Investigation of the axial thrust load using numerical and experimental techniques during turbocharger operation

2017 ◽  
Vol 232 (6) ◽  
pp. 755-765 ◽  
Author(s):  
In-Beom Lee ◽  
Seong-Ki Hong ◽  
Bok-Lok Choi
Keyword(s):  
Axial Force ◽  
Thermal Effects ◽  
High Speed ◽  
Operating Conditions ◽  
Axial Thrust ◽  
Turbine Wheel ◽  
Compressor Wheel ◽  
The Relationship ◽  
Thrust Load ◽  
Calibration Equations

Identification of the axial thrust load during the operating conditions of a turbocharger provides useful information to turbocharger designers. The axial force acting on the thrust bearing is mainly caused by the imbalance between the turbine wheel and the compressor wheel. It has a significant influence on the friction losses, which reduce the efficiency and the performance of a high-speed turbocharger. Well-known formulae for calculating the thrust load and the mechanical friction have been given in the literature. However, it is difficult to determine an accurate axial force by an analytical approach. This paper presents a detailed procedure for prediction of the axial thrust load during turbocharger operation. The first step is to identify the relationship between the externally applied load and the strain response using a specially designed test device and a numerical method. Next, if the operating strains and temperatures are measured, the strain signals due to the axial thrust can be adjusted by subtracting the thermal effects from the measured strains. Finally, the thrust loads in particular operating conditions are inversely obtained by inserting the adjusted strains into the calibration equations.

scholarly journals Prediction of Axial Thrust Load under Turbocharger Operating Conditions

2016 ◽  
Vol 24 (6) ◽  
pp. 642-648 ◽  
Author(s):  
Inbeom Lee ◽  
Seongki Hong ◽  
Youngchul Kim ◽  
Boklok Choi
Keyword(s):  
Operating Conditions ◽  
Axial Thrust ◽  
Thrust Load

An Externally Pressurized Air Bearing System, Journals and Thrust, for Application to Small Turbomachinery

1992 ◽  
Author(s):  
A. B. Turner ◽  
S. J. Davies ◽  
Y. L. Nimir ◽  
J. D. Richardson
Keyword(s):  
High Speed ◽  
Dynamic Test ◽  
Maximum Temperature ◽  
Air Bearing ◽  
Axial Thrust ◽  
Turbine Wheel ◽  
Air Supply ◽  
Gauge Pressure ◽  
Compressor Impeller ◽  
Bearing System

An aerostatic (externally pressurized) air bearing system for application to small high speed, low temperature turbomachinery has been designed and successfully tested at over 100,000 rpm using an air supply at a gauge pressure of 3.4 bar (50 psig). The test rig used a Holset turbocharger centrifugal compressor impeller and radial turbine wheel mounted at either end of a 150 mm long 40 mm diameter shaft with two 23 mm long inboard journal bearings mounted on either side of an integral 100 mm diameter tapered thrust collar. The turbine was driven by an independent air supply with a maximum temperature of 200°C, and the unit was operated with the shaft vertical. A static axial thrust capability of over 1000 N (225 lbf) has been demonstrated using a novel plenum chamber arrangement to overcome pneumatic instability (air hammer) problems. The paper presents details of the design, some static rig tests and the dynamic test conditions and results.

The Development of a Miniature, High Speed Telemetry System For Dynamic Stress Analysis

1968 ◽  
Vol 90 (1) ◽  
pp. 55-64 ◽  
Author(s):  
W. M. Krassick
Keyword(s):  
High Speed ◽  
Field Testing ◽  
Operating Conditions ◽  
Dynamic Strain ◽  
Telemetry System ◽  
Turbine Wheel ◽  
Engine Operation ◽  
Design Modification ◽  
Physical Tests ◽  
Dynamic Stress Analysis

Twenty years ago diesel engine manufacturers guaranteed and expected 50,000 to 100,000 miles of trouble-free engine operation. Today’s standards are set at 250,000 to 1/2 million miles operation without a major overhaul. These continually expanding requirements have created new problems for the design engineer. To be competitive and to develop an efficient, long life product the design engineer must have a more complete understanding of his product’s capabilities. He can not always rely on calculations or instinct but must confirm his theories and designs by conducting more comprehensive physical tests. Many months of field testing often was required to evaluate the effect of a single design modification on the durability of the part. If a means could be found to measure the stress levels in these components under actual operating conditions in the laboratory answers could be obtained in a matter of days rather than months. A lack of commercially available test equipment suitable for obtaining these measurements resulted in a decision by Schwitzer to develop such equipment. By the end of 1963 a high speed telemetry system was in operation that could accurately transmit dynamic strain signals from a gas turbine wheel rotating over 100,000 rpm in a 1400 deg F environment. This paper reviews the several phases of this project and describes the telemetry system that finally evolved.

Transient Thrust Forces on a Twin Scroll Turbocharger

2017 ◽  
Author(s):  
Janakiraman Thiyagarajan ◽  
Erik Halldorf ◽  
Jens Fridh
Keyword(s):  
Experimental Approach ◽  
Operating Conditions ◽  
Boost Pressure ◽  
Transient Pressure ◽  
Axial Loads ◽  
Compressor Wheel ◽  
Heavy Duty Truck ◽  
Exhaust Energy ◽  
Thrust Load ◽  
Thrust Forces

The bearing system of turbochargers used in trucks needs to be optimized in order to reduce the frictional losses. This helps in transmitting the exhaust energy more efficiently to the compressor wheel to increase boost pressure. Understanding the thrust loading on the axial bearing helps in optimal design of the bearing and the associated lubrication system. With the advent of twin scroll turbochargers, it is necessary to understand the thrust load behaviour at different operating conditions. This paper pioneers in studying the unsteady axial loads measured on a twin scroll turbocharger mounted on a 6 cylinder, 13 litre diesel engine used in the truck industry along with the corresponding analytical predictions for varied engine speeds and loading conditions. Transient thrust forces were measured using a weakened bearing in the experimental approach along with transient pressure measurments on the turbocharger. The axial bearing weakening required a design trade-off between flexibility and rigidity of the bearing. The results from the experimental and analytical methods provide better understanding of the characteristics of transient thrust forces that act on a turbocharger mounted on an engine of a heavy duty truck along with its design implications. The maximum normalized axial load measured and predicted were −90 N and −100 N, respectively.

Axial Load Control on High-Speed Turbochargers: Test and Prediction

2008 ◽  
Author(s):  
Kostandin Gjika ◽  
Gerald D. LaRue
Keyword(s):  
Axial Load ◽  
High Speed ◽  
Control Volume ◽  
Fluid Dynamic ◽  
Test Facility ◽  
Load Control ◽  
Lateral Motion ◽  
Radial Vibrations ◽  
Axial Thrust ◽  
Thrust Load

This paper deals with axial thrust load control in high-speed turbochargers. A specific test facility was developed to demonstrate the feasibility of axial load measurement and control. A special turbocharger was developed and instrumented to measure axial load and other test parameters. The axial load was controlled by throttling the compressor inlet and/or outlet flow. Extensive testing and analysis during both steady state and transient behavior conditions were completed on a special test bench. A thrust load map was developed and superimposed on the compressor map, and the relationship between turbocharger aerodynamics performance and axial thrust load was identified. During testing, the interaction between axial load, rotating group lateral motion and radial vibrations on the turbocharger housing was also identified. Running the turbocharger with low axial load shows no major problems on rotating group lateral motion or oil leakage. An analytical approach using a control volume type fluid dynamic model and a prediction code for axial thrust load has been developed. It shows good agreement between measured and predicted thrust load.

scholarly journals Analysis of an Arched Outer-Race Ball Bearing Considering Centrifugal Forces

1973 ◽  
Vol 95 (3) ◽  
pp. 265-271 ◽  
Author(s):  
B. J. Hamrock ◽  
W. J. Anderson
Keyword(s):  
Thermal Effects ◽  
High Speed ◽  
Ball Bearing ◽  
Centrifugal Forces ◽  
Angular Contact Ball Bearing ◽  
Outer Race ◽  
Contact Loads ◽  
Thrust Load ◽  
Raphson Method ◽  
Life Evaluations

A thrust load analysis of an arched outer-race ball bearing which considers centrifugal forces but which neglects gyroscopics, elastohydrodynamics, and thermal effects was performed. A Newton-Raphson method of iteration was used in evaluating the radial and axial projection of the distance between the ball center and the outer raceway groove curvature center (V and W). Fatigue life evaluations were made. The similar analysis of a conventional bearing can be directly obtained from the arched bearing analysis by simply letting the amount of arching be zero (g = 0) and not considering equations related to the unloaded half of the outer race. The analysis was applied to a 150-mm angular contact ball bearing. Results for life, contact loads, and angles are shown for a conventional bearing (g = 0) and two arched bearings (g = 0.127 mm (0.005 in.), and 0.254 mm (0.010 in.)). The results indicate that an arched bearing is highly desirable for high speed applications. In particular, for a DN value of 3 million (20000 rpm) and an applied axial load of 4448 N (1000 lb), an arched bearing shows an improvement in life of 306 percent over that of a conventional bearing. At 4.2 million DN (28000 rpm), the corresponding improvement is 340 percent. It was also found for low speeds, the arched bearing does not offer the advantages that it does for high speed applications.

Flow Investigation Around a V-Sector Ball Valve

2001 ◽  
Vol 123 (3) ◽  
pp. 662-671 ◽  
Author(s):  
P. Merati ◽  
M. J. Macelt ◽  
R. B. Erickson
Keyword(s):  
High Speed ◽  
Dynamic Pressure ◽  
Three Dimensional ◽  
Ball Valve ◽  
Operating Conditions ◽  
Mean Velocity ◽  
Model Flow ◽  
Flow Investigation ◽  
And Behavior ◽  
The Relationship

Experimental and computational methods were used to study the structure and behavior of the shedded vortices around a V-ball valve. Strouhal frequency for shedded vortices around the valve over a range of operating conditions and flow rates using water as the medium were measured. The information gathered in this study would help to predict at what operating conditions pipe ruptures might occur. A dynamic pressure transducer was used to determine the Strouhal frequency. LDV was used to measure the mean velocity and turbulence magnitudes. FLUENT was used to develop a two dimensional fluid dynamics model. Flow was visualized using high-speed video photography. A dominant large three-dimensional vortex downstream of the valve was detected. The centerline of this vortex is a shadow of the valve lip. A fifth degree polynomial describing the relationship between the Strouhal number and Reynolds number is obtained.

Paper 4: Development of High-Pressure Boiler Feed Pumps in Britain during the Last Decade

1966 ◽  
Vol 181 (14) ◽  
pp. 6-16 ◽  
Author(s):  
G. F. Arkless
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Material Selection ◽  
Operating Conditions ◽  
Feed Water ◽  
Feed Pump ◽  
Feed System ◽  
Axial Thrust ◽  
Advantages And Disadvantages ◽  
Component Design

This paper traces the evolution of the high-pressure feed pump in this country over the last decade, concentrating on its application in land-based, steam power plant. The influence of the choice of feed system and the effect of mounting feed water flow rates, pressure, and temperature on the design of the feed pump is discussed. Advantages and disadvantages of the various methods of driving a feed pump are enumerated and attention given to the reasons for the adoption of higher running speeds, and the means whereby high-speed pumps have been accommodated in view of their higher net positive suction head requirements. Material selection and component design is also considered in the light of the changing requirements brought about by larger size, more onerous operating conditions, and higher running speed. Glands, axial thrust balancing devices, impeller mountings, controls, and high-pressure joints, are each briefly discussed.

Vibration analysis of a test rig for a radial compressor

2001 ◽  
Vol 215 (1) ◽  
pp. 21-29
Author(s):  
S U Lee ◽  
D Robb ◽  
C Besant
Keyword(s):  
High Speed ◽  
Performance Testing ◽  
Operating Conditions ◽  
Fe Model ◽  
Aerodynamic Efficiency ◽  
Radial Compressor ◽  
Turbine Engine ◽  
Compressor Performance ◽  
The Relationship ◽  
Rotor Dynamic

A radial compressor has been designed at Imperial College for cooling a high-speed generator (HSG) coupled directly to a small gas turbine engine to produce 100kW electric power. The compressor has a significant influence on the overall dynamics of the generator. Therefore, it is designed to be lightweight for rotor-dynamic reasons together with reasonable aerodynamic efficiency. An experimental rig for the compressor performance testing was also designed. In order to operate this rig safely, it is very important to be able to predict and analyse its dynamic behaviour. For this purpose, a systematic procedure was used to develop a finite element (FE) model to predict natural frequencies under operating conditions. In the procedure, the relationship between FE analyses, modal analyses and results of a running test are established. Vibration analyses of the compressor rig using the proposed procedure are carried out. Finally, the results of computations and experiments for the rig are presented and compared.

Experimental and Analytical Investigation of High Speed Turbocharger Ball Bearings

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
Ankur Ashtekar ◽  
Farshid Sadeghi
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Analytical Investigation ◽  
Rotor System ◽  
Operating Conditions ◽  
Experimental Results ◽  
Test Rig ◽  
Angular Contact Ball Bearing ◽  
Turbine Wheel ◽  
Bearing Dynamics

The objectives of this investigation were to design and construct a high speed turbocharger test rig (TTR) to measure dynamics of angular contact ball bearing rotor system, and to develop a coupled dynamic model for the ball bearing rotor system to corroborate the experimental and analytical results. In order to achieve the objectives of the experimental aspect of this study, a test rig was designed and developed to operate at speeds up to 70,000 rpm. The rotating components (i.e., turbine wheels) of the TTR were made to be dynamically similar to the actual turbocharger. Proximity sensors were used to record the turbine wheel displacements while accelerometers were used to monitor the rotor vibrations. The TTR was used to examine the dynamic response of the turbocharger under normal and extreme operating conditions. To achieve the objectives of analytical investigation, a discrete element ball bearing model was coupled through a set of interface points with a component mode synthesis rotor model to simulate the dynamics of the turbocharger test rig. Displacements of the rotor from the analytical model were corroborated with experimental results. The analytical and experimental results are in good agreement. The bearing rotor system model was used to examine the bearing component dynamics. Effects of preloading and imbalance were also found to have significant effects on turbocharger rotor and bearing dynamics.

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