scholarly journals Numerical Analysis of Engine Exhaust Flow Parameters for Resolving Pre-Turbine Pulsating Flow Enthalpy and Exergy

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6183
Author(s):  
Beichuan Hong ◽  
Varun Venkataraman ◽  
Andreas Cronhjort
Keyword(s):  
High Resolution ◽  
Flow Velocity ◽  
Flow Parameter ◽  
Pulsating Flow ◽  
Specific Enthalpy ◽  
Engine Exhaust ◽  
Global Sensitivity ◽  
Temperature Pulse ◽  
Flow Parameters ◽  
Crank Angle

Energy carried by engine exhaust pulses is critical to the performance of a turbine or any other exhaust energy recovery system. Enthalpy and exergy are commonly used concepts to describe the energy transport by the flow based on the first and second laws of thermodynamics. However, in order to investigate the crank-angle-resolved exhaust flow enthalpy and exergy, the significance of the flow parameters (pressure, velocity, and temperature) and their demand for high resolution need to be ascertained. In this study, local and global sensitivity analyses were performed on a one-dimensional (1D) heavy-duty diesel engine model to quantify the significance of each flow parameter in the determination of exhaust enthalpy and exergy. The effects of parameter sweeps were analyzed by local sensitivity, and Sobol indices from the global sensitivity showed the correlations between each flow parameter and the computed enthalpy and exergy. The analysis indicated that when considering the specific enthalpy and exergy, flow temperature is the dominant parameter and requires high resolution of the temperature pulse. It was found that a 5% sweep over the temperature pulse leads to maximum deviations of 31% and 27% when resolving the crank angle-based specific enthalpy and specific exergy, respectively. However, when considering the total enthalpy and exergy rates, flow velocity is the most significant parameter, requiring high resolution with a maximum deviation of 23% for the enthalpy rate and 12% for the exergy rate over a 5% sweep of the flow velocity pulse. This study will help to quantify and prioritize fast measurements of pulsating flow parameters in the context of turbocharger turbine inlet flow enthalpy and exergy analysis.

Analysis of pulsating flow measurement of engine exhaust by a Pitot tube flowmeter

2005 ◽  
Vol 6 (1) ◽  
pp. 85-93 ◽  
Author(s):  
H Nakamura ◽  
I Asano ◽  
M Adachi ◽  
J Senda
Keyword(s):  
Fast Response ◽  
Differential Pressure ◽  
Pulsating Flow ◽  
Pitot Tube ◽  
Engine Exhaust ◽  
Idle Speed ◽  
Pressure Transducers ◽  
Vehicle Engine ◽  
Before And After ◽  
Response Pressure

The Pitot tube flowmetering technique has been used to measure pulsating flow from a vehicle engine exhaust. In general, flowmetering techniques that utilize differential pressure measurements based on Bernoulli's theory are likely to show erroneous readings when measuring an average flowrate of pulsating flow. The primary reason for this is the non-linear relationship between the differential pressure and the flowrate; i.e. the flowrate is proportional to the square root of the differential pressure. Therefore, an average of the differential pressure does not give an average of pulsating flow. In this study, fast response pressure transducers have been used to measure the pulsating pressure. Then the pulsating differential pressure is converted to the flowrate while keeping the pulsation unaveraged. An average flowrate is then calculated in the flowrate domain in order to maintain linearity before and after averaging. The peak amplitude of a pulsation measured here was about 1800 L/min at an average flowrate of 70 L/min when the engine ran at idle speed. This measurement has been confirmed by measuring the pulsation with a gas analyser. The results show a large amount of back and forth gas movement in the exhaust tube. This magnitude of pulsation can cause as much as five times higher erroneous results with the pressure domain averaging when compared to a flowrate domain averaging.

scholarly journals Global Sensitivity Analysis with 2D Hydraulic Codes: Application on Uncertainties Related to High-Resolution Topographic Data

2015 ◽  
pp. 301-315 ◽  
Author(s):  
Morgan Abily ◽  
Olivier Delestre ◽  
Philippe Gourbesville ◽  
Nathalie Bertrand ◽  
Claire-Marie Duluc ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
High Resolution ◽  
Global Sensitivity Analysis ◽  
Global Sensitivity ◽  
Topographic Data

Echo-planar high-resolution flow velocity mapping

1989 ◽  
Vol 12 (3) ◽  
pp. 316-327 ◽  
Author(s):  
D. N. Firmin ◽  
R. H. Klipstein ◽  
G. L. Hounsfield ◽  
M. P. Paley ◽  
D. B. Longmore
Keyword(s):  
High Resolution ◽  
Flow Velocity ◽  
Velocity Mapping ◽  
Echo Planar

High-Resolution Film Cooling Effectiveness Measurements of Axial Holes Embedded in a Transverse Trench With Various Trench Configurations

2006 ◽  
Vol 129 (2) ◽  
pp. 294-302 ◽  
Author(s):  
Scot K. Waye ◽  
David G. Bogard
Keyword(s):  
High Resolution ◽  
Film Cooling ◽  
Density Ratio ◽  
Field Measurements ◽  
Suction Side ◽  
Lateral Spreading ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Flow Parameters ◽  
Adiabatic Effectiveness

Adiabatic film cooling effectiveness of axial holes embedded within a transverse trench on the suction side of a turbine vane was investigated. High-resolution two-dimensional data obtained from infrared thermography and corrected for local conduction provided spatial adiabatic effectiveness data. Flow parameters of blowing ratio, density ratio, and turbulence intensity were independently varied. In addition to a baseline geometry, nine trench configurations were tested, all with a depth of 1∕2 hole diameter, with varying widths, and with perpendicular and inclined trench walls. A perpendicular trench wall at the very downstream edge of the coolant hole was found to be the key trench characteristic that yielded much improved adiabatic effectiveness performance. This configuration increased adiabatic effectiveness up to 100% near the hole and 40% downstream. All other trench configurations had little effect on the adiabatic effectiveness. Thermal field measurements confirmed that the improved adiabatic effectiveness that occurred for a narrow trench with perpendicular walls was due to a lateral spreading of the coolant and reduced coolant jet separation. The cooling levels exhibited by these particular geometries are comparable to shaped holes, but much easier and cheaper to manufacture.

High Resolution Particle Image Velocimetry and CH-PLIF Measurements and Analysis of a Shear Layer Stabilized Flame

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
C. W. Foley ◽  
I. Chterev ◽  
J. Seitzman ◽  
T. Lieuwen
Keyword(s):  
Particle Image Velocimetry ◽  
High Resolution ◽  
Shear Layer ◽  
Flow Velocity ◽  
Particle Image ◽  
Flame Stabilization ◽  
Flow Conditions ◽  
Local Flow ◽  
Image Velocimetry ◽  
Flow Velocities

Understanding the mechanisms and physics of flame stabilization and blowoff of premixed flames is critical toward the design of high velocity combustion devices. In the high bulk flow velocity situation typical of practical combustors, the flame anchors in shear layers where the local flow velocities are much lower. Within the shear layer, fluid strain deformation rates are very high and the flame can be subjected to significant stretch levels. The main goal of this work was to characterize the flow and stretch conditions that a premixed flame experiences in a practical combustor geometry and to compare these values to calculated extinction values. High resolution, simultaneous particle image velocimetry (PIV) and planar laser induced fluorescence of CH radicals (CH-PLIF) measurements are used to capture the flame edge and near-field stabilization region. When approaching lean limit extinction conditions, we note characteristic changes in the stretch and flow conditions experienced by the flame. Most notably, the flame becomes less critically stretched when fuel/air ratio is decreased. However, at these lean conditions, the flame is subject to higher mean flow velocities at the edge, suggesting less favorable flow conditions are present at the attachment point of the flame as blowoff is approached. These measurements suggest that blowoff of the flame from the shear layer is not directly stretch extinction induced, but rather the result of an imbalance between the speed of the flame edge and local tangential flow velocity.

Pulsating Flow Induced Vibration in a Rotor-Seal System

2012 ◽  
Vol 542-543 ◽  
pp. 66-69
Author(s):  
Nan Zhang
Keyword(s):  
Fluid Flow ◽  
Numerical Simulations ◽  
Flow Velocity ◽  
Nonlinear Models ◽  
Sine Wave ◽  
Point Of View ◽  
Pulsating Flow ◽  
Flow Induced Vibration ◽  
Matlab Simulink ◽  
Pulsating Fluid

The pulsating flow is an important factor affecting the performance of the rotor-seal system. From the point of view of pulsating flow induced vibration, the nonlinear models of the rotor-seal system with the pulsating fluid flow are established. Based on the numerical simulations by Matlab/Simulink, the characteristics of pulsating flow induced vibration with the flow velocity in a form of sine wave or/and a constant have been quantitatively analyzed. The investigation also demonstrates that the proposed models, from the point of view of pulsating flow induced vibration, can be effectively applied to the analysis of the rotor-seal system.

Nonlinear Vibrations of Plates in Axial Pulsating Flow

2014 ◽  
Author(s):  
E. Tubaldi ◽  
M. Amabili ◽  
F. Alijani
Keyword(s):  
Flow Velocity ◽  
Nonlinear Vibrations ◽  
Plate Theory ◽  
Fluid Model ◽  
Equations Of Motion ◽  
Transmural Pressure ◽  
Pulsating Flow ◽  
Pulsation Frequency ◽  
Rectangular Plates ◽  
Flow Perturbation

A theoretical approach is presented to study nonlinear vibrations of thin infinitely long rectangular plates subjected to pulsatile axial inviscid flow. The case of plates in axial uniform flow under the action of constant transmural pressure is also addressed for different flow velocities. The equations of motion are obtained based on the von Karman nonlinear plate theory retaining in-plane inertia via Lagrangian approach. The fluid model is based on potential flow theory and the Galerkin method is applied to determine the expression of the flow perturbation potential. The effect of different system parameters such as flow velocity, pulsation amplitude, pulsation frequency, and channel pressurization on the stability of the plate and its geometrically nonlinear response to pulsating flow are fully discussed. In case of zero uniform transmural pressure numerical results show hardening type behavior for the entire flow velocity range when the pulsation frequency is spanned in the neighbourhood of the plate’s fundamental frequency. Conversely, a softening type behavior is presented when a uniform transmural pressure is introduced.

scholarly journals Measurement and modelling of high-resolution flow-velocity data under simulated rainfall on a low-slope sandy soil

2008 ◽  
Vol 348 (1-2) ◽  
pp. 1-12 ◽  
Author(s):  
L. Tatard ◽  
O. Planchon ◽  
J. Wainwright ◽  
G. Nord ◽  
D. Favis-Mortlock ◽  
...  
Keyword(s):  
High Resolution ◽  
Flow Velocity ◽  
Sandy Soil ◽  
Simulated Rainfall ◽  
Velocity Data
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