Innovative Variable Turbine Concept for Turbochargers

2011 ◽  
Author(s):  
Elias Chebli ◽  
Michael Casey ◽  
Markus Mu¨ller ◽  
Siegfried Sumser ◽  
Gernot Hertweck ◽  
...  
Keyword(s):  
Aerodynamic Performance ◽  
Cfd Simulations ◽  
Flow Variability ◽  
Variable Turbine Geometry ◽  
Turbine Efficiency ◽  
New Concepts ◽  
Specific Speed ◽  
Turbine Impeller ◽  
Flow Cross ◽  
Wide Operating

New concepts for the optimisation of supercharging systems have been analysed to improve fuel consumption, emissions and transient diesel engine response. In addition to the conventional VTG (Variable Turbine Geometry) where the variability takes place upstream of the turbine impeller, a new innovative variable turbine geometry called VOT (Variable Outlet Turbine) is investigated in this paper where the variability takes place at impeller exit. The flow variability is achieved by variation of the flow cross-section at the turbine outlet using an axial displacement of a sliding sleeve over the exducer and provides a simple solution for flow variability. The flow field of the VOT is calculated by means of steady state 3D-CFD simulations to predict the aerodynamic performance as well as to analyse the loss mechanisms. The VOT design is optimised by finding a good balance between clearance and outlet losses to improve the turbine efficiency. Furthermore, experimental results of the VOT are presented and compared to a turbine equipped with a waste gate (WG) that verify the efficiency advantage of the VOT. In general, it is found that the use of the VOT at high specific speed is important to reduce the outlet losses and to improve the turbine efficiency over a wide operating range.

The Variable Outlet Turbine Concept for Turbochargers

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Elias Chebli ◽  
Michael Casey ◽  
Ricardo Martinez-Botas ◽  
Siegfried Sumser ◽  
Markus Müller ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Engine Performance ◽  
Engine Fuel ◽  
Performance Measurements ◽  
Flow Variability ◽  
Variable Turbine Geometry ◽  
Turbine Efficiency ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations ◽  
Flow Cross

A variable geometry concept for advanced turbocharger (TC) systems is presented. The variability of the device is based on outlet area changes as opposed to the more common systems that are based on inlet turbine geometry changes. In addition to the conventional variable turbine geometry (VTG), the new variable turbine type is termed variable outlet turbine (VOT). The flow variability is achieved by variation of the flow cross section at the turbine outlet using an axial displacement of a sliding sleeve over the exducer and provides a simple solution for flow variability. In order to predict the aerodynamic performance and to analyze the loss mechanisms of this new turbine, the flow field of the VOT is calculated by means of steady state 3D-CFD (computational fluid dynamics) simulations. The VOT design is optimized by finding a good balance between clearance and outlet losses. Furthermore, experimental results of the VOT are presented and compared to a turbine equipped with a waste gate (WG) that demonstrates an efficiency advantage of 5%. Additionally, engine performance measurements were carried out to investigate the influence of the VOT on fuel consumption and to asses the functionality of the new pneumatic actuating system. The VOT engine tests show also performance advantage in comparison to a WG turbine especially toward high engine loads. It is found that the use of the VOT at this condition shows a turbine efficiency advantage of 6% related to a reduction in engine fuel consumption of 1.4%. The behavior at part load is neutral and the peak turbine efficiency of the VOT is comparable with a fix turbine geometry.

A comparative study of the performance of the mixed flow and radial flow variable geometry turbines for an automotive turbocharger

2018 ◽  
Vol 233 (8) ◽  
pp. 2696-2712 ◽  
Author(s):  
K Ramesh ◽  
BVSSS Prasad ◽  
K Sridhara
Keyword(s):  
Mass Flow ◽  
Flow Parameter ◽  
Radial Flow ◽  
Velocity Ratio ◽  
Variable Geometry ◽  
Flow Variable ◽  
Mixed Flow ◽  
Turbine Efficiency ◽  
Variable Geometry Turbine ◽  
Specific Speed

A new design of a mixed flow variable geometry turbine is developed for the turbocharger used in diesel engines having the cylinder capacity from 1.0 to 1.5 L. An equivalent size radial flow variable geometry turbine is considered as the reference for the purpose of bench-marking. For both the radial and mixed flow turbines, turbocharger components are manufactured and a test rig is developed with them to carry out performance analysis. Steady-state turbine experiments are conducted with various openings of the nozzle vanes, turbine speeds, and expansion ratios. Typical performance parameters like turbine mass flow parameter, combined turbine efficiency, velocity ratio, and specific speed are compared for both mixed flow variable geometry turbine and radial flow variable geometry turbine. The typical value of combined turbine efficiency (defined as the product of isentropic efficiency and the mechanical efficiency) of the mixed flow variable geometry turbine is found to be about 25% higher than the radial flow variable geometry turbine at the same mass flow parameter of 1425 kg/s √K/bar m2 at an expansion ratio of 1.5. The velocity ratios at which the maximum combined turbine efficiency occurs are 0.78 and 0.825 for the mixed flow variable geometry turbine and radial flow variable geometry turbine, respectively. The values of turbine specific speed for the mixed flow variable geometry turbine and radial flow variable geometry turbine respectively are 0.88 and 0.73.

Performance of a High-Solidity Wells Turbine for an OWC Wave Power Plant

1996 ◽  
Vol 118 (4) ◽  
pp. 263-268 ◽  
Author(s):  
L. M. C. Gato ◽  
V. Warfield ◽  
A. Thakker
Keyword(s):  
Experimental Investigation ◽  
Power Plant ◽  
Pressure Drop ◽  
Flow Rate ◽  
Aerodynamic Performance ◽  
Wave Power ◽  
Wells Turbine ◽  
Guide Vanes ◽  
Turbine Efficiency ◽  
Pressure Distributions

The paper describes an experimental investigation, and presents the results of the aerodynamic performance of a high-solidity Wells turbine for a wave power plant. A monoplane turbine of 0.6 m rotor diameter with guide vanes was built and tested. The tests were conducted in unidirectional steady airflow. Measurements taken include flow rate, pressure drop, torque, and rotational speed, as well as velocity and pressure distributions. Experimental results show that the presence of guide vanes can provide a remarkable increase in turbine efficiency.

scholarly journals The onset of compressibility effects for aerofoils in ground effect

2007 ◽  
Vol 111 (1126) ◽  
pp. 797-806 ◽  
Author(s):  
G. Doig ◽  
T. J. Barber ◽  
E. Leonardi ◽  
A. J. Neely
Keyword(s):  
Mach Number ◽  
High Speed ◽  
Subsonic Flow ◽  
Flow Characteristics ◽  
Ground Effect ◽  
Aerodynamic Performance ◽  
Computational Studies ◽  
Pressure Gradients ◽  
Cfd Simulations ◽  
Compressibility Effects

Abstract The influence of flow compressibility on a highly-cambered inverted aerofoil in ground effect is presented, based on two-dimensional computational studies. This type of problem has relevance to open-wheel racing cars, where local regions of high-speed subsonic flow form under favourable pressure gradients, even though the maximum freestream Mach number is typically considerably less than Mach 0·3. An important consideration for CFD users in this field is addressed in this paper: the freestream Mach number at which flow compressibility significantly affects aerodynamic performance. More broadly, for aerodynamicists, the consequences of this are also considered. Comparisons between incompressible and compressible CFD simulations are used to identify important changes to the flow characteristics caused by density changes, highlighting the inappropriateness of incompressible simulations of ground effect flows for freestream Mach numbers as low as 0·15.

A Study of the Three-Dimensional Unsteady Real-Gas Flows Within a Transonic ORC Turbine

2014 ◽  
Author(s):  
Andrew P. S. Wheeler ◽  
Jonathan Ong
Keyword(s):  
Three Dimensional ◽  
Organic Rankine Cycle ◽  
Leading Edge ◽  
Rankine Cycle ◽  
Gas Flows ◽  
Cfd Simulations ◽  
Significant Drop ◽  
Real Gas ◽  
Turbine Efficiency ◽  
Real Gas Effects

In this paper we investigate the three-dimensional unsteady real-gas flows which occur within Organic Rankine Cycle (ORC) turbines. A radial-inflow turbine stage operating with supersonic vane exit flows (M ≈ 1.4) is simulated using a RANS solver which includes real-gas effects. Steady CFD simulations show that small changes in the inducer shape can have a significant effect on turbine efficiency due to the development of supersonic flows in the rotor. Unsteady predictions show the same trends as the steady CFD, however a strong interaction between the vane trailing-edge shocks and rotor leading-edge leads to a significant drop in efficiency.

scholarly journals Effect of Ducted Multi-Propeller Configuration on Aerodynamic Performance in Quadrotor Drone

Drones ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 101
Author(s):  
Yi Li ◽  
Koichi Yonezawa ◽  
Hao Liu
Keyword(s):  
Optimal Design ◽  
High Performance ◽  
Lift Force ◽  
Force Production ◽  
Aerodynamic Performance ◽  
Aerodynamic Design ◽  
Cfd Simulations ◽  
Height Difference ◽  
Noticeable Effect ◽  
Propeller Design

Motivated by a bioinspired optimal aerodynamic design of a multi-propeller configuration, here we propose a ducted multi-propeller design to explore the improvement of lift force production and FM efficiency in quadrotor drones through optimizing the ducted multi-propeller configuration. We first conducted a CFD-based study to explore a high-performance duct morphology in a ducted single-propeller model in terms of aerodynamic performance and duct volume. The effect of a ducted multi-propeller configuration on aerodynamic performance is then investigated in terms of the tip distance and the height difference of propellers under a hovering state. Our results indicate that the tip distance-induced interactions have a noticeable effect in impairing the lift force production and FM efficiency but are limited to small tip distances, whereas the height difference-induced interactions have an impact on enhancing the aerodynamic performance over a certain range. An optimal ducted multi-propeller configuration with a minimal tip distance and an appropriate height difference was further examined through a combination of CFD simulations and a surrogate model in a broad-parameter space, which enables a significant improvement in both lift force production and FM efficiency for the multirotor, and thus provides a potential optimal design for ducted multirotor UAVs.

Results From High Temperature Turbine Test on the HPT of the AGTJ-100A

1984 ◽  
Author(s):  
Masashi Arai ◽  
Kiyomi Teshima ◽  
Sunao Aoki ◽  
Hiroyuki Yamao
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
High Temperature ◽  
Aerodynamic Performance ◽  
Inlet Temperature ◽  
Test Results ◽  
Mechanical Reliability ◽  
High Pressure Turbine ◽  
Turbine Inlet Temperature ◽  
Turbine Efficiency

An experimental investigation was conducted through the use of a High Temperature Turbine Developing Unit (HTDU) having the same two stage turbine as the high pressure turbine (HPT) of the AGTJ-100A, to ascertain the aerodynamic performance, cooling characteristics and mechanical reliability. The test was performed in three phases, and the maximum turbine inlet temperature was about 1,573 K. The test results showed that turbine efficiency was 90.2 %, the level of metal temperature for nozzles and blades was as expected, and there was little trouble with the hot parts. This paper will present these test results.

Improving Accuracy and Comparability of Turbocharger Performance Measurements

2019 ◽  
Author(s):  
Mario Schinnerl ◽  
Mathias Bogner ◽  
Jan Ehrhard
Keyword(s):  
Turbine Stage ◽  
Performance Measurements ◽  
Cfd Simulations ◽  
Operating Range ◽  
Turbine Efficiency ◽  
Run Up ◽  
Improving Accuracy ◽  
Compressor Power ◽  
The Impact ◽  
Operating Points

Abstract The reduction of fuel consumption and emissions is the most dominant challenge in powertrain development. Therefore, engine and turbocharger have to be matched with high accuracy to achieve optimum powertrain efficiencies. With respect to relevant engine operating points, compressor maps can be measured in full operating range on a standard hot gas test bench. Even though there is no need for extrapolation of the operating range, they have to be corrected for the impact of heat transfer to represent the adiabatic performance of the compressor stage. The common approach to evaluate the turbine efficiency is to apply the energy balance of the entire turbocharger where the turbine power is the sum of the compressor power and the friction losses of the radial and axial journal bearings. The adiabatic compressor power in combination with the calculation of the friction losses by using validated run-up simulations enables the evaluation of the isentropic turbine efficiency and the comparability to CFD simulations of the turbine stage. For reasons of comparability to CFD simulations, which can predict a wide operating range of the turbine stage, the limited measureable turbine operating range is enhanced by a so-called compressor closed loop unit (CCLU). This additional test device enables to vary the demand of compressor power for the same operating points as in the standard mapping and therefore to enlarge the measureable turbine operating range. In combination with proper extrapolation methods, the isentropic turbine efficiency can now be compared to CFD simulations.

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