Droplet evaporation in a turbulent atmosphere at elevated pressure – Experimental data

2013 ◽  
Vol 34 (1) ◽  
pp. 1577-1584 ◽  
Author(s):  
Madjid Birouk ◽  
Sean C. Fabbro
Keyword(s):  
Experimental Data ◽  
Turbulent Atmosphere ◽  
Elevated Pressure ◽  
Droplet Evaporation

Development of a RANS Premixed Turbulent Combustion Model Based on the Algebraic Flame Surface Density Concept

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Usman Allauddin ◽  
Michael Pfitzner
Keyword(s):  
Experimental Data ◽  
Surface Density ◽  
Turbulent Flame ◽  
Theoretical Models ◽  
Elevated Pressure ◽  
Navier Stokes ◽  
Combustion Model ◽  
Flame Surface ◽  
Flame Surface Density ◽  
Premixed Turbulent Combustion

Recently, a fractal-based algebraic flame surface density (FSD) premixed combustion model has been derived and validated in the context of large eddy simulation (LES). The fractal parameters in the model, namely the cut-off scales and the fractal dimension were derived using theoretical models, experimental and direct numerical simulation (DNS) databases. The model showed good performance in predicting the premixed turbulent flame propagation for low to high Reynold numbers (Re) in ambient as well as elevated pressure conditions. Several LES combustion models have a direct counterpart in the Reynolds-averaged Navier–Stokes (RANS) context. In this work, a RANS version of the aforementioned LES subgrid scale FSD combustion model is developed. The performance of the RANS model is compared with that of the original LES model and validated with the experimental data. It is found that the RANS version of the model shows similarly good agreement with the experimental data.

A Comparative Performance Study of Soot Formation Models in Methane Elevated Pressure Non-Premixed Flames

2011 ◽  
Vol 110-116 ◽  
pp. 18-22 ◽  
Author(s):  
A. Yunardi ◽  
B. Elwina ◽  
Sylvia Novi ◽  
D. Wusnah ◽  
Bindar Yazid
Keyword(s):  
Experimental Data ◽  
Soot Formation ◽  
Elevated Pressure ◽  
Single Step ◽  
Performance Study ◽  
Ethylene Flame ◽  
Step Model ◽  
Radial Profiles ◽  
Dissipation Model ◽  
Soot Model

This paper presents results obtained from the application of a computational fluid dynamics (CFD) code Fluent 6.3 to modeling of elevated pressure methane non-premixed sooting flames. The study focuses on comparing the two soot models available in the code for the prediction of the soot level in the flames. A standard k-ε model and Eddy Dissipation model are utilized for the representation of flow field and combustion of the flame being investigated. For performance comparison study, a single step soot model of Khan and Greeves and two-step soot model proposed by Tesner are tested. The results of calculations are compared with experimental data of methane sooting flame taken from literature. The results of the study show that a combination of the standard k-ε turbulence model and eddy dissipation model is capable of producing reasonable predictions of temperature both in axial and radial profiles; although further downstream of the flame over-predicted temperature is evidence. With regard to soot model performance study, it shows that the two-step model clearly performed far better than the single-step model in predicting the soot level in ethylene flame at both axial and radial profiles. With a modification in the constant α of the soot formation equation, the two-step model was capable of producing prediction of soot level closer to experimental data. In contrast, the single-step soot model produced very poor results, leading to a significant under-prediction of soot levels in both flames. Although the Tesner’s soot model is simpler than the current available models, this model is still capable of providing reasonable agreement with experimental data, allowing its application for the purpose of design and operation of an industrial combustion system.

Numerical and Experimental Study of Spray Produced by an Airblast Atomizer Under Elevated Pressure Conditions

2008 ◽  
Author(s):  
M. Chrigui ◽  
A. Sadiki ◽  
Feras Z. Batarseh ◽  
I. Roisman ◽  
C. Tropea
Keyword(s):  
Experimental Data ◽  
Average Velocity ◽  
Control Design ◽  
Elevated Pressure ◽  
Prediction Ability ◽  
Experimental Database ◽  
Numerical Studies ◽  
Piv Technique ◽  
Transparent Windows ◽  
Evaluation Techniques

This work has two-fold contributions. First, a detailed experimental database that allows an understanding of important aspects of the spray generated by an airblast atomizer, including atomization and spray propagation, at various ambient pressures is provided. Second, as the control, design or optimization tasks are repetitive and costly, the ability of a recently developed numerical spray module (Sadiki et al. 2005) based on a Euler-Lagrangian method to well capture spray properties under elevated pressure is evaluated. Such a module should help to provide early detailed information at moderate costs of processes under study. The experiments have been performed in a pressure chamber equipped with transparent windows allowing optical access to the spray. By means of PIV technique and Phase Doppler instrument the spray properties have been characterized at various ambient pressures (between 1 and 18 bars). Especially three average velocity components and droplet diameters of the spray have been measured. Numerical studies of the spray transport have been achieved by using advanced URANS-based models. An overall agreement between experimental data and numerical simulation points out the accuracy of the evaluation techniques used for the measurement treatment and demonstrated the prediction ability of the mathematical spray model.

Poly-Disperse Droplet Evaporation Model — Comparison With Experimental Results

2013 ◽  
Author(s):  
Michael D. Protheroe ◽  
Ahmed M. Al-Jumaily ◽  
Roy J. Nates
Keyword(s):  
Experimental Data ◽  
Air Temperature ◽  
Model Comparison ◽  
Droplet Evaporation ◽  
Evaporation Model ◽  
Air Stream ◽  
Experimental Apparatus ◽  
Micron Size ◽  
Droplet Sizes ◽  
Disperse Droplet

Experimental data for the evaporation of micron-size, poly-disperse water droplets into air has been generated in order to validate a theoretical poly-disperse droplet evaporation model. The model considers air and droplets flowing along a tube and predicts changes in droplet sizes and temperatures as well as air temperature and humidity as functions of distance along the tube. There are small discrepancies between experimental and model results which can be explained in terms of the lack of mixing between the droplets and air stream and also possible settling of the larger droplets in the experimental apparatus.

An expression for droplet evaporation incorporating thermal effects

2011 ◽  
Vol 667 ◽  
pp. 260-271 ◽  
Author(s):  
K. SEFIANE ◽  
R. BENNACER
Keyword(s):  
Experimental Data ◽  
Thermal Effects ◽  
Droplet Evaporation ◽  
Theoretical Expression ◽  
Dimensionless Number ◽  
Wide Range ◽  
Isothermal Diffusion ◽  
Rate Of Evaporation ◽  
First Time ◽  
Kinetics Of

We propose a general theoretical expression for sessile droplets' evaporation, incorporating thermal effects related to the thermal resistance of the substrate and liquid properties. We develop an expression which accounts for thermal effects associated with evaporative cooling; the latter leads to a reduction in the rate of evaporation, which is not accounted for in the current theories, i.e. ‘isothermal diffusion theories’. The threshold for transition to a regime in which thermal effects start to be significant is identified through a dimensionless number which includes substrate and liquid properties as well as the kinetics of evaporation. The proposed theory is validated against experimental data in a very wide range of conditions and for a variety of systems. The developed expression extends the domain of use of diffusion-based models for droplet evaporation and accurately describes some aspects of the phenomenon which, to the best of our knowledge, are highlighted for the first time.

scholarly journals Numerical Investigation of a High Momentum Jet Flame at Elevated Pressure: A Quantitative Validation with Detailed Experimental Data

2020 ◽  
Vol 4 ◽  
pp. 264-273
Author(s):  
Michael Pries ◽  
Andreas Fiolitakis ◽  
Peter Gerlinger
Keyword(s):  
Experimental Data ◽  
Temperature Distribution ◽  
Combustion Chamber ◽  
Cfd Simulation ◽  
Elevated Pressure ◽  
Type Model ◽  
High Momentum ◽  
Jet Flame ◽  
Combustion Modelling ◽  
Combustion Processes

The development of efficient low emission combustion systems requires methods for an accurate and reliable prediction of combustion processes. Computational Fluid Dynamics (CFD) in combination with combustion modelling is an important tool to achieve this goal. For an accurate computation adequate boundary conditions are crucial. Especially data for the temperature distribution on the walls of the combustion chamber are usually not available. The present work focuses on numerical simulations of a high momentum jet flame in a single nozzle FLOX® type model combustion chamber at elevated pressure. Alongside the balance equations for the fluid the energy equation for the solid combustor walls is solved. To assess the accuracy of this approach, the temperature distribution on the inner combustion chamber wall resulting from this Conjugate Heat Transfer (CHT) simulation is compared to measured wall temperatures. The simulation results within the combustion chamber are compared to detailed experimental data. This includes a comparison of the flow velocities, temperatures as well as species concentrations. To further assess the benefit of including the solid domain in a CFD simulation the results of the CHT simulation are compared to results of a CFD computation where constant temperatures are assumed for all walls of the combustion chamber.

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