scholarly journals Computational Study of Transverse Slot Injection in Supersonic Flow

2018 ◽  
Vol 68 (2) ◽  
pp. 121 ◽  
Author(s):  
Malsur Dharavath ◽  
P. Manna ◽  
Debasis Chakraborty
Keyword(s):  
Supersonic Flow ◽  
Stokes Equations ◽  
Computational Study ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Injection Pressure ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Scramjet Combustor ◽  
Flow Features

The knowledge of transverse sonic injection flow field is very important for the design of scramjet combustor. Three dimensional Reynolds-Averaged Navier Stokes equations alongwith turbulence models are solved to find the effect of transverse sonic slot injection into a supersonic flow. Grid sensitivity of the results is studied for various structured grids. Simulations with different turbulence models (i.e., k-ε, k-ω, SST-kω, and RNG-kε) reveals that RNG-kε turbulence model better predicts the flow features. Computational fluid dynamics predicted wall pressure distribution for various injection pressures matches well with experimental data. The extent of upstream separated region increases with the increase of the injection pressure. The increase of slot width makes the interaction between transverse jet and free stream more intense and causes more spreading and penetration of injectant in the downstream region.

scholarly journals Numerical Study on the Solid Fuel Rocket Scramjet Combustor with Cavity

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1235 ◽  
Author(s):  
Chaolong Li ◽  
Zhixun Xia ◽  
Likun Ma ◽  
Xiang Zhao ◽  
Binbin Chen
Keyword(s):  
Solid Fuel ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Combustion Efficiency ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Particle Combustion ◽  
Scramjet Combustor ◽  
Cavity Configuration

Scramjet based on solid propellant is a good supplement for the power device of future hypersonic vehicles. A new scramjet combustor configuration using solid fuel, namely, the solid fuel rocket scramjet (SFRSCRJ) combustor is proposed. The numerical study was conducted to simulate a flight environment of Mach 6 at a 25 km altitude. Three-dimensional Reynolds-averaged Navier–Stokes equations coupled with shear stress transport (SST) k − ω turbulence model are used to analyze the effects of the cavity and its position on the combustor. The feasibility of the SFRSCRJ combustor with cavity is demonstrated based on the validation of the numerical method. Results show that the scramjet combustor configuration with a backward-facing step can resist high pressure generated by the combustion in the supersonic combustor. The total combustion efficiency of the SFRSCRJ combustor mainly depends on the combustion of particles in the fuel-rich gas. A proper combustion organization can promote particle combustion and improve the total combustion efficiency. Among the four configurations considered, the combustion efficiency of the mid-cavity configuration is the highest, up to about 70%. Therefore, the cavity can effectively increase the combustion efficiency of the SFRSCRJ combustor.

Multigrid Computation of Incompressible Flows Using Two-Equation Turbulence Models: Part II—Applications

1997 ◽  
Vol 119 (4) ◽  
pp. 900-905 ◽  
Author(s):  
X. Zheng ◽  
C. Liao ◽  
C. Liu ◽  
C. H. Sung ◽  
T. T. Huang
Keyword(s):  
Turbulent Flows ◽  
Incompressible Flows ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Time Stepping ◽  
Grid Algorithm ◽  
High Reynolds

In this paper, computational results are presented for three-dimensional high-Reynolds number turbulent flows over a simplified submarine model. The simulation is based on the solution of Reynolds-Averaged Navier-Stokes equations and two-equation turbulence models by using a preconditioned time-stepping approach. A multiblock method, in which the block loop is placed in the inner cycle of a multi-grid algorithm, is used to obtain versatility and efficiency. It was found that the calculated body drag, lift, side force coefficients and moments at various angles of attack or angles of drift are in excellent agreement with experimental data. Fast convergence has been achieved for all the cases with large angles of attack and with modest drift angles.

Strongly Coupled Fluid-Structure Interactions via a New Navier-Stokes Method for Prediction of Vortex-Induced Vibrations

2005 ◽  
Author(s):  
Yannis Kallinderis ◽  
Hyung Taek Ahn
Keyword(s):  
Stokes Equations ◽  
Computational Cost ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Design Tool ◽  
Navier Stokes ◽  
Time Step ◽  
Navier Stokes Equations ◽  
Vortex Induced Vibrations ◽  
Offshore Industry

Numerical prediction of vortex-induced vibrations requires employment of the unsteady Navier-Stokes equations. Current Navier-Stokes solvers are quite expensive for three-dimensional flow-structure applications. Acceptance of Computational Fluid Dynamics as a design tool for the offshore industry requires improvements to current CFD methods in order to address the following important issues: (i) stability and computation cost of the numerical simulation process, (ii) restriction on the size of the allowable time-step due to the coupling of the flow and structure solution processes, (iii) excessive number of computational elements for 3-D applications, and (iv) accuracy and computational cost of turbulence models used for high Reynolds number flow. The above four problems are addressed via a new numerical method which employs strong coupling between the flow and the structure solutions. Special coupling is also employed between the Reynolds-averaged Navier-Stokes equations and the Spalart-Allmaras turbulence model. An element-type independent spatial discretization scheme is also presented which can handle general hybrid meshes consisting of hexahedra, prisms, pyramids, and tetrahedral.

Numerical research on the performance of solid fuel rocket scramjet combustor

2021 ◽  
pp. 095441002110372
Author(s):  
Hao Huang ◽  
Zhiwei Feng ◽  
Likun Ma ◽  
Tao Yang ◽  
Chaolong Li
Keyword(s):  
Solid Fuel ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Combustion Efficiency ◽  
Navier Stokes ◽  
Height Ratio ◽  
Navier Stokes Equations ◽  
Carbon Particles ◽  
Scramjet Combustor ◽  
Numerical Research

Combustion efficiency is the main factor affecting the performance of solid fuel rocket scramjet. To reveal the influence of combustor configuration on performance and further improve combustion efficiency, the influence of the width-height ratio of the rectangle-section combustor on the performance of solid fuel rocket scramjet is investigated numerically in this article. Three-dimensional compressible Reynolds-averaged Navier-Stokes equations coupled with shear stress transport k– ω turbulence model are employed to simulate the aerodynamics. The Euler–Lagrange approach is used to calculate the multiphase flow. Combustion of carbon particles is modeled by the improved Moving Flame Front model. Accuracy of the present numerical model is validated by the experimental data of a rectangle-section combustor from literature. Results show that as the width-height ratio increases, the combustion efficiency increases first and then decreases. The influence of cavity and its position on the performance are also investigated. Results show that cavity can significantly improve combustion efficiency. The effect of cavity position on performance is related to the distribution of particles.

scholarly journals The Modelling of Flow in the Volute and Vanes of a High Pressure Radial Inflow Turbine

1993 ◽  
Author(s):  
M. Lobo ◽  
R. L. Elder
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Experimental Measurements ◽  
General Description ◽  
Navier Stokes Equations ◽  
Flow Modelling ◽  
Comparison With Experiment ◽  
Flow Features ◽  
Radial Inflow Turbine

The flow in a vaned volute of a radial inflow turbine is analysed using PHOENICS, a very general three-dimensional viscous CFD code based on finite-volume pressure-correction techniques for solving the Navier-Stokes equations. The study involves two physically complementary but mathematically very different problems — flow modelling in the vaneless section of the volute and flow modelling in the vanes. Each of these problems is considered in turn — and each presents characteristic hurdles. Particular attention is paid to grid-generation and the process is carried out alongside the flow computation, the grids being modified in such a way so as to facilitate convergence and accuracy. Numerical results are presented in the form of vector plots for purposes of general description and tables for comparison with experiment. Agreement with experiment is good. However experimental results, for comparison are available only in the vanes. In the vaneless section of the volute, the converged solution depicts some interesting secondary flow features — in regions inaccesible to the current experimental measurements.

A computational study of the topology of vortex breakdown

1991 ◽  
Vol 435 (1894) ◽  
pp. 321-337 ◽  
Keyword(s):  
Topological Structure ◽  
Stokes Equations ◽  
Vortex Breakdown ◽  
Computational Study ◽  
Double Helix ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Streamwise Direction ◽  
Navier Stokes Equations ◽  
Axial Velocity Distribution

A fully three-dimensional numerical simulation of vortex breakdown using the unsteady, incompressible Navier–Stokes equations has been performed. Solutions to four distinct types of breakdown are identified and compared with experimental results. The computed solutions include weak helical, double helix, spiral, and bubble-type breakdowns. The topological structure of the various breakdowns as well as their interrelationship are studied. The data reveal that the asymmetric modes of breakdown may be subject to additional breakdowns as the vortex core evolves in the streamwise direction. The solutions also show that the freestream axial velocity distribution has a significant effect on the position and type of vortex breakdown.

Flow Analysis of the M151 Aircraft Model Using the Academic CFD Code Galatea

2017 ◽  
Author(s):  
Dimitrios A. Inglezakis ◽  
Georgios N. Lygidakis ◽  
Ioannis K. Nikolos
Keyword(s):  
Turbulent Flows ◽  
Stokes Equations ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Research Association ◽  
Navier Stokes Equations ◽  
Aircraft Model ◽  
Short Period

CFD (Computational Fluid Dynamics) solvers have become nowadays an integral part of the aerospace manufacturing process and product design, as their implementation allows for the prediction of the aerodynamic behavior of an aircraft in a relatively short period of time. Such an in-house academic solver, named Galatea, is used in this study for the prediction of the flow over the ARA (Aircraft Research Association) M151/1 aircraft model. The proposed node-centered finite-volume solver employs the RANS (Reynolds-Averaged Navier-Stokes) equations, combined with appropriate turbulence models, to account for the simulation of compressible turbulent flows on three-dimensional hybrid unstructured grids, composed of tetrahedral, prisms, and pyramids. A brief description of Galatea’s methodology is included, while attention is mainly directed toward the accurate prediction of pressure distribution on the wings’ surfaces of the aforementioned airplane, an uncommon combat aircraft research model with forward swept wings and canards. In particular, two different configurations of M151/1 were examined, namely, with parallel and expanding fuselage, while the obtained results were compared with those extracted with the commercial CFD software ANSYS CFX. A very good agreement is reported, demonstrating the proposed solver’s potential to predict accurately such demanding flows over complex geometries.

Effect of rocket exhaust of canisterized missile on adjoining launching system

2016 ◽  
Vol 231 (11) ◽  
pp. 2085-2097 ◽  
Author(s):  
MSR Chandra Murty ◽  
PK Sinha ◽  
D Chakraborty
Keyword(s):  
Stokes Equations ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Test Configuration ◽  
Instantaneous Position ◽  
Flow Features ◽  
Scale Down ◽  
Parametric Studies

Transient numerical simulations are carried out to study missile motion in a vertical launch system and to estimate the effect of missile exhaust in the adjoining launch structure. Three-dimensional Navier–Stokes equations along with k–ɛ turbulence model and species transport equations are solved using commercial computational fluid dynamics software. Dynamic grid movement is adopted and one degree of freedom trajectory equations are integrated with the computational fluid dynamic solver to obtain the instantaneous position of the missile. Multi-zone grid generation approach with sliding interface method through layering technique is adopted to address the changing boundary problem. The computational methodology is applied to study the missile motion in a scale-down test configuration as well as in the flight condition. The computations capture all essential flow features of test and flight conditions in active cell as well as in adjacent cells. Parametric studies are conducted to study the effect geometrical features and measurement uncertainty in the input data. Computed pressures in the adjacent cells in the launch system match better (∼12%) with the experimental and flight results compared to distant cells.

Numerical Simulation of Dual-Mode Scramjet Combustor with Significant Upstream Interaction

2012 ◽  
Vol 2 (3) ◽  
pp. 60-74
Author(s):  
Rahul Ingle ◽  
Debasis Chakraborty
Keyword(s):  
Surface Pressure ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Interaction Model ◽  
Navier Stokes ◽  
Dual Mode ◽  
Fast Kinetics ◽  
Scramjet Combustor ◽  
Flow Features

This paper is concerned with a numerical study corresponding to experimental investigation of Chinzei and co-workers on hydrogen fueled dual-mode scramjet engine essentially to understand the key features of upstream interaction, mixing and combustion. Three dimensional Navier Stokes equations along with a K-? turbulence model and infinitely fast kinetics are solved using commercial CFD software. Reasonable agreement has been obtained between the computed surface pressure with experimental values and the results of other numerical simulations. Insights into the flow features inside the combustor are obtained through analysis of various thermochemical parameters. The comparison of surface pressure with experimental results and other numerical results demonstrated that simple kinetics and turbulence – chemistry interaction model may be adequate to address the overall flow features in the combustor. A principal conclusion is that the boundary layer at the combustor entry has a pronounced effect on the flow development in the dual-mode scramjet combustor and causes significant upstream interaction.

A Computational Study of Tip Desensitization in Axial Flow Turbines: Part 1 — Baseline Turbine Computations and Comparisons With Measurement

2004 ◽  
Author(s):  
James A. Tallman
Keyword(s):  
Turbulence Modeling ◽  
Stokes Equations ◽  
Computational Study ◽  
Three Dimensional ◽  
Axial Flow ◽  
Numerical Procedure ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Penn State ◽  
High Pressure Stage

This study used Computational Fluid Dynamics (CFD) to investigate modified turbine blade tip shapes as a means of reducing the leakage flow and vortex. The subject of this study was the single-stage experimental turbine facility at Penn State University, with scaled three-dimensional geometry representative of a modern high-pressure stage. To validate the numerical procedure, the rotor flowfield was first computed with no modification to the tip, and the results compared with measurements of the flowfield. The flow was then predicted for a variety of different tip shapes: first with coarse grids for screening purposes and then with more refined grids for final verification of preferred tip geometries. Part 1 of this two-part paper focuses on the turbine case description, numerical procedure, baseline flat-tip computations, and comparison of the baseline results with measurement. A Runge-Kutta time-marching CFD solver (ADPAC) was used to solve the Reynolds-Averaged Navier-Stokes equations. Two-equation turbulence modeling with low Reynolds number adjustments was used for closure. The baseline rotor flowfield was computed twice: with a moderately sized mesh (720,000 nodes) and also with a much more refined mesh (7.2 million nodes). Both solutions showed good agreement with previously taken measurements of the rotor flowfield, including five-hole probe measurements of the velocity and total pressure inside the passage, as well as pressure measurements on the blade and casing surfaces.

Sign in / Sign up

Export Citation Format

Share Document