scholarly journals Analytical Shock Jump Formulae for Cryogenic Homogeneous Two-Phase Nozzle Flow.

2000 ◽  
Vol 43 (140) ◽  
pp. 67-76
Author(s):  
I.Sinan AKMANDOR ◽  
Toshio NAGASHIMA
Keyword(s):  
Nozzle Flow ◽  
Two Phase ◽  
Shock Jump

Steady one-dimensional nozzle flow solutions of liquid–gas mixtures

2013 ◽  
Vol 737 ◽  
pp. 146-175 ◽  
Author(s):  
S. LeMartelot ◽  
R. Saurel ◽  
O. Le Métayer
Keyword(s):  
Two Phase Flow ◽  
Gas Mixtures ◽  
Ideal Gas ◽  
Nozzle Flow ◽  
Pure Liquid ◽  
Phase Flow ◽  
Two Phase ◽  
One Dimensional ◽  
Flow Models ◽  
Relaxation Effects

AbstractExact compressible one-dimensional nozzle flow solutions at steady state are determined in various limit situations of two-phase liquid–gas mixtures. First, the exact solution for a pure liquid nozzle flow is determined in the context of fluids governed by the compressible Euler equations and the ‘stiffened gas’ equation of state. It is an extension of the well-known ideal-gas steady nozzle flow solution. Various two-phase flow models are then addressed, all corresponding to limit situations of partial equilibrium among the phases. The first limit situation corresponds to the two-phase flow model of Kapila et al. (Phys. Fluids, vol. 13, 2001, pp. 3002–3024), where both phases evolve in mechanical equilibrium only. This model contains two entropies, two temperatures and non-conventional shock relations. The second one corresponds to a two-phase model where the phases evolve in both mechanical and thermal equilibrium. The last one corresponds to a model describing a liquid–vapour mixture in thermodynamic equilibrium. They all correspond to two-phase mixtures where the various relaxation effects are either stiff or absent. In all instances, the various flow regimes (subsonic, subsonic–supersonic, and supersonic with shock) are unambiguously determined, as well as various nozzle solution profiles.

The Effect of Droplet Solidification Upon Two-Phase Nozzle Flow

1971 ◽  
Vol 93 (4) ◽  
pp. 594-602
Author(s):  
P. N. Shankar
Keyword(s):  
Singular Perturbation ◽  
Phase Change ◽  
Liquid Fraction ◽  
Feedback Effect ◽  
Nozzle Flow ◽  
Phase Flow ◽  
Droplet Temperature ◽  
Two Phase ◽  
First Order ◽  
Perturbation Procedure

The handling of changes of phase in perturbation treatments of two-phase nozzle flow requires particular care. Droplet solidification, the phase change considered here, introduces two novel complications in a perturbation treatment of the problem. First, the boundaries of the zone of solidification are shifted by first-order corrections to the droplet temperature and liquid fraction, and these shifts introduce, in turn, further first-order corrections. This feedback effect is of particular interest and the magnitudes of the corrections are very significant. Second, a singular perturbation procedure is required to handle the problem at points where solidification first starts and where it is completed. The techniques presented here should be applicable to other problems involving phase change in two-phase flow.

An implicit algorithm of thin layer equations in viscous, transonic, two-phase nozzle flow

1994 ◽  
Vol 15 (4) ◽  
pp. 323-334
Author(s):  
He Hong-qing ◽  
Hou Xiao ◽  
Cai Ti-min ◽  
Wu Xing-ping
Keyword(s):  
Thin Layer ◽  
Nozzle Flow ◽  
Two Phase ◽  
Implicit Algorithm

Investigation of Nozzle Flow and Cavitation Characteristics in a Diesel Injector

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
S. Som ◽  
S. K. Aggarwal ◽  
E. M. El-Hannouny ◽  
D. E. Longman
Keyword(s):  
Nozzle Exit ◽  
Critical Role ◽  
Injection Pressure ◽  
Nozzle Flow ◽  
Two Phase ◽  
Cavitation Inception ◽  
Diesel Fuels ◽  
Needle Position ◽  
Primary Breakup ◽  
Cavitation Behavior

Cavitation and turbulence inside a diesel injector play a critical role in primary spray breakup and development processes. The study of cavitation in realistic injectors is challenging, both theoretically and experimentally, since the associated two-phase flow field is turbulent and highly complex, characterized by large pressure gradients and small orifice geometries. We report herein a computational investigation of the internal nozzle flow and cavitation characteristics in a diesel injector. A mixture based model in FLUENT V6.2 software is employed for simulations. In addition, a new criterion for cavitation inception based on the total stress is implemented, and its effectiveness in predicting cavitation is evaluated. Results indicate that under realistic diesel engine conditions, cavitation patterns inside the orifice are influenced by the new cavitation criterion. Simulations are validated using the available two-phase nozzle flow data and the rate of injection measurements at various injection pressures (800–1600 bar) from the present study. The computational model is then used to characterize the effects of important injector parameters on the internal nozzle flow and cavitation behavior, as well as on flow properties at the nozzle exit. The parameters include injection pressure, needle lift position, and fuel type. The propensity of cavitation for different on-fleet diesel fuels is compared with that for n-dodecane, a diesel fuel surrogate. Results indicate that the cavitation characteristics of n-dodecane are significantly different from those of the other three fuels investigated. The effect of needle movement on cavitation is investigated by performing simulations at different needle lift positions. Cavitation patterns are seen to shift dramatically as the needle lift position is changed during an injection event. The region of significant cavitation shifts from top of the orifice to bottom of the orifice as the needle position is changed from fully open (0.275 mm) to nearly closed (0.1 mm), and this behavior can be attributed to the effect of needle position on flow patterns upstream of the orifice. The results demonstrate the capability of the cavitation model to predict cavitating nozzle flows in realistic diesel injectors and provide boundary conditions, in terms of vapor fraction, velocity, and turbulence parameters at the nozzle exit, which can be coupled with the primary breakup simulation.

B22 High-Speed Gas-Liquid Two-Phase Nozzle Flow for Carbon Dioxide : Consideration of Gas-Liquid Friction Force

2011 ◽  
Vol 2011 (0) ◽  
pp. 57-58
Author(s):  
Suguru KATAYAMA ◽  
Yoichi KINOUE ◽  
Norimasa SHIOMI ◽  
Toshiaki SETOGUCHI
Keyword(s):  
Carbon Dioxide ◽  
Friction Force ◽  
High Speed ◽  
Nozzle Flow ◽  
Two Phase

4B2 High-Speed Gas-Liquid Two-Phase Nozzle Flow for Carbon Dioxide : Velocity Measurement by PIV

2014 ◽  
Vol 2014 (0) ◽  
pp. _4B2-1_-_4B2-2_
Author(s):  
Satoshi UENO ◽  
Wakana TURU ◽  
Yoichi KINOUE ◽  
Morimasa SHIOMI ◽  
Toshiaki SETOGUCHI
Keyword(s):  
Carbon Dioxide ◽  
Velocity Measurement ◽  
High Speed ◽  
Nozzle Flow ◽  
Two Phase

scholarly journals Two-phase nozzle flow and the subcharacteristic condition

2015 ◽  
Vol 426 (2) ◽  
pp. 917-934 ◽  
Author(s):  
Gaute Linga ◽  
Peder Aursand ◽  
Tore Flåtten
Keyword(s):  
Nozzle Flow ◽  
Two Phase

Numerical Simulation of Two-Phase Flow in Injection Nozzles: Interaction of Cavitation and External Jet Formation

2003 ◽  
Vol 125 (6) ◽  
pp. 963-969 ◽  
Author(s):  
Weixing Yuan ◽  
Gu¨nter H. Schnerr
Keyword(s):  
Numerical Simulation ◽  
Boundary Conditions ◽  
Strong Interaction ◽  
Two Phase Flow ◽  
Nozzle Flow ◽  
Phase Flow ◽  
Jet Formation ◽  
Two Phase ◽  
Internal Problem

The present investigation demonstrates the strong interaction of cavitating nozzle flow with the outside jet formation. Due to the strong sensitivity of cavitation on the imposed boundary conditions, simulations with restriction on the internal problem are qualitatively and quantitatively incorrect, so that phenomena like hydraulic flip and supercavitation cannot be revealed. Our results indicate the potential of cavitation for enhancement of atomization and spray quality.

Validation of a Three-Dimensional Internal Nozzle Flow Model Including Automatic Mesh Generation and Cavitation Effects

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Hongwu Zhao ◽  
Shaoping Quan ◽  
Meizhong Dai ◽  
Eric Pomraning ◽  
P. K. Senecal ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Nozzle Flow ◽  
Two Phase ◽  
Flow Solver ◽  
Fuel Injectors ◽  
Contour Shape ◽  
Engine Combustion ◽  
Nozzle Configuration ◽  
Computational Fluid Dynamics Cfd ◽  
Automatic Mesh

Fuel injectors often experience cavitation due to regions of extremely low pressure. In this work, a cavitation modeling method is implemented in the CONVERGE computational fluid dynamics (CFD) code in order to model the flow in fuel injectors. The CONVERGE code includes a Cartesian mesh based flow solver. In this solver, a volume of fluid (VOF) method is used to simulate the multiphase flow. The cavitation model is based on a flash-boiling method with rapid heat transfer between the liquid and vapor phases. In this method, a homogeneous relaxation model is used to describe the rate at which the instantaneous quality, the mass fraction of vapor in a two-phase mixture, will tend towards its equilibrium value. The model is first validated with the nozzle flow case of Winklhofer by comparing the mass flow rate with experimentally measured values at different outlet pressures. The cavitation contour shape is also compared with the experimental observations. Flow in the Engine Combustion Network Spray-A nozzle configuration is simulated. The mesh dependency is also studied in this work followed by validation against discharge coefficient data. Finally, calculations of a five-hole injector, including moving needle effects, are compared to experimental measurements.

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