CFD Analysis of Engines: An Advanced Approach Based on Codes Dynamically Coupled

2003 ◽  
Author(s):  
Angelo De Vita ◽  
Luca Di Angelo ◽  
Luca Andreassi
Keyword(s):  
Data Exchange ◽  
Internal Combustion Engines ◽  
Gas Flow ◽  
Three Dimensional ◽  
Test Case ◽  
3D Effects ◽  
Flow Effects ◽  
Race Cars ◽  
Direct Feedback ◽  
Physical Phenomena

An advanced approach to evaluate the gas flow in internal combustion engines has been carried out. It is based on an interactive procedure which dynamically couples one-dimensional (1D) and three dimensional (3D) computational fluid dynamics codes. Direct feedback between the codes has been assured allowing 3D fluid flow effects to be fed back into the 1D system. A cycle-by-cycle convergence of results in the data exchange sections has been guaranteed. The capability of describing physical phenomena increases and some numerical problems, as the reflection of pressure waves on the 3D grid boundaries, can be avoided. The procedure has been applied to a simple test case and to a typical engine application where 3D effects are not negligible: flow field definition within an air box for race cars. The procedure has proven effective and could be easily adapted for further different applications.

The exploitation of three-dimensional flow in turbomachinery design

1998 ◽  
Vol 213 (2) ◽  
pp. 125-137 ◽  
Author(s):  
J. D. Denton ◽  
L Xu
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Field Calculation ◽  
3D Flow ◽  
Three Dimensional Flow ◽  
Approximate Methods ◽  
Blade Row ◽  
3D Effects ◽  
Flow Effects ◽  
Turbomachinery Design

Many of the phenomena involved in turbomachinery flow can be understood and predicted on a two-dimensional (2D) or quasi-three-dimensional (Q3D) basis, but some aspects of the flow must be considered as fully three-dimensional (3D) and cannot be understood or predicted by the Q3D approach. Probably the best known of these fully 3D effects is secondary flow, which can only be predicted by a fully 3D calculation which includes the vorticity at inlet to the blade row. It has long been recognized that blade sweep and lean also produce fully 3D effects and approximate methods of calculating these have been developed. However, the advent of fully 3D flow field calculation methods has made predictions of these complex effects much more readily available and accurate so that they are now being exploited in design. This paper will attempt to describe and discuss fully 3D flow effects with particular reference to their use to improve turbomachine performance. Although the discussion is restricted to axial flow machines, many of the phenomena discussed are equally applicable to mixed and radial flow turbines and compressors.

Three-Dimensional Simulation of Plasma Spray Jet

2003 ◽  
Author(s):  
H. Xiong ◽  
L. L. Zheng ◽  
S. Sampath ◽  
Jim Fincke ◽  
Richard Williamson
Keyword(s):  
Plasma Spray ◽  
Gas Flow ◽  
Probability Distributions ◽  
Three Dimensional ◽  
Plasma Jet ◽  
Carrier Gas ◽  
Spray Process ◽  
Lagrangian Coordinate ◽  
Dimensional Simulation ◽  
Physical Phenomena

A three-dimensional computational model has been developed to describe the compressible, multi-component, turbulent, reacting plasma jet coupled with the orthogonal injection of carrier gas and particles. This model has been applied to plasma spray process that includes physical phenomena such as heating, melting, accelerating, and evaporation of in-flight particles. The entrained particles, NiCrAlY and ZrO2, are discretely treated in a Lagrangian coordinate and stochastically generated by sampling from the probability distributions of the particle size and its velocity at the injection nozzle. In this study, special attention has been directed to the effects of carrier gas injection on the characteristics of plasma jet. The computational results show that the injection of carrier gas from the orthogonal injector above the plasma jet introduce the 3-D phenomena of plasma gas flow. The plasma jet is defected and the thermo-fluid flow near the injector is locally deformed.

scholarly journals The Correctness of the Simplified Bernoulli Trial (SBT) Collision Scheme of Calculations of Two-Dimensional Flows

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 127
Author(s):  
Kiril Shterev
Keyword(s):  
Gas Flow ◽  
Three Dimensional ◽  
Direct Simulation Monte Carlo ◽  
Mean Free Path ◽  
Cumulative Distribution ◽  
Test Case ◽  
Two Dimensional ◽  
Bernoulli Trial ◽  
The Mean ◽  
Two Dimensional Flows

Micro-electromechanical systems (MEMS) have developed rapidly in recent years in various technical fields that have increased their interest in the Direct Simulation Monte Carlo (DSMC) method. In this paper, we present a simple representation of the DSMC collision scheme and investigate the correctness of the Simplified Bernoulli Trial (SBT) collision scheme for the calculation of two-dimensional flows. The first part of the collision scheme, which determines collision pairs, is presented following the derivation of the expression for the mean free path and using the cumulative distribution function. Approaches and conclusions based on one-dimensional flows are not always directly applicable to two- and three-dimensional flows. We investigated SBT correctness by using the two-dimensional pressure-driven gas flow of monoatomic gas as a test case. We studied the influence of shuffling of the list of particles per cell (PPC) before the collision scheme’s execution, as well as the minimal and maximal number of PPC, on the correctness of the solution. The investigation showed that shuffling and the number of PPC played an important role in the correctness of SBT. Our recommendations are straightforwardly applicable to three-dimensional flows. Finally, we considered the mixing of two gases and compared the results available in the literature.

RESEARCH OF SEPARATION GRADIENT AEROSOL TECHNOLOGIES FOR INTENSIFICATION OF HEAT AND MASS TRANSFER PROCESSES IN SYSTEMS OF HIGHLY TURBULENT DISPERSED BIPHASIC FLOWS. APPLICATION OF THREEDIMENSIONAL MODELING FOR GRADIENT AEROSOL TECHNOLOGIES FOR SEPARATING GRANKCASE GASES

2019 ◽  
pp. 62-69
Author(s):  
Sergiy Ryzhkov
Keyword(s):  
Internal Combustion Engines ◽  
Gas Flow ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Combustion Engines ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Mass Transfer Processes ◽  
Three Dimensional Models ◽  
Special Stand

Three-dimensional modeling has been applied for gradient aerosol technologies designed for separating crankcase gases of internal combustion engines. Three-dimensional models are created for the numerical experiment of an improved prototype oil separator. Studies are carried out for the range of the crankcase gas flow rate of 2...10 m3/h. Based on the calculations, a prototype separator was developed; its experimental studies were carried out on a special stand. The coefficient of the total purification efficiency is determined; it reaches 99.9 %.

A Study of Fan-Distortion Interaction Within the NASA Rotor 67 Transonic Stage

2010 ◽  
Author(s):  
V. Jerez Fidalgo ◽  
C. A. Hall ◽  
Y. Colin
Keyword(s):  
Total Pressure ◽  
Three Dimensional ◽  
Measurement Data ◽  
Test Case ◽  
Complex Flow ◽  
Inlet Flow ◽  
Flow Features ◽  
Work Input ◽  
Flow Effects ◽  
Transonic Fan

The performance of a transonic fan operating within non-uniform inlet flow remains a key concern for the design and operability of a turbofan engine. This paper applies computational methods to improve the understanding of the interaction between a transonic fan and an inlet total pressure distortion. The test case studied is the NASA rotor 67 stage operating with a total pressure distortion covering a 120-degree sector of the inlet flow-field. Full-annulus, unsteady, three-dimensional CFD has been used to simulate the test rig installation and the full fan assembly operating with inlet distortion. Novel post-processing methods have been applied to extract the fan performance and features of the interaction between the fan and the non-uniform inflow. The results of the unsteady computations agree well with the measurement data. The local operating condition of the fan at different positions around the annulus has been tracked and analysed, and this is shown to be highly dependent on the swirl and mass flow redistribution that the rotor induces ahead of it due to the incoming distortion. The upstream flow effects lead to a variation in work input that determines the distortion pattern seen downstream of the fan stage. In addition, the unsteady computations also reveal more complex flow-features downstream of the fan stage, which arise due to the three-dimensionality of the flow and unsteadiness.

A Study of Fan-Distortion Interaction Within the NASA Rotor 67 Transonic Stage

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
V. Jerez Fidalgo ◽  
C. A. Hall ◽  
Y. Colin
Keyword(s):  
Total Pressure ◽  
Three Dimensional ◽  
Measurement Data ◽  
Test Case ◽  
Complex Flow ◽  
Inlet Flow ◽  
Flow Features ◽  
Work Input ◽  
Flow Effects ◽  
Transonic Fan

The performance of a transonic fan operating within nonuniform inlet flow remains a key concern for the design and operability of a turbofan engine. This paper applies computational methods to improve the understanding of the interaction between a transonic fan and an inlet total pressure distortion. The test case studied is the NASA rotor 67 stage operating with a total pressure distortion covering a 120-deg sector of the inlet flow field. Full-annulus, unsteady, three-dimensional CFD has been used to simulate the test rig installation and the full fan assembly operating with inlet distortion. Novel post-processing methods have been applied to extract the fan performance and features of the interaction between the fan and the nonuniform inflow. The results of the unsteady computations agree well with the measurement data. The local operating condition of the fan at different positions around the annulus has been tracked and analyzed, and this is shown to be highly dependent on the swirl and mass flow redistribution that the rotor induces ahead of it due to the incoming distortion. The upstream flow effects lead to a variation in work input that determines the distortion pattern seen downstream of the fan stage. In addition, the unsteady computations also reveal more complex flow features downstream of the fan stage, which arise due to the three dimensionality of the flow and unsteadiness.

A Three-Dimensional Model for the Prediction of Shock Losses in Compressor Blade Rows

1983 ◽  
Author(s):  
Arthur J. Wennerstrom ◽  
Steven L. Puterbaugh
Keyword(s):  
Aspect Ratio ◽  
Three Dimensional ◽  
Leading Edge ◽  
Compressor Blade ◽  
Turbine Engines ◽  
Test Case ◽  
Three Dimensional Model ◽  
Aspect Ratios ◽  
Flow Effects ◽  
Shock Loss

A design trend evident in newly evolving aircraft turbine engines is a reduction in the aspect ratio of blading employed in fans, compressors, and turbines. As aspect ratio is reduced, various three-dimensional flow effects become significant which at higher aspect ratios could safely be neglected. This paper presents a new model for predicting the shock loss through a transonic or supersonic compressor blade row operating at peak efficiency. It differs from the classical Miller-Lewis-Hartmann normal shock model by taking into account the spanwise obliquity of the shock surface due to leading-edge sweep, blade twist, and solidity variation. The model is evaluated in combination with two test cases. Each was a low-aspect-ratio transonic stage which had exceeded its efficiency goals. Use of the revised shock loss model contributed 2.11 points to the efficiency of the first test case and 1.08 points to the efficiency of the second.

A Three-Dimensional Model for the Prediction of Shock Losses in Compressor Blade Rows

1984 ◽  
Vol 106 (2) ◽  
pp. 295-299 ◽  
Author(s):  
A. J. Wennerstrom ◽  
S. L. Puterbaugh
Keyword(s):  
Aspect Ratio ◽  
Three Dimensional ◽  
Leading Edge ◽  
Compressor Blade ◽  
Turbine Engines ◽  
Test Case ◽  
Three Dimensional Model ◽  
Aspect Ratios ◽  
Flow Effects ◽  
Shock Loss

A design trend evident in newly evolving aircraft turbine engines is a reduction in the aspect ratio of blading employed in fans, compressors, and turbines. As aspect ratio is reduced, various three-dimensional flow effects become significant which at higher aspect ratios could safely be neglected. This paper presents a new model for predicting the shock loss through a transonic or supersonic compressor blade row operating at peak efficiency. It differs from the classical Miller-Lewis-Hartmann normal shock model by taking into account the spanwise obliquity of the shock surface due to leading-edge sweep, blade twist, and solidity variation. The model is evaluated in combination with three test cases. Each was a low-aspect-ratio transonic stage which had exceeded its efficiency goals. Use of the revised shock loss model contributed 2.11 points to the efficiency of the first test case, 1.08 points to the efficiency of the second, and 1.38 points to the efficiency of the third.

Real gas flow fields about three dimensional configurations

1983 ◽  
Author(s):  
A. BALAKRISHNAN ◽  
C. LOMBARD ◽  
W.C. DAVY
Keyword(s):  
Gas Flow ◽  
Three Dimensional ◽  
Flow Fields ◽  
Real Gas

scholarly journals Modeling of three-dimensional exciplex pumped fluid Cs vapor laser with transverse and longitudinal gas flow

2021 ◽  
Vol 9 ◽  
Author(s):  
Chenyi Su ◽  
Xingqi Xu ◽  
Jinghua Huang ◽  
Bailiang Pan
Keyword(s):  
Wall Temperature ◽  
Laser Power ◽  
Gas Flow ◽  
Particle Density ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Heat Accumulation ◽  
Vapor Laser ◽  
Output Laser Power ◽  
Output Laser

Abstract Considering the thermodynamical fluid mechanics in the gain medium and laser kinetic processes, a three-dimensional theoretical model of an exciplex-pumped Cs vapor laser with longitudinal and transverse gas flow is established. The slope efficiency of laser calculated by the model shows good agreement with the experimental data. The comprehensive three-dimensional distribution of temperature and particle density of Cs is depicted. The influence of pump intensity, wall temperature, and fluid velocity on the laser output performance is also simulated and analyzed in detail, suggesting that a higher wall temperature can guarantee a higher output laser power while causing a more significant heat accumulation in the cell. Compared with longitudinal gas flow, the transverse flow can improve the output laser power by effectively removing the generated heat accumulation and alleviating the temperature gradient in the cell.

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