Air Momentum Research Articles

Parametric study on a wall-mounted attached ventilation system for night cooling with different supply air conditions

Night ventilation is a sustainable approach to achieve comfortable built environment with relatively low energy consumption in summer. However, the cooling performance of conventional night ventilation in the hot summer climate zone is unsatisfactory due to the insignificant climatic potential. Considering that a large proportion of the heat gains is stored in the building envelope, particularly in the external wall, we propose a novel wall-mounted attached night ventilation (WANV) for night cooling. This novel system is capable of generating a downward air jet that directly flows over the internal surface of the west-external wall to achieve enhanced convective cooling performance on the west wall during the nighttime. The present paper numerically investigates the air flow patterns and temperature field distributions in the test chamber with WANV under different supply air conditions (air velocity and temperature). The shear-stress transport k–omega turbulence model, a blending two-equation eddy-viscosity turbulence model which is suitable to capture airflows with strong streamline curvature and separation, is employed in the numerical study. Comparisons between the experimental data and the simulation results are carried out, and the good agreement suggests that the numerical model is able to predict the air velocity and temperature profiles of the chamber with WANV. The simulation results show that intensive air recirculation and enhanced convection are achieved due to the high turbulent air momentum in the scenario with WANV. A similar tendency of the decay of air velocities in the near-wall region is observed regardless of the supply air velocity. Furthermore, a correlation between the air velocity and the height above the floor is proposed. The cooling performance of WANV is significantly improved by decreasing the supply air temperature. Additionally, the impact of supply air conditions on the cooling performance is quantified using the relative heat releasing effectiveness index, which suggests that the optimal supply air velocity is approximately 4 m/s in hot summer at Chongqing or locations with similar climate conditions.

Numerical Simulations of Heat and Mass Transfer Process of a Direct Evaporative Cooler From a Porous Layer

This paper deals with the numerical study of the combined heat and mass exchanges in the process of direct evaporative cooler, from a porous media of laminar air flow between two parallel insulated walls. The numerical model implements momentum, energy, and mass conservation equations of humid air and water flow incorporating non-Darcian model in the porous region. The finite volume method is used for the mathematical model resolution, and the velocity–pressure coupling is treated with the SIMPLE algorithm. The main objective of this study is to examine the influences of ambient conditions and the porous medium properties (porosity and porous layer thickness) on the direct evaporative cooling performance from a porous layer. The major results of this study demonstrate that the porous evaporative wall could, in a satisfying manner, reduce the bulk air temperature. The better cooling performance can be achieved for lower air mass flow at the entrance and relative humidity. Additionally, the evaporative cooler is more effective for a high porosity and a thick porous medium, with an improvement achieving 23% for high porosity.

Numerical study on air ventilation in the workshop room with multiple heat sources

In the present study, the application of computational fluid dynamic (CFD) to analyze air quality and thermal distribution in the workshop room with the multiple heat sources are investigated. In numerical study, a three-dimensional of a single-phase turbulent flow model is employed to analyze temperature distribution and fluid flow in workshop room. The initial and boundary conditions of the models are based on the experimental data. By solving the equations of continuity, momentum, and energy, the velocity and temperature distributions of air within workshop room are presented. It was found that the predicted air temperature and air velocity within the workshop room are consistent with the experimental results. The ventilation system positions and the installed position of equipment inside the workshop have significant effect on suction force which results in the accumulated heat and transport air pollution within the workshop room. The obtained results of the study are expected to lead to guidelines that will allow the designing the ventilation of air-cooling system to transport air pollution and accumulated heat for large workshop room coupled with multiple heat sources.

Industrial gas turbine engine response and combustion performance to fuel changeovers in compositions and heating values

Extension of gaseous fuel flexibility for an industrial gas turbine engine is reported in this paper. A Siemens SGT-400 engine with 13.4 MW rating with hybrid combustion system configuration was string tested to operate on and switch between three different gaseous fuels with temperature corrected Wobbe Index varying between 45 MJ/m3, 38 MJ/m3 and 30 MJ/m3. The alteration of fuel heating value was achieved by injection or withdrawal of N2 into or from the fuel system. The results show that NOx decreases for fuels with lower heating value at the same engine output power and most importantly the engine can maintain stable operation on, and switching between these three different fuels with heating values changeover rate faster than 10% per minute without shutdown or change in load condition. The effect of gaseous fuels with different compositions and heating values on turbine entry temperature, NOx emission and combustion was further investigated in a high pressure combustion testing rig and it is found that the peak temperature and temperature gradient of turbine entry temperature are reduced by application of lower heating value of fuels. It is also noted that for the fuels having the same heating value different diluent, either CO2 or N2, has insignificant effect on hot gas temperature profile, however, different diluent does have impact on NOx emission and NOx emissions is lower by up to 5 ppm if CO2 is selected as diluent compared to N2 as diluent. The physical and chemical mechanisms for NOx reduction for gas turbine engines operating on lower heating value fuels have been identified: improving fuel and air mixing by stronger fuel to air momentum ratio and enhanced turbulence level, slowing chemical reaction by decreasing laminar flame speed and reduction of thermal NOx due to decrease in adiabatic flame temperature and flame shifted to downstream.

Comparative analysis of experimental investigations and numericalsimulation of single-row finned tube bundle at mixed convection

Mixed convective heat transfer is very important for a wide class of engineering tasks. However, the experimental study of mixed convection requires significant implementation costs, high-power equipment, as well as large time costs, so it is proposed to expand the scope of experimental studies using numerical simulation. Numerical simulation of the single-row bundle consisting of bimetallic finned tubes at mixed air convection conditions was performed and experimental data were compared. The formulation of the third-dimensional problem for numerical simulation was realized. The conjugated problem for heat exchange modeling from the tube fins to air was solved. In numerical simulation of air momentum it was taken into account that the Reynolds number based on tube diameter and velocity in the space between fins was varied from 100 to 720. Menter’s k–ω shear stress transport model in standard formulation was used to close the Reynolds equations. Flow visualization on the tube surface revealed the transient nature of the air flow. The temperature distribution visualization in the bundle and the exhaust mine made it possible to see the nature of cooling the finned bundle at mixed convection. Results of numerical simulation and experimental investigations are in good agreement and can be used for expansion of the scope of experiments. The experimental data and the numerical simulation results for the single-row bundle consisting of bimetallic finned tubes at mixed air convection are compared in this paper. Flow near tube surfaces was visualized, and the temperature and velocity distributions in a bundle and in the exhaust mine were obtained.

Effect of Orifice Geometry on Column Trajectories of Liquid Jets in Crossflows

Effects of orifice geometry on liquid column trajectories of liquid jets in subsonic crossflows were experimentally studied. One circular and four elliptical plain-orifice injectors with different aspect ratios of 1/3 to 3, were designed and utilized. By changing the injection pressure drop from 1 bar to 6 bar with an increment of 1 bar, and thus the liquid–air momentum flux ratio from 15 to 106, back-lit spray photographs of liquid jets in crossflows were taken and then analyzed using an in-house code to detect the upper boundary and centerline of the liquid jet before the breakup point. Analytical liquid column trajectories for circular and elliptical liquid jets were derived through simple assumptions and compared with present experimental data. It was found that the aspect ratio affected the difference between the analytical drag coefficient and the experimental one. Novel empirical equations for liquid column trajectories of circular and elliptical liquid jets in crossflows were suggested as a function of equivalent orifice diameter, liquid–air momentum flux ratio and aspect ratio. The results showed that the present empirical equation for the circular orifice injector could be reasonably applied to the elliptical orifice injectors when the aspect ratio was below one.

Advanced CFD modelling of air and recycled flue gas staging in a waste wood-fired grate boiler for higher combustion efficiency and greater environmental benefits

Grate-fired boilers are commonly used to burn biomass/wastes for heat and power production. In spite of the recent breakthrough in integration of advanced secondary air systems in grate boilers, grate-firing technology needs to be advanced for higher efficiency and lower emissions. In this paper, innovative staging of combustion air and recycled flue gas in a 13 MWth waste wood-fired grate boiler is comprehensively studied based on a numerical model that has been previously validated. In particular, the effects of the jet momentum, position and orientation of the combustion air and recycled flue gas streams on in-furnace mixing, combustion and pollutant emissions from the boiler are examined. It is found that the optimized air and recycled flue gas jets remarkably enhance mixing and heat transfer, result in a more uniform temperature and velocity distribution, extend the residence time of the combustibles in the hot zone and improve burnout in the boiler. Optimizing the air and recycled flue gas jet configuration can reduce carbon monoxide emission from the boiler by up to 86%, from the current 41.0 ppm to 5.7 ppm. The findings of this study can serve as useful guidelines for novel design and optimization of the combustion air supply and flue gas recycling for grate boilers of this type.

The study of the effects of sea-spray drops on the marine atmospheric boundary layer by direct numerical simulation

The detailed knowledge of turbulent exchange processes occurring in the atmospheric marine boundary layer are of primary importance for their correct parameterization in large-scale prognostic models. These processes are complicated, especially at sufficiently strong wind forcing conditions, by the presence of sea-spray drops which are torn off the crests of sufficiently steep surface waves by the wind gusts. Natural observations indicate that mass fraction of sea-spray drops increases with wind speed and their impact on the dynamics of the air in the vicinity of the sea surface can become quite significant. Field experiments, however, are limited by insufficient accuracy of the acquired data and are in general costly and difficult. Laboratory modeling presents another route to investigate the spray-mediated exchange processes in much more detail as compared to the natural experiments. However, laboratory measurements, contact as well as Particle Image Velocimetry (PIV) methods, also suffer from inability to resolve the dynamics of the near-surface air-flow, especially in the surface wave troughs. In this report, we present a first attempt to use Direct Numerical Simulation (DNS) as tool for investigation of the drops-mediated momentum, heat and moisture transfer in a turbulent, droplet-laden air flow over a wavy water surface. DNS is capable of resolving the details of the transfer processes and do not involve any closure assumptions typical of Large-Eddy and Reynolds Averaged Navier-Stokes (LES and RANS) simulations. Thus DNS provides a basis for improving parameterizations in LES and RANS closure models and further development of large-scale prognostic models. In particular, we discuss numerical results showing the details of the modification of the air flow velocity, temperature and relative humidity fields by multidisperse, evaporating drops. We use Eulerian-Lagrangian approach where the equations for the air-flow fields are solved in a Eulerian frame whereas the drops dymanics equations are solved in a Largangain frame. The effects of air flow and drops on the water surface wave are neglected. A point-force approximation is employed to model the feed-back contributions by the drops to the air momentum, heat and moisture transfer.

Semi-empirical estimation and experimental method for determining inertial properties of the Unmanned Aerial System – UAS-S4 of Hydra Technologies

ABSTRACTThis article presents a structural analysis of the Unmanned Aerial System UAS-S4 ETHECATL. Mass, centre of gravity position and principal mass moment of inertia are numerically determined and further experimentally verified using the ‘pendulum method’. The numerical estimations are computed through Raymer and DATCOM statistical-empirical methods coupled with mechanical calculations. The mass of the UAS-S4 parts are estimated according to their sizes and the UAS-S4 class, by the means of Raymer statistical equations. The UAS-S4 is also decomposed in several simple geometrical figures which centres of gravity are individually computed, weighted and then arithmetically averaged to find the whole UAS-S4 centre of gravity. In the same way, DATCOM equations allows us to estimate the mass moments of inertia of each UAS-S4 parts that are finally sum up according to the Huygens-Steiner theorem for computing the principal moment of inertia of the whole UAS-S4. The mass of de UAS-S4 is experimentally determined with two scales. Its centre of gravity coordinates and its mass moment of inertia are found using the pendulum method. A bifilar torsion-type pendulum methodology is used for the vertical axis(14)and a simple pendulum methodology is used for the longitudinal and transversal axes(12). The test object is installed on a pendulum (simple or bifilar torsion pendulum) which is led to oscillate freely while recording the oscillation's angles and speed, by the means of three sensors (an accelerometer, a gyroscope and a magnetometer) that the calibration is also discussed. Simultaneously, nonlinear dynamic models are developed for the rotational motion of pendulums, including the effects of large-angle oscillations, aerodynamic drag, viscous damping and additional momentum of air. ‘Algorithms of minimization’ are then used to simulate and actualise the dynamic models and finally chose the model that simulated data best fit the experimentally recorded one. Pendulum parameters, such as mass moment of inertia, are lastly extracted from the chosen model. To determine the accuracy of the nonlinear dynamics approach of the pendulum method, the experimental results for an object of uniform density for which the mass moments of inertia are computed numerically from geometrical data are presented along with the experimental results obtained for the UAS-S4 ETHECATL. For the uniform density object, the experimental method gives, with respect to the numerical results, an error of 4.4% for the mass moment of inertia around theZaxis and 9.5% for the moment of inertia around theXandYaxes. In addition, the experimental results for the UAS-S4 inertial values validate the numerical calculation through DATCOM method with a relative error of 6.52% on average.

Effects of oxidant distribution mode and burner configuration on oxy-fuel combustion characteristics in a 600 MWe utility boiler

The application of oxy-fuel combustion in utility boilers has drawn increasing attention in recent years. The previous numerical studies on oxy-fuel utility boilers mainly focused on effects of O2 concentration and flue gas recycle mode. In the present study, the effects of oxidant distribution mode and burner configuration on characteristics of oxy-fuel combustion were numerically investigated. The simulation results showed that a similar aerodynamic field and a higher char burnout compared with those of air-combustion were obtained by closing the separated over fire air (SOFA) nozzles under oxy-fuel condition. After the oxidant staging was employed in oxy-fuel combustion, the NOx emission was decreased to approximately half of that in air, but the momentum of second air (SA) suffered a remarkable reduction. The undesired reduction of second air momentum could result in some serious problems. A burner configuration and a new oxidant distribution mode were proposed to solve the problem of insufficient momentum of SA after the oxidant staging was adopted. The incomplete combustion heat loss could decrease to the same level as that of air combustion after the proposed burner configuration was employed. The present investigation is beneficial for offering guidance in both retrofitting and operation of oxy-fuel utility boiler.

Experimental investigation of an active control casing treatment of centrifugal compressors

This paper presents an experimental investigation of stability enhancement of a centrifugal compressor using an Active Control Casing Treatment (ACCT) system. In order to evaluate the effect of ACCT structure on the stability enhancement of centrifugal compressor, experiments were performed at different rotational speeds and various numbers of injection holes and mass flow of injected air by means of the centrifugal compressor test rig with a maximum rotational speed of 15,000rpm. The experimental results show that the stable working range of centrifugal compressor was extended by 32.73% with injection of 4.5% of design mass flow at an operating speed of 10,586rpm and by utilizing ACCT with 4 holes. It was found that the enhancement ability increases with the decrease in rotating speed and the injection of 4.5% of design mass flow. The pressure ration of the centrifugal compressor with ACCT was increased due to added momentum of injection air. The pressure ratio of the centrifugal compressor with 16 holes ACCT could be increased by about 1.72% at different mass flow of air injection when the rotational speed was 10,586rpm.

A Review on Empirical Correlations for Jet/Spray Trajectory of Liquid Jet in Uniform Cross Flow

The empirical correlations for the prediction of jet/spray penetration of liquid jet in subsonic uniform crossflow are reviewed in this study. Considerable number of empirical correlations had been proposed by many investigators. It has generally known that the jet/spray trajectory of a liquid jet in a cross-flow is a function of the liquid to air momentum flux ratio and the normalized distance in the airstream direction from the injector. However, several researchers incorporated the Weber number, liquid-to-water or air viscosity ratio, pressure ratio or Reynolds number, temperature ratio in the empirical correlations. Two different classification methods of correlations, i.e. classification based on mathematic functional form and classification based on flow regime, are introduced in this study. The one classification of existing correlations based on functional form includes correlations in a power-law, logarithmic, and exponential forms, respectively. The other classification of previous correlations based on flow regime includes one, two and three regime, correlations. Correlations in a power-law functional form can be further divided into three groups such as momentum flux ratio, Weber number and other parameters forms. Correlations in logarithmic functional form can be also grouped as momentum flux ratio and Weber number forms. Most of the evaluation studies reported the significant discrepancies of predicted values by the existing correlations. The possible reasons for discrepancies will be summarized as measurement technique, assumptions made in defining terms in the liquid to air momentum flux ratio, difficulties in defining the boundaries of the liquid jets, turbulence level in the core and boundary layer of incoming jet and gas flows, nozzle/injector geometry and its position in the crossflow. However, it can be found from the several evaluation studies that the power-law functional form with momentum flux ratio and two regimes correlations provided relatively the best fit to experimental data.

The Flow Field in a Virtual Model of a Rotary Kiln as a Function of Inlet Geometry and Momentum Flux Ratio

The rotary kiln is the middle part of a grate-kiln iron ore pelletizing process and consists of a large, cylindrical rotating oven with a burner in one end. The flame is the heart of the process, delivering the necessary heat. The combustion process is largely controlled by the turbulent diffusion mixing between the primary fuel jet and the combustion air, called the secondary air, which is mostly induced through the kiln hood. The relatively high momentum of the secondary air implies that the resulting flow field has a significant impact on the combustion process, justifying a systematic study of the factors influencing the dynamics of the secondary air flow field, by neglecting the primary fuel jet and the combustion. The objective of this work is thus to investigate how the geometry and the momentum flux ratio of the inlets affect the flow field in the kiln. Down-scaled models of the kiln are investigated numerically. It is found that the resulting flow field is highly affected by both the geometry and momentum flux ratio of the inlet flows, including effects from pressure driven secondary flow occurring in the semicircular inlet ducts. The dynamics of the flow is further investigated using proper orthogonal decomposition (POD) resulting in a deeper understanding of the forming, interaction and convection of the vortical structures.

Effects of Heating Location and Size on Natural Convection in Partially Heated Open-Ended Enclosure by Using Lattice Boltzmann Method

Natural convection heat transfer in an square enclosure, consisting of a partially heated west wall with east end open to ambient, is investigated numerically by using an in-house computational fluid dynamics solver based on thermal lattice Boltzmann method. In particular, the influences of Rayleigh number (103–106), heating location (bottom, middle, and top) on west wall, and dimensionless heating length (0.25–0.75) on momentum and heat transfer characteristics of air are presented and discussed. The streamline patterns show bifurcation at the lowest Rayleigh number for bottom and middle heating, whereas at the highest Rayleigh number, all heating positions yield bifurcation and elongation of flow patterns with a secondary vortex near the lower side of open end. The middle and bottom heating locations show a linear increase in Nusselt number with heater size, whereas inverse dependence is seen for top heating. The maximum heat transfer is observed in the case of middle heating. As expected, average Nusselt number increased with increasing Rayleigh number. Finally, the functional dependence of the average Nusselt number on flow governing parameters (Rayleigh number and heating length) for different heating locations is presented as a simple predictive empirical relationship.

Hydrodynamic and Mixing Characteristics of Gas–Solid Flow in a Pulsed Spouted Bed

The flow behavior and particle motion in a pulsed gas–solid spouted bed was investigated using the Eulerian-Lagrangian approach. The computational fluid dynamics-discrete element method (CFD-DEM) was used to evaluate the gas flow field and particle trajectories. The model was four-way coupled to account for fluid–particle, particle–fluid, and particle–particle interactions. A column of 150 × 15 mm cross-section and height 750 mm containing 24500 particles of diameter 2.5 mm was investigated. Gas entered through a 10 × 15 mm slot at the base of the bed. Steady spouting was compared with pulsed spouting at frequencies of 1, 4, and 10 Hz, with superficial velocity amplitude of 0.5 and 1 m/s and a mean superficial spouting velocity of 2 m/s. In addition to comparing the bed pressure drop versus time and its Fourier decomposition, the hydrodynamics in the spout and annulus regions were examined. A new procedure was introduced to assess spouted bed mixing and homogeneity. Flow pulsation was shown to provide stronger upward air momentum, less horizontal gas percolation, better circulation, higher downward particle flux near the sidewalls, better mixing, and greater homogeneity.

Experimental Investigation of Breakup of Annular Liquid Sheet in a Hybrid Atomizer

Disintegration of annular liquid sheets is an important field of study that plays a crucial role in engine combustion. The focus of this study is to analyze different modes of sheets experimentally in an advanced hybrid injector, which uses both pressure swirl and air momentum to impart instability into the sheet. Apart from measurement of certain macroscopic spray physical parameters like breakup length and sheet width, the images for different sheet profiles were processed to obtain fractal dimensions, temporal frequency, and different orthogonal modes using proper orthogonal decomposition. A moderate airflow is seen to create a stable liquid sheet with increased breakup length, whereas higher airflows at low liquid flows create an air-blast type of spray with disintegration very close to the nozzle. The latter shows dominance of multiple smaller temporal frequencies with relatively lower power spectral densities. A spray with high liquid flow and relatively low airflows shows a longer and wider sheet with a single dominant frequency.

Spray and combustion characteristics of biodiesel: Non-reacting and reacting

The cold spray and spray combustion characteristics of palm biodiesel were investigated and compared with baseline Jet-A1 fuel. Both fuel sprays were generated from an airblast type atomizer and compared under the same atomizing air-to-liquid mass ratio (ALR). Under non-reacting spray condition, droplet velocity profiles for both sprays peak at the centerline due to high atomizing air momentum, while the droplet size is smallest at the spray core. Palm biodiesel generated slightly larger droplet size compared to Jet-A1 due to the effect of higher viscosity and lower volatility. Utilising an airblast atomizer-based swirl burner, spray flames of Jet-A1 and palm biodiesel were established and compared under continuous, steady swirl conditions. The droplet velocity and diameter distributions within the reacting spray flames were significantly different compared to non-reacting spray due to interaction with swirl air flow and flame within the combustor. Spray flame reaction zones obtained via OH* chemiluminescence imaging showed that fuel droplets evaporated rapidly within 20 mm from the burner outlet. Reacting Jet-A1 flame showed smaller droplet size compared to biodiesel due to higher vaporisation rate and close proximity to flame reaction zone. Palm biodiesel showed consistently lower NOx but slightly higher CO emissions per unit energy compared to Jet-A1 under a range of ALR tested.

Optical diagnostics of fuel–air mixing and vortex formation in a cavity combustor

The current work reports optical diagnostic measurements of fuel–air mixing and vortex structure in a single cavity trapped vortex combustor (TVC). Specifically, the mixture fraction using acetone PLIF technique in the non-reacting flow, and PIV measurements in the reacting flow are reported for the first time in trapped vortex combustors. The fuel–air momentum flux ratio, where the air momentum corresponds to that entering the cavity through a specially-incorporated flow guide vane, is used to characterize the mixing. The acetone PLIF experiments show that at high momentum flux ratios, the fuel–air mixing in the cavity is very minimal and is enhanced as the momentum flux ratio reduces, due to a favourable vortex formation in the cavity. Stoichiometric mixture fraction surfaces show that the mixing causes the reaction surfaces to shift from non-premixed to partially-premixed stratified mixtures. PIV measurements conducted in the non-reacting flow in the cavity further reinforce this observation. The scalar dissipation rates of mixture fraction were compared with the contours of RMS of fluctuating velocity and showed very good agreement. The regions of maximum mixing are observed to be along the fuel air interface. Reacting flow PIV measurements which differ substantially from the non-reacting cases primarily because of the heat release from combustion and the resulting gas expansion show that the vortex is displaced from the centre of the cavity towards the guide vane. Overall, the measurements show interesting features of the flow including the presence of the dual cavity structure and lead to a clear understanding of the underlying physics of the cavity flow highlighting the importance of the fuel–air momentum ratio parameter.

An experimental study on a full-scale indoor thermal environment using an Under-Floor Air Distribution system

Abstract Characteristics of thermal environment in a full-scale indoor space utilizing an Under-Floor Air Distribution (UFAD) system are investigated by conducting and analyzing experimental measurements. The indoor air stratification of different locations in the steady state for three supply flow rate options is presented. This research focuses on the influence of supply air flow rate, and its corresponding momentum and buoyancy fluxes, on the vertical temperature profile in the indoor environment. Temperature measurements show that the indoor vertical temperature profile is influenced highly by the distance away from the supply diffuser position. Experimental results also show that the supply air flow rate has a strong effect on the vertical temperature profile. When the supply air flow rate of a given diffuser increases, and then the supply air momentum flux increases as well, the gradient of the vertical temperature profile becomes gentler. The stratification height in the indoor environment ascends with a higher total flow rate. The almost same throw height at the supply diffuser is observed for the identical flow rate option in two sets of experiments with different total flow rates.

Atomization of Liquid Jet in High-Pressure and High-Temperature Subsonic Crossflow

Experimental data on atomization and trajectories of a water jet injected into a subsonic crossflow air under elevated pressure and temperature are provided. Correlations are obtained for the windward and centerline spray trajectories in terms of the principal variables, such as crossflow and liquid jet velocities and gas and liquid physical properties, as well as a function of pertinent nondimensional numbers (i.e., liquid to crossflow air momentum ratio and the channel and liquid jet Reynolds numbers). In addition, the effect of the process parameters on the shape and the streamwise area of the spray plume and spray penetration height is studied. In particular, the effect of liquid jet and crossflow air velocity on the penetration height and spray area is studied in detail. It is noted that, at a given pressure, temperature, and crossflow air velocity, there is an optimum liquid jet velocity that corresponds to a maximum spray area and an optimum atomization process.