A Computational Study of the Mixture Preparation in a Direct–Injection Hydrogen Engine

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Jerome Le Moine ◽  
P. K. Senecal ◽  
Sebastian A. Kaiser ◽  
Victor M. Salazar ◽  
Jon W. Anders ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Computational Study ◽  
Early Stage ◽  
Direct Injection ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Fuel Mixture ◽  
Compression Stroke ◽  
Mixture Preparation

This paper reports the validation of a three-dimensional numerical simulation of the mixture preparation in a direct-injection (DI) hydrogen-fueled engine. Computational results from the commercial code CONVERGE are compared to the experimental data obtained from an optically accessible engine. The geometry used in the simulation is a passenger-car sized, four-stroke, and spark-ignited engine. The simulation includes the geometry of the combustion chamber as well as the intake and exhaust ports. The hydrogen is supplied at 100 bar from a centrally located injector with a single-hole nozzle. The comparison between the simulation and experimental data is made on the central vertical plane. The fuel mole concentration and flow field are compared during the compression stroke at different crank angles (CA). The comparison shows good agreement between the numerical and experimental results during the early stage of the compression stroke. The penetration of the jet and the interaction with the cylinder walls are correctly predicted. The fuel spreading is under predicted which results in differences in flow field and fuel mixture during the injection between experimental and numerical results. At the end of the injection, the fuel distribution shows some disagreement which gradually increases during the rest of the simulation.

A Computational Study of the Mixture Preparation in a Direct Injection Hydrogen Engine

2014 ◽  
Author(s):  
Jerome Le Moine ◽  
P. K. Senecal ◽  
Sebastian A. Kaiser ◽  
Victor M. Salazar ◽  
Jon W. Anders ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Computational Study ◽  
Early Stage ◽  
Direct Injection ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Fuel Mixture ◽  
Compression Stroke ◽  
Mixture Preparation

This paper reports the validation of a three-dimensional numerical simulation of the mixture preparation in a direct-injection hydrogen-fueled engine. Computational results from the commercial code CONVERGE are compared to the experimental data obtained from an optically accessible engine. The geometry used in the simulation is a passenger-car sized, four-stroke, spark-ignited engine. The simulation includes the geometry of the combustion chamber as well as the intake and exhaust ports. The hydrogen is supplied at 100 bar from a centrally located injector with a single-hole nozzle. The comparison between the simulation and experimental data is made on the central vertical plane. The fuel mole concentration and flow field are compared during the compression stroke at different crank angles. The comparison shows good agreement between the numerical and experimental results during the early stage of the compression stroke. The penetration of the jet and the interaction with the cylinder walls are correctly predicted. The fuel spreading is under predicted which results in differences in flow field and fuel mixture during the injection between experimental and numerical results. At the end of the injection, the fuel distribution shows some disagreement which gradually increases during the rest of the simulation.

Aero-Thermal Investigation of a Rib-Roughened Trailing Edge Channel With Crossing-Jets: Part I—Flow Field Analysis

2008 ◽  
Author(s):  
Alessandro Armellini ◽  
Filippo Coletti ◽  
Tony Arts ◽  
Christophe Scholtes
Keyword(s):  
Flow Field ◽  
Computational Study ◽  
Three Dimensional ◽  
Side Wall ◽  
Field Analysis ◽  
Trailing Edge ◽  
Present Contribution ◽  
Numerical Predictions ◽  
Flow Features ◽  
Rib Roughened

The present contribution addresses the aero-thermal experimental and computational study of a trapezoidal cross-section model simulating a trailing edge cooling cavity with one rib-roughened wall. The flow is fed through tilted slots on one side wall and exits through straight slots on the opposite side wall. The flow field aerodynamics is investigated in part I of the paper. The reference Reynolds number is defined at the entrance of the test section and set at 67500 for all the experiments. A qualitative flow model is deduced from surface-streamline flow visualizations. Two-dimensional Particle Image Velocimetry measurements are performed in several planes around mid-span of the channel and recombined to visualize and quantify three-dimensional flow features. The jets issued from the tilted slots are characterized and the jet-rib interaction is analyzed. Attention is drawn to the motion of the flow deflected by the rib-roughened wall and impinging on the opposite smooth wall. The experimental results are compared with the numerical predictions obtained from the finite volume, RANS solver CEDRE.

Blade-Row Interactions in an LP Turbine at Design and Strong Off-Design Operation

2014 ◽  
Author(s):  
Martin Lipfert ◽  
Jan Habermann ◽  
Martin G. Rose ◽  
Stephan Staudacher ◽  
Yavuz Guendogdu
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Three Dimensional ◽  
Suction Side ◽  
Test Facility ◽  
Time Resolved ◽  
Joint Project ◽  
Multi Stage ◽  
Blade Row ◽  
Wake Interactions

In a joint project between the Institute of Aircraft Propulsion Systems (ILA) and MTU Aero Engines a two-stage low pressure turbine is tested at design and strong off-design conditions. The experimental data taken in the altitude test-facility aims to study the effect of positive and negative incidence of the second stator vane. A detailed insight and understanding of the blade row interactions at these regimes is sought. Steady and time-resolved pressure measurements on the airfoil as well as inlet and outlet hot-film traverses at identical Reynolds number are performed for the midspan streamline. The results are compared with unsteady multi-stage CFD predictions. Simulations agree well with the experimental data and allow detailed insights in the time-resolved flow-field. Airfoil pressure field responses are found to increase with positve incidence whereas at negative incidence the magnitude remains unchanged. Different pressure to suction side phasing is observed for the studied regimes. The assessment of unsteady blade forces reveals that changes in unsteady lift are minor compared to changes in axial force components. These increase with increasing positive incidence. The wake-interactions are predominating the blade responses in all regimes. For the positive incidence conditions vane 1 passage vortex fluid is involved in the midspan passage interaction leading to a more distorted three-dimensional flow field.

scholarly journals On the formation of the counter-rotating vortex pair in transverse jets

2001 ◽  
Vol 446 ◽  
pp. 347-373 ◽  
Author(s):  
L. CORTELEZZI ◽  
A. R. KARAGOZIAN
Keyword(s):  
Flow Field ◽  
Computational Study ◽  
Near Field ◽  
Three Dimensional ◽  
Vortex Pair ◽  
Transverse Jets ◽  
Vortical Structures ◽  
Jet In Crossflow ◽  
Dynamical Generation ◽  
Counter Rotating Vortex Pair

Among the important physical phenomena associated with the jet in crossflow is the formation and evolution of vortical structures in the flow field, in particular the counter-rotating vortex pair (CVP) associated with the jet cross-section. The present computational study focuses on the mechanisms for the dynamical generation and evolution of these vortical structures. Transient numerical simulations of the flow field are performed using three-dimensional vortex elements. Vortex ring rollup, interactions, tilting, and folding are observed in the near field, consistent with the ideas described in the experimental work of Kelso, Lim & Perry (1996), for example. The time-averaged effect of these jet shear layer vortices, even over a single period of their evolution, is seen to result in initiation of the CVP. Further insight into the topology of the flow field, the formation of wake vortices, the entrainment of crossflow, and the effect of upstream boundary layer thickness is also provided in this study.

Blade–Row Interactions in a Low Pressure Turbine at Design and Strong Off-Design Operation

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Martin Lipfert ◽  
Jan Habermann ◽  
Martin G. Rose ◽  
Stephan Staudacher ◽  
Yavuz Guendogdu
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Three Dimensional ◽  
Suction Side ◽  
Low Pressure ◽  
Test Facility ◽  
Time Resolved ◽  
Joint Project ◽  
Low Pressure Turbine ◽  
Blade Row

In a joint project between the Institute of Aircraft Propulsion Systems (ILA) and MTU Aero Engines, a two-stage low pressure turbine is tested at design and strong off-design conditions. The experimental data taken in the Altitude Test Facility (ATF) aims to study the effect of positive and negative incidence of the second stator vane. A detailed insight and understanding of the blade row interactions at these regimes is sought. Steady and time-resolved pressure measurements on the airfoil as well as inlet and outlet hot-film traverses at identical Reynolds number are performed for the midspan streamline. The results are compared with unsteady multistage computational fluid dynamics (CFD) predictions. Simulations agree well with the experimental data and allow detailed insights in the time-resolved flow-field. Airfoil pressure field responses are found to increase with positive incidence whereas at negative incidence the magnitude remains unchanged. Different pressure to suction side (SS) phasing is observed for the studied regimes. The assessment of unsteady blade forces reveals that changes in unsteady lift are minor compared to changes in axial force components. These increase with increasing positive incidence. The wake-interactions are predominating the blade responses in all regimes. For the positive incidence conditions, vane 1 passage vortex fluid is involved in the midspan passage interaction, leading to a more distorted three-dimensional (3D) flow field.

scholarly journals Design and analysis of flow rectifier of gas turbine flowmeter

2013 ◽  
Vol 17 (5) ◽  
pp. 1504-1507 ◽  
Author(s):  
Zhi-Fei Li ◽  
Zheng Du ◽  
Kai Zhang ◽  
Dong-Sheng Li ◽  
Zhong-Di Su ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Computational Model ◽  
Pressure Distribution ◽  
Gas Turbine ◽  
Turbulence Model ◽  
Pressure Loss ◽  
Three Dimensional ◽  
Turbine Flowmeter ◽  
Good Agreement

Three-dimensional computational model for a gas turbine flowmeter is proposed, and the finite volume based SIMPLEC method and k-? turbulence model are used to obtain the detailed information of flow field in turbine flowmeter, such as velocity and pressure distribution. Comparison between numerical results and experimental data reveals a good agreement. A rectifier with little pressure loss is optimally designed and validated numerically and experimentally.

Numerical Investigation of the 3D Flow Field in a Steam Turbine Axial Exhaust Diffuser: Comparison With Experimental Data and Performance Evaluation

2013 ◽  
Author(s):  
Federico Daccà ◽  
Claudio Canelli ◽  
Stefano Cecchi
Keyword(s):  
Experimental Data ◽  
Performance Evaluation ◽  
Flow Field ◽  
Steam Turbine ◽  
Three Dimensional ◽  
Measured Data ◽  
Accurate Performance ◽  
And Performance ◽  
Lp Turbine ◽  
Actual Geometry

The purpose of this paper is to present a numerical analysis carried out for the performance evaluation of the axial exhaust diffuser of a LP steam turbine. A set of measured data in an actual real scale steam turbine is available for direct comparison. The three dimensional exhaust flow in a LP steam turbine provided with a 48″ LSB is numerically investigated in different real working conditions by means of 3D CFD analysis. A detailed 3D model of the actual geometry is used in order to catch the highly 3D features of the flow field, avoiding the use of numerical periodicity conditions. Boundary conditions are derived both from experimental data and from specific validated 3D simulations of the main flow of the entire LP turbine section from front stages up to the LSN. The comparison with measured data allows to validate the performed CFD simulations and to provide a reliable complete performance curve of the exhaust diffuser geometry coupled with the 48″ LSB design. An important outcome of the work consists also in a generalized method for accurate performance evaluation of axial diffusers.

Experimental and Computational Study of Oscillating Turbine Cascade and Influence of Part-Span Shrouds

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
X. Q. Huang ◽  
L. He ◽  
David L. Bell
Keyword(s):  
Experimental Data ◽  
Computational Study ◽  
Three Dimensional ◽  
Unsteady Flows ◽  
Correction Method ◽  
Influence Coefficient ◽  
Turbine Cascade ◽  
Test Configuration ◽  
Practical Applications ◽  
Influence Coefficient Method

This paper presents a combined experimental and computational study of unsteady flows in a linear turbine cascade oscillating in a three-dimensional bending/flapping mode. Detailed experimental data are obtained on a seven-bladed turbine cascade rig. The middle blade is driven to oscillate and oscillating cascade data are obtained using an influence coefficient method. The numerical simulations are performed by using a 3D nonlinear time-marching Navier–Stokes flow solver. Single-passage domain computations for arbitrary interblade phase angles are achieved by using the Fourier shape correction method. Both measurements and predictions demonstrate a fully 3D behavior of the unsteady flows. The influence of the aerodynamic blockage introduced by part-span shrouds on turbine flutter has been investigated by introducing flat plate shaped shrouds at 75% span. In contrast to practical applications, in the present test configuration, the mode of vibration of the blades remains unchanged by the introduction of the part-span shroud. This allows the influence of the aerodynamic blockage introduced by the part-span shroud to be assessed in isolation from the change in mode shape. A simple shroud model has been developed in the computational solver. The computed unsteady pressures around the shrouds are in good agreement with the experimental data, demonstrating the validity of the simple shroud model. Despite of notable variations in local unsteady pressures around the shrouds, the present results show that the blade aerodynamic damping is largely unaffected by the aerodynamic blockage introduced by part-span shrouds.

Numerical Investigation of a Centrifugal Compressor for Supercritical CO2 Cycles

2020 ◽  
Author(s):  
Renan Emre Karaefe ◽  
Pascal Post ◽  
Marwick Sembritzky ◽  
Andreas Schramm ◽  
Francesca di Mare ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Flow Field ◽  
Numerical Simulations ◽  
Centrifugal Compressor ◽  
Supercritical Co2 ◽  
Solution Method ◽  
Three Dimensional ◽  
Solution Procedure ◽  
Test Loop

Abstract In this work, the performance characteristics and the flow field of a centrifugal compressor operating with supercritical CO2 are investigated by means of three-dimensional CFD. The considered geometry is based on main dimensions of the centrifugal compressor installed in the supercritical CO2 compression test-loop operated by Sandia National Laboratories. All numerical simulations are performed with a recently developed in-house hybrid CPU/GPU compressible CFD solver. Thermodynamic properties are computed through an efficient and accurate tabulation technique, the Spline-Based Table Look-Up Method (SBTL), particularly optimised for the applied density-based solution procedure. Numerical results are compared with available experimental data and accuracy as well as potentials in computational speedup of the solution method in combination with the SBTL are evaluated in the context of supercritical CO2 turbomachinery.

PIV Measurements of Recirculation Patterns in a Stirred Tank

2001 ◽  
Author(s):  
Khaled J. Hammad ◽  
George Papadopoulos
Keyword(s):  
Flow Field ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Vertical Axis ◽  
Transitional Flow ◽  
Piv Measurements ◽  
Vortical Structures ◽  
Blade Passage ◽  
Flow Field Characteristics

Abstract Phase-resolved PIV measurements were performed to reveal the detailed flow features within a triple impeller stirredtank. Two tests were performed: low and high rotational speeds, 175 and 575 RPM, respectively. The tests used an optically transparent mixing vessel to measure the 2D flow field characteristics along a vertical plane passing through the tank center. The measurements disclosed interesting in-plane vortical behavior that when measured at two angular positions with respect to the blade passage further indicated the three-dimensional flow behavior. For the low RPM case, a laminar flow nature was apparent, whereby vortical toroidal structures spanned around the stirrer vertical axis. Six such structures were dominant. For the high RPM case and for θ = 0° six dominant vortical structures were apparent. Their r-z plane location and size were different from that for the low RPM case. With blade passage four of these vortical structures appeared to merge into two, suggesting that constant toroidal vortical structures spanning around the stirrer axis were absent from the high RPM case. A switch between six distinct and four distinct in-plane vortical structures as the blades pass through the measurement plane further suggested a transitional flow field at 575 RPM.

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