Daniel OrejonThe University of Edinburgh | UoE · Institute for Multiscale Thermofluids, School of Engineering
Daniel Orejon
PhD, FHEA AMIChemE
About
67
Publications
12,378
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1,574
Citations
Citations since 2017
Introduction
Dani is a Senior Lecturer in Chemical Engineering at the Institute for Multiscale Thermofluids IMT at the University of Edinburgh; where he serves as School Postgraduate Progression Committee Representative and as Teaching Laboratory Manager. In addition, Dani has been appointed WPI-I2CNER Visiting Associate Professor since April 2019, he serves as Associate Editor for the International Journal of Heat and Mass Transfer since January 2021 and he is a Fellow of the Higher Education Academy.
Additional affiliations
May 2021 - present
January 2021 - February 2022
April 2019 - present
International Institute for Carbon-Neutral Energy Research, Kyushu University
Position
- Visiting Associate Professor
Publications
Publications (67)
The dynamics of the three-phase contact line for water and ethanol is experimentally investigated using substrates of various hydrophobicities. Different evolutions of the droplet profile (contact line, R, and contact angle, θ) are found to be dependent on the hydrophobicity of the substrate. A simple theoretical approach based on the unbalanced Yo...
Understanding drop evaporation mechanisms is important for many industrial, biological, and other applications. Drops of organic solvents undergoing evaporation have been found to display distinct thermal patterns, which in turn depend on the physical properties of the liquid, the substrate, and ambient conditions. These patterns have been reported...
Superhydrophobicity has received significant attention over the past three decades owing to its significant potential in self-cleaning and anti-icing surfaces, drag reduction, energy harvesting devices, anti-bacterial coatings, and enhanced heat transfer applications. Superhydrophobicity can be obtained via the roughening of an intrinsically hydrop...
Non-wetting surfaces engineered from intrinsically hydrophilic metallic materials are promising for self-cleaning, anti-icing and/or condensation heat transfer applications where the durability of the coating is an issue. In this work, we fabricate and study the wetting behaviour and the condensation performance on two metallic non-wetting surfaces...
Liquid surface tension as well as solid structure play a paramount role on the intimate wetting and non-wetting regimes and interactions between liquids droplets and solid substrates. We hypothesise that the coupling of these two variables, independently addressed in the past, eventually offer a wider range of understanding to the surface science a...
Boiling phase-change plays a crucial role in heat transfer as it can dissipate higher heat fluxes than single phase. Bubble nucleation, growth, motion (oscillation or leaping), coalescence and departure, govern the boiling and the heat transfer performance on wires. Many factors affect the bubble mechanisms and interactions taking place, which incl...
This work investigates the bubble dynamics during pool boiling from isolated cavities on a horizontal silicon substrate with three surface coatings, silicon oxide, Perfluorodecyltrichlorosilane, and silica nanoparticles. The experiments were conducted with FC-72 under various superheat degrees. In the case of vertical coalescence, coalescences at t...
For sessile droplets of pure liquid on a surface, evaporation depends on surface wettability, the surrounding environment, contact angle hysteresis (CAH) and surface roughness. For non-pure liquids the evaporation characteristics are further complicated by the constituents and impurities within the droplet. For saline solutions, this complication t...
This paper presents an experimental investigation regarding the drag and instabilities involved in free-falling cylinders across different boiling regimes. We aim to identify the mechanisms that cause the instabilities as well as to quantify the strength of these forces for temperatures between 25oC and 550oC. Understanding the forces involved acro...
Multiphase flow and boiling phase-change within microchannels are of paramount importance to thermal management and electronics cooling, among others. The present experimental study investigated the bubble dynamics and flow patterns during flow boiling in a high aspect ratio microchannel at different channel microchannel with a width-to-height aspe...
Wetting plays a major role in the close interactions between liquids and solid surfaces, which can be tailored by modifying the chemistry as well as the structures of the surfaces' outermost layer. Several methodologies, such as chemical vapor deposition, physical vapor deposition, electroplating, and chemical reactions, among others, have been ado...
This paper presents experimental investigations of submerged self-propulsion due to the Leidenfrost effect. We aim to identify and quantify the forces governing the free-fall of heated cylinders at temperatures between 25 °C and 550 °C. Understanding the forces involved within three-phase systems is essential when designing sensitive instruments, s...
Superhydrophobicity is usually achieved by a combination of chemical hydrophobicity and surface topography due to an inability to attain complete non-wetting on the smooth surface of existing materials. Here, we experimentally report high non-wetting of condensation-induced droplets with contact angles approaching 180° on a smooth surface of suspen...
Fluid instability was investigated experimentally during flow-boiling of Perfluorohexane (FC-72) in a flat horizontal micro/mini channel with a hydraulic diameter of 909 μ m and an aspect ratio of 10 (5 mm x 0.5 mm). One-sided heating at different azimuth channel orientations (θ) in terms of gravity were considered, which ranged from bottom-heating...
Slippery Lubricant Infused Porous Surfaces (SLIPSs) have received increasing attention in the past decade owing to their low adhesion, minimising the interactions between liquids and such infused surfaces. The nature of the lubricant infused within the structures, mainly viscosity, has been extensively studied with greater droplet mobility velociti...
Superhydrophobicity has only ever been achieved by a combination of chemical hydrophobicity and surface topography due to our inability to attain complete non-wetting on the smooth surface of any known material. Here, we report extreme non-wetting of condensation-induced droplets with contact angles approaching 180° on a smooth surface using suspen...
Phase change slippery liquid-infused porous surfaces (PC-SLIPSs) are presented with emphasis on surface wetting characteristics and droplet dynamics influencing the water vapor condensation and the corresponding heat transfer. The functionalized nano-porous copper plate is infused with paraffin wax-xylene solution via dip coating method to prepare...
Wetting and evaporation of sessile droplets are ubiquitous in nature and of importance to many industrial and everyday processes. While most of the research on sessile droplets has been constraint to single component droplets, complex multicomponent droplets are in fact the most common systems in the natural and industrial fields. Multicomponent dr...
The surface free energy of rare earth oxides (REOs) has been debated during the last decade, with some reporting REOs to be intrinsically hydrophilic, while others reporting hydrophobic. Here, we investigate the wettability and surface chemistry of pristine and smooth REO surfaces, conclusively showing that hydrophobicity stems from wettability tra...
Bioinspired smart functional surfaces have received increasing attention in recent years owed to their tunable wettability and enhanced droplet transport suggesting them as excellent candidates for industrial and nanotechnology-related applications. More specifically, bioinspired slippery lubricant infused porous surfaces (SLIPSs) have been propose...
Spontaneous motion of liquid droplets can occur on hydrophobic, micro-structured, solid surfaces comprising a structural gradient. In this study, we examine such motion experimentally and explain our observations by invoking variable droplet–surface interactions (both actuation and resistance forces) arising from the structural gradient. The oscill...
Evaporation is a ubiquitous and complex phenomenon of importance to many natural and industrial systems. Evaporation occurs when molecules near the free interface overcome intermolecular attractions with the bulk liquid. As molecules escape the liquid phase, heat is removed, causing evaporative cooling. The influence of evaporative cooling on induc...
Research into evaporating droplets on patterned surfaces has grown exponentially, since the capacity to control droplet morphology has proven to have significant technological utility in emerging areas of fundamental research and industrial applications. Here, we incorporate two interest domains — complex wetting patterns of droplets on structured...
Slippery liquid-infused porous surfaces (SLIPSs) prepared with phase invariant materials (e.g., Krytox GPL oil) have been increasingly researched as low adhesion engineered functional surfaces in the last decade. However, phase change materials (PCMs) have been scarcely adopted, although they are potential candidates due to their inherent lubricant...
Liquid droplets move readily under the influence of surface tension gradients on their substrates. Substrates decorated with parallel microgrooves, or striations, presenting the advantage of homogeneous chemical properties yet varying the topological characteristics on either side of a straight-line boundary, are considered in this study. The basic...
In recent years, slippery lubricant infused porous surfaces (SLIPSs) have received important attention due to their excellent performance in applications such as condensation, low friction, self-cleaning and anti-icing, which is owed to the presence of an infused lubricant or oil effectively decreasing the liquid-solid interactions and enhancing dr...
In all kinds of liquid desiccant dehumidification systems, the temperature increase of the desiccant solution due to the effect of absorptive heating is one of the main reasons of performance deterioration. In this study, we look into the thermal effects during vapor absorption into single hygroscopic liquid desiccant droplets. Specifically, the ef...
Liquid droplets move readily under the influence of surface tension gradients on their substrates. Substrates decorated with parallel microgrooves, or striations, presenting the advantage of homogeneous chemical properties yet varying the topological characteristics on either side of a straight-line boundary, are considered in this study. The basic...
We report a systematic study of the role of Marangoni convection in the evaporation kinetics of pure water drops, considering the influence of the heating regime and surface wettability. Marangoni flows were induced via heating under constant wall temperature (uniform heating) and constant heat flux (local heating) regimes below the drops. To visua...
The study of vapor absorption into liquid desiccant droplets is of general relevance to a better understanding and description of vapor absorption phenomena occurring at the macroscale as well as for practical optimization of dehumidification and refrigeration processes. Hence, in the present work, we provide the first systematic experimental study...
The effect of ambient temperature and relative humidity on the dynamics of ethanol drop evaporation is investigated. Although drop evaporation of mixtures and pure fluids has been extensively studied, very...
Superhydrophobic surfaces (SHSs) and slippery lubricant-infused porous surfaces (SLIPSs) are receiving increasing attention for their excellent anti-icing, anti-fogging, self-cleaning and condensation heat transfer properties. The ability of such surfaces to passively shed and repel water is mainly due to the low-adhesion between the liquid and the...
Water collection via heterogeneous condensation and fog harvesting has important implications in everyday life and in several industrial applications. Recently, the unique combination of surface morphology and wettability exhibited by natural and biological species is receiving increasing attention from the scientific community. Surface morphology...
Condensation phase change and more specifically dropwise condensation have received important attention in the past decades. Aiming to decrease the contact angle hysteresis between the solid surface and the condensate and hence to increase the droplet shedding performance, slippery lubricant infused porous surfaces (SLIPSs) are being proposed. On S...
Condensation phase change has received increasing attention in the past decades due to its importance implications in applications such as: electricity generation, air conditioning or water desalination, among others. The size, shape and wettability of the micro- and nano-structures present underneath the condensate have been found paramount for th...
The effect of the filling ratio (25% ≤ FR ≤ 98%) on the heat transfer performance of a novel two-phase closed thermosyphon (TPCT) combined with a superhydrophilic (SHi) evaporator and slippery lubricant-infused porous surface (SLIPS) condenser (TPCT-SHiSL) is systematically investigated in the present study. On the evaporator side, experimental res...
While wicking or spreading of a liquid through microstructures has been found to be promising for applications such as textiles, microelectronics or heat sinks, the effects of such structured surfaces on condensation phase change has received less attention. On a hydrophilic surface and for a fixed micropillar aspect ratio (height/diameter), the sp...
Superhydrophobic surfaces are receiving increasing attention due to the enhanced condensation heat transfer, self-cleaning and anti-icing properties by easing droplet self-removal. Despite the extensive research carried out in this topic, the presence or absence of microstructures on droplet adhesion during condensation has not been addressed yet....
We report on the optimal configuration for enhanced heat transfer performance of a two-phase closed thermosyphon (TPCT), incorporating a superhydrophilic (SHi) evaporator with a slippery lubricant-infused porous surface (SLIPS) condenser (TPCT-SHiSL). For the conditions examined, the overall heat transfer performance of the TPCT-SHiSL was enhanced...
We report contrasting enhancement in the solid state and liquid state thermal conductivity of phase change nanocomposite seeded with various carbon nano inclusions. Phase change nanocomposites were prepared using n-Dodecanoic acid as the host matrix. Single-walled carbon nanohorns, multi-walled carbon nanotubes and few-layer graphene nanosheets wer...
Understanding the fundamental mechanisms governing vapor condensation on non-wetting surfaces is crucial to a wide range of energy and water applications. In this paper, we reconcile classical droplet growth modeling barriers by utilizing two-dimensional axisymmetric numerical simulations to study individual droplet heat transfer on non-wetting sur...
We examine the effects of nanoparticle addition at low concentration on the evaporation kinetics of droplets in the constant radius mode. The evaporative behaviour of deionized water and Al2O3 nanoparticle laden water on an aluminium substrate was observed at atmospheric and at different sub-atmospheric pressures. The two fluids exhibit the same ev...
We demonstrate the migration of small water droplets from the side wall of a micropillar onto its top surface during dropwise condensation without application of an external force. The observed droplet migration occurs due to the difference in wettability between the hydrophobic sides and hydrophilic top surfaces of the micropillars imposed by a no...
We previously found residual water after the complete evaporation of volatile droplets such as organic solvents, which was considered to be condensed from ambient onto the droplet interface. Since evaporation of these liquids into moist environments is ubiquitous, the understanding of the influence of surrounding moisture on evaporation process is...
In this work we investigate the effect of relative humidity and ambient temperature on the self-generated hydrothermal waves at the liquid-vapor interface of evaporating ethanol drops by means of infrared thermography and CCD camera. Absorption and/or condensation of water vapor onto the drop was found to have a strong impact on the thermal pattern...
Thermal conductivity of lauric acid with graphene nano inclusions were measured. Inclusion of 1 vol% of graphene enhances the thermal conductivity by 230%. Model calculations show graphene performs superiorly than other nano materials. Phase change enthalpy and melting temperature remains unaltered at 1 vol% loading. a b s t r a c t In this work, w...
The objective of this study is to clarify the role of ambient gas on hydrothermal waves in evaporating volatile droplets and evaporation. Experiments were conducted in a large chamber where the temperature and relative humidity of water can be controlled. An infrared camera and a CCD camera were used to determine the temperature distribution inside...
In this work, we prepared Laurie acid based phase change nanocomposites with chemically functionalized graphene nanoplatelets and measured its thermal conductivity using transient hot wire method. We show that inclusion of graphene nanoplatelets increase the thermal conductivity of phase change material by 230 % at a loading of 1 vol %. Comparing t...
The accurate prediction and control of the interaction of liquids with hot surfaces is paramount in numerous areas, including cooling applications. We present results illustrating the effect of ambient pressure on the temperature required for a droplet to levitate over a hot surface, i.e., the Leidenfrost temperature. In the present study the depen...
Platinum-free oxygen reduction reaction (ORR) catalysts could help reduce the cost of future generations of polymer electrolyte membrane fuel cells (PEFCs). One class of non-precious catalyst for PEFCs are nanostructured Fe/C/N-based materials. In these, the nature of the active site is still hotly contested. Resolving this issue could lead to the...
Evaporation and wetting of droplets are a phenomena present in everyday life and in
many industrial, biological or medical applications; thus controlling and
understanding the underlying mechanisms governing this phenomena becomes of
paramount importance. More recently, breakthroughs in the fabrication of new
materials and nanomaterials have led to...
A considerable growth of interest in electrowetting (EW) has stemmed from the potential exploitation of this technique in numerous industrial and biological applications, such as microfluidics, lab-on-a-chip, electronic paper, and bioanalytical techniques. The application of EW to droplets of liquids containing nanoparticles (nanofluids) is a new a...
We present the results of an experimental study investigating electrowetting effects in nano-suspension drops. Wetting of sessile drops of titanium oxide (TiO2) nano-particles dispersed in deionised water was studied under a DC voltage potential. The presence of nano-particles is found to further enhance spreading of drops when a DC potential is ap...
We report on the structure of ring deposits formed following the free evaporation of a sessile droplet containing nanoparticles. The nanostructure of the evaporatively formed deposits was revealed using atomic force microscopy (AFM). The structures were found to form a peak about 5 microns wide and one micron high and to exhibit a gentle slope grad...
Questions
Question (1)
The Eric Birse Trust was founded in 1984 by the family of Dr Eric A B Birse to commemorate his life and work. The primary intention of the Trust is to fund, via The Eric Birse Studentship, PhD research in the field of Chemical Engineering. To date the Studentship has supported eight PhD students, each of whom has progressed to have successful careers in industry and academia.
A PhD Scholarship supported by the Eric Birse Trust is available at the School of Engineering at the University of Edinburgh. The Studentship is open to all who wish to work in this discipline subject to meeting the Eligibility criteria and to complying with the Application Procedure. Student must apply with your own Research Proposal and nominate the most suitable academic within the Institute of Materials and Processes (IMP) or the Institute of Multiscale Thermofluids (IMT) to supervise this research.
More specifically at the Institute of Mutliscale Thermofluids we are carrying out research work on both experiments and computations, with an emphasis on multiscale and multiphase fluid systems interfaces and phase change from nano- to macro-scales undergoing heat transfer. Topics include phase change, wetting and associated capillary phenomena, and boiling (e.g. at microfluidic scales). IMP and IMT academics can be found using this filterable list. The closing date for applications is 31 December 2019.
This is an excellent opportunity for mentoring a young researcher in the ambit of phase-change and heat transfer. If interested and not aware of the type of project that can be carried out, feel free to contact Daniel Orejon for more information on d.orejon@ed.ac.uk and 0131 650 5735.
Link to the Eric Birse Trust: https://www.eng.ed.ac.uk/studying/postgraduate/research/phd/eric-birse-trust-chemical-engineering-phd-studentship
Projects
Project (1)
Engineered non-wetting surfaces are promising for self-cleaning, anti-icing and condensation heat transfer applications.
In this project, we investigate the effect of surface structure and wettability throughout nucleation, growth, coalescence and shedding of the condensate on hydrophilic, hydrophobic and superhydrophobic surfaces.
Surfaces were either engineered from easy and scalable fabrication procedures or bioinspired.