Cyril Crua

Cyril Crua
University of Brighton · School of Computing, Engineering and Mathematics

B.Eng, PhD

About

107
Publications
36,751
Reads
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1,655
Citations
Additional affiliations
March 2014 - June 2016
University of Brighton
Position
  • Professor (Full)
February 2013 - February 2014
University of Brighton
Position
  • Principal Research Fellow
June 2006 - January 2013
University of Brighton
Position
  • Senior Researcher
Education
September 1999 - September 2002
University of Brighton
Field of study
  • Combustion Processes in a Diesel Engine
September 1997 - June 1999
University of Brighton
Field of study
  • Mechanical Engineering

Publications

Publications (107)
Article
Full-text available
Detailed measurements of near-nozzle spray formation are essential to better understand and predict the physical processes involved in diesel fuel atomisation. We used long-range microscopy to investigate the primary atomisation of diesel, biodiesel and kerosene fuels in the near-nozzle region, both at atmospheric and realistic engine conditions. H...
Article
Full-text available
In order to enable investigations of the fuel flow inside unmodified injectors, we have developed a new experimental approach to measure time-resolved vibration spectra of diesel nozzles using a three dimensional laser vibrometer. The technique we propose is based on the triangulation of the vibrometer and fuel pressure transducer signals, and enab...
Article
Effects of droplet evaporation, break-up and air entrainment on diesel fuel spray penetration have been studied theoretically at the initial stage of spray penetration when the influence of air entrainment is small (up to 0.1?0.2 ms after the start of injection). Theoretical plots of spray penetration versus time are compared with experimental resu...
Conference Paper
Full-text available
The morphological composition of a typical modern Diesel spray is known to include complex structures such as ligaments and amorphous droplets, but most laser dropsizing techniques cannot diagnose drops that deviate from the spherical shape. Whilst direct imaging has potential for resolving arbitrary shapes, challenges remain to measure microscopic...
Article
It is well established that emissions and inefficiencies primarily arise from localised fuel rich regions, which do not undergo complete combustion. In order to achieve significant reductions in NOx and soot, modern engines employ multiple injection and flow rate profiling strategies. However, during the end of each injection event, the needle rest...
Article
Full-text available
Pre-catalyst engine emissions and detrimental injector deposits have been widely associated with the near-nozzle fluid dynamics during and after the injection events. Although the heating and evaporation of fuel films on the nozzle surface directly affects some of these processes, there are no experimental data for the transient evolution of nozzle...
Article
Full-text available
Transient injection phases have been identified as a prominent source of inefficiencies and exhaust gas constituents detrimental to both public health and the environment. The rapid reduction of in-nozzle flow rate at the end of diesel injection events inhibits spray atomisation and releases large slow-moving liquid structures into the cylinder. Th...
Article
Full-text available
Bioartificial Liver (BAL) devices are extracorporeal systems designed to support or recover hepatic function in patients with liver failure. The design of an effective BAL remains an open challenge since it requires a complex co-optimisation of cell colonisation, biomaterial scaffold and BAL fluid dynamics. Building on previous evidence of suitabil...
Article
Full-text available
Liquid penetration analysis in porous media is of great importance in a wide range of applications such as ink jet printing technology, painting and textile design. This article presents an investigation of droplet impingement onto metallic meshes, aiming to provide insights by identifying and quantifying impact characteristics that are difficult t...
Article
Full-text available
While intraocular lenses (IOL) are used to restore visual acuity in cataract patients, they are limited in their development as no clinically available lens can effectively mimic the accommodative function of the eye's natural lens. The optoelectronic properties of 2D transition metal carbides and/or nitrides (MXenes), including high electronic con...
Article
Full-text available
Post-injection fuel dribble is known to lead to incomplete atomisation and combustion due to the release of slow-moving , and often surface-bound, liquid fuel after the end of injection. This can have a negative effect on engine emissions, performance and injector durability. To better quantify this phenomenon, we developed an image-processing appr...
Article
The physics of high-speed liquid jets injected in elevated temperature and pressure conditions are extremely complex due to the multi-scale and multi-phase flow characteristics. Large eddy simulations (LES) are widely applied for simulations of multi-phase flows because large scale mixing of ambient gas with the liquid vapour (when evaporation is o...
Conference Paper
Full-text available
With the ever increasing operating pressures of modern fuel injectors, the spray formation processes are increasingly influenced by the inception and development of cavitation inside the injector orifices and nozzle. The turbulent effects that contribute to the jet formation and subsequent break-up processes are enhanced by the growth and destructi...
Article
Full-text available
A new simple model for the puffing/micro-explosion of water-fuel emulsion droplets is suggested. The model is based on the assumption that a spherical water sub-droplet is located in the centre of a larger fuel droplet. The fuel is approximated by n-dodecane. The fuel droplet surface temperature is assumed to be fixed, and fuel evaporation is ignor...
Article
Full-text available
The interaction between drops and porous matter has important applications in many fields such as painting, paper coating, design of textiles, filtration and therapeutic delivery, the latter can include also reconstructive surgery processes. Since the phenomenon of droplet impact onto a porous surface is particularly complex, a first step consists...
Conference Paper
Full-text available
Water-in-diesel emulsions are known to lead to micro-explosions when exposed to high temperatures, thereby offering a technology that could improve the mixing of fuels with the ambient gas. Several factors such as the surfactant type, dispersed water droplet size, water content and coalescence rate play a key role in the onset of micro-explosion oc...
Conference Paper
Full-text available
Water-in-diesel emulsions are known to lead to micro-explosions when exposed to high temperatures, thereby offering a technology that could improve the mixing of fuels with the ambient gas. Several factors such as the surfactant type, dispersed water droplet size, water content and coalescence rate play a key role in the onset of micro-explosion oc...
Article
Primary rainbow (Debye series, p=2) of a common liquid droplet, i.e., water drop, has a smooth Airy rainbow structure, and the superimposed high frequency ripple structures are mostly generated by interference of refraction (p=2) and reflection (p=0). In this work, the primary rainbow (p=2) of a particle with high refractive index (1.547<n<2) is fo...
Article
Full-text available
Crank angle-resolved temperatures have been measured using laser induced grating spectroscopy (LIGS) in a motored reciprocating compression machine to simulate diesel engine operating conditions. A portable LIGS system based on a pulsed Nd:YAG laser, fundamental emission at 1064 nm and the fourth harmonic at 266 nm, was used with a c.w. diode-pumpe...
Article
Droplet evaporation characterization, although of great significance, is still challenging. The recently developed phase rainbow refractometry (PRR) is proposed as an approach to measuring the droplet temperature, size as well as evaporation rate simultaneously, and is applied to a single flowing n-heptane droplet produced by a droplet-on-demand ge...
Article
Full-text available
Water-in-diesel emulsions potentially favor the occurrence of micro-explosions when exposed to elevated temperatures, thereby improving the mixing of fuels with the ambient gas. The distributions and sizes of both spray and dispersed water droplets have a significant effect on puffing and micro-explosion behavior. Although the injection pressure is...
Conference Paper
Full-text available
The physics of high speed liquid jets injected in elevated temperature and pressure conditions are extremely complex due to the multi-scale and multi-phase flow characteristics. Large eddy simulations (LES) are widely applied for simulations of multi-phase flows because large scale mixing of ambient air with the liquid vapour (when evaporation is o...
Conference Paper
Full-text available
Phase change phenomena resulting in bubble formation and collapse inside micro channels influence the subsequent jet formation in spray injection processes through their effect on the local flow. Flow turbulence, that contributes to the jet formation and break-up processes can be enhanced by the growth and violent collapse of cavitation bubbles. At...
Article
Full-text available
The number and size distributions of the water dispersed phase have a significant effect on both the long-term stability of an emulsion, and the probability of micro-explosions inside an engine. The emulsions are subjected to intense pressure and shear flow in the fuel injection equipment resulting in changes in the number and size distributions of...
Article
The accurate measurements of droplet temperature, size and evaporation rate are of great importance to characterize the heat and mass transfer during evaporation/condensation processes. The nanoscale size change of a micron-sized droplet exactly describes its transient mass transfer, but is difficult to measure because it is smaller than the resolu...
Article
Water-in-diesel emulsions are known to lead to micro-explosions when exposed to high temperatures, thereby offering a technology that could improve the mixing of fuels with the ambient gas. The number and size distributions of the dispersed phase have a significant effect on both the long-term stability of the emulsion and the probability of micro-...
Article
A new model for heating and evaporation of a multi-component liquid film, based on the analytical solutions to the heat transfer and species diffusion equations inside the film, is suggested. The Dirichlet boundary condition is used at the wall and the Robin boundary condition is used at the film surface for the heat transfer equation. For the spec...
Conference Paper
Full-text available
Emulsion droplet size plays a key role in the micro-explosion occurrence as well as the stability of the emulsion. In a high-pressure common rail system, the water-in-diesel emulsion is subjected to intense pressure, temperature and shear when passing through the common rail and injector nozzle thereby altering the droplet size distributions as wel...
Article
The main ideas of the model for multi-component droplet heating and evaporation, based on the analytical solutions to the heat conduction and species diffusion equations in the liquid phase, and its implementation into ANSYS Fluent CFD software are described. The model is implemented into this software via User-Defined Functions (UDF). The predicti...
Article
Full-text available
Whilst the physics of both classical evaporation and supercritical fluid mixing are reasonably well characterized and understood in isolation, little is known about the transition from one to the other in the context of liquid fuel systems. The lack of experimental data for microscopic droplets at realistic operating conditions impedes the developm...
Conference Paper
Full-text available
Designing future ultra-high efficiency, ultra-low emission engines requires an in depth understanding of the multi- scale, multi-phase phenomena taking place in the combustion chamber. The performance of the fuel delivery system is key in the air fuel mixture formation and hence the combustion characteristics, however in most spray modelling approa...
Conference Paper
The mixing of fuels with oxidizer has been an increasingly interesting area of research with new engine technologiesand the need to reduce emissions, while leveraging efficiency. High-efficiency combustion systems such as diesel engines rely on elevated chamber pressures to maximize power density, producing higher output. In such systems, the fuel...
Conference Paper
Full-text available
The drop impact onto porous surfaces has important applications in many fields, such as painting, paper coating,drug delivery and cosmetic sprays. In most of these applications, the optimisation of the deposition process is carried out empirically, without a proper understanding of the physics and a theoretical modelling of the spreading and the im...
Conference Paper
Full-text available
In a fuel injector at the end of the injection, the needle descent and the rapid pressure drop in the nozzle leads todischarge of large, slow-moving liquid structures. This unwanted discharge is often referred as fuel ‘dribble’ and results in near-nozzle surface wetting, creating fuel-rich regions that are believed to contribute to unburnt hydrocar...
Conference Paper
Full-text available
A model for heating and evaporation of mono- and multi-component droplets, based on analytical solutions to the heat transfer and species diffusion equations in the liquid phase, is summarised. The implementation of the model into ANSYS Fluent via User-Defined Functions (UDF) is described. The model is applied to the analysis of pure acetone, ethan...
Article
Full-text available
Thermometry using laser-induced grating spectroscopy (LIGS) is reported using a high-repetition rate laser system, extending the technique to allow time-resolved measurements of gas dynamics. LIGS signals were generated using the second harmonic output at 532 nm of a commercially available high-repetition rate Nd:YAG laser with nitrogen dioxide as...
Conference Paper
Full-text available
Post-injection dribble is known to lead to incomplete atomisation and combustion due to the release of slow moving, and often surface-bound, liquid fuel after the end of the injection event. This can have a negative effect on engine emissions, performance, and injector durability. To better quantify this phenomenon we present a new image processing...
Article
Most of the currently used models for droplet heating and evaporation are based on the assumption that droplets are perfect spheres. At the same time the shapes of many observed droplets in engineering applications are far from spherical. We have studied the influence of droplet non-sphericity on their heating and evaporation, approximating droplet...
Article
The microexplosion evolution phenomenon of single droplets of water in pure diesel emulsion under Leidenfrost effect has been studied. The tested emulsions were stabilized with a blend of commercial surfactants with three different water contents of 9%, 12%, and 15%. A high speed camera synchronized with backlight technique was used to capture the...
Conference Paper
The microexplosion evolution phenomenon of single droplets of water in pure diesel emulsion under Leidenfrost effect has been studied. The tested emulsions were stabilized with a blend of commercial surfactants with three different water contents of 9%, 12% and 15%. A high speed camera synchronized with backlight technique was used to capture the e...
Article
The main ideas of the model for droplet heating and evaporation, based on the analytical solution to the heat conduction equation inside the droplet, and its implementation into ANSYS Fluent are described. The model is implemented into ANSYS Fluent using User-Defined Functions (UDF). The predictions of ANSYS Fluent with the new model are verified a...
Article
Purpose – The purpose of this paper is to examine the aerodynamical and air mass flow phenomena taking place in the channel of a modified version of one of the well-known Sistan wind mills, in order to improve its aerodynamic performance. Design/methodology/approach – The simulations are done by means of the finite volume method associated to the...
Article
Full-text available
Emulsified fuels considered as a promising alternative fuel that could solve and meet the increasingly stringent emission regulations for diesel engines due to their capability of reduction the harmful exhaust emission, such as carbon monoxide (CO), nitrogen oxides (NOx) and particulate matter (PM). The admission of water into the diesel fuel has s...
Article
The rise in carbon dioxide (CO2) concentration in the Earth’s atmosphere, and the associated strengthening of the greenhouse effect, requires the development of low carbon technologies. New carbon capture processes are being developed to remove CO2 that would otherwise be emitted from industrial processes and fossil fuel power stations. Given the i...
Article
The rise in carbon dioxide (CO2) concentration in the Earth’s atmosphere, and the associated strengthening of the greenhouse effect, requires the development of low carbon technologies. New carbon capture processes are being developed to remove CO2 that would otherwise be emitted from industrial processes and fossil fuel power stations. Given the i...
Conference Paper
This project is a part of E3C3 (Energy Efficiency and Environment Cross-Channel Cluster), which is an INTERREG program between France and England. The goal of E3C3 is to create a training and research group for the development of knowledge, optimization and tools to improve energy production system for a clean combustion based on consumption of liq...
Conference Paper
Considering the negative environmental impact of carbon dioxide (CO2) emissions, several ways of mitigation exist such as capture, storage and valorization. Capture and storage solutions are still expansive, and may lead to further environmental risks. However, chemical valorization offers great potential through the recuperation of CO2 and, throug...
Conference Paper
Full-text available
2015) Droplet size and morphology characterization for diesel sprays under atmospheric operating conditions. Abstract The shape of microscopic fuel droplets may differ from the perfect sphere, affecting their external surface area and thus the heat transfer with the surrounding gas. Hence there is a need for the characterization of droplet shapes,...
Conference Paper
Full-text available
Whilst the physics of both classical evaporation and miscible fluid mixing are reasonably well characterized and understood in isolation, little is known about the transition from one to the other in the context of liquid fuel systems. To address these issues we performed systematic measurements using a high-speed camera fitted with a long-distance...
Article
This article describes thermal risk assessment of vegetable oil epoxidation by peroxycarboxylic acid. It is a liquid–liquid system where several exothermic reactions occur. Acetic acid was used as the carboxylic acid, and oleic acid was chosen as a model molecule because it is a common fatty acid in the triglyceride molecule. Differential scanning...
Conference Paper
Full-text available
This paper presents the application of the Discrete Component Model for heating and evaporation to multi-component biodiesel fuel droplets in direct injection internal combustion engines. This model takes into account the effects of temperature gradient, recirculation and species diffusion inside droplets. A distinctive feature of the model used in...