Performance of Radial Flow Turbines Under Pulsating Flow Conditions

1976 ◽  
Vol 98 (1) ◽  
pp. 53-59 ◽  
Author(s):  
H. Kosuge ◽  
N. Yamanaka ◽  
I. Ariga ◽  
I. Watanabe
Keyword(s):  
Steady Flow ◽  
Pressure Pulse ◽  
Radial Flow ◽  
Pressure Ratio ◽  
Pulse Frequency ◽  
Pulsating Flow ◽  
Frequency Range ◽  
Flow Conditions ◽  
Transient Pressure ◽  
Empirical Parameter

Investigations of the pulsating flow performances of an inward radial flow turbine were performed. The quasi-steady flow performances predicted from the measured transient pressure ratio and from steady flow performance data were compared with the measured mean performances under pulsating flow conditions over the pulse frequency range of 30 Hz–70 Hz. The validity of this quasi-steady flow assumption was treated more generally than by the hitherto employed method by adopting a new empirical parameter which indicates both the pressure pulse shape and the amplitude of pressure fluctuation, in addition to the pulse frequency.

scholarly journals Performance of Radial Flow Turbines under Pulsating Flow Conditions : Quasi-Steady Flow Analysis

1978 ◽  
Vol 44 (386) ◽  
pp. 3497-3505
Author(s):  
Hideaki KOSUGE ◽  
Naoharu YAMANAKA ◽  
Ichiro ARIGA ◽  
Ichiro WATANABE
Keyword(s):  
Steady Flow ◽  
Radial Flow ◽  
Flow Analysis ◽  
Pulsating Flow ◽  
Flow Conditions

Numerical and Experimental Investigation of Pulsating Flow Effect on a Nozzled and Nozzleless Mixed Flow Turbine for an Automotive Turbocharger

2014 ◽  
Author(s):  
M. H. Padzillah ◽  
M. Yang ◽  
W. Zhuge ◽  
R. F. Martinez-Botas
Keyword(s):  
Pressure Ratio ◽  
Turbine Blades ◽  
Computational Cost ◽  
Operating Conditions ◽  
Pulsating Flow ◽  
Angle Distribution ◽  
Operating Pressure ◽  
Flow Conditions ◽  
Flow Angle ◽  
Turbine Speed

To achieve better flow guidance into the turbine blades, nozzle vanes were added as an integral part of the stator design. However, the full investigation that directly addresses the comparison between the two turbine arrangements under pulsating flow conditions is still not available in literature. This work represents the first attempt to observe differences, particularly in the circumferential flow angle distribution between both volute arrangements under steady and pulsating flow operating conditions. Experimentally validated Computational Fluid Dynamics (CFD) simulations have been conducted in order to achieve this aim. As the experimental data within the Turbocharger Group at Imperial College are extensive, the simulation procedures are optimized to achieve the best compromise between the computational cost and prediction accuracy. A single operating pressure ratio is selected for the steady and pulsating environment in order to provide consistent comparison for both volute arrangements. The simulation results presented in this work are conducted at the turbine speed of 48000rpm and 60Hz flow frequency for the pulsating flow simulations. The results indicated that there are significant differences in the flow angle behavior for both volutes regardless of the flow conditions (steady or unsteady). It is also found that the differences in flow angle distribution between increasing and decreasing pressure instances during pulsating flow operation is more prominent in the nozzleless volute than its nozzled counterpart.

scholarly journals Size Effects in Small Radial Turbines

1984 ◽  
Author(s):  
K. H. Scrimshaw ◽  
T. J. Williams
Keyword(s):  
Size Effect ◽  
Internal Pressure ◽  
Steady Flow ◽  
Fatigue Failure ◽  
Significant Influence ◽  
Size Effects ◽  
Radial Flow ◽  
Flow Conditions ◽  
Peak Efficiency ◽  
Radial Turbines

The existence of size effects in small radial flow turbines, such as those used in automotive turbocharger units, has been investigated under steady flow conditions. Three geometrically similar turbines (rotor diameters 101.6, 67.73 and 50.8 mm respectively) have been tested and a ‘size’ effect was observed with the dimensionless mass flow and peak efficiency diminishing with a decrease in rotor diameter. Internal pressure variations were observed in all three turbines which could have a significant influence in relation to blade fatigue failure.

Paper 23: An Experimental Investigation of Non-Steady Flow in a Radial Gas Turbine

1965 ◽  
Vol 180 (10) ◽  
pp. 74-85 ◽  
Author(s):  
R. S. Benson ◽  
K. H. Scrimshaw
Keyword(s):  
Steady Flow ◽  
Mass Flow ◽  
Pulse Generator ◽  
Flow Analysis ◽  
Pulse Frequency ◽  
Exhaust Pipe ◽  
Transient Pressure ◽  
Radial Turbine ◽  
Admission Data ◽  
Partial Admission

Comprehensive steady and non-steady flow tests on a small radial turbine turbo-charger are given. Steady flow tests included both full admission and partial admission over the whole speed and pressure range from zero flow to maximum flow. Non-steady flow tests were carried out over a pulse frequency range from 30 to 70 pulses/s and turbine speeds from 30 000 to 60 000 rev/min with the turbine coupled to the exhaust system of a six-cylinder pulse generator under partial admission conditions. Extensive transient pressure and temperature measurements were taken upstream and downstream (pressure only) of the turbine. The total mass flow and power were also measured. A quasi-steady flow analysis was carried out using the steady flow test data. The tests results showed that for a six-cylinder exhaust pipe configuration, with two exhaust pipes entering separate nozzle segments in the radial turbine, the quasi-steady flow analysis using partial admission data grossly underestimated the mass flow and power output of the turbine. Using full admission data the ratio of measurement mass flow and horsepower to the calculated mass flow and horsepower was nearly always greater than unity. Furthermore, the average turbine efficiency was greater under non-steady flow than under steady flow. The magnitude of the recorded effects was dependent on the pulse frequency and turbine speed.

Impact of the wastegate opening on radial turbine performance under steady and pulsating flow conditions

2019 ◽  
Vol 234 (2-3) ◽  
pp. 652-668 ◽  
Author(s):  
Ahmed Ketata ◽  
Zied Driss ◽  
Mohamed Salah Abid
Keyword(s):  
Mass Flow ◽  
Large Deviation ◽  
Pulse Frequency ◽  
Pulsating Flow ◽  
Flow Conditions ◽  
One Dimensional ◽  
Loop Area ◽  
Modeling Methodology ◽  
Turbine Performance ◽  
The One

The present article attempts to describe the behavior of wastegated turbines under various steady and pulsating flow conditions. For this, meanline and one-dimensional numerical codes including appropriate modeling approaches for wastegated turbines have been developed with the FORTRAN language. These codes were validated against experiments with an established test rig at the National School of Engineers of Sfax. The discharge coefficient map of the wastegate was determined with a developed correlation built from experiments, and it was served as an input to the developed codes for interpolations during computation. This correlation is based on a two-dimensional non-linear dose-response fitting relationship instead of classical polynomial function which is one novelty of the article in addition to the one-dimensional modeling methodology. The normalized root mean square error (NRMSE) of both cycle-averaged efficiency and mass flow parameter (MFP) remains below 2% which confirms the validity of the proposed calculation approach. The results indicated a large deviation in the turbine performance under pulsating flow conditions compared to the steady state ones. The shape of the hysteresis loop of the turbine efficiency remains unchanged toward the variation of the wastegate valve angle at the same pulse frequency. The mass flow hystereses loop area is decreased by around 50% as the pulse frequency increases from 33 up to 133.33 Hz. An increase of less than 1% of the cycle-averaged efficiency has been reported when the bypass flow through the wastegate increases. The fluctuation of the efficiency is decreased by 1.5% when the wastegate valve becomes fully opened under the whole range of the pulse frequency.

Performance of a Mixed Flow Turbocharger Turbine Under Pulsating Flow Conditions

1995 ◽  
Author(s):  
C. Arcoumanis ◽  
I. Hakeem ◽  
L. Khezzar ◽  
R. F. Martinez-Botas ◽  
N. C. Baines
Keyword(s):  
High Efficiency ◽  
Pressure Ratio ◽  
Velocity Ratio ◽  
Pulsating Flow ◽  
Flow Conditions ◽  
Mixed Flow ◽  
Engine Exhaust ◽  
High Pressure Ratio ◽  
Design Speed ◽  
Swallowing Capacity

The performance of a high pressure ratio (P.R.=2.9) mixed flow turbine for an automotive turbocharger has been investigated and the results revealed its better performance relative to a radial-inflow geometry under both steady and pulsating flow conditions. The advantages offered by the constant blade angle rotor allow better turbocharger-engine matching and maximization of the energy extracted from the pulsating engine exhaust gases. In particular, the mixed inlet blade geometry resulted in high efficiency at high expansion ratios where the engine-exhaust pulse energy is maximum. The efficiency characteristics of the mixed flow turbine under steady conditions were found to be fairly uniform when plotted against the velocity ratio, with a peak efficiency at the design speed of 0.75. The unsteady performance as indicated by the mass-averaged total-to-static efficiency and the swallowing capacity exhibited a departure from the quasi-steady assumption which is analysed and discussed.

The Pulsating-Flow Performance of Inward Radial-Flow Turbines

1965 ◽  
Author(s):  
F. J. Wallace ◽  
G. P. Blair
Keyword(s):  
Internal Combustion Engines ◽  
Radial Flow ◽  
Flow Behavior ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Pulsating Flow ◽  
Critical Conditions ◽  
Rotary Valve ◽  
Pipe Length ◽  
Operating Variables

The study of the pulsating-flow behavior of small inward radial-flow turbines as used in automotive type turbosuperchargers is of great importance in relation to the mode of operation of such units in conjunction with internal-combustion engines. In complete engine-turbocharger systems detailed analysis of turbine behavior is handicapped by the complex interaction of engine and turbocharger, with resultant interdependence of operating variables. In the present investigation the use of a rotary valve driven at various predetermined speeds and discharging cold air under critical conditions ensures close control of the pressure pulses constituting the turbine-energy input. It has therefore been possible to investigate systematically the influence of the most important parameters, viz., (a) pulse frequency, (b) pulse form, (c) pulse amplitude, (d) pipe length, (e) pipe diameter, and (f) turbine speed.

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