Navier-Stokes Investigation on Reacting Flow Field of HTPB/O2 Hybrid Motor and Regression Rate Evaluation

2003 ◽  
Author(s):  
Nadir Serin ◽  
Yalcin Gogus
Keyword(s):  
Flow Field ◽  
Navier Stokes ◽  
Reacting Flow ◽  
Regression Rate ◽  
Rate Evaluation ◽  
Hybrid Motor

Significant of Isothermal Flow Studies for High Swirling Flow in Unconfined Burner

2015 ◽  
Vol 789-790 ◽  
pp. 477-483
Author(s):  
A.R. Norwazan ◽  
M.N. Mohd Jaafar
Keyword(s):  
Flow Field ◽  
Combustion Chamber ◽  
Turbulent Flows ◽  
Recirculation Zone ◽  
Swirling Flow ◽  
Numerical Study ◽  
Tangential Velocity ◽  
Radial Distance ◽  
Navier Stokes ◽  
Reacting Flow

This paper is presents numerical simulation of isothermal swirling turbulent flows in a combustion chamber of an unconfined burner. Isothermal flows of with three different swirl numbers, SN of axial swirler are considered to demonstrate the effect of flow axial velocity and tangential velocity to define the center recirculation zone. The swirler is used in the burner that significantly influences the flow pattern inside the combustion chamber. The inlet velocity, U0 is 30 m/s entering into the burner through the axial swirler that represents a high Reynolds number, Re to evaluate the differences of SN. The significance of center recirculation zone investigation affected by differences Re also has been carried out in order to define a good mixing of air and fuel. A numerical study of non-reacting flow into the burner region is performed using ANSYS Fluent. The Reynolds–Averaged Navier–Stokes (RANS) realizable k-ε turbulence approach method was applied with the eddy dissipation model. An attention is focused in the flow field behind the axial swirler downstream that determined by transverse flow field at different radial distance. The results of axial and tangential velocity were normalized with the U0. The velocity profiles’ behaviour are obviously changes after existing the swirler up to x/D = 0.3 plane. However, their flow patterns are similar for all SN after x/D = 0.3 plane towards the outlet of a burner.

Application of Machine Learning in Turbulent Combustion for Aviation Gas Turbine Combustor Design

2021 ◽  
Author(s):  
Vishwas Verma ◽  
Kiran Manoharan ◽  
Jaydeep Basani
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Flow Field ◽  
Gas Turbine ◽  
Computational Cost ◽  
Data Driven ◽  
Navier Stokes ◽  
Computational Time ◽  
Reacting Flow ◽  
Data Driven Approach

Abstract Numerical simulation of gas turbine combustors requires resolving a broad spectrum of length and time scales for accurate flow field and emission predictions. Reynold’s Averaged Navier Stokes (RANS) approach can generate solutions in few hours; however, it fails to produce accurate predictions for turbulent reacting flow field seen in general combustors. On the other hand, the Large Eddy Simulation (LES) approach can overcome this challenge, but it requires orders of magnitude higher computational cost. This limits designers to use the LES approach in combustor development cycles and prohibits them from using the same in numerical optimization. The current work tries to build an alternate approach using a data-driven method to generate fast and consistent results. In this work, deep learning (DL) dense neural network framework is used to improve the RANS solution accuracy using LES data as truth data. A supervised regression learning multilayer perceptron (MLP) neural network engine is developed. The machine learning (ML) engine developed in the present study can compute data with LES accuracy in 95% lesser computational time than performing LES simulations. The output of the ML engine shows good agreement with the trend of LES, which is entirely different from RANS, and to a reasonable extent, captures magnitudes of actual flow variables. However, it is recommended that the ML engine be trained using broad design space and physical laws along with a purely data-driven approach for better generalization.

Simulation of Two-Dimensional Scramjet Combustor Reacting Flow Field Using Reynolds Averaged Navier-Stokes WENO Solver

2015 ◽  
Vol 18 (4) ◽  
pp. 1181-1210 ◽  
Author(s):  
Juan-Chen Huang ◽  
Yu-Hsuan Lai ◽  
Jeng-Shan Guo ◽  
Jaw-Yen Yang
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Navier Stokes ◽  
Reacting Flow ◽  
Simulation Tool ◽  
Fuel Injector ◽  
Steady State Condition ◽  
Scramjet Combustor ◽  
Combustion Properties ◽  
Reynolds Averaged Navier Stokes

AbstractThe non-equilibrium chemical reacting combustion flows of a proposed long slender scramjet system were numerically studied by solving the turbulent Reynolds averaged Navier-Stokes (RANS) equations. The Spalart-Allmaras one equation turbulence model is used which produces better results for near wall and boundary layer flow field problems. The lower-upper symmetric Gauss-Seidel implicit scheme, which enables results converge efficiently under steady state condition, is combined with the weighted essentially non-oscillatory (WENO) scheme to yield an accurate simulation tool for scramjet combustion flow field analysis. Using the WENO schemes high-order accuracy and its non-oscillatory solution at flow discontinuities, better resolution of the hypersonic flow problems involving complex shock-shock/shock-boundary layer interactions inside the flow path, can be achieved. Two types of scramjet combustor with cavity-based and strut-based fuel injector were considered as the testing models. The flow characteristics with and without combustion reactions of the two types combustor model were studied with a transient hydrogen/oxygen combustion model. The detailed results of aerodynamic data are obtained and discussed, moreover, the combustion properties of varying the equivalent ratio of hydrogen, including the concentration of reacting species, hydrogen and oxygen, and the reacting products, water, are demonstrated to study the combustion process and performance of the combustor. The comparisons of flow field structures, pressure on wall and velocity profiles between the experimental data and the solutions of the present algorithms, showed qualitatively as well as the quantitatively in good agreement, and validated the adequacy of the present simulation tool for hypersonic scramjet reacting flow analysis.

Burning rate augmentation in solid fuel ramjets by swirling inlet air stream

2021 ◽  
pp. 095441002110014
Author(s):  
Amir Mahdi Tahsini
Keyword(s):  
Flow Field ◽  
Burning Rate ◽  
Solid Fuel ◽  
Swirling Flow ◽  
Reacting Flow ◽  
Linear Distribution ◽  
Regression Rate ◽  
Inlet Stream ◽  
Air Stream ◽  
Transfer Method

The influence of the inlet swirling flow on the regression rate of the fuel in the combustion chamber of the solid fuel ramjet is investigated in this study using numerical simulations. The finite-volume solver of the compressible turbulent reacting flow is developed to study the flow field where the burning rate is computed using the conjugate heat transfer method for the solid fuel. The correlation is found for the maximum regression rate versus an imposed inlet swirl when the linear distribution of the circumferential velocity is applied at the inlet stream. Although the regression rate augmentation is considerable due to the swirling flow field in the combustor, it is shown that the swirl is effective if is applied near the shear layer of the backstep flow in the combustor. The modified swirler with short blades is suggested to be used in solid fuel ramjets to increase the regression rate of the fuel and improve the performance, but with lower pressure loss.

CFD prediction of the reacting flow field inside a subscale scramjetcombustor

1988 ◽  
Author(s):  
T. CHITSOMBOON ◽  
G. NORTHAM ◽  
R. ROGERS ◽  
G. DISKIN
Keyword(s):  
Flow Field ◽  
Reacting Flow

scholarly journals Manifold reduction techniques for the comparison of crank angle-resolved particle image velocimetry (PIV) data and Reynolds-averaged Navier-Stokes (RANS) simulations in a spark ignition direct injection (SIDI) engine

2021 ◽  
pp. 146808742110131
Author(s):  
Xiaohang Fang ◽  
Li Shen ◽  
Christopher Willman ◽  
Rachel Magnanon ◽  
Giuseppe Virelli ◽  
...  
Keyword(s):  
Flow Field ◽  
Particle Image ◽  
Direct Injection ◽  
Linear Manifold ◽  
Main Flow ◽  
Navier Stokes ◽  
Reduction Techniques ◽  
Image Velocimetry ◽  
Manifold Reduction ◽  
Relevance Index

In this article, different manifold reduction techniques are implemented for the post-processing of Particle Image Velocimetry (PIV) images from a Spark Ignition Direct Injection (SIDI) engine. The methods are proposed to help make a more objective comparison between Reynolds-averaged Navier-Stokes (RANS) simulations and PIV experiments when Cycle-to-Cycle Variations (CCV) are present in the flow field. The two different methods used here are based on Singular Value Decomposition (SVD) principles where Proper Orthogonal Decomposition (POD) and Kernel Principal Component Analysis (KPCA) are used for representing linear and non-linear manifold reduction techniques. To the authors’ best knowledge, this is the first time a non-linear manifold reduction technique, such as KPCA, has ever been used in the study of in-cylinder flow fields. Both qualitative and quantitative studies are given to show the capability of each method in validating the simulation and incorporating CCV for each engine cycle. Traditional Relevance Index (RI) and two other previously developed novel indexes: the Weighted Relevance Index (WRI) and the Weighted Magnitude Index (WMI), are used for the quantitative study. The results indicate that both POD and KPCA show improvements in capturing the main flow field features compared to ensemble-averaged PIV experimental data and single cycle experimental flow fields while capturing CCV. Both methods present similar quantitative accuracy when using the three indexes. However, challenges were highlighted in the POD method for the selection of the number of POD modes needed for a representative reconstruction. When the flow field region presents a Gaussian distribution, the KPCA method is seen to provide a more objective numerical process as the reconstructed flow field will see convergence with an increasing number of modes due to its usage of Gaussian properties. No additional criterion is needed to determine how to reconstruct the main flow field feature. Using KPCA can, therefore, reduce the amount of analysis needed in the process of extracting the main flow field while incorporating CCV.

On the Flow Fields of Inertial Impactors

1974 ◽  
Vol 96 (4) ◽  
pp. 394-400 ◽  
Author(s):  
V. A. Marple ◽  
B. Y. H. Liu ◽  
K. T. Whitby
Keyword(s):  
Flow Field ◽  
Stokes Equations ◽  
Relaxation Method ◽  
Water Model ◽  
Navier Stokes ◽  
Visualization Technique ◽  
Navier Stokes Equations ◽  
Theoretical Results ◽  
Plate Distance ◽  
Good Agreement

The flow field in an inertial impactor was studied experimentally with a water model by means of a flow visualization technique. The influence of such parameters as Reynolds number and jet-to-plate distance on the flow field was determined. The Navier-Stokes equations describing the laminar flow field in the impactor were solved numerically by means of a finite difference relaxation method. The theoretical results were found to be in good agreement with the empirical observations made with the water model.

Numerical Simulation of Muzzle Flow Field of Gun Based on CFD

2013 ◽  
Vol 291-294 ◽  
pp. 1981-1984
Author(s):  
Zhang Xia Guo ◽  
Yu Tian Pan ◽  
Yong Cun Wang ◽  
Hai Yan Zhang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Stokes Equation ◽  
Wave Structure ◽  
Flow Fields ◽  
Single Equation ◽  
Navier Stokes ◽  
Turbulent Model ◽  
Navier Stokes Equation ◽  
Numerical Simulation Result

Gunpowder was released in an instant when the pill fly out of the shell during the firing, and then formed a complicated flow fields about the muzzle when the gas expanded sharply. Using the 2 d axisymmetric Navier-Stokes equation combined with single equation turbulent model to conduct the numerical simulation of the process of gunpowder gass evacuating out of the shell without muzzle regardless of the pill’s movement. The numerical simulation result was identical with the experimental. Then simulated the evacuating process of gunpowder gass of an artillery with muzzle brake. The result showed complicated wave structure of the flow fields with the muzzle brake and analysed the influence of muzzle brake to the gass flow field distribution.

Fluid flow over and through a regular bundle of rigid fibres

2016 ◽  
Vol 792 ◽  
pp. 5-35 ◽  
Author(s):  
Giuseppe A. Zampogna ◽  
Alessandro Bottaro
Keyword(s):  
Porous Medium ◽  
Fluid Flow ◽  
Flow Field ◽  
Stokes Equations ◽  
Transversely Isotropic ◽  
Navier Stokes ◽  
Leading Order ◽  
Macroscopic Scale ◽  
Navier Stokes Equations ◽  
Homogenized Model

The interaction between a fluid flow and a transversely isotropic porous medium is described. A homogenized model is used to treat the flow field in the porous region, and different interface conditions, needed to match solutions at the boundary between the pure fluid and the porous regions, are evaluated. Two problems in different flow regimes (laminar and turbulent) are considered to validate the system, which includes inertia in the leading-order equations for the permeability tensor through a Oseen approximation. The components of the permeability, which characterize microscopically the porous medium and determine the flow field at the macroscopic scale, are reasonably well estimated by the theory, both in the laminar and the turbulent case. This is demonstrated by comparing the model’s results to both experimental measurements and direct numerical simulations of the Navier–Stokes equations which resolve the flow also through the pores of the medium.

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