Numerical Simulation of a High Pressure Supersonic Multiphase Jet Flow Through a Gaseous Medium

2004 ◽  
Author(s):  
Randy S. Lagumbay ◽  
Oleg V. Vasilyev ◽  
Andreas Haselbacher ◽  
Jin Wang
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Gaseous Medium ◽  
Fuel Injection ◽  
Stokes Equations ◽  
Complex Structure ◽  
Jet Flow ◽  
Multiphase Model ◽  
Mixture Density ◽  
Flow Through

Computational Fluid Dynamics (CFD) analysis is used to numerically study the structure and dynamics of a high-pressure, high-speed jet of a gas/liquid mixture through a gaseous medium close to the nozzle region. The complex structure of the jet near the nozzle region is captured before it breaks-up downstream. A new multiphase model based on a mixture formulation of the conservation laws for a multiphase flows is used in the simulation. The model does not require ad-hoc closure for the variation of mixture density with pressure and yields thermodynamically accurate acoustic propagation for multiphase mixtures. The numerical formulation has been implemented to a multi-physics unstructured code “RocfluMP” that solves the modified three-dimensional time-dependent Euler/Navier-Stokes equations for a multiphase framework in integral form. The Roe’s approximate Riemann solver is used to allow capturing of shock waves and contact discontinuities. For a very steep gradient, an HLLC scheme is used to resolved the isolated shock and contact waves. The developed flow solver provides a general coupled incompressible-compressible multiphase framework that can be applied to a variety of supersonic jet flow problems including fuel injection systems, thermal and plasma spray coating, and liquid-jet machining. Preliminary results for shock tube analysis and gas/liquid free surface jet flow through a gaseous medium are presented and discussed.

Numerical Simulation of a Supersonic Three-Phase Cavitating Jet Flow Through a Gaseous Medium in Injection Nozzle

2005 ◽  
Author(s):  
Randy S. Lagumbay ◽  
Oleg V. Vasilyev ◽  
Andreas Haselbacher ◽  
Jin Wang
Keyword(s):  
Multiphase Flow ◽  
Gaseous Medium ◽  
Fuel Injection ◽  
Stokes Equations ◽  
Jet Flow ◽  
Injection Nozzle ◽  
Mixture Density ◽  
Three Phase ◽  
Flow Through ◽  
Cavitating Jet

A new multiphase mathematical model based on a mixture formulation of the laws of conservation for a multiphase flow is used to simulate a supersonic three-phase cavitating jet flow through a gaseous medium. The model does not require an adhoc closure for the variation of mixture density with regards to the attendant pressure and yields a thermodynamically accurate value for the acoustical propagation generated by the process. A source term for cavitation is added into the equations of the mixture formulation and the resultant cavitation is mathematically modeled accordingly. The new numerical formulation has been incorporated into a multi-physics unstructured code “RocfluMP” that solves the modified three-dimensional time-dependent Euler/Navier-Stokes equations for a multiphase framework in integral form. A modified form of the Harten, Lax and van Leer approximate Riemann equations are used to resolve the isolated shock and contact waves. The newly developed multiphase flow equations provide a general framework for analyzing coupled incompressible-compressible multiphase flows that can be applied to a variety of supersonic multiphase jet flow problems such as fuel injection systems and liquid-jet machining. Preliminary results for three-phase cavitating jet flow through a gaseous medium in injection nozzle are presented and discussed.

An Image Analysis of High Speed Combustion Photographs for D.I. Diesel Engine with High Pressure Fuel Injection

1990 ◽  
Author(s):  
Ikuo Yamaguchi ◽  
Toshio Nakahira ◽  
Masanori Komori ◽  
Shinji Kobayashi
Keyword(s):  
High Pressure ◽  
Image Analysis ◽  
Diesel Engine ◽  
High Speed ◽  
Fuel Injection

Detecting and Correcting Cylinder Imbalance in Direct Injection Engines

2000 ◽  
Vol 123 (3) ◽  
pp. 413-424 ◽  
Author(s):  
M. J. van Nieuwstadt ◽  
I. V. Kolmanovsky
Keyword(s):  
High Pressure ◽  
Diesel Engine ◽  
High Speed ◽  
Fuel Injection ◽  
Direct Injection ◽  
Direct Injection Engines ◽  
High Speed Diesel ◽  
On Line ◽  
Manufacturing Accuracy ◽  
Adaptation Scheme

Modern direct injection engines feature high pressure fuel injection systems that are required to control the fuel quantity very accurately. Due to limited manufacturing accuracy these systems can benefit from an on-line adaptation scheme that compensates for injector variability. Since cylinder imbalance affects many measurable signals, different sensors and algorithms can be used to equalize torque production by the cylinders. This paper compares several adaptation schemes that use different sensors. The algorithms are evaluated on a cylinder-by-cylinder simulation model of a direct injection high speed diesel engine. A proof of stability and experimental results are reported as well.

scholarly journals Numerical Investigations on the Water Entry of Cylindrical Projectiles with Different Initial Conditions

2019 ◽  
Vol 9 (9) ◽  
pp. 1858 ◽  
Author(s):  
Jianguo Gao ◽  
Zhihua Chen ◽  
Wei-Tao Wu ◽  
Xin Li
Keyword(s):  
High Speed ◽  
Gas Flow ◽  
Stokes Equations ◽  
Initial Conditions ◽  
Water Entry ◽  
Navier Stokes ◽  
Multiphase Model ◽  
Entry Angle ◽  
Vibration Period ◽  
Small Water

In this paper, coupled with Reynolds-averaged Navier–Stokes equations and ballistic equations, the numerical simulations of high-speed water entry of projectiles under different conditions have been conducted. The water-gas flow was modeled by the mixture multiphase model. The numerical results indicated that the simulations agree well with analytical solutions by two cavity models, which validates the model applied. Then the effects of variations of project length, entry angle and velocity on the entry process of projectiles were further investigated. The results show that, for small water entry angles, the cavity wall interacts with the projectile, affects the trajectory of the projectile, and even ricochets for projectiles with small length (5D). On the other hand, the projectile vibrates during the whole process of water entry; the vibration amplitude decreases with the increase of projectile length and entry angle; however, it is the contrary for the vibration period. Furthermore, after the initial impact period, the influence of these parameters on the drag coefficient is not obvious.

Comparison of Different Shroud Configurations in High-Pressure Turbines Using Unsteady CFD

2006 ◽  
Author(s):  
P. Adami ◽  
A. Milli ◽  
F. Martelli ◽  
S. Cecchi
Keyword(s):  
High Pressure ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Labyrinth Seals ◽  
Navier Stokes Equations ◽  
Jet Interaction ◽  
Potential Source ◽  
Flow Through ◽  
Numerical Solver ◽  
End Wall

The objective of this work is to analyze the end wall leakage interaction in shrouded high pressure turbines to provide useful indications about the flow pattern and its impact on performances. The prediction of flow through the seal and the understanding of the leakage jet interaction with the main flow in turbine end wall regions is nowadays possible using 3D CFD approaches. Modern solvers allow the coupling of the labyrinth and the main vane flows accounting for most of the geometric and aerodynamic features characterizing this phenomenon. Two similar shroud configurations are here analysed for two high pressure turbine configurations. Each configuration refers to a different blade technology commonly used by ANSALDO ENERGIA. The computational algorithm is based on a numerical solver developed and applied for the simulation of compressible Navier-Stokes equations in a multi rows unsteady environment. In order to reproduce the basic physic of the leakages, the problem has been investigated modelling the unsteady 1 1/2 stage interaction together with the complete geometry of the labyrinth seals. The CFD results are commented addressing the potential source of losses to help the development of solutions for reducing the leakage losses.

Development of a High-Pressure, High-Temperature, Optically Accessible Continuous-Flow Vessel for Fuel-Injection Experiments

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Kemar C. James ◽  
Jin Wang ◽  
Michael C. Maynard ◽  
Zackery B. Morris ◽  
Brian T. Fisher
Keyword(s):  
High Pressure ◽  
Continuous Flow ◽  
High Speed ◽  
Fuel Injection ◽  
Light Emitting Diode ◽  
Cone Angle ◽  
High Speed Camera ◽  
Light Emitting ◽  
High Pressure High Temperature ◽  
Spray Visualization

A vessel has been designed for nonreacting fuel-injection experiments with continuous flow of sweep gas at pressures up to 1380 kPa and temperatures up to 200 °C. Four orthogonal windows provide optical access for high-speed spray-visualization using a fast-pulsed light emitting diode (LED) and a high-speed camera. Initial experiments have been conducted to determine spray characteristics of n-heptane. At room conditions, liquid length and cone angle were 170 mm and 14.5 deg, respectively. With air flow in the chamber at 690 kPa and 100 °C, liquid length was considerably shorter at 92 mm and cone angle was wider at 16.5 deg.

Analysis of the effect of variations in fuel line pressure in high-speed direct injection diesel engines, with high-pressure common rail fuel injection systems on heat release, cylinder pressure, performance, and NOx emissions

2005 ◽  
Vol 219 (3) ◽  
pp. 413-422 ◽  
Author(s):  
F J Wallace ◽  
J G Hawley
Keyword(s):  
High Pressure ◽  
Heat Release ◽  
Diesel Engines ◽  
High Speed ◽  
Fuel Injection ◽  
Direct Injection ◽  
Common Rail ◽  
Injection Velocity ◽  
Engine Simulation ◽  
High Pressure Common Rail

This paper is a further development of work previously reported on a wholly analytical approach to heat release modelling and is applicable to high-speed direct injection (HSDI) diesel engines operating with high-pressure common rail fuel injection systems under conditions of predominantly mixing-controlled combustion. The key variable in this treatment is the fuel preparation or combustion rate factor WH which, in conjunction with the primary injection variables, i.e. rail pressure, injection velocity and duration, defines the shape and amplitude of the heat release curve. It was shown in a previous paper that by expressing the fuel preparation rate factor WH as a function of time rather than crank angle, i.e. WHt instead of WHθ, the former can be presented as a nearly linear function of the square of injection velocity, i.e. WHt is directly proportional to the kinetic energy of the injected fuel spray, the latter evidently being the primary influence on the rate of the fuel-air mixing process. The analytical treatment developed in the authors' previous paper then allows heat release rates in the engine, dQ/dθ, to be calculated over a wide range of engine speeds and loads, with the aid of the existing engine simulation code ODES (Otto diesel engine simulation) to predict the associated engine performance and emissions, without resorting to further engine testing.

scholarly journals Approaches for Detailed Investigations on Transient Flow and Spray Characteristics during High Pressure Fuel Injection

2020 ◽  
Vol 10 (12) ◽  
pp. 4410 ◽  
Author(s):  
Noritsune Kawaharada ◽  
Lennart Thimm ◽  
Toni Dageförde ◽  
Karsten Gröger ◽  
Hauke Hansen ◽  
...  
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Transient Flow ◽  
Numerical Models ◽  
Near Field ◽  
Transient Nature ◽  
Injector Nozzle ◽  
Considerable Impact

High pressure injection systems have essential roles in realizing highly controllable fuel injections in internal combustion engines. The primary atomization processes in the near field of the spray, and even inside the injector, determine the subsequent spray development with a considerable impact on the combustion and pollutant formation. Therefore, the processes should be understood as much as possible; for instance, to develop mathematical and numerical models. However, the experimental difficulties are extremely high, especially near the injector nozzle or inside the nozzle, due to the very small geometrical scales, the highly concentrated optical dense spray processes and the high speed and drastic transient nature of the spray. In this study, several unique and partly recently developed techniques are applied for detailed measurements on the flow inside the nozzle and the spray development very near the nozzle. As far as possible, the same three-hole injector for high pressure diesel injection is used to utilize and compare different measurement approaches. In a comprehensive section, the approach is taken to discuss the measurement results in comparison. It is possible to combine the observations within and outside the injector and to discuss the entire spray development processes for high pressure diesel sprays. This allows one to confirm theories and to provide detailed and, in parts, even quantitative data for the validation of numerical models.

CFD ANALYSIS OF UNSTEADY FLOWS DUE TO SUPERCRITICAL HEAT ADDITION IN HIGH SPEED CONDENSING STEAM

2015 ◽  
Vol 76 (10) ◽  
Author(s):  
Norhazwani Abd Malek ◽  
Syarir Akram Jamaluddin ◽  
Mohd Zamri Yusoff ◽  
Hasril Hasini
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Unsteady Flows ◽  
Navier Stokes ◽  
Multiphase Model ◽  
Steam Turbines ◽  
Wet Steam ◽  
Navier Stokes Equations ◽  
Heat Addition ◽  
Wet Steam Flow

This study is mainly to investigate the unsteady flows due to supercritical heat addition in high speed condensing steam in steam turbines. To achieve this, condensation flow characteristic is investigated on 2D converging-diverging nozzle. A Computational Fluid Dynamics (CFD) code (FLUENT package) that adopted the Eulerian-Eulerian approach for modeling wet steam flow, was used. The condensing flow is governed by the compressible Navier-Stokes equations in conjunction with a wet steam multiphase model. The turbulence model selected for this work is Spalart Allmaras model which is based on the Reynolds Averaged Navier Stoke (RANS) model available in FLUENT. Results are then compared with previous researchers that use different methods including user defined code and experiment. The importance of this research study is to determine the accuracy of the software and method used and to compare the results with other researchers.The current work shows good agreement with the experimental data done by Skilling [1] and 2D calculations done by Yusoff et al. [2]. It is found from the numerical simulation results that the supercritical heat addition has caused the flow in the condensing steam to retard and gives rise to pressure oscillations. The unsteady supercritical heat addition reveals promising results indicating the capability of FLUENT to calculate this phenomenon which might cause instability in turbine channel.

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