Comparison and Application of Dynamic Mesh Techniques in Nozzle-Flow Simulation

2017 ◽  
Author(s):  
Chao Gong ◽  
Roland Baar
Keyword(s):  
Flow Simulation ◽  
Dynamic Mesh ◽  
Nozzle Flow

Coupled in-nozzle flow and spray simulation of Engine Combustion Network Spray-G injector

2020 ◽  
pp. 146808742096061
Author(s):  
Balaji Mohan ◽  
Jihad Badra ◽  
Jaeheon Sim ◽  
Hong G Im
Keyword(s):  
Cone Angle ◽  
Flow Simulation ◽  
Published Data ◽  
Nozzle Flow ◽  
Piv Measurements ◽  
Injection Model ◽  
Image Velocimetry ◽  
Spray Plume ◽  
Engine Combustion ◽  
Phase Change Phenomena

A coupled Eulerian-Lagrangian approach was employed to Engine Combustion Network (ECN) Spray-G simulations. The Eulerian in-nozzle flow simulation was conducted with a small plenum attached to the nozzles, and the results were fed to the Lagrangian spray simulation. For Eulerian simulation, the homogeneous relaxation model (HRM) coupled with the volume of fluid (VOF) method was used. HRM proved to be good at predicting the phase change phenomena due to vaporization mechanisms, that is, both cavitation and flash boiling. As a one-way coupling, quantities such as rate of injection (ROI), mass injected through each hole, discharge coefficient, spray plume angle and half cone angle predicted from the Eulerian simulations were used as the initial and boundary conditions for the subsequent Lagrangian spray simulations using the blob injection model. Non-flashing (Spray-G1) and flashing (Spray-G2) spray was simulated, and the results were validated quantitatively against the published data in terms of the liquid and vapor penetration lengths, and good agreements were obtained. Furthermore, the simulation predicted the liquid and gas axial velocity and sauter mean diameter for Spray-G1 condition in agreement with the droplet size and particle image velocimetry (PIV) measurements from literature.

Prototype and numerical studies of interference characteristics of two ski-jump jets from opening spillway gates

2015 ◽  
Vol 32 (2) ◽  
pp. 289-307 ◽  
Author(s):  
Yexiang Xiao ◽  
Zhengwei Wang ◽  
Jidi Zeng ◽  
jintai Zheng ◽  
Jiayang Lin ◽  
...  
Keyword(s):  
Secondary Flow ◽  
Field Test ◽  
Transient Flow ◽  
Scale Effects ◽  
Flow Behavior ◽  
Flow Simulation ◽  
Dynamic Mesh ◽  
Content Type ◽  
Transient Simulations ◽  
Large Dam

Purpose – The purpose of this paper is to experimentally and numerically investigate the interference characteristics between two ski-jump jets on the flip bucket in a large dam spillway when two floodgates are running. Design/methodology/approach – The volume of fluid (VOF) method together with the Realizable k-ε turbulence model were used to predict the flow in two ski-jump jets and the free surface motion in a large dam spillway. The movements of the two gates were simulated using a dynamic mesh controlled by a User Defined Function (UDF). The simulations were run using the prototype dam as the field test to minimize errors due to scale effects. The simulation results are compared with field test observations. Findings – The transient flow calculations, accurately predict the two gate discharges compared to field data with the predicted ski-jump jet interference flow pattern similar to the observed shapes. The transient simulations indicate that the main reason for the deflected nappe is the larger opening difference between the two gates as the buttress side gate closes. When both gates are running, the two ski-jump jets interfere in the flip bucket and raise the jet nappe to near the buttress to form a secondary flow on this jet nappe surface. As the gate continues to close, the nappe surface continues to rise and the surface secondary flow become stronger, which deflects the nappe over the side buttress. Originality/value – A dynamic mesh is used to simulate the transient flow behavior of two prototype running gates. The transient flow simulation clarifies the hydraulics mechanism for how the two ski-jump jets interfere and deflect the nappe.

Effect of Ambient Pressure on the Behavior of Single-Component Fuels in a Gasoline Multi-Hole Injector

2019 ◽  
Author(s):  
Lorenzo Nocivelli ◽  
Junhao Yan ◽  
Kaushik Saha ◽  
Gina M. Magnotti ◽  
Chia-Fon Lee ◽  
...  
Keyword(s):  
Ambient Pressure ◽  
Light Attenuation ◽  
Flow Simulation ◽  
Nozzle Flow ◽  
Numerical Representation ◽  
Air Mixing ◽  
Nominal Condition ◽  
Flash Boiling ◽  
Characteristic Features ◽  
Attenuation Profiles

Abstract The injection characteristics of neat ethanol and pure iso-octane are studied under different ambient pressure and temperature conditions. Injection under flash-boiling conditions can enhance liquid atomization and evaporation, providing the possibility of improvement in the fuel/air mixing. These super-heated conditions often introduce phenomena that are not taken into account in the standard modeling of sprays for engine applications. The present work proposes a numerical investigation of the behavior of Engine Combustion Network’s 8-hole spray-G injector, starting at the subcooled nominal condition and reducing the ambient pressure at constant low temperature to reach the flare flash-boiling condition. To initialize the properties of the injected fuel, the flow in the nozzle is simulated with a Eulerian approach, handling the two phases with a mixture model and the phase change, due to cavitation and flash boiling, with the Homogenous Relaxation Model. A map of the mixture’s kinematic and thermal behavior is obtained at the interface between the injector and the chamber to initialize the Lagrangian simulations. A literature-based vaporization model is implemented to obtain the proper description of the characteristic features of a multi-hole spray under super-heated conditions, like plume-plume interaction. The numerical representation of the spray is validated in terms of penetration and radial spreading on DBI images, reproducing the light attenuation profiles caused by the presence of the liquid spray. Simulations show that coupled nozzle flow and spray calculations capture the spray morphology and shape better compared to calculations performed without considering the nozzle flow simulation details, especially under flare flash conditions.

Nozzle Flow Simulation of GDi for Measuring Near-Field Spray Angle and Plume Direction

2019 ◽  
Author(s):  
Raul Payri ◽  
Jaime Gimeno ◽  
Pedro Marti-Aldaravi ◽  
María Martínez
Keyword(s):  
Near Field ◽  
Flow Simulation ◽  
Spray Angle ◽  
Nozzle Flow

scholarly journals Numerical Analysis of Nozzle Flow and Spray Characteristics from Different Nozzles Using Diesel and Biofuel Blends

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 281 ◽  
Author(s):  
M.H.H Ishak ◽  
Farzad Ismail ◽  
Sharzali Che Mat ◽  
M.Z. Abdullah ◽  
M.S. Abdul Aziz ◽  
...  
Keyword(s):  
Aerodynamic Drag ◽  
Flow Simulation ◽  
Nozzle Flow ◽  
Fuel Injector ◽  
Discrete Phase Model ◽  
Spray Cone ◽  
Discrete Phase ◽  
Nozzle Shape ◽  
Computer Fluid Dynamics ◽  
Spray Characteristic

In this paper, the discrete phase model (DPM) was introduced to study the fuel injector cavitations process and the macro spray characteristic of three different types of nozzle spray shape with diesel and hybrid biofuel blend for several injection pressures and backpressures. The three types of nozzle spray shapes used were circle, elliptical A type, and elliptical B type. The cavitations’ flows inside the injector nozzles were simulated with Computer Fluid Dynamics (CFD) simulations using the cavitations mixture approach. The effect of nozzle spray shape towards the spray characteristic of hybrid biofuel blends is analyzed and compared with the standard diesel. Furthermore, a verification and validation from both the experimental results and numerical results are also presented. The nozzle flow simulation results indicated that the fuel type did not affect the cavitation area vastly, but were more dependent on the nozzle spray shape. In addition, the spray width of the elliptical nozzle shape was higher as compared to the circular spray. Moreover, as the backpressure increased, the spray width downstream increased as well. The spray tip penetration for the elliptical nozzle shape was shorter than the circular nozzle shape due to circular nozzles having smaller nozzle widths and lesser spray cone angles. Thus, this resulted in smaller aerodynamic drag.

Development of a Short-Duration Rocket Nozzle Flow Simulation Facility

AIAA Journal ◽  
2015 ◽  
Vol 53 (9) ◽  
pp. 2713-2725 ◽  
Author(s):  
G. Yahiaoui ◽  
H. Olivier
Keyword(s):  
Short Duration ◽  
Flow Simulation ◽  
Nozzle Flow ◽  
Rocket Nozzle

Starting nozzle flow simulation using K-G two-equation turbulence model

Shock Waves ◽  
2005 ◽  
pp. 1175-1180
Author(s):  
G. W. Yang ◽  
Z. M. Hu ◽  
Z. Jiang
Keyword(s):  
Turbulence Model ◽  
Flow Simulation ◽  
Nozzle Flow
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