Numerical Study of the Implementation of an Active Control Turbocharger on Automotive Diesel Engines

Active control turbocharger (ACT) has been proposed as a way to improve turbocharger performance under highly pulsating exhaust flows. This technique implies that the variable geometry mechanism in the turbine is used to optimize its position as a function of the instantaneous mass flow during the engine cycle. Tests presented in the literature showed promising results in a pulsating gas-stand. In this work, a modeling study has been conducted at different engine conditions aimed to quantify the gain in on-engine conditions and to develop a strategy to integrate the ACT system within the engine. Different ways of changing the displacement of the variable mechanism have been analyzed by means of a one-dimensional gas dynamic model. The simulations have been carried out at constant engine operating points defined by fixed air-to-fuel ratio for different mechanism displacement functions around an average position that guarantees the desired amount of intake air. The benefits in overall engine efficiency are lower to those predicted in the literature. It can be concluded that it is not possible to use the ACT system to optimize the turbine operating point and at the same time to control the engine operating point.

Download Full-text

A Numerical Study on the Influence of Vane-Blade Spacing on a Compressor Stage at Sub- and Transonic Operating Conditions

Volume 6: Turbo Expo 2003, Parts A and B ◽

10.1115/gt2003-38020 ◽

2003 ◽

Cited By ~ 6

Author(s):

Andreas Zachcial ◽

Dirk Nu¨rnberger

Keyword(s):

Numerical Study ◽

Suction Side ◽

Operating Conditions ◽

Operating Point ◽

Maximum Efficiency ◽

Rotor Profile ◽

Stage Performance ◽

Rotor Losses ◽

Vortex Patterns ◽

Operating Points

A detailed numerical investigation into the influence of the axial gap between the blade rows of a stator/rotor compressor configuration is presented. Unsteady, two-dimensional simulations at both subsonic and transonic operating points have been performed for several axial spacings. From time-averaged data, the influence of the axial gap setting on stage efficiency at the subsonic operating point was found to be opposite to that at the transonic operating point. By examining the passage losses, a correlation between the trends in stage performance and rotor losses as a function of the axial spacing was found. At maximum efficiency, the unsteady flow fields at both operating points show similar vortex patterns. These vortices are rotating clockwise and are located near the suction side of the rotor profile. It was found that these vortices affect the boundary layer behaviour of the rotor and lead to a gain in performance due to a reduction of the rotor losses. This process depends on the operating point and the axial spacing between the rows. Through a detailed analysis of the time-averaged and instantaneous data, the influence of the upstream wake on the stage performance is assessed and discussed in the context of future designs.

Download Full-text

One-dimensional numerical study of compressible flow ejector

AIAA Journal ◽

10.2514/3.15219 ◽

2002 ◽

Vol 40 ◽

pp. 1469-1472

Author(s):

S. Han ◽

J. Peddieson

Keyword(s):

Compressible Flow ◽

Numerical Study ◽

One Dimensional

Download Full-text

Coupled Engine-Propeller Selection Procedure to Minimize Fuel Consumption at a Specified Speed

Journal of Marine Science and Engineering ◽

10.3390/jmse9010059 ◽

2021 ◽

Vol 9 (1) ◽

pp. 59

Author(s):

Mina Tadros ◽

Roberto Vettor ◽

Manuel Ventura ◽

Carlos Guedes Soares

Keyword(s):

Fuel Consumption ◽

Selection Procedure ◽

Optimization Procedure ◽

Operating Point ◽

Power Prediction ◽

Ship Routing ◽

Marine Propellers ◽

Operational Profile ◽

Calm Water ◽

Engine Operating Point

This study presents a practical optimization procedure that couples the NavCad power prediction tool and a nonlinear optimizer integrated into the Matlab environment. This developed model aims at selecting a propeller at the engine operating point with minimum fuel consumption for different ship speeds in calm water condition. The procedure takes into account both the efficiency of the propeller and the specific fuel consumption of the engine. It is focused on reducing fuel consumption for the expected operational profile of the ship, contributing to energy efficiency in a complementary way as ship routing does. This model assists the ship and propeller designers in selecting the main parameters of the geometry, the operating point of a fixed-pitch propeller from Wageningen B-series and to define the gearbox ratio by minimizing the fuel consumption of a container ship, rather than only maximizing the propeller efficiency. Optimized results of the performance of several marine propellers with different number of blades working at different cruising speeds are also presented for comparison, while verifying the strength, cavitation and noise issues for each simulated case.

Download Full-text

Numerical study of finite size effects in the one-dimensional two-impurity Anderson model

Physical Review B ◽

10.1103/physrevb.77.235103 ◽

2008 ◽

Vol 77 (23) ◽

Cited By ~ 7

Author(s):

S. Costamagna ◽

J. A. Riera

Keyword(s):

Anderson Model ◽

Size Effects ◽

Numerical Study ◽

Finite Size ◽

Finite Size Effects ◽

One Dimensional ◽

The One

Download Full-text

Numerical Modeling of the Interaction of Solitary Waves and Submerged Breakwaters with Sharp Vertical Edges Using One-Dimensional Beji & Nadaoka Extended Boussinesq Equations

International Journal of Oceanography ◽

10.1155/2013/691767 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 4

Author(s):

Mohammad H. Jabbari ◽

Parviz Ghadimi ◽

Ali Masoudi ◽

Mohammad R. Baradaran

Keyword(s):

Solitary Waves ◽

Numerical Study ◽

Time Integration ◽

Boussinesq Equations ◽

Linear Interpolation ◽

Reflected Waves ◽

One Dimensional ◽

Propagating Waves ◽

Linear Elements ◽

Predictor Corrector

Using one-dimensional Beji & Nadaoka extended Boussinesq equation, a numerical study of solitary waves over submerged breakwaters has been conducted. Two different obstacles of rectangular as well as circular geometries over the seabed inside a channel have been considered in view of solitary waves passing by. Since these bars possess sharp vertical edges, they cannot directly be modeled by Boussinesq equations. Thus, sharply sloped lines over a short span have replaced the vertical sides, and the interactions of waves including reflection, transmission, and dispersion over the seabed with circular and rectangular shapes during the propagation have been investigated. In this numerical simulation, finite element scheme has been used for spatial discretization. Linear elements along with linear interpolation functions have been utilized for velocity components and the water surface elevation. For time integration, a fourth-order Adams-Bashforth-Moulton predictor-corrector method has been applied. Results indicate that neglecting the vertical edges and ignoring the vortex shedding would have minimal effect on the propagating waves and reflected waves with weak nonlinearity.

Download Full-text

A numerical study of tropospheric photochemistry using a one-dimensional model

Journal of Geophysical Research Atmospheres ◽

10.1029/jc082i037p05897 ◽

1977 ◽

Vol 82 (37) ◽

pp. 5897-5906 ◽

Cited By ~ 102

Author(s):

Jack Fishman ◽

Paul J. Crutzen

Keyword(s):

Numerical Study ◽

Dimensional Model ◽

One Dimensional ◽

Tropospheric Photochemistry

Download Full-text

Numerical study of belt-pinch stability, using a one-dimensional finite-element code

Nuclear Fusion ◽

10.1088/0029-5515/16/2/016 ◽

1976 ◽

Vol 16 (2) ◽

pp. 337-339

Author(s):

F. Hofmann ◽

K. Appert ◽

R. Gruber

Keyword(s):

Finite Element ◽

Numerical Study ◽

Finite Element Code ◽

One Dimensional ◽

Dimensional Finite Element

Download Full-text

On the numerical study of thermohydrodynamics and biochemistry of inland water bodies

10.5194/egusphere-egu21-13335 ◽

2021 ◽

Author(s):

Daria Gladskikh ◽

Evgeny Mortikov ◽

Victor Stepanenko

Keyword(s):

Mixed Layer ◽

Numerical Study ◽

Three Dimensional ◽

Water Bodies ◽

Dimensional Model ◽

Three Dimensional Model ◽

One Dimensional ◽

Lake Model ◽

Upper Mixed Layer ◽

The One

The study of thermodynamic and biochemical processes of inland water objects using one- and three-dimensional RANS numerical models was carried out both for idealized water bodies and using measurements data. The need to take into account seiche oscillations to correctly reproduce the deepening of the upper mixed layer in one-dimensional (vertical) models is demonstrated. We considered the one-dimensional LAKE model [1] and the three-dimensional model [2, 3, 4] developed at the Research Computing Center of Moscow State University on the basis of a hydrodynamic code combining DNS/LES/RANS approaches for calculating geophysical turbulent flows. The three-dimensional model was supplemented by the equations for calculating biochemical substances by analogy with the one-dimensional biochemistry equations used in the LAKE model. The effect of mixing processes on the distribution of concentration of greenhouse gases, in particular, methane and oxygen, was studied.The work was supported by grants of the RF President&#8217;s Grant for Young Scientists (MK-1867.2020.5, MD-1850.2020.5) and by the RFBR (19-05-00249, 20-05-00776).&#160;1. Stepanenko V., Mammarella I., Ojala A., Miettinen H., Lykosov V., Timo V. LAKE 2.0: a model for temperature, methane, carbon dioxide and oxygen dynamics in lakes // Geoscientific Model Development. 2016. V. 9(5). P. 1977&#8211;2006. 2. Mortikov E.V., Glazunov A.V., Lykosov V.N. Numerical study of plane Couette flow: turbulence statistics and the structure of pressure-strain correlations // Russian Journal of Numerical Analysis and Mathematical Modelling. 2019. 34(2). P. 119-132. 3. Mortikov, E.V. Numerical simulation of the motion of an ice keel in stratified flow // Izv. Atmos. Ocean. Phys. 2016. V. 52. P. 108-115. 4. Gladskikh D.S., Stepanenko V.M., Mortikov E.V. On the influence of the horizontal dimensions of inland waters on the thickness of the upper mixed layer // Water Resourses. 2021.V. 45, 9 pages. (in press)&#160;

Download Full-text

Discrete-time quantum walks generated by aperiodic fractal sequence of space coin operators

International Journal of Modern Physics C ◽

10.1142/s0129183118500985 ◽

2018 ◽

Vol 29 (10) ◽

pp. 1850098 ◽

Cited By ~ 1

Author(s):

R. F. S. Andrade ◽

A. M. C. Souza

Keyword(s):

Wave Function ◽

Probability Distribution ◽

Discrete Time ◽

Numerical Study ◽

Entanglement Entropy ◽

Quantum Effects ◽

Quantum Walks ◽

Cantor Set ◽

One Dimensional ◽

Time Quantum

Properties of one-dimensional discrete-time quantum walks (DTQWs) are sensitive to the presence of inhomogeneities in the substrate, which can be generated by defining position-dependent coin operators. Deterministic aperiodic sequences of two or more symbols provide ideal environments where these properties can be explored in a controlled way. Based on an exhaustive numerical study, this work discusses a two-coin model resulting from the construction rules that lead to the usual fractal Cantor set. Although the fraction of the less frequent coin [Formula: see text] as the size of the chain is increased, it leaves peculiar properties in the walker dynamics. They are characterized by the wave function, from which results for the probability distribution and its variance, as well as the entanglement entropy, were obtained. A number of results for different choices of the two coins are presented. The entanglement entropy has shown to be very sensitive to uncovering subtle quantum effects present in the model.

Download Full-text