Underexpanded Micro-nozzle Flow Simulation with Coupled Thermal-Fluid Modeling

2007 ◽  
Author(s):  
Jose Hermida Quesada ◽  
Jose A. Morinigo ◽  
Francisco Caballero Requena
Keyword(s):  
Flow Simulation ◽  
Nozzle Flow ◽  
Fluid Modeling ◽  
Micro Nozzle

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.

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

Coupled FVM-DSMC Simulation of Micro-Nozzle With Unstructured-Grid

2008 ◽  
Author(s):  
Zhixin Sun ◽  
Zengyao Li ◽  
Yaling He ◽  
Wenquan Tao
Keyword(s):  
Flow Field ◽  
Unstructured Grid ◽  
Direct Simulation Monte Carlo ◽  
Flow Simulation ◽  
Dsmc Method ◽  
Structured Grid ◽  
Micro Nozzle ◽  
Dsmc Simulation ◽  
Volume Method ◽  
Solid Area

The flow field and temperature distributions of free molecular micro-electro-thermal resist jet (FMMR) were studied resorting to DSMC-FVM coupled method. Direct Simulation Monte Carlo (DSMC) method is the most useful tool to simulate the flow field of FMMR and unstructured grid is suitable for the flow simulation in a complicated region with tilted wall surface. DSMC code based on unstructured grid system was developed and then the result was compared with that of structured grid and analytical solution to validate the reliability of the developed code. The DSMC method was then used to simulate the fluid flow in the micro-nozzle (Kn>0.01) and the temperature distribution in the nozzle wall was obtained by the Finite Volume Method (FVM). The Dirichlet-Neumann method was used to couple the wall heat flux and temperature between flow field and solid area. The effect of different income pressure was studied in detail and the results showed that the temperature of solid area changed drastically at different income pressure, so the commonly-adopted method of pre-setting boundary temperature before simulation was unreasonable. The results showed that the influence of boundary layer decreased as the pressure increased.

Optical Measurements of Density and Species Concentration in a Low Reynolds Number Micro-Nozzle Flow

2015 ◽  
Author(s):  
David A. Rosenberg ◽  
Bradley A. Williams ◽  
Steven G. Tuttle ◽  
Michael F. Osborn ◽  
Logan T. Williams
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Optical Measurements ◽  
Nozzle Flow ◽  
Species Concentration ◽  
Micro Nozzle ◽  
Low Reynolds

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
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