Dynamic Mass Flow Research Articles

Analysis of the Forces Driving the Oscillations in 3D Fluidic Oscillators

One of the main advantages of fluidic oscillators is that they do not have moving parts, which brings high reliability whenever being used in real applications. To use these devices in real applications, it is necessary to evaluate their performance, since each application requires a particular injected fluid momentum and frequency. In this paper, the performance of a given fluidic oscillator is evaluated at different Reynolds numbers via a 3D-computational fluid dynamics (CFD) analysis. The net momentum applied to the incoming jet is compared with the dynamic maximum stagnation pressure in the mixing chamber, to the dynamic output mass flow, to the dynamic feedback channels mass flow, to the pressure acting to both feedback channels outlets, and to the mixing chamber inlet jet oscillation angle. A perfect correlation between these parameters is obtained, therefore indicating the oscillation is triggered by the pressure momentum term applied to the jet at the feedback channels outlets. The paper proves that the stagnation pressure fluctuations appearing at the mixing chamber inclined walls are responsible for the pressure momentum term acting at the feedback channels outlets. Until now it was thought that the oscillations were driven by the mass flow flowing along the feedback channels, however in this paper it is proved that the oscillations are pressure driven. The peak to peak stagnation pressure fluctuations increase with increasing Reynolds number, and so does the pressure momentum term acting onto the mixing chamber inlet incoming jet.

Evaluation of hole-specific injection rate based on momentum flux measurement in GDI systems

A novel methodology for the estimation of the mass flow rate delivered by each hole of a multi-hole GDI nozzle is presented and discussed in this paper. The proposed method is based on the measurement of the impact force of each jet and it is able to evaluate the individual hole injection rate and injected mass using the relationship between the spray momentum flux and the mass flow rate. Three different nozzles are tested, one featuring equal hole diameters and two with differentiated hole-to-hole dimensions. Firstly, results are validated in terms of total injection rate, comparing the sum of the individual hole flow rates with the signal from a Zeuch-based flow meter. Secondly, outcomes are compared with the direct measurement of the injected quantity by means of a special device able to collect and weight the fuel delivered from each hole.Results evidence an excellent agreement in terms of mass flow rate dynamic profile as the proposed method is able to detect both opening and closure transients and the static flow rate. The proposed method proved to be able to capture the dynamic mass flow rate in transient conditions, i.e. very short injections, overcoming a limitation of the methodology proposed in a previous study. Moreover, in terms of injected mass, the results show a percentage error lower than 5% for medium and long energizing times and a maximum error of 9.5% for short injections in ballistic operating conditions.

True eddy accumulation trace gas flux measurements: proof of concept

Abstract. Micrometeorological methods to quantify fluxes of atmospheric constituents are key to understanding and managing the impact of land surface sources and sinks on air quality and atmospheric composition. Important greenhouse gases are water vapor, carbon dioxide, methane, and nitrous oxide. Further important atmospheric constituents are aerosols, which impact air quality and cloud formation, and volatile organic compounds. Many atmospheric constituents therefore critically affect the health of ecosystems and humans, as well as climate. The micrometeorological eddy covariance (EC) method has evolved as the method of choice for CO2 and water vapor flux measurements using fast-response gas analyzers. While the EC method has also been used to measure other atmospheric constituents including methane, nitrous oxide, and ozone, the often relatively small fluxes of these constituents over ecosystems are much more challenging to measure using eddy covariance than CO2 and water vapor fluxes. For many further atmospheric constituents, eddy covariance is not an option due to the lack of sufficiently accurate and fast-response gas analyzers. Therefore, alternative flux measurement methods are required for the observation of atmospheric constituent fluxes for which no fast-response gas analyzers exist or which require more accurate measurements. True eddy accumulation (TEA) is a direct flux measurement technique capable of using slow-response gas analyzers. Unlike its more frequently used derivative, known as the relaxed eddy accumulation (REA) method, TEA does not require the use of proxies and is therefore superior to the indirect REA method. The true eddy accumulation method is by design ideally suited for measuring a wide range of trace gases and other conserved constituents transported with the air. This is because TEA obtains whole air samples and is, in combination with constituent-specific fast or slow analyzers, a universal method for conserved scalars. Despite the recognized value of the method, true eddy accumulation flux measurements remain very challenging to perform as they require fast and dynamic modulation of the air sampling mass flow rate proportional to the magnitude of the instantaneous vertical wind velocity. Appropriate techniques for dynamic mass flow control have long been unavailable, preventing the unlocking of the TEA method's potential for more than 40 years. Recently, a new dynamic and accurate mass flow controller which can resolve turbulence at a frequency of 10 Hz and higher has been developed by the first author. This study presents the proof of concept that practical true eddy accumulation trace gas flux measurements are possible today using dynamic mass flow control, advanced real-time processing of wind measurements, and fully automatic gas handling. We describe setup and methods of the TEA and EC reference flux measurements. The experiment was conducted over grassland and comprised 7 d of continuous flux measurements at 30 min flux integration intervals. The results show that fluxes obtained by TEA compared favorably to EC reference flux measurements, with coefficients of determination of up to 86 % and a slope of 0.98. We present a quantitative analysis of uncertainties of the mass flow control system, the gas analyzer, and gas handling system and their impact on trace gas flux uncertainty, the impact of different approaches to coordinate rotation, and uncertainties of vertical wind velocity measurements. Challenges of TEA are highlighted and solutions presented. The current results are put into the context of previous works. Finally, based on the current successful proof of concept, we suggest specific improvements towards long-term and reliable true eddy accumulation flux measurements.

Dynamic response of submarine obstacles to two-phase landslide and tsunami impact on reservoirs

Submarine landslides may generate super-tsunamis as they interact with water bodies such as oceans, mountain lakes or reservoirs. These water bodies may contain solid objects (obstacles), which substantially alter the mass flow dynamics and reduce the devastating effects of submarine landslide and tsunami. Submarine landslides, the related tsunamis, and their interactions with obstacles are more complex than subaerial landslides and their obstacle-interactions. In order to mitigate mountain and coastal hazards and maintain the integrity of a hydraulic reservoir, it is important to properly understand submarine landslide and tsunami interactions with obstacles. Existing approaches cannot take into account other important aspects of interfacial momentum transfer in mixture flows such as interfacial drag, buoyancy, mobility of the fluid at the particle surface, and virtual mass force, which play important roles in the more accurate prediction of mixture flow dynamics by dynamic interactions between the landslide mass and the water. In order to include these important physics of two-phase mass flows and especially to include dynamic interactions between the landslide mass and the water, we apply a general two-phase mass flow model (Pudasaini in J Geophysics Res 117:F03010, 2012. https://doi.org/10.1029/2011JF002186 ) and present high-resolution novel simulation results for a two-phase landslide impacting a fluid reservoir. Our simulations demonstrate that the intense flow-obstacle-interaction dramatically reduces the flow momentum resulting in the rapid energy dissipation around the obstacles. With the increase in obstacle height, overtopping decreases, but the deflection and capturing (holding) of solid mass increases. Due to multiple obstacles, the moving mass decreases both in amount and speed showing fingering and meandering multiple streamed lobes. The varying location of the obstacles changes the deflection pattern, holding of mass, and tsunami intensity and mobility. Our simulations and findings enrich our understanding of mixing and separation between phases, generation and propagation of special solid and fluid structures, and transitions during the flow process, that may form a basis for the hazard mitigation in coastal regions.

Xylooligosaccharides production from lignocellulosic biomass using a pilot-scale pretreatment continuous tubular reactor. Modelling and experimental validation

This work proposes a mathematical model for describing the dynamics of xylan depolymerisation of lignocellulosic biomass in a pilot-scale pretreatment continuous tubular reactor. Xylan depolymerisation, modelled as pseudo-homogeneous first order reactions and mass flow dynamics, are described as a set of ordinary differential equations. The model accurately describes the dynamics of xylooligosaccharides and other depolymerisation products at the reactor output. Experimental validations of residence time distribution, mass flow rates and kinetics were carried out at 18 and 37 min of mean residence time for wheat straw, corn stover and sugar cane bagasse. Wheat straw exhibited the highest production of xylooligosaccharides (approximately 70%) without degradation at 37 min of residence time.

Modelling engineered nanomaterials in wet-weather discharges

The impacts of the unintended release of engineered nanomaterials (ENMs) and the resulting exposure to the ecosystems are still poorly understood and intensively debated. In current mass flow models, a global transfer coefficient is used to account for ENMs discharged from sewer systems to surface waters during rain events. However, different types of sewer systems and specific ENM applications likely require a more elaborate approach to quantify ENM loads entering surface waters during rain events.Therefore, we evaluated the impact of distinguishing between different application areas of ENMs (indoor/outdoor) and different types of sewer systems (combined/separate) on the loads of selected ENMs passing through wastewater systems and reaching the surface water. We applied a dynamic mass flow analysis to eight substances (TiO2, ZnO, Ag, SiO2, FeOx, CuO, CeO2 and carbon black) for six different sewer system configurations. To estimate the runoff from streets and facades, we used a hydrological model developed for dissolved substances. For areas with separate sewer systems only and ENMs predominantly used in and released from outdoor applications (e.g. CuO, carbon black), up to ~80% of the annual loads entering the sewer systems never reach a sewage treatment plant. Those ENMs are directly discharged to surface waters via stormwater outlets. For combined sewer systems and ENMs mainly applied indoors (e.g. Ag, ZnO), the percentage of ENM bypassing sewage treatment plants remains below 2%. Although the model is setup for Switzerland and other geographical areas will show for example different rain characteristics, the relative importance of the different release pathways will broadly remain the same and the results should, therefore, be transferrable to other countries.

Modelling and observer design for a methane bioconversion process

Abstract Methane is currently an emerging alternative feedstock for biological processes. In this paper, we study a particular methane bioconversion process based on the bacterium Methylomicrobium buryatense 5GB1, with the aim of improving accessibility of the process to state estimation and control. First, a non-linear unsegregated, unstructured model, consisting of 8 dynamic mass flow balance equations and 8 state variables, is constructed and implemented as a dynamic simulator in MATLAB and Simulink. Second, an observability analysis is performed with the aim of finding suitable sensor configurations for state estimation, and the resulting observable configurations are further evaluated by checking the performance of linear Kalman filters for each configuration. This evalution shows that including a biomass sensor in the measurements for the Kalman filter may have conflicting effects on estimation accuracy.

An extended quasi two-phase mass flow model

Employing a physics-based full dimensional two-phase mass flow model (Pudasaini, 2012), we construct an extended quasi two-phase bulk mixture model for a debris flow as a mixture of non-Newtonian viscous fluid and solid particles down a channel. The newly derived model is a set of highly non-linear, coupled mass and momentum balance equations together with virtual mass force induced extended pressure Poisson equation. The model includes mechanically very important first order, and novel effects of drag, virtual mass force and mobility of the fluid at the interface with solid particles in the mixture flow. These aspects were not included in the previous simple bulk mixture models. We demonstrate that these new mechanical aspects of drag, virtual mass and mobility play dominant role in the mass flow dynamics; as seen in the extended inertial coefficients, mixture viscosities, mixture and phase velocities and pressure. This shows that we must retain these effects to obtain physically more accurate results for wider application potential. There are additional contributions to the mixture viscosity due to mobility and diffusion of mass fluxes. Diffusion process seem to be much more complex for the bulk mixture flow than for the two-phase flow. The new extended model leads to the exclusive emergence of diffusion and anti-diffusion fluxes and the associated diffusion- and anti-diffusion viscosities, and mass flux enhancement. The system could be diffusion only or, simultaneously could also include important anti-diffusion process. Comparison between the diffusion and anti-diffusion viscosities reveals fundamentally different mechanical processes in mixture mass flows. Typically, anti-diffusion process is pronounced for higher solid fraction. Furthermore, the main mechanics governed by the extended mixture viscosity, and dynamical variables (mixture pressure and velocities) are all controlled by the drag, virtual mass and mobility. The drag intensity in bulk mixture flow appears to be much more sensitive and non-linear than in the two-phase flow. The new model that retains several important physics of two-phase mass flow is expected to simulate mixture velocities and pressure much faster than the two-phase flow model, but physically more accurate than the previous simple mixture flow models. The two-phase dynamics can be reconstructed with the velocity and pressure drifts. Model solutions are extensively presented and discussed for extended inertial coefficients, drag intensities, mass flux enhancement, incipient and depositional processes, mixture viscosity, and diffusion and anti-diffusion processes. This shows the realistic application potential of the new extended model.

Import, use, and emissions of PCBs in Switzerland from 1930 to 2100.

Polychlorinated biphenyls (PCBs) are persistent organic compounds that are ubiquitously found in the environment. Their use and manufacture were restricted or banned in many countries in the 1970–1980s, however, they still persist in the antroposphere, the environment and in biota worldwide today. Conventions like the Convention on Long-range Transboundary Air Pollution encourage or bind the member parties to annually submit emission inventories of regulated air pollutants. Unfortunately, several member states have not yet reported PCB emissions. The identification and quantification of stocks and emissions sources is, however, an important precondition to handle and remove the remaining reservoirs of PCBs and, thus, to be able to reduce emissions and subsequently environmental exposure. Here, we estimate past, present, and future emissions of PCBs to air in Switzerland and provide emission factors for all relevant emission categories. Switzerland hereby represents a typical developed industrial country, and most of the assumptions and parameters presented here can be used to calculate PCB emission also for other countries. PCB emissions to air are calculated using a dynamic mass flow and emissions model for Switzerland, which is run for the years 1930–2100. The results point out the importance of the use of PCBs in open applications, which have largely been previously overlooked. Additionally, we show that PCBs will persist in applications during the coming decades with ongoing emissions. Especially the use of PCBs in open applications will cause Swiss emissions to remain above 100 kg PCB per year, even after the year 2030. Our developed model is available in Excel/VBA and can be downloaded with this article.

Flow behavior of powder particles in layering process of selective laser melting: Numerical modeling and experimental verification based on discrete element method

Abstract Powder-layering is an essential process of selective laser melting (SLM), but the underlying mechanisms of powder movement and packing at particle scale is unclear. Based on discrete element method (DEM), this study proposed a numerical model to investigate the flowing behavior of powder layered by a blade, where the contact force and cohesion force between individual particles were considered. DEM simulations gave visual morphologies of the flow profiles and velocity fields for powder-layering at particle scale, as well as the relationships between the quality of powder bed and the layering parameters. The model was validated by experiment results in terms of the macroscopic profiles of powder during layering, showing good prediction accuracy. Then, dynamic repose angle (DRA) and mass flow rate (MFR) were defined to make quantitative evaluation on the powder flow. Preliminary research shows that, the powder fluidity increases with the decreasing of particle friction coefficients, resulting in a denser and more uniform powder bed. The decreasing of particle radius R over the range of R > 21.8 μm can benefit the powder fluidity. However, when the particle radius decreases in the range of R

Instantaneous Mass Flow Rate Measurements Via Transfer Matrix and Modal Analysis for an Internal Combustion Engine Application

The gas flow through engines is governed by intake and exhaust pipe arrangements. The pressure waves generated at the valves interface interact with the geometry through reflection, transmission and propagation and induce a standing wave action inside the pipes. This in turn causes fluctuations of mass flow at the same characteristic frequencies. Therefore measurement of the unsteady behavior of mass flow is necessary in order to obtain an accurate understanding of the influence of wave action on engine performance and consumption. In this paper, an experimental mass flow impulse technique is employed to characterize dynamic pressure and mass flow inside a pipe equipped with two pressure sensors. The technique is based on a modal decomposition of resonant frequencies which is explained along with the calibration procedure to cover a sufficient frequency spectrum. The result is a transfer matrix formulation written in terms of pressure and mass flow that can be used to calculate instantaneous dynamic mass flow using the two pressure signals. This was done on three engine cases using GT-Power simulations, where the GT-Power mass flow results were compared to the ones given by the experimental transfer matrix. Finally the procedure of applying the transfer matrices methodology for more complex elements of engine is presented and explained. This methodology gives the possibility to measure instantaneous air mass flow rate on a real engine just by using two separate pressure taps anywhere on the line. Only two sensors at fixed positions are necessary without any calibration. Another possibility is to include this kind of transfer matrix in an ECU in order to improve the internal combustion engine control especially for the pollutant emissions reduction.

Environmental life cycle risk modeling of nuclear waste recycling systems

A dynamic simulation model, named NUCYCLE, for nuclear fuel cycle systems was developed to analyze the lifecycle environmental impact of complex combinations of various fuel cycle processes and reactor types. The dynamic mass flow analysis capability of the developed model was verified against the OECD/NEA benchmark scenarios. The results of the open fuel cycle in this model are in close agreement with other models. As the complexity of fuel cycle systems increases with multiple recycling, the developed model produces results that are slightly different from other models, but the overall trends observed in the model are similar to those of other models for all the benchmark scenarios. The model was also applied to assess the environmental impact of three nuclear fuel cycle transition scenarios used for the verification study. The life cycle assessment estimates the remaining stockpile of high level waste and the accumulated emission of CO2 ranged 3–4 gCO2/kWh. Full recycling has the lowest CO2 emission because of reduced activities in uranium mining, conversion, and enrichment.

Thermodynamic Properties of the Superconducting Dipole Magnet of the SIS100 Synchrotron

The Heavy Ion Synchrotron SIS100 is the core facility of the international FAIR project at GSI in Darmstadt. The magnet system of the synchrotron will operate with a high cycle frequency up to 1Hz. The magnet coils are made of a hollow NbTi composite cable cooled by forced flow of two phase helium. The dynamic heat losses in the magnets caused by fast ramping provide the major part of the heat load to the cryogenic system of SIS100. Recently the first series dipole magnet was produced and is being intensively tested at the cryogenic magnet test facility at GSI. We present the status of these tests together with the obtained opera- tion characteristics like a cool down and training behaviour, dynamic heat release and mass flow rates.

Advances in Signal Acquisition and Signal Processing of Coriolis Flow Meters

Abstract Smart signal acquisition and signal processing methods are necessary for a robust and highly dynamic mass flow measurement on basis of the Coriolis principle, which allows the direct determination of the mass flow independent of process conditions with a precision of 0.2% of reading. Optical sensors which record the movement of the flow pipe have been designed and arranged with focus on fast signal processing and low complexity for a Cramer-Rao optimal information analysis. Therefore it is possible to recognize and compensate superimposed movements of the flow pipe in all six degrees of freedom as well as aging effects of the sensor elements. This leads to an increased zero point stability and a greater flow measurement range. Several algorithms for online phase estimation like Hilbert transform, correlation, discrete-time Fourier transform and quadrature demodulation in combination with minimum phase filters are investigated to develop a system with minimal time delay.

Obtaining Time-Varying Pulsatile Gas Flow Rates With the Help of Dynamic Pressure Difference and Other Measurements for an Orifice-Plate Meter

Use of a conventional orifice-plate meter is typically restricted to measurements of steady flow rates. For any gas flowing within a duct in a pulsatile manner (i.e., large amplitude mass flow rate fluctuations relative to its steady-in-the-mean value), this paper proposes a new and effective approach for obtaining its time-varying mass flow rate at a specified cross section of an orifice meter. The approach requires time-varying (dynamic) pressure difference measurements across an orifice-plate meter, time-averaged mass flow rate measurements from a separate device (e.g., Coriolis meter), and a dynamic absolute pressure measurement. Steady-in-the-mean turbulent gas flows (Reynolds number ≫2300) with low mean Mach numbers (<0.2) exhibit effectively constant densities over long time-durations and are often made pulsatile by the presence of rotary or oscillatory devices that drive the flow (compressors, pumps, pulsators, etc.). In these pulsatile flows, both flow rate and pressure-difference fluctuation amplitudes at or near the device driver frequency (or its harmonics) are large relative to their steady mean values. The time-varying flow rate values are often affected by transient compressibility effects associated with acoustic waves. If fast Fourier transforms of the absolute pressure and pressure-difference measurements indicate that the predominant frequency is characterized by fp, then the acoustic effects lead to a nonnegligible rate of change of stored mass (associated with density changes) over short time durations (∼ 1/fP) and modest volumes of interest. As a result, for the same steady mean mass flow rate, the time variations (that resolve these density changes over short durations) of mass flow rates associated with pulsatile (and turbulent) gas flows are often different at different cross sections of the orifice meter (or duct). Together with the experimental measurements concurrently obtained from the three recommended devices, a suitable computational approach (as proposed and presented here) is a requirement for effectively converting the experimental information on time-varying pressure and pressure-difference values into the desired dynamic mass flow rate values. The mean mass flow rate measurement assists in eliminating variations in its predictions that arise from the use of turbulent flow simulation capabilities. Two independent verification approaches establish that the proposed measurement approach works well.

Design Optimization of Multi Vacuum Manifold for Semiconductor Industry

This paper presents the design optimization of multi vacuum manifold in gripping system for semiconductor industry. The objectives of this study were to investigate the parameter of designing manifold in vacuum system and analyze the results base on simulation software. The study was focused on the air flow in manifold system. The pressure drop, type of flow involved, and improper design were the factors that influenced the flow efficiency in manifold system. The study of multi vacuum manifold was carried out the design parameters involved such as various sizes of inlet, number of inlet used and the distance between the inlets used. The simulation was performed using CAD software to present the dynamic pressure and mass flow rates. Based on the simulation result, the design with the total cross section area inlets is less or equal to out resulted better value of velocity and suction pressure distributed in each inlet. In addition, the longer distance travels by fluid from inlet to outlet affects the result obtained. In conclusion, the new design of multi vacuum manifold for semiconductor industry was proposed.

Molecular dynamics approach to sodium–water reaction compensating macroscopic heat and mass flow dynamics for LMFBR safety

AbstractThe potential (reaction) energy and reaction rate of an accidental sodium−water reaction are investigated for fast breeder nuclear reactor safety. The potential energy is calculated using the molecular orbital method with accurate Gaussian Quadratures in the density functional scheme. The gaseous reaction rate analysis focuses on collision theory rather than transition state theory; the latter of which is more for solvents/solutions. The rate constant was derived using classical molecular dynamics (MDs) in two dimensions (2D) with the rigid sphere model. The MD calculation reveals analytic sequences suppressing error accumulations and time consumptions. The 2D result is converted to the 3D value via a corresponding cross section ratio with a form factor, reproducing the experimental value. The availability of microscopic results to macroscopic flow dynamics is appended; renormalizing the kinematic viscosity coefficient with scale‐independent constants. An effective (pseudo‐) MD for the heat transfer is also appended. © 2012 Wiley Periodicals, Inc.

Design and analysis of compact work-recovery phase shifter for pulse tube refrigerator

This paper proposes and describes a compact work-recovery phase shifter of a pulse tube refrigerator. Most pulse tube refrigerators recently developed utilize a long inertance tube and a reservoir for phase control between dynamic pressure and mass flow rate at the cold-end of pulse tube refrigerators. An inertance tube-type phase shifter (long inertance tube and reservoir), however, sometimes creates a problem of compact packaging in cryocooler applications and dissipates the work transferred from a compressor as heat. To overcome this disadvantage, an inertance tube-type phase shifter is replaced with a compact work-recovery phase shifter composed of a mass–spring–damper system and a linear generator in a pulse tube refrigerator. This process is achieved by using analogy of the inertance tube-type phase shifter and the mass–spring–damper system. This paper describes a specific configuration of the designed compact work-recovery phase shifter. Using the simulation code, the performance of the pulse tube refrigerator with the compact work-recovery phase shifter is estimated. As a result, the pulse tube refrigerator with the compact work-recovery phase shifter has the comparable cooling capacity with the pulse tube refrigerator with the inertance tube-type phase shifter. If the recovery work is properly utilized, it can also achieve higher efficiency than that of the pulse tube refrigerator with a typical inertance tube-type phase shifter. In this paper, the parametric study of the mass, the spring and damper coefficients of the compact work-recovery phase shifter has been done and their effects are specifically evaluated.

Application of ECT to solid concentration measurements during granular flow in a rectangular model silo

The paper presents results of concentration changes in cohesionless sand during dynamic mass flow in a rectangular model silo composed of a bin and hopper. Electrical capacitance tomography (ECT) was used. Sensors were located outside the silo along both the periphery and height. Local horizontal one-dimensional and cross-sectional two-dimensional evolutions of solid concentrations in dry sand during silo discharge were determined. The first ones were estimated from the raw data and the latter were obtained with the aid of the reconstructed data using a Linear Back Projection algorithm (LBP) to solve an inverse problem. Experiments in a model silo were carried out with two different initial sand densities and wall roughness grades. The measured results with ECT were compared with corresponding ones obtained with a Particle Image Velocimetry (PIV) method.

A CFD model of the laser, coaxial powder stream and substrate interaction in laser cladding

In laser cladding, the interaction of the substrate material, the laser beam and the powder stream play important roles in determining how the material is deposited. Previous models of the coaxial powder stream have concentrated either on mass flow dynamics or stream heating, neglecting the effect of the substrate. In this work, a comprehensive numerical model that considers the important parameters of the powder stream, the laser beam and the substrate material, is developed. It is clear from the work that the full three-way interaction of these elements, as in real processing situations, is necessary to accurately and reliably predict particle heating and effective fusion into the melt pool.