, low-temperature reactors, and an HCCI engine

Journal Article · Fri Nov 29 00:00:00 EST 2019 · Combustion and Flame

DOI:https://doi.org/10.1016/j.combustflame.2019.11.023· OSTI ID:1581978

Schmitt, Steffen ^[1]; Wick, Maximilian  ^[2]; Wouters, Christian  ^[3]; Ruwe, Lena ^[1]; Graf, Isabelle ^[1]; Andert, Jakob  ^[4]; Hansen, Nils ^[5]; Pischinger, Stefan ^[3]; Kohse-Höinghaus, Katharina ^[1]

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1. Bielefeld Univ. (Germany)
2. FEV Europe GmbH, Aachen (Germany)
3. RWTH Aachen Univ. (Germany). Inst. for Combustion Engines
4. RWTH Aachen Univ. (Germany)
5. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Combustion Research Facility

In this work, the effect of H₂O injection on the combustion process of iso-octane was investigated with the aim to better understand the suitability of water addition as a potential engine control parameter for homogeneous-charge compression ignition (HCCI) combustion. Several experiments were combined including premixed low-pressure flames, a jet-stirred reactor (JSR) and a plug-flow reactor (PFR), both at atmospheric pressure, and a single-cylinder research engine (SCRE) operated with either iso-octane or RON 98 gasoline. The thermal effect of H₂O addition was determined in laminar premixed iso-octane/O₂/Ar flames (equivalence ratio $$Φ$$=1.4, 40 mbar) with H₂O mole fractions of 0 to 0.22, where water addition reduced the temperature measured by laser-induced fluorescence (LIF) by up to 110 K. Speciation data were obtained from these flames as well as in the JSR ($$Φ$$=0.65, 933 mbar) and PFR experiments ($$Φ$$=0.65, 970 mbar) with and without H₂O addition in the low- to intermediate temperature regime from 700–1100 K. The chemical analysis in these flame and reactor experiments was performed using molecular-beam mass spectrometry (MBMS) employing either electron ionization (EI) in the PFR and premixed flame or single-photon ionization (PI) by tunable vacuum-ultraviolet radiation in the JSR. The effects on species mole fractions were small which is supported by predictions from chemical-kinetic simulations. Quantitative speciation data of the exhaust gas of the SCRE were obtained by using Fourier-transform infrared (FTIR) spectroscopy. A very similar species pool was detected in the laboratory-scale experiments and for the engine operation. It is thus assumed that these results could assist in guiding both the improvement of fundamental chemical-kinetic as well as HCCI engine control models.

• Research Organization: Sandia National Lab. (SNL-CA), Livermore, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division, Washington, DC (United States); German Research Foundation (DFG), Bonn (Germany); USDOE National Nuclear Security Administration (NNSA), Washington, DC (United States)
• Contributing Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
• Grant/Contract Number: AC04-94AL85000; NA0003525; AC02-05CH11231
• OSTI ID: 1581978
• Alternate ID(s): OSTI ID: 1576641
• Report Number(s): SAND-2019-14039J; 681566
• Journal Information: Combustion and Flame, Vol. 212, Issue C; ISSN 0010-2180
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
water addition
iso-octane
premixed flame
FTIR exhaust gas measurements
jet-stirred reactor
HCCI engine