Steady and Transient CFD Approach for Port Optimization

Gaikwad, Surendra; Arora, Kunal; Korivi, Vamshi; Cho, Su K.

doi:10.4271/2008-01-1430

Cited by 22 publications

(5 citation statements)

References 5 publications

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“…Generally, large energetic turbulent structures imply a substantial proportion of turbulent dissipation [27]. Hence, the LES approach reassembles a suitable trade between accuracy, reliability, and effort, which has been successfully applied to optimize the port geometry of internal combustion engines [28]. Many numerical investigations analyze the flow in the intake port and the consequences on the in-cylinder flow.…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, the flow in the ports of an internal combustion engine with pulsating boundary conditions has been simulated, e.g. [28]. However, the most studies emphasize on the computation models, performance parameter, or optimization of the geometry rather than giving insight into the generated flow structures occurring in the exhaust port.…”

Section: Introductionmentioning

confidence: 99%

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Flow effects due to pulsation in an internal combustion engine exhaust port

Semlitsch¹,

Wang²,

Mihăescu³

2014

Energy Conversion and Management

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In an internal combustion engine, the residual energy remaining after combustion in the exhaust gasses can be partially recovered by a downstream arranged device. The exhaust port represents the passage guiding the exhaust gasses from the combustion chamber to the energy recovering device, e.g. a turbocharger. Thus, energy losses in the course of transmission shall be reduced as much as possible. However, in one-dimensional engine models used for engine design, the exhaust port is reduced to its discharge coefficient, which is commonly measured under constant inflow conditions neglecting engine-like flow pulsation. In this present study, the influence of different boundary conditions on the energy losses and flow development during the exhaust stroke are analyzed numerically regarding two cases, i.e. using simple constant and pulsating boundary conditions. The compressible flow in an exhaust port geometry of a truck engine is investigated using three-dimensional Large Eddy Simulations (LES). The results contrast the importance of applying engine-like boundary conditions in order to estimate accurately the flow induced losses and the discharge coefficient of the exhaust port. The instantaneous flow field alters significantly when pulsating boundary conditions are applied. Thus, the induced losses by the unsteady flow motion and the secondary flow motion are increased with inflow pulsations. The discharge coefficient decreased about 2% with flow pulsation. A modal flow decomposition method, i.e. Proper Orthogonal Decomposition (POD), is used to analyze the coherent structures induced with the particular inflow and outflow conditions. The differences in the flow field for different boundary conditions suggest to incorporate a modeling parameter accounting for the quality of the flow at the turbocharger turbine inlet in one-dimensional simulations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Flow effects due to pulsation in an internal combustion engine exhaust port

Semlitsch¹,

Wang²,

Mihăescu³

2014

Energy Conversion and Management

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“…Bianchi et al [6] analyzed the vortex formation for small C/D ratio engines. Blaxill et al [7] presented a parametric analysis carried out detecting six fundamental geometric parameters capable to describe the intake duct with a fixed inlet valve lift, while Gaikwad et al [8] carried out an optimization process on an intake duct. In [9] results obtained performing experimental tests on three different intake ducts were reported.…”

Section: Literature Summary On the Tumble Motionmentioning

confidence: 99%

3D CFD Analysis of the Influence of Some Geometrical Engine Parameters on Small PFI Engine Performances - The Effects on Tumble Motion and Mean Turbulent Intensity Distribution

Falfari¹,

Bianchi²,

Nuti³

2012

SAE Technical Paper Series

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In scooter/motorbike engines coherent and stable tumble motion generation is still considered an effective mean in order to both reduce engine emissions and promote higher levels of combustion efficiency. The promotion of a stable and coherent tumble structure is largely believed in literature to enhance in-cylinder turbulence accelerating combustion process. In small PFI engine layout and weight constraints limit the adoption of more advanced concepts. In previous technical papers the authors demonstrated the influence of head shape and squish area on tumble vortex formation, development, breakdown and on final value of turbulence close to spark plug for small PFI engines. The main result of the this research was that the combustion chamber having the less squish area resulted to have the highest level of turbulence close to spark plug at ignition time. The geometry under analysis in the current paper is a 3-valves pent-roof motorcycle engine. 3D CFD simulations were ran at 6500 rpm with AVL FIRE code. The chosen engine geometry was the geometry found to be the best setup in terms of turbulence and combustion performances in the previous paper. In the present paper the head shape and the squish area were kept constant and the following engine parameters were varied: the intake duct angle (the angle of the intake duct entering the head was reduced of 6%, i.e. it was more directed toward the exhaust side of the chamber), the piston shape, and finally the compression ratio (it was reduced of 9%). The main goal of the current analysis is to understand which of these parameters is predominant in accelerating combustion for directing engine design toward the best setup .

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“…(1) carrying out steady-state port flow CFD analysis with design of experiment (DOE) to identify the best trade-off for port design (2) selecting few candidate designs and performing transient engine CFD analysis [2,3] Farly experimental and computational works contributed to the understanding of intake flow. Previous experimental studies of Tanka [4], Kastner et.al [5], and Bicen and Whitelaw et.al [6] investigated flow in the intake port and identified four regimes of now separation from low to high valve lift.…”

Section: Introductionmentioning

confidence: 99%

“…Although many articles related to steady-state intake port fiow simulation are available [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], many numerical details that affect solution accuracy were not presented or discussed. This report is an attempt to address the issue, in particular, effects of flow box orientation, upstream/downstream-plenum shape and size, and details of mesh topology.…”

Section: Introductionmentioning

confidence: 99%

Pitfalls for Accurate Steady-State Port Flow Simulations

Yang¹,

Chen²,

Kuo

2013

Journal of Engineering for Gas Turbines and Power

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Steady-state port flow simulations were carried out with a commercial three-dimensional (3D} computational fluid dynamics (CFD) code using Cartesian mesh with cut cells to study the prediction accuracy. The accuracy is assessed by comparing predicted and measured mass-flow rate and swirl and tumble torques at various valve lifts using different boundary condition setup and mesh topology relative to port orientation. The measured data are taken from standard steady-state flow bench tests of a production intake pott. The predicted mass-flow rates agree to within 1% with the measured data between the intermediate and high valve lifts. At low valve lifts, slight overptediction in mass-flow rate can be observed. The predicted swirl and tumble torques are within 25% of the flow bench measwements. Several meshing parameters were examined in this study. These include: inlet plenum shape and outlet plenum/extension size, embedded sphere with varying minimum mesh size,flner meshes on port and valve surface, orientation of valve, and port centerline relative to the mesh lines. For all model orientations examined, only the mesh topology with the valve axis aligned closely with the mesh lines can capture the mass-flow rate drop for very high valve lifts due to flow separation. This study further demonstrated that it is possible to pet form 3D CFD flow analyses to adequately simulate steady-state flow bench tests.

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Steady and Transient CFD Approach for Port Optimization

Cited by 22 publications

References 5 publications

Flow effects due to pulsation in an internal combustion engine exhaust port

Flow effects due to pulsation in an internal combustion engine exhaust port

3D CFD Analysis of the Influence of Some Geometrical Engine Parameters on Small PFI Engine Performances - The Effects on Tumble Motion and Mean Turbulent Intensity Distribution

Pitfalls for Accurate Steady-State Port Flow Simulations

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