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Arabian Journal for Science and Engineering

, Volume 43, Issue 9, pp 4763–4781 | Cite as

Experimental Analysis for Performance Evaluation and Unsteadiness Quantification for One Turbocharger Vane-Less Radial Turbine Operating on a Gasoline Engine

  • Ahmed Ketata
  • Zied Driss
  • Mohamed Salah Abid
Research Article - Mechanical Engineering

Abstract

Most of the available test rigs of turbochargers use a specified device to reproduce the waveform of the engine exhaust gas which is not physically pertinent regarding that several parameters can influence the pulse form of the flow at the engine exhaust manifold. In order to overcome this drawback, a new test rig of one turbocharger vane-less radial turbine operating on a four-stroke engine to characterize this turbomachine under its real flow conditions was built. Based on test data collected from the test rig, developed at the National School of Engineers of Sfax, a characterization of the turbine performance under different operating conditions has been carried out. To validate the experimental methodology, an uncertainty analysis has been performed. The results prove that the performance and flow characteristics of the studied turbine present a high sensitivity to the gas waveform and the pulse frequency of the flow coming from the engine exhaust manifold. Besides, a Strouhal number analysis using a fast Fourier series transform has been made to characterize the unsteadiness level of the flow within the present turbine. The results show an important impact of the pulse frequency on the turbine unsteady characteristics.

Keywords

Turbocharger Turbine ICE Performance Efficiency Pulse 

List of Symbols

A

Area (\(\hbox {m}^{2}\))

a

Speed of sound (\(\hbox {m}\,\hbox {s}^{-1}\))

\({a}_{k}\)

Fourier real coefficients

\({b}_{k}\)

Fourier imaginary coefficients

\({c}_{{p}}\)

Specific heat capacity at constant pressure, (\(\hbox {J}\,\hbox {K}^{-1}~\hbox {kg}^{-1}\))

D

Diameter (m)

f

Frequency (Hz)

\({f}_\mathrm{c}\)

Cut-off frequency (Hz)

\({f}_\mathrm{p}\)

Pulse frequency (Hz)

FSt

Fourier series Strouhal number (dimensionless)

FaSt

Fourier series acoustic Strouhal number (dimensionless)

FPSt

Fourier series pressure Strouhal number (dimensionless)

\({F}\beta \)

Fourier series reduced frequency (dimensionless)

h

Enthalpy per unit mass (\(\hbox {J}\,\hbox {kg}^{-1}\))

L

Length (m)

\(\dot{{m}}\)

Mass flow rate (\(\hbox {kg}\,\hbox {s}^{-1}\))

\({n}_\mathrm{e}\)

Exhaust group number (dimensionless)

\({n}_{s}\)

Stroke number (dimensionless)

\({N}_\mathrm{e}\)

Engine speed (rpm)

N

Turbine speed (rpm)

P

Pressure (Pa)

St

Strouhal number (dimensionless)

aSt

Acoustic Strouhal number (dimensionless)

PSt

Pressure acoustic Strouhal number (dimensionless)

R

Universal gas constant (\(\hbox {J}\,\hbox {K}^{-1}\,\hbox {mol}^{-1}\))

T

Temperature (K)

t

Time (s)

u

Velocity (\(\hbox {m}\,\hbox {s}^{-1}\))

W

Power (W)

\(\beta \)

Reduced frequency or diameter ratio (dimensionless)

\(\varepsilon \)

Expansion factor (dimensionless)

\(\rho \)

Density (\(\hbox {kg}\,\hbox {m}^{-3}\))

\(\omega \)

Window function, or angular frequency (\(\hbox {rad}\,\hbox {s}^{-1}\))

\(\tau \)

Torque (N m)

\(\eta \)

Total-to-static efficiency, dimensionless

\(\gamma \)

Specific heat capacity ratio

\(\phi \)

Scalar variable

\(\Delta \)

Change

Subscript

1

Turbine upstream

2

Turbine downstream

0

Stagnation condition

A

Signal A

avg

Average

act

Actual

B

Signal B

is

Isentropic

Abbreviation

BTSR

Blade tip speed ratio

BDC

Bottom dead center

C2R

Complex-to-real

FFT

Fast fourier series transform

IFFT

Inverse fast fourier series transform

MFP

Mass flow parameter

R2C

Real-to-complex

R2R

Real-to-real

RSS

Root-sum-square

TS

Total-to-static

TDCF

Top dead center firing

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Copyright information

© King Fahd University of Petroleum & Minerals 2018

Authors and Affiliations

  1. 1.Laboratory of Electro-Mechanic SystemsNational School of Engineers of Sfax, University of SfaxSfaxTunisia

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