Vapor Jet Research Articles

Fundamental physics effects of background gas species and pressure on vapor plume structure and spatter entrainment in laser melting

First-principles modeling, based on the direct simulation Monte Carlo (DSMC) method, is applied to quantitatively explain the physics of stainless-steel (SS316L) vapor plumes and jets and powder particle entrainment under conditions relevant to laser welding and laser powder bed fusion additive manufacturing. The DSMC is a particle-based gas kinetic simulation approach, with few built-in assumptions, that resolves the Knudsen and diffusion layers in vapor microjets. The simulations are performed for different background gas species (argon, helium, and neon) at background gas pressures from 0.1 to 5 bar and molten pool temperatures from 3250 K to 4000 K. The simulations capture the evolution of the vapor jet structure from unsteady to steady-state vapor flow, the transition from subsonic flow at low surface temperatures to supersonic flow at surface temperatures close to boiling, as well as the effects of the background gas species and pressure. The simulations show that the vapor jet structure, as well as the magnitude and direction of the entrained gas close to the laser spot, greatly affects the process environment, creating particle spatter and denudation around the laser track. High pressure and lighter background gas can decrease the amount of spatter. At high pressure, the evaporation is reduced, which forms a low-velocity subsonic plume. For lighter gas species, the gas-entrainment velocity increases while the jet radius decreases which forces entrained particles to merge with the melt pool. The powder particle simulations reveal that the width of the denudation zone strongly depends on particle diameter and increases at low pressure and lighter background gas. This study emphasizes that the ambient gas species and the pressure in the build chamber should be treated as process parameters that are as important as controlling laser power and scan speed when trying to prevent defects. • Kinetic modeling reveals strong effect of molecular diffusion in AM vapor microjets. • The laser power and surface temperature stronlgy affect the transition from subsonic to supersonic vapor jet. • Ambient gas chamber species and pressure strongly affect the dynamics (gas, powder) near the laser spot. d. • Strong gas flow (helium) does not necessarily create more spatter as these merge with the melt pool and disappear. • The width of the vapor plume is more strongly dependent on the ambient gas pressure than on the laser beam size.

The interplay between vapour, liquid, and solid phases in laser powder bed fusion

The capability of producing complex, high performance metal parts on demand has established laser powder bed fusion (LPBF) as a promising additive manufacturing technology, yet deeper understanding of the laser-material interaction is crucial to exploit the potential of the process. By simultaneous in-situ synchrotron x-ray and schlieren imaging, we probe directly the interconnected fluid dynamics of the vapour jet formed by the laser and the depression it produces in the melt pool. The combined imaging shows the formation of a stable plume over stable surface depressions, which becomes chaotic following transition to a full keyhole. We quantify process instability across several parameter sets by analysing keyhole and plume morphologies, and identify a previously unreported threshold of the energy input required for stable line scans. The effect of the powder layer and its impact on process stability is explored. These high-speed visualisations of the fluid mechanics governing LPBF enable us to identify unfavourable process dynamics associated with unwanted porosity, aiding the design of process windows at higher power and speed, and providing the potential for in-process monitoring of process stability.

Steven V. Abramson: An OLED Unicorn Setting a Shining Example for the Industry

Steven V. Abramson: An OLED Unicorn Setting a Shining Example for the Industry

Direct numerical simulation of film boiling on a horizontal periodic surface in three dimensions using front tracking

This study investigates film boiling on a horizontal periodic surface in three dimensions through direct numerical simulations. To solve the momentum and energy equations in both phases, a finite difference/front tracking method is used that accounts for inertia, viscosity, and interface deformation. The mathematical formulation and numerical method are presented. One of the challenging aspects of the front tracking method is breakup and coalescence of bubbles. Previous works continued the simulations up to the breakup and release of the bubble. We use an innovative topology changing algorithm to overcome this challenge. So, simulations are carried out over sufficiently long times to capture several bubble release cycles and to evaluate the quasi steady-state Nusselt number Nu¯. Effect of the Grashof and Jacob numbers on the interface dynamics, heat transfer, and fluid flow is studied. By increasing the Grashof number, buoyancy suppresses the viscous effect, so the average size of departing bubbles decreases, and the average Nusselt number increases. Wall superheat has direct influence on the Jacob number. At relatively low superheats, the bubbles are released periodically from the vapor film, but as the wall superheat increases, permanent vapor jets are formed and become thicker. However, the bubble size and the average Nusselt number decrease. The effect of unit cell size is investigated. It is observed that Nu¯ does not change much with unit cell size. To examine the effect of initial perturbation, single mode and multimode cases were simulated. The initial perturbation has no significant effect on the Nu¯. The density ratio was studied, and it is observed that the stationary steady state condition is reached at a shorter time.

Impact of Process Variables of Acetone Vapor Jet Drilling on Surface Roughness and Circularity of 3D-Printed ABS Parts: Fabrication and Studies on Thermal, Morphological, and Chemical Characterizations.

Ever since the introduction of 3D printing, industries have seen an exponential growth in production and efficiency. Three-dimensional printing is the process of additive manufacturing (AM) in which the conventional method of material removal is challenged. Layer-on-layer deposition is the basic principle of the AM. Additive manufacturing technologies are used to create 3D-printed objects. An object is built in an additive technique by laying down successive layers of material until the object is complete. Each of these layers can be viewed as a cross-section of the item that has been lightly cut. When compared to traditional production methods, 3D printing allows the creation of complicated shapes with less material. In conventional methods, the materials go through several damages due to the tool–workpiece contact creating friction between them and the dissipated heat that damages the material. Overcoming the conventional method of machining with the help of 3D printing is a new advancement in the industries. The process involves using non-conventional methods for the machining of the parts. This research was oriented towards the chemical vapor jet drilling of the acrylonitrile–butadiene–styrene (ABS) materials. ABS materials are highly machinable and can be recycled for further usage. This paper focused on the usage of acetone as the chemical for drilling. The surface roughness and circularity of the drilled hole was taken into account for this research paper. We set up a manual experiment to run tests and get results. A vapor jet machine was designed with acetone as the core for the vapor. Various analyses were also formulated and conducted during experimentations. Surface roughness analysis provided the insight of roughness after the machining with the help of acetone vapor jet spray. SEM and micro-image parameters were also considered for more clear and advanced reports. In this research paper, DSC and FTIR analysis were performed to understand changes in the internal structure and the material properties of the ABS. Moreover, the research aimed to investigate the effect of various inputs processing parameters such as pressure, flow rate, and stand-off distance on the surface roughness and circularity of ABS workpiece material. The Taguchi L9 orthogonal array design was utilized to conduct tests by chemical vapor jet drilling using acetone and to evaluate the performance of the set-up while reducing the influence of interfering factors in order to provide reliable surface finish and circularity results. The results and conclusion of the research paper aimed to determine the most suitable parameters for the non-conventional acetone vapor jet drilling of the ABS material. The theoretical calculations predicted 1.64432 and 0.3289080 values of surface roughness and circularity, respectively. On the other hand, the experimental values were recorded as 1.598 for surface roughness and 0.322 for circularity. Therefore, a negligible error of 0.046 for surface roughness and 0.0031 for circularity, respectively, was noted which validate the statistical equations and the consistency of the combined vapor jet drilling process.

Boiling Transitions During Droplet Contact on Superheated Nano/Micro-Structured Surfaces.

Manipulating surface topography is one of the most promising strategies for increasing the efficiency of numerous industrial processes involving droplet contact with superheated surfaces. In such scenarios, the droplets may immediately boil upon contact, splash and boil, or could levitate on their own vapor in the Leidenfrost state. In this work, we report the outcomes of water droplets coming in gentle contact with designed nano/microtextured surfaces at a wide range of temperatures as observed using high-speed optical and X-ray imaging. We report a paradoxical increase in the Leidenfrost temperature (TLFP) as the texture spacing is reduced below a critical value (∼10 μm) that represents a minima in TLFP. Although droplets on such textured solids appear to boil upon contact, our studies suggest that their behavior is dominated by hydrodynamic instabilities implying that the increase in TLFP may not necessarily lead to enhanced heat transfer. On such surfaces, the droplets display a new regime characterized by splashing accompanied by a vapor jet penetrating through the droplets before they transition to the Leidenfrost state. We provide a comprehensive map of boiling behavior of droplets over a wide range of texture spacings that may have significant implications toward applications such as electronics cooling, spray cooling, nuclear reactor safety, and containment of fire calamities.

Backward jet propulsion of particles by femtosecond pulses in hollow-core photonic crystal fiber

A dielectric microparticle, optically trapped within an air-filled hollow-core photonic crystal fiber (PCF), is accelerated backwards close to the speed of sound when a single guided femtosecond pulse is incident upon it. Acting as a spherical lens, the particle focuses a fraction of the pulse energy onto its inner rear surface, causing the material to ablate. The resulting plasma and vapor jet act like a rocket motor, driving the particle backward at peak accelerations conservatively estimated at more than a million times gravity. Using counter-propagating pulses to suppress particle motion, the effect may permit the inner core walls to be coated locally with different materials, allowing optical devices to be created at otherwise inaccessible points inside long lengths of hollow-core PCF.

Evaluation of spatter particles, metal vapour jets, and depressions considering influence of laser incident angle on melt pool behaviour

The building of practical parts involves the application of metal-based powder bed fusion using a laser beam (PBF-LB/M), owing to its high-precision manufacturing. However, the quality of built parts obtained via the PBF-LB/M process varies with the building conditions, and a thorough understanding of the building mechanism has not been achieved owing to the complex and interrelated process parameters involved. The incident angle of the laser beam, which changes on the platform during the laser beam scan owing to the designed three-dimensional data, is among the principle parameters that affect the building aspects. In this study, the melt pool in the single-track formation during the PBF-LB/M process was visualised using a high-speed camera, and the influence of the laser incident angle on the ejection characteristics of spatter particles formed around the laser-irradiated area was investigated. Consequently, the spatter particles and metal vapour jets behaviour varied with the laser incident angle. There was a reduction in number of spatter particles owing to the origin of the incident direction being from behind the laser irradiation area. Additionally, the laser incident angle affected the melt pool morphology because of the depression in the melting. Furthermore, the burial depth of the pores varied with the laser incident angle, and was related to the depth of the depression during the melt pool formation.

Nanostructured silver substrates produced by cluster-assisted gas jet deposition for surface-enhanced Raman spectroscopy

The gas jet deposition (GJD) technique is a very promising method for synthesis of nanostructured films allowing fabrication of uniform thin layers over large areas with high growth rates. In this work, thin silver films of various morphology with the thickness in the range 10–50 nm are produced by the GJD method using a supersonic jet of silver vapor with helium as a carrier gas. The film morphology transformation with increasing thickness is shown to occur from individual nanostructures to a continuous film. The jet is investigated by time-of-flight mass spectrometry and small silver clusters in the deposited flow are observed which are supposed to play a key role in the nanostrtucture formation. The GJD-produced films demonstrate excellent uniformity over a ∼100 cm2 deposited area and exhibit remarkable plasmonic properties. The surface-enhancement Raman scattering (SERS) activity of the films to R6G is investigated and the enhancement factor of about 105 is obtained with the detection limit of 10−8 M R6G. The influence of morphology on plasmonic properties of the films is discussed.

Influence of discharge gap on material removal and melt pool movement in EDM discharge process

In electrical discharge machining (EDM), gap control is the key to stable processing; the discharge gap plays a significant role in EDM. To determine the influence of the discharge gap on material removal and melt pool movement, which are two fundamental issues in EDM, high-speed photography and molecular dynamics (MD) simulations were used to study the discharge process. Research results demonstrate that the discharge gap has a significant influence on material removal during the discharge process. A smaller gap width produces more and larger removed materials. The influence mechanism of the gap width on material removal is explained as follows. A smaller gap width produces discharge plasma with a smaller diameter and greater heat flux. Discharge with a greater heat flux generates more material removed during the discharge process. In addition, a smaller gap width and greater heat flux produce a stronger interaction of metal vapor jets, generating a stronger shear force acting on the melt pool. The discharge gap also influences the movement of the melt pool and the final topography of the discharge crater through external pressure acting on the melt pool. Smaller gap width produces greater external pressure acting on the melt pool, generating a bowl-shaped melt pool and a discharge crater with a depression in the center and a bulge around the edge. A larger gap width produces less external pressure acting on the melt pool, generating a flat melt pool and a discharge crater with swelling in the center and a depression around the edge.

Modeling of two-phase refrigerant distribution in brazed plate heat exchangers

This paper presents a mechanistic model that predicts two-phase refrigerant distribution in brazed plate heat exchangers. The modeling of two-phase distribution is based on the flow visualization in the inlet header, in which the flow regime is identified to be periodic and one cycle includes two or three flow stages, given a fully developed stratified/stratified-wavy flow is present at the heat exchanger entrance. To predict the vapor refrigerant distribution, this model considers two different flow stages in the inlet header: for the top corner vapor flow, the vapor refrigerant distribution is predicted by the balance between the suction force (radial pressure gradient) and the axial momentum of each phase; for the vapor jet flow, the vapor refrigerant is assumed to be distributed evenly among the channels. The time ratio of the two flow stages is estimated by assuming the irregular large-amplitude rolling waves in the feeding tube, which lead to the vapor jet flow in the header, to have the most dangerous wavelength and their traveling time can be related to the liquid slug frequency. The apparent vapor refrigerant distribution is the time average of the vapor distributions at the two stages. For the liquid refrigerant distribution, it is predicted by imposing an equal total pressure drop for each flow path. The proposed model is validated against the experimental results: quantified two-phase refrigerant distribution, heat exchanger capacities, pressure profiles in the headers, and surface temperature of the sidewalls.

Preliminary investigations on performance of acetone vapour jet drilling operations on 3d printed abs parts

Since the debut of 3D printing, industries have seen an exponential increase in output and efficiency. 3D printing is an Additive Manufacturing (AM) approach that challenges the traditional method of manufacturing and finishing. The underlying idea of AM is layer–on–layer deposition. In traditional procedures, the materials are subjected to a number of damages as a result of the tool-workpiece contact, which causes friction and heat dissipation. The use of 3D printing to overcome the traditional way of machining is a new innovation in the industries. Non-traditional approaches are further adopted for post processing of 3D printed manufactured parts. In the present study, influence of Acetone Vapour jet drilling process on Acrylonitrile butadiene styrene substrates have been investigated in order to identify range of parameters i.e. pressure of jet, flow rate and distance between workpiece and nozzle, which have significant impact on output responses viz. surface roughness and circularity. After successful experimentation it has been found that pressure 3 to 5 bar,flow rate 13 to 19 ml/min and standoff distance 1.5 to 3.5 mm range are the most impactful range of parameters.

The interaction of volatile metal coatings during the laser powder bed fusion of copper

The high optical reflectance of Cu at near-infrared wavelengths narrows the process window to fabricate Cu parts by laser powder bed fusion (LPBF). Coating powders with optically absorptive materials has been investigated to improve processability and enhance part properties. However, given the intense heat localization and thin coating layers relative to the powder, the mechanisms of thin film coating interaction in LPBF remain unclear, despite recent work showing the importance of the near-track environment in deposition behavior. In this study, optically absorptive Zn-coated Cu powders were prepared by physical vapor deposition and characterized. Single LPBF tracks were fabricated to elucidate material incorporation phenomena influenced by the volatile Zn coating. It is shown that Zn-coated powder enhances accretion at fastest effective scan speed tested (100 mm/s), where mean track volumes are increased from 0.72 ± 0.05 mm3 (as-received) to 0.91 ± 0.01 mm3 (Zn-coated). This has been correlated to the stronger vapor jet from the volatile Zn-coating, which denudes the surrounding powder bed. This exhausts the powder bed at slower effective scan speeds, causing instability and balling when compared to the as-received powder. It is shown that Zn is localized at the track surface and is undetectable in the track bulk, indicating Zn vaporization on interaction with the incident beam. Zn present mainly occurs through secondary deposition mechanisms like spatter and condensation, rather than in-process alloying. Coating powder feedstocks for use in LPBF therefore affects composition, laser beam absorptivity, and the near-track vapor environment that is known to influence material incorporation behavior.

Application of piezo quartz microweights for express out-of-laboratory determination of actual resins in diesel fuels

The article shows the possibility of using the piezo quartz microweighting method and a portable device model based on highly sensitive piezoweights for express assessment of the concentration of actual resins in diesel fuel. A comparative characteristic of the methods for determining the actual resins in diesel fuel is given: the standard Budarov method is evaporation to a dry residue under a jet of water vapor to a constant mass, the fractional distillation method is heating to the evaporation temperature, cooling the gas fraction and measuring the volume of the non-distillable residue. The device of highly sensitive quartz piezoweights, the main patterns, characteristics during operation are considered. Samples of diesel fuel of the brand L-0,2-62 GOST 305-82 "Diesel fuel" were selected as objects of research. Technical specifications" of different manufacturers and filling dates provided in the fleet of the FVA RVSN im. Peter the Great (Serpukhov city). The results of a study of diesel fuel according to standard methods for determining the content of actual resins, cetane number, density, kinematic viscosity, acidity, water–soluble acids and alkalis, mechanical impurities and water content, fractional composition - distillation temperatures of 50 and 96% of fuel, flash point in a closed crucible, turbidity temperature and solidification temperature, test on a copper plate are presented. The characteristic of the operational properties of each sample is given. The method of piezo-quartz microweighting with a one-way load of the investigated diesel fuel breakdown of the resonator electrode, mass-sensitive (OAV-type), is applied. The correlation between the results obtained by piezo-quartz microweighting and the standard method was studied. The possibility of using the piezo-quartz microweighting method for the development of express out-of-laboratory determination of non-volatile residue in diesel fuel is positively evaluated.

An analytical model for prediction of denudation zone width in laser powder bed fusion additive manufacturing

Accurately modeling the physics of laser-powder interaction is needed for predicting the probabilities of performance-limiting defects in parts additively manufactured using laser powder bed fusion. In this paper, we present an analytical model for rapid prediction of denudation width in laser powder bed fusion additive manufacturing process. The model is based on the force balance analysis for a powder particle sitting on top of the powder bed. The model relates the laser power and laser scan speed to the vapor jet speed and consequently to the inward entrainment gas velocity. The effects of laser power and laser speed on denudation width are investigated and compared with experimental data. In addition, a criterion for the onset of denudation is presented which accounts for chamber gas, powder particle size and density. The results show that for a given laser power the denudation width increases as the laser speed decreases.

Parametric Effects of Heater Size, Contact Angle, and Surrounding Vessel Size on Pool Boiling Critical Heat Flux From Horizontal Surfaces

Abstract Saturated water at one-atmosphere pressure was boiled on horizontal flat copper disks of diameters 1.0, 1.5, and 2.0 cm, respectively. The contact angle was varied from about 10 to 80 deg by controlling thermal oxidation of the disks, while the surrounding vessel size was changed by placing glass tubes of different inner diameters around the disks. Nucleate boiling heat transfer data were obtained up to critical heat flux (CHF), where vapor removal pattern was photographed. Vapor jet diameter and the dominant wavelength at water–steam interface were measured from the photographs for the well wetted disks. For well wetted surfaces, the magnitude of CHF increased when the heater size was reduced from 2.0 to 1.0 cm. Improving the wettability enhanced the CHF substantially, whereas the increased size of the liquid-holding vessel had a smaller effect. The highest measured CHF is 233 W/cm2 or 2.11 times Zuber's CHF prediction for infinite horizontal flat plates. It was obtained on a 1.0-cm-diameter disk of contact angle about 10 deg surrounded by a large vessel. The CHF for this surface was increased from 203 to 233 W/cm2 when the ratio of heater size to surrounding vessel size was decreased from 1 to about 0.

Analysis the dynamics formation of a vapor supersonic jet under outflow from thin nozzle

The dynamics formation of a vapor jet with near-critical state parameters outflowing from a high-pressure vessel through a thin nozzle is studied. The numerical modeling of this process, by using a system of model equations for gas-vapor-liquid mixture, which include conservation laws of mass, momentum, and energy of phases in accordance with one-pressure, one-velocity and two-temperature approximations, was conducted, taking into account heat and mass transfer processes of evaporation and condensation under conditions of equilibrium state with modified reactingTwoPhaseEulerFoam solver of open package OpenFOAM. The process of barrel shock formation in supersonic boiling jet with shaping Mach disk is shown. It was found that the process of boiling fluid outflow is accompanied by formation of vortex zones near axis of symmetry and leads to generation of acoustic wave pulses series preceding the main jet flow, which are the source of pulsations, observed in experiments. The justification of applied numerical method reliability is shown by comparing the computational and analytical solutions for Sedov’s problem of a point explosion in gas-water mixture at the plane case.

Modelling the complex evaporated gas flow and its impact on particle spattering during laser powder bed fusion

The additive manufacturing (AM) of metals is becoming an increasingly important production process with the potential to replace traditional techniques such as casting. Laser Powder Bed Fusion (LPBF) is used in many applications to print metal parts from powder. The metal powder is heated locally with sufficient laser radiation that the liquid melt easily reaches its boiling temperature, which leads to a metallic vapour jet that can entrain both powder bed particles and molten droplets. The small size of laser-matter interaction site makes a detailed experimental analysis of the process challenging. Synchrotron X-ray imaging experiments are one of the few methods which can capture the dynamic melting and solidification processes. Comparing such experiments with computer simulations of the process is an important approach in order to better understand the manufacturing process and to analyse the influence of process parameters on the evaporated gas jet and the subsequent impact on particle ejection, leading to potentially reduced AM component quality. The melting and solidification of the metal powder is simulated using an Eulerian multiphase approach based on a control volume discretization of powder bed and substrate and a volume of liquid separation from melt and gas phase. The gas phase modelled as an ideal gas reaches velocities up to 100 m/s. Lagrangian particle tracking in the simulation demonstrates that the velocity fields calculated by the Eulerian multi-phase approach in combination with a standard drag-force model lead to particle accelerations in good agreement with those measured experimentally. In order to avoid numerical laborious Lagrangian calculations, a direct method to compare an Eulerian multiphase simulation with synchrotron X-ray experiments was introduced and validated . This approach is used to analyse the influence of process parameters including laser power and laser speed on the maximal acceleration of particles from the melt pool area. While the particle acceleration increases linearly with line energy in the conduction mode, a linear decrease of the acceleration with increasing line energy can be found in the transition mode before the acceleration increases again with line energy in the keyhole mode.

Visualization of two-phase refrigerant flow in the inlet header of brazed plate heat exchangers and its effect on distribution

• Two-phase flow visualization is achieved by a clear window on the inlet header. • Flow regime in the inlet header is periodic and one cycle has two or three stages. • Flow regime in the inlet header significantly affects the two-phase distribution. • Effects of mass flux, inlet vapor quality, and the number of plates are examined. This paper presents an experimental study of two-phase R134a flow in the inlet header of brazed plate heat exchangers and its effect on flow distribution among the channels. Visualization of the two-phase flow is accomplished through a 3-D printed transparent window on the inlet header of the heat exchangers. The two-phase flow distribution among channels is quantified based on infrared images of the heat exchanger sidewalls. At the test conditions, the observed flow regimes in the inlet header are periodic and two or three stages are identified in one cycle: top corner vapor flow, vapor jet flow, and (conditional) liquid blockage flow. Among them, the top corner vapor flow affects the distribution most, in which the vapor refrigerant is mainly present at the top corner of the header and branches out through the first several channels, leaving the liquid refrigerant to occupy the rest flow area of the inlet header and present a single-phase like distribution profile. When the inlet vapor quality increases, the distribution of the liquid refrigerant is improved since the vapor refrigerant can reach more downstream channels to help balance the total pressure drop. With the mass flux increases, the maldistribution caused by the header induced pressure drop is more significant, which compromises the benefit brought by the higher vapor momentum. When the number of plates is increased, the liquid refrigerant distribution is worse due to an increased pressure drop in the headers.

Comparing Global Spray Combustion Characteristics and Local Shot-to-Shot Variations in a Reacting n-Heptane Spray

Abstract In support of efforts to develop improved models of turbulent spray behavior and combustion in diesel engines, experimental data and analysis must be obtained for guidance and validation. For Reynolds-averaged Navier–Stokes (RANS)-based Computational fluid dynamics (CFD) modeling approaches, representative ensemble average experimental results are important. For high-fidelity models such as large eddy simulations (LES)-based CFD, precise individual experimental results are desirable. However, making comparisons between a given experiment and LES is a challenge since local parameters cannot be directly compared. In this work, an optically accessible constant pressure flow rig (CPFR) is utilized to acquire diesel-like fuel injection and reaction behavior simultaneously with three optical diagnostic techniques: rainbow Schlieren deflectometry (RSD), OH* chemiluminescence (OH*), and two-color pyrometry (2CP). The CPFR allows a large number of repeated injection experiments to be performed for statistical analysis and convergence using ensemble-averaging techniques, while maintaining highly repeatable test conditions. Even for stable test conditions, variations in local turbulent fuel–air mixing introduce variability, which manifests as significant differences in OH* and 2CP results. Experimental measurements of characteristic parameters including liquid and vapor jet penetration, liftoff length, soot temperature and concentration, and turbulent flame speed, along with the shot-to-shot variability of each dataset, are presented and discussed. A statistical method is utilized to analyze the extent of this variability, and to identify superlative injections within the dataset for discussion and analysis of shot-to-shot variations.