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Effect of 4500bar injection pressure and super-critical phase change of surrogate and real-world fuels enriched with additives and powering Diesel engines on soot emissions reduction

Periodic Reporting for period 2 - IPPAD (Effect of 4500bar injection pressure and super-critical phase change of surrogate and real-world fuels enriched with additives and powering Diesel engines on soot emissions reduction)

Reporting period: 2017-09-01 to 2019-08-31

The IPPAD ITN network has developed novel state-of-the-art computational model for Diesel fuel properties at elevated pressures and temperature, fuel injection at supercritical conditions and soot formation in Diesel engines, validated against new and unique experimental data. These models have included aspects of real-fluid thermodynamics, advanced numerical methods and combustion sciences, which have been linked to methodologies for industrial-scale problems.
The work has been completed according to the Grant Agreement, fully respecting the overall project aim. The scientific outcomes of IPPAD have been published in numerous peer-reviewed and highly esteemed journal papers and conference proceedings. In addition to the conducted research, the IPPAD network has trained the ESRs on a range of unique scientific modules, that have broadened their perspectives in both research and classical engineering skills. Equally important, ESRs have been trained on a range of transferable skills. Last but not least, the ESRs have been engaged in numerous outreach activities, disseminating their work to relevant non-specialised communities that made the EU funding and the impact of the performed research visible to the general public.
IPPAD has successfully addressed the following scientific objectives:
1. Developed an experimental database for the effects of three representative additives (detergent, soot reducer and ignition improver) for injection pressures up to 3,000 bar, fuel temperature up to critical point and three different fuels (surrogate Diesel, EU summer Diesel and low-quality Diesel).

2. Develop equations of state for Diesel physical properties and vapour liquid equilibrium (VLE) implemented in both newly-developed as well commercial, diffused interface mixing CFD spray models able to simulate simultaneously the in-nozzle flow and spray dispersion.

3. Performed experiments quantifying the effects of selected additives on soot formation processes; these have included ‘soot reducers’ and ‘ignition improvers’ on flame burners utilising pre-vaporised Diesel as well as ‘detergents’, for new and coked nozzles. Experiments have been performed in both CVC and optical engines.

4. Implemented the validated models in URANS and LES solvers and applied them for the prediction of in-nozzle flow, spray mixing, engine combustion and soot/NOx emissions.

5. In addition, the IPPAD team developed a training programme for the ESRs, which covered: (a) specialised training courses offered by the participating institutions; (b) network-wide training activities in the format of seminar, workshop, conference and summer school; (c) knowledge exchange with the members of the network through activities such as secondments and open events.
The IPPAD project has advanced state-of-the-art in the following ways:

•Provided new and unique experimental data for Diesel fuel properties at elevated pressures and temperatures, spray mixing in CVC and optical engines and soot emissions in burners and Diesel engines.
•Developed new thermodynamic closure models utilising real-fluid thermodynamics suitable for diffuse interface methods; these have been implemented into existing as well as newly developed LES and URANS computational fluid dynamics solvers.
•Applied the developed models to a wide range of industrial applications; simulations performed for the first time with the new models have provided physical inside leading effects of extreme fuel pressurisation, thermal effects in fuel injectors leading to erosion, spray mixing and combustion at supercritical P-T conditions.

Impact can be foreseen on: (a) the career of the ESRs, (b) scientific/technological advances, (c) institutional level and (d) general public well-being.
(a) Career of ESRs: the training by research that lead to their PhDs, the transferable skill training, their interaction and exposure to industrial practice and new cultures will inevitably shape their future careers.
(b) Scientific/technological advances: the novel areas of research addressed have provided new physical insight in the aforementioned areas and resulted to new computational tools adopted by a wide range of industries; this is expected to pave the way towards the design of more energy/environmentally efficient engines for the fuel and fuel additives, automotive and heavy-duty industries involved in IPPAD.
(c) Institutional level: the academic beneficiaries and partners have greatly benefited from IPPAD through the new publications in highly esteemed journals, dissemination of their research to the wider community during conference and workshops and the formation of new partnerships that have resulted to new funded projects. The non-academic beneficiaries and partners have also greatly benefited from the new design tools available, which can assist in their future businesses.
(d) General public: the new technology/designs obtained as a result of IPPAD, will have an impact to the general public well-being, as more efficient heavy-duty Diesel engines can result to enormous savings in greenhouse gases.
Fluid Properties measurement test rig
Supercritical N2 jet
Soot development in the spray flame from 800 µs to 2200 µs after injection