Non-spherical droplets in high pressure sprays

This page now redirects to Pure and an alias is included to reroute the former, parallel page under AEC earlier website, 

https://research.brighton.ac.uk/en/projects/investigation-of-non-spherical-droplets-in-high-pressure-fuel-spr

established May 2024

 

 

Understanding the mechanisms that lead to the breakup and evaporation of liquids is a key step towards the design of efficient and clean combustion systems. The complexity of the processes involved in the atomisation of Diesel fuels is such that many facets involved are still not understood. 

The morphological composition of a typical Diesel spray includes structures such as ligaments, amorphous and spherical droplets, but the quantity of fuel occupied by perfectly spherical droplets can represent a small proportion of the total injected volume. These relatively large non-spherical structures have never been thoroughly investigated and documented in high-pressure sprays, even though the increase in heat transfer surface area of deformed droplets is an influential factor for predicting the correct trend of evaporating Diesel sprays.

The characterisation of fuel spray droplets is generally conducted using laser diagnostics that can measure droplet diameters with a high level of accuracy, but they are fundamentally unable to measure the size or shape of non-spherical droplets and ligaments. Hence the data obtained through these diagnostic techniques provide a partial and biased characterisation of the spray.

The experimental bias towards spherical droplets is compounded by the complexity of modelling the heating and evaporation of deformed droplets. Consequently, theoretical models for liquid fuel atomisation and vaporisation are based on a number of simplifying hypotheses including the assumption of dispersed spherical droplets.

Full details of papers and outputs from this project are available in the table below.

Project timeframe

The project ran from November 2013 to July 2017.

High-resolution-microscopic-images

Project aims

Our proposal seeks to initiate a step change in the description of petroleum and bio fuel spray formation by developing diagnostics and numerical models specifically focused on non-spherical droplets and ligaments. Our approach will build upon recent advances with microscopic imaging to build novel diagnostics and algorithms that can measure the shape, size, velocity and gaseous surrounding of individual droplets and ligaments. This morphological classification, along with the velocity measurements, will be used to develop new phenomenological and numerical models for spray breakup, heating and evaporation. The models will then be implemented into computational fluid dynamics (CFD) codes to simulate spray mixing under modern engine conditions, and generate information where optical diagnostics cannot be applied. These goals will be achieved by combining the expertise of the academic and industrial partners with that of international experts from the University of Bergamo, CORIA, and Moscow State University.

Pictured below are high-resolution microscopic images of Diesel sprays injected. Locations are shown on an 18 mm side-lit spray, and correspond to 10 and 18 mm from the nozzle orifice.

Project findings and impact

The project's concerted approach, aimed at removing the experimental and numerical biases towards spherical droplets, will establish a unique world leading research capability with potential impact for numerous practical spray applications. The project would underpin research in areas that rely upon the atomisation or evaporation of liquids, including the efficient delivery of liquid fuel, pharmaceutical drugs, cryogens, lubricants and selective catalytic reductants.

 

Selected outputs

Some of our recent papers from Fuel are available here

  1. Crua C, Heikal MR and Gold, MR 2015 Fuel 157 
  2. Al Qubeissi M, Sazhin SS, Turner J, Begg S, Crua C, Heikal MR, 2015, . Fuel 159:373-384, .
  3. Al Qubeissi M, Sazhin SS, Crua C, Turner J, Heikal MR, 2015, . Fuel 154:308-318, .
Fuel-cover

Project participants


Professor Morgan Heikal
Professor Gianpietro Elvio Cossali (Università degli studi di Bergamo, Italy)
Dr Christophe Dumouchel (CORIA - CNRS UMR 6614, France)
Dr Vitaliy Sechenyh
Dr Vladimir Zubkov
Jack Turner
Dr Slava Stetsyuk
Dr Benjamin Duret

 

 

Outputs

  1. Crua C, Manin J, Pickett LM, 2017 On the transcritical mixing of fuels at diesel engine conditions Fuel 208
  2. Crua C, Heikal MR and Gold, MR 2015 Fuel 157 
  3. Al Qubeissi M, Sazhin SS, Turner J, Begg S, Crua C, Heikal MR, 2015, . Fuel 159:373-384, .
  4. Al Qubeissi M, Sazhin SS, Crua C, Turner J, Heikal MR, 2015, . Fuel 154:308-318, .
  5. Turner JE, Stetsyuk V, Crua C, Gold MR, Pearson RJ, 2015, The effect of operating conditions on post-injection fuel discharge in an optical engine. in ICLASS. Tainan, Taiwan, 23-27 August 2015,
  6. Stetsyuk V, Turner JE, Crua C, Gold MR, Pearson RJ, 2015, Droplet size and morphology characterization for diesel sprays under atmospheric operating conditions. in ICLASS. Tainan, Taiwan, 23-27 August 2015,
  7. Manin J, Pickett LM, Crua C, 2015, Microscopic observation of miscible mixing in sprays at elevated temperatures and pressures. in ILASS. Raleigh, NC, USA, 17-20 May 2015,
  8. Crua C, Manin J, Pickett LM, 2015, Transition from droplet evaporation to miscible mixing at diesel engine conditions. in ICLASS. Tainan, Taiwan, 23-27 August 2015,
  9. Stetsyuk V, Crua C, de Sercey G, Pearson R, Gold M, 2014, . in ILASS Europe. Bremen, Germany, 8-10 September 2014,
  10. Duret B, Al Qubeissi M, Sazhin S, Crua C, 2014, . in ILASS Europe. Bremen, Germany, 8-10 September 2014

Project partners

City University London (Professor Manolis Gavaises)

BP Global Fuels Technology

Project funding

Total project value: £1.3 million for three years

EPSRC grant reference: EP/K020528/1