A generalised Fully Lagrangian Approach for gas-droplet flows

Lead Research Organisation: University of Brighton
Department Name: Sch of Computing, Engineering & Maths

Abstract

The proposed project is based on the synthesis of mathematical and engineering approaches to simulate gas-droplet flows. It comprises the development of a new mathematical formalism, which will then be applied to enhance an existing approach to simulate two-phase flows. It will make it possible to perform simulations with higher resolution: more accurate calculations, and more physical phenomena will be captured.
The project will focus on non-trivial generalisation of the mathematical approach to spray modelling developed by Professor Osiptsov, known as the Fully Lagrangian Approach (FLA). In the mathematical modelling community, this method is known as a promising approach to calculate particle/droplet concentrations. However, its current applications are restricted to simplistic flows with dilute mono-sized admixture. In the framework of the project, droplet evaporation, polydispersity of admixture, and the effect of droplets on the carrier phase (two-way coupling) will be taken into account and incorporated in the model. The corresponding mathematical model will be implemented in the Computational Fluid Dynamics (CFD) software OpenFOAM. The developed model will be applied to simulate the evolution of droplet distribution in sprays formed in direct-injection internal combustion (Diesel and gasoline) engines. The results of numerical simulations will be validated against experimental data provided by colleagues in the Advanced Engineering Centre, University of Brighton. OpenFOAM is an open-source and widely used CFD software, which will make the project outcomes accessible to specialists interested in sprays.

Planned Impact

The project will have an impact in the following areas:
1. Academics in mathematical modelling (short-, mid- and long-term)
2. CFD development (short-, mid- and long-term)
3. Automotive engineering (mid- and long-term)
4. Academics in research of 'gas-droplet' and 'gas-particle' flows (engineering, pharmacy, biomedical and environmental studies) (long-term)
5. Industry, which relies on 'gas-droplet' and 'gas-particle' flows (engineering, pharmacy, biomedical technology) (long-term)

The new mathematical formalism, which will be developed in the framework of the proposed project, will be of interest to specialists in applied mathematics and mathematical modelling of multiphase fluid flow. It will be a non-trivial generalisation of the Fully Lagrangian Approach to simulate two-phase flows. This impact will be delivered through the Advanced Engineering Centre (AEC) (University of Brighton) networks, presentations at the workshops with industrial partner Ricardo UK Ltd, international conferences and publications in leading international refereed journals.

The implementation of the new model within an open-source CFD software OpenFOAM as a Lagrangian solver will be beneficial for the CFD developers' community. The new solver will be available to this community; it will be demonstrated how the developed methods can be implemented in any other in-house, open-source or commercial CFD packages.

Within the proposed project framework, the developed model will be applied to fuel sprays in direct injection engines. The AEC has a comprehensive database of experimental data. This will be used for validation purposes. Designers of fuel injection systems and the automotive industry in general will benefit from an in-depth understanding of the processes involved, which would allow them to identify scenarios for optimal fuel vapour mixture preparation, and to minimise fuel consumption and emissions. This is aligned with the interest of the project's industrial partner, Ricardo UK Ltd, and will have an impact on future developments in the UK automotive industry. The wider public will also benefit from the impact of more efficient and 'green' combustion engines. The AEC infrastructure will enable the research team to disseminate the results of research effectively through regular AEC-Ricardo meetings programmes, and existing AEC networks. The AEC is a member of the Engine Combustion Network (ECN), the Internal Combustion Engine Thermal Efficiency Spoke within the Advanced Propulsion Centre UK (APC), UK Fluid Network.

Gas-droplet flows are essential not only in internal combustion engines but also in many other industrial (cooling, surface coating and processing, delivery of lubricants), medical (pharmaceutical drug manufacturing by spray drying, inhalers), and environmental applications (atmosphere flows, ocean sprays). In all these applications, it is essential to predict droplet dynamics and concentration with high accuracy, which will be provided by the new version of particle-tracking Lagrangian-based solver of OpenFOAM. The new model could be applied to the above-named applications. The new expertise will also facilitate cross-disciplinary research collaborations. This impact will be delivered through existing AEC (University of Brighton) networks, presentations at workshops, international conferences and publications in leading international refereed journals.

Publications

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Zaripov T (2018) A model for heating and evaporation of a droplet cloud and its implementation into ANSYS Fluent in International Communications in Heat and Mass Transfer

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Strizhak P (2018) Heating and evaporation of suspended water droplets: Experimental studies and modelling in International Journal of Heat and Mass Transfer

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Sazhin S (2018) A new model for a drying droplet in International Journal of Heat and Mass Transfer

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Sazhin S (2019) A simple model for puffing/micro-explosions in water-fuel emulsion droplets in International Journal of Heat and Mass Transfer

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Papoutsakis A (2018) Modelling of the evolution of a droplet cloud in a turbulent flow in International Journal of Multiphase Flow

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Nissar Z (2020) A model for puffing/microexplosions in water/fuel emulsion droplets in International Journal of Heat and Mass Transfer

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Kudryavtsev A (2019) Numerical simulation of aerodynamic focusing of particles in supersonic micronozzles in International Journal of Multiphase Flow

 
Description The main outcomes are:
1. A novel mathematical formalism for polydisperse sprays in evaporating conditions has been developed. The model is a generalisation of the Fully Lagrangian approach for dilute gas-particle mixture flows, but where the Lagrangian set of variables is extended to include initial droplet size and the number density is generalised to a droplet distribution function defined over space, time and droplet sizes, and the set of equations is complemented with an expression for evaporation/condensation.
2. The original Fully Lagrangian approach has been implemented as a set of additional libraries to OpenFOAM, an open-source computational fluid dynamics software, and tested.
3. The new model of generalised Fully Lagrangian Approach has been tested on simple cases and then implemented as a set of additional libraries to OpenFOAM.
4. A new model to analyse drying of chitosan dissolved in water was developed. The model is based on multicomponent droplet heating and evaporation with a non-evaporative component (chitosan).
5. Improved codes have been developed for coupling with the CFD software ANSYS Fluent. The codes include the fully Lagrangian approach (FLA) to the calculation of the number density of admixture, the previously developed model for droplet heating and evaporation, and more detailed properties of liquids. The codes are now publicly available and are being used by researchers outside our research group.
6. A new model for heating and evaporation of a suspended droplet was proposed. The new model includes effects of temperature gradient, recirculation inside the droplet, and the effect of the support.
7. A new model for water/fuel droplets to predict puffing/micro-explosions was suggested and applied in a number of studies for validation, which allowed to explore the limits of application of the new model.
8. The Fully Lagrangian apporach was applied to model particle flow in micronozzles with identification of optimal regimes for particle focusing. An interesting and unexpected feature of aerodynamic focusing is that the beam collimation is observed in two different ranges of particle sizes. In the first range, for relatively large particles, the collimated beam consists only of particles seeded close to the nozzle axis. In the second range, for smaller particles, the beam includes also a great portion of peripheral particles. The numerical simulation also shows that aerodynamic focusing in a supersonic, convergent-divergent, nozzle enables one to increase significantly the velocity of the collimated beams compared to previously reported results for convergent subsonic nozzles.
The above-mentioned achievements are confirmed by publications in international refereed journals, with exception of the first three. For the first three outcomes, one paper was submitted in February, another one is in preparation for submission.
Exploitation Route It is envisaged that short-term and mid-term beneficiaries of the project findings are academics in mathematical modelling, computational fluid dynamics (CFD) developers, academic and industrial researchers specialising in 'gas-droplet' and 'gas-particle' flows. The findings are being disseminated by a range of methods, including workshops, conferences, research publications, and online presence. A specialised web-page as well as a repository on a public platform GitHub have been created. The repository is used to share research codes developed during the project. The research codes might be useful to other researchers, especially the codes, which can be coupled with conventional CFD software. For example, three repositories contain special functions that can be coupled with ANSYS Fluent, which is widely used in academia and industry. The links are shared using existing networks.
Examples of collaborations, which resulted from this work, include two visiting research students (Tomsk Polytechnic University, Russia, 3 month and Federal University of Uberlândia, Brazil, 6 months), collaboration with a research group from Institute of Thermophysics, Novosirsk on nanodroplet heating and evaporation, Tel-Aviv University on development of the microexplosion model.
We have records of two groups external to our research group using the codes for their research. Few more groups expressed interest and requested information about the software.
Another direction of potential development is cross-disciplinary collaboration for environmental/medical/pharmaceutical application. This is, however, still at early stages. A bid for a research funding to develop the model for pressurised-metered dose inhalers has been submitted.
Sectors Aerospace, Defence and Marine,Agriculture, Food and Drink,Chemicals,Energy,Environment,Pharmaceuticals and Medical Biotechnology

URL https://research.brighton.ac.uk/en/projects/a-generalised-fully-lagrangian-approach-for-gas-droplet-flows
 
Description Next generation spray simulation model (NGSSM)
Amount £1,124,894 (GBP)
Funding ID MR/T043326/1 
Organisation United Kingdom Research and Innovation 
Sector Public
Country United Kingdom
Start 02/2021 
End 01/2025
 
Title A generalised Fully Lagrangian Approach for gas-droplet flows 
Description This project synthesises mathematical and engineering approaches to the simulation of gas-droplet flows, and includes the development of a novel mathematical formalism. The project focuses on non-trivial generalisation of the version of the Fully Lagrangian Approach (FLA) developed by Osiptsov, also known as the Osiptsov method. This method is recognised as a promising approach to calculating particle/droplet concentrations. However, its current applications are restricted to specific types of flow within a dilute mono-sized admixture. The novel model to be developed in the framework of the project will take into account droplet evaporation, polydispersity of an admixture, and the effect of droplets on the carrier phase (two-way coupling). The corresponding mathematical model will be formulated and implemented in the Computational Fluid Dynamics (CFD) software OpenFOAM, an open-source and widely used CFD software, which will make the project outcomes accessible to specialists interested in sprays. The developed model will be applied to simulate the evolution of droplet distribution in sprays formed by a gasoline or diesel injector. The results of the numerical simulations will be validated against experimental data collected in the Advanced Engineering Centre (AEC), at the University of Brighton (UoB). 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
URL http://researchdata.brighton.ac.uk/id/eprint/78
 
Title A model for heating and evaporation of a droplet cloud and its implementation into ANSYS Fluent. 
Description A model for heating and evaporation of a cloud of monocomponent droplets in air, taking into account the evolution of droplet number densities, is developed and implemented into ANSYS Fluent. Functionality testing of the new customised version of ANSYS Fluent is based on its application to the analysis of a droplet cloud in a two-phase back-step flow. It is shown that the effect of the droplet cloud needs to be taken into account when estimating the heat and mass transfer rates from the carrier phase to the droplets. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
 
Title Generalised FLA for polydispersed sprays with phase exchange 
Description A novel mathematical formalism to describe polydisperse sprays with evaporation and condensation. The model was implemented as additional libraries to OpenFOAM. The paper is in preparation. 
Type Of Material Computer model/algorithm 
Year Produced 2019 
Provided To Others? No  
Impact No notable impact yet. It is still early stages for promoting the model. 
 
Title A generalised Fully Lagrangian Approach for gas-droplet flows 
Description This OpenFOAM library for a generalised Fully Lagrangian Approach is created based on the existing Lagrangian module and PIMPLE solver in OpenFOAM 6.0 
Type Of Technology Software 
Year Produced 2020 
Open Source License? Yes  
Impact Implementation of generalised Fully Lagrangian Approach demonstrated the potential of the model, which was realised in securing funding for 'Next generation spray simulation model (NGSSM)' project. 
URL https://researchdata.brighton.ac.uk/78/
 
Title Code for simulation of water in n-dodecane droplet heating to predict times to puffing 
Description This is code for simulation of water in n-dodecane droplet heating to predict times to puffing 
Type Of Technology Software 
Year Produced 2018 
Open Source License? Yes  
Impact The only recorded impact is that a research group from Universiti Teknologi PETRONAS is using it for their project. 
 
Title Coupled ANSYS UDFs for Fully Lagrangian Approach (FLA) for spray modelling with the heat and mass modelling for a single component droplet. 
Description Coupled ANSYS UDFs for Fully Lagrangian Approach (FLA) foro spray modelling with the heat and mass modelling for a single component droplet. The code was tested with ANSYS Fluent 17.2 A user can select from water, n-dodecane, and iso-octane droplets. 
Type Of Technology Software 
Year Produced 2018 
Open Source License? Yes  
Impact The code has been used within the research group. The link to the repository has been shared on UK Fluid Network website (https://fluids.ac.uk/researcher-resources). However, no notable impact has been registered so far. 
 
Title UDF for heating and evaporation of an acetone/ethanol droplet 
Description UDF for defining the heat and mass transport for Bi-component Droplet vaporization. The UDF has been tested with ANSYS Fluent 17.2 
Type Of Technology Software 
Year Produced 2018 
Open Source License? Yes  
Impact No notable impact has been recorded so far. 
 
Title UDF for heating and evaporation of an n-dodecane/isooctane/water droplet 
Description ANSYS Fluent UDF for defining the heat and mass transport for n-dodecane droplet. Has been tested with ANSYS Fluent 17.2. Physical properties are taken from: Abramzon, B. and W.A. Sirignano, Droplet Vaporization Model for Spray Combustion Calculations. International Journal of Heat and Mass Transfer, 1989. 32(9): p. 1605-1618. 
Type Of Technology Software 
Year Produced 2018 
Open Source License? Yes  
Impact It is recorded that the code has been used by a research group at Coventry University, and a group at Tomsk Polytechnical University. It lead to collaboration with Tomsk Polytechnical University: visit to Tomsk Polytechnical University (Russia), placement student from Tomsk Polytechnical University in February 2020, another placement was successful in securing funding. Unfortunately, the first placement was interrupted and the second placement did not take place due to COVID19 pandemic. There was interest from other research groups, for example using for a PhD research project, however, there are no records of further development yet. 
 
Description AEC research seminars 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Professional Practitioners
Results and Impact Being a member of the Advanced Engineering Centre (AEC), the team attended and presented at the regular AEC research seminars, which in late 2019 were merged with the School of Computing, Engineering and Mathematics regular research seminar. The purpose of the seminar is to share research. As a result, especially after the last presentation in 2020, there was a good discussion with an interest in a collaboration with other AEC's researchers supported by experimental study.
Year(s) Of Engagement Activity 2018,2019,2020
 
Description ILASS 2019 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The study was presented at ILASS 2019 conference, which sparked a lot of interest.
Year(s) Of Engagement Activity 2019
URL https://ilass19.sciencesconf.org/
 
Description SIG meetings 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact My research team and i were members of the Special Interest Group 'Sprays in engineering applications: modelling and experimental studies' supported by the UK Fluids network. Overall, there study outcomes were presented at 3 SIG meetings, with 7 presentations.
Year(s) Of Engagement Activity 2018,2019,2020
 
Description UK Fluids 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact Presentation of the work at the UK Fluids conference in August 2019.
Year(s) Of Engagement Activity 2019
 
Description Workshop in Novosibirsk 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The study was presented at an international workshop 'Conventional and nanofluid droplet heating and evaporation', raised a lot of interest.
Year(s) Of Engagement Activity 2020
 
Description Workshop in Tomsk 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact The study was presented at a workshop at Tomsk Polytechnical University during a research visit, there was an interest in the study and suggested ideas for further publication.
Year(s) Of Engagement Activity 2020