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.

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.

scholarly journals Improvement of a multiphase flow model for wellhead chokes under critical and subcritical conditions using field data

2021 ◽  
Vol 11 (3) ◽  
pp. 1487-1503
Author(s):  
Mariella Leporini ◽  
Alessandro Terenzi ◽  
Barbara Marchetti
Keyword(s):  
Multiphase Flow ◽  
Field Data ◽  
Discharge Coefficient ◽  
Model Parameters ◽  
Incoming Stream ◽  
Three Phase ◽  
Production Wells ◽  
Three Phase Flow ◽  
Flow Through ◽  
Definition Of

AbstractThe characterization of the multiphase flow through valves and orifices is a problem yet to be solved in engineering design, and there is a need for a prediction model able to simulate the complexity of this kind of flow in relation to fluid thermodynamic behaviour, and applicable to different incoming stream conditions and compositions. The present paper describes the development of a global model for the calculation of the discharge coefficient of orifices and choke valves operating under two- and three-phase flow as well as critical and subcritical conditions. The model generalizes the hydrovalve model developed by Selmer-Olsen et al. (in: Wilson (ed) Proceedings of 7th international conference on Multiphase Production, BHR Group, pp 441–446, 1995) and the Henry–Fauske (J Heat Transfer 93: 179–187, 1971. 10.1115/1.3449782) non-equilibrium model on the basis of an updated definition of the discharge coefficient. The model has been adapted to real choke valve geometries, by fitting the discharge coefficient and model parameters using field data from three production wells. The model developed is a global quartic function with different constants for the different valve geometries. The new discharge coefficient allows to simulate field data with high accuracy.

scholarly journals Numerical investigation of injection parameters and piston bowl geometries on emission and thermal performance of DI diesel engine

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Ikhtedar Husain Rizvi ◽  
Rajesh Gupta
Keyword(s):  
Diesel Engine ◽  
Thermal Performance ◽  
Equivalence Ratio ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Injection Nozzle ◽  
Piston Bowl ◽  
Injection Parameters ◽  
Nozzle Size ◽  
Engine Emission

AbstractTightening noose on engine emission norms compelled manufacturers globally to design engines with low emission specially NOx and soot without compromising their performance. Amongst various parameters, shape of piston bowls, injection pressure and nozzle diameter are known to have significant influence over the thermal performance and emission emanating from the engine. This paper investigates the combined effect of fuel injection parameters such as pressure at which fuel is injected and the injection nozzle size along with shape of piston bowl on engine emission and performance. Numerical simulation is carried out using one cylinder naturally aspirated diesel engine using AVL FIRE commercial code. Three geometries of piston bowls with different tumble and swirl characteristics are considered while maintaining the volume of piston bowl, compression ratio, engine speed and fuel injected mass constant along with equal number of variations for injection nozzle size and pressures for this analysis. The investigation corroborates that high swirl and large turbulence kinetic energy (TKE) are crucial for better combustion. TKE and equivalence ratio also increased as the injection pressure increases during the injection period, hence, enhances combustion and reduces soot formation. Increase in nozzle diameter produces higher TKE and equivalence ratio, while CO and soot emission are found to be decreasing and NOx formation to be increasing. Further, optimization is carried out for twenty-seven cases created by combining fuel injection parameters and piston bowl geometries. The case D2H1P1 (H1 = 0.2 mm, P1 = 200 bar) found to be an optimum case because of its lowest emission level with slightly better performance.

scholarly journals Transient Pressure-Driven Electroosmotic Flow through Elliptic Cross-Sectional Microchannels with Various Eccentricities

Computation ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 27
Author(s):  
Nattakarn Numpanviwat ◽  
Pearanat Chuchard
Keyword(s):  
Laplace Transform ◽  
Electroosmotic Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Mathieu Functions ◽  
Navier Stokes Equations ◽  
Flow Rates ◽  
Elliptic Cross ◽  
Flow Through ◽  
Relative Errors

The semi-analytical solution for transient electroosmotic flow through elliptic cylindrical microchannels is derived from the Navier-Stokes equations using the Laplace transform. The electroosmotic force expressed by the linearized Poisson-Boltzmann equation is considered the external force in the Navier-Stokes equations. The velocity field solution is obtained in the form of the Mathieu and modified Mathieu functions and it is capable of describing the flow behavior in the system when the boundary condition is either constant or varied. The fluid velocity is calculated numerically using the inverse Laplace transform in order to describe the transient behavior. Moreover, the flow rates and the relative errors on the flow rates are presented to investigate the effect of eccentricity of the elliptic cross-section. The investigation shows that, when the area of the channel cross-sections is fixed, the relative errors are less than 1% if the eccentricity is not greater than 0.5. As a result, an elliptic channel with the eccentricity not greater than 0.5 can be assumed to be circular when the solution is written in the form of trigonometric functions in order to avoid the difficulty in computing the Mathieu and modified Mathieu functions.

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