Single-Stage High-Pressure Turbocharging

2009 ◽  
Author(s):  
Tobias Gwehenberger ◽  
Martin Thiele ◽  
Martin Seiler ◽  
Douglas Robinson
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Pressure Ratio ◽  
Continuous Operation ◽  
Single Stage ◽  
Gas Treatment ◽  
Brake Mean Effective Pressure ◽  
Compressor Pressure Ratio ◽  
Component Efficiency ◽  
Shaft Seals

To meet the ever-increasing demands that will be made on engines, and especially on planned new engine generations, in the future, the power density of their turbochargers will have to be significantly increased. Raising the brake mean effective pressure, introducing Miller timing and providing support for exhaust-gas treatment all presuppose an increase in the turbo’s compressor pressure ratio while keeping the turbo unit as compact as possible. To fulfill all of these conditions with single-stage turbocharging, a new approach to future turbocharger design is needed, especially when additional expensive materials, such as titanium, are not to be used. On the compressor side, when using proven aluminum compressors, this requires additional cooling of the compressor wheels. But other turbocharger components too, such as the turbine, bearings, shaft seals and also the casings and their connections, are exposed to higher thermal and mechanical stresses as a result of the pressure ratios being far higher than those of turbochargers currently on the market. The challenge, which could also be called a balancing act, in dimensioning new turbochargers for single-stage high-pressure turbocharging with aluminum compressors is to design the components with the help of the available tools such that sufficient safety and component lifetime are achieved while performance and component efficiency are optimized. By using the available calculation tools, such as FEM or for the fluid dynamics CFD, it is now possible to achieve compressor pressure ratios of up to 5.8 in continuous operation with single-stage turbocharging while ensuring a compact turbocharger design and aluminum compressors. The paper describes how ABB Turbo Systems Ltd has successfully developed and qualified a new single-stage high-pressure turbocharger generation with radial turbine which allows compressor pressure ratios of up to 5.8 in continuous operation at 100% engine load. First successful engine tests with the new A100 radial turbocharger generation have been carried out both on medium- and on high-speed engines. The first frame sizes of the new A100 high-pressure turbocharger series have been released for market introduction, setting a significant new benchmark for turbocharging advanced diesel and gas engines.

Design and Test Results of a Ultra High Loaded Single Stage High Pressure Turbine

2013 ◽  
Author(s):  
Harjit S. Hura ◽  
Scott Carson ◽  
Rob Saeidi ◽  
Hyoun-Woo Shin ◽  
Paul Giel
Keyword(s):  
High Pressure ◽  
Total Pressure ◽  
High Speed ◽  
Pressure Ratio ◽  
Single Stage ◽  
Test Results ◽  
High Pressure Turbine ◽  
Technology Program ◽  
High Pressure Ratio ◽  
Expected Performance

This paper describes the engine and rig design, and test results of an ultra-highly loaded single stage high pressure turbine. In service aviation single stage HPTs typically operate at a total-to-total pressure ratio of less than 4.0. At higher pressure ratios or energy extraction the nozzle and blade both have regions of supersonic flow and shock structures which, if not mitigated, can result in a large loss in efficiency both in the turbine itself and due to interaction with the downstream component which may be a turbine center frame or a low pressure turbine. Extending the viability of the single stage HPT to higher pressure ratios is attractive as it enables a compact engine with less weight, and lower initial and maintenance costs as compared to a two stage HPT. The present work was performed as part of the NASA UEET (Ultra-Efficient Engine Technology) program from 2002 through 2005. The goal of the program was to design and rig test a cooled single stage HPT with a pressure ratio of 5.5 with an efficiency at least two points higher than the state of the art. Preliminary design tools and a design of experiments approach were used to design the flow path. Stage loading and through-flow were set at appropriate levels based on prior experience on high pressure ratio single stage turbines. Appropriate choices of blade aspect ratio, count, and reaction were made based on comparison with similar HPT designs. A low shock blading design approach was used to minimize the shock strength in the blade during design iterations. CFD calculations were made to assess performance. The HPT aerodynamics and cooling design was replicated and tested in a high speed rig at design point and off-design conditions. The turbine met or exceeded the expected performance level based on both steady state and radial/circumferential traverse data. High frequency dynamic total pressure measurements were made to understand the presence of unsteadiness that persists in the exhaust of a transonic turbine.

scholarly journals The Design and Evaluation of a High Pressure Ratio Radial Turbine

1992 ◽  
Author(s):  
K. R. Pullen ◽  
N. C. Baines ◽  
S. H. Hill
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Pressure Ratio ◽  
Performance Measurements ◽  
Turbine Engine ◽  
High Pressure Ratio ◽  
Turbine Efficiency ◽  
Wide Range ◽  
Dimensional Parameters ◽  
Very High

A single stage, high speed, high pressure ratio radial inflow turbine was designed for a single shaft gas turbine engine in the 200 kW power range. A model turbine has been tested in a cold rig facility with correct simulation of the important non-dimensional parameters. Performance measurements over a wide range of operation were made, together with extensive volute and exhaust traverses, so that gas velocities and incidence and deviation angles could be deduced. The turbine efficiency was lower than expected at all but the lowest speed. The rotor incidence and exit swirl angles, as obtained from the rig test data, were very similar to the design assumptions. However, evidence was found of a region of separation in the nozzle vane passages, presumably caused by a very high curvature in the endwall just upstream of the vane leading edges. The effects of such a separation are shown to be consistent with the observed performance.

Development of New Single and High-Density Heat-Flux Gauges for Unsteady Heat Transfer Measurements for a Rotating Transonic Turbine

2020 ◽  
Author(s):  
Richard Celestina ◽  
Spencer Sperling ◽  
Louis Christensen ◽  
Randall Mathison ◽  
Hakan Aksoy ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Pressure ◽  
Pressure Ratio ◽  
High Density ◽  
Secondary Flows ◽  
Single Stage ◽  
High Pressure Turbine ◽  
Transonic Turbine ◽  
New Generation

Abstract This paper presents the development and implementation of a new generation of double-sided heat-flux gauges at The Ohio State University Gas Turbine Laboratory (GTL) along with heat transfer measurements for film-cooled airfoils in a single-stage high-pressure transonic turbine operating at design corrected conditions. Double-sided heat flux gauges are a critical part of turbine cooling studies, and the new generation improves upon the durability and stability of previous designs while also introducing high-density layouts that provide better spatial resolution. These new customizable high-density double-sided heat flux gauges allow for multiple heat transfer measurements in a small geometric area such as immediately downstream of a row of cooling holes on an airfoil. Two high-density designs are utilized: Type A consists of 9 gauges laid out within a 5 mm by 2.6 mm (0.20 inch by 0.10 inch) area on the pressure surface of an airfoil, and Type B consists of 7 gauges located at points of predicted interest on the suction surface. Both individual and high-density heat flux gauges are installed on the blades of a transonic turbine experiment for the second build of the High-Pressure Turbine Innovative Cooling program (HPTIC2). Run in a short duration facility, the single-stage high-pressure turbine operated at design-corrected conditions (matching corrected speed, flow function, and pressure ratio) with forward and aft purge flow and film-cooled blades. Gauges are placed at repeated locations across different cooling schemes in a rainbow rotor configuration. Airfoil film-cooling schemes include round, fan, and advanced shaped cooling holes in addition to uncooled airfoils. Both the pressure and suction surfaces of the airfoils are instrumented at multiple wetted distance locations and percent spans from roughly 10% to 90%. Results from these tests are presented as both time-average values and time-accurate ensemble averages in order to capture unsteady motion and heat transfer distribution created by strong secondary flows and cooling flows.

Temperature Measurement System for Low Pressure Ratio Turbine Testing

2003 ◽  
Author(s):  
R. Va´zquez ◽  
J. M. Sa´nchez
Keyword(s):  
Temperature Measurement ◽  
Measurement System ◽  
High Speed ◽  
New Technologies ◽  
Pressure Ratio ◽  
Low Pressure ◽  
High Accuracy ◽  
Single Stage ◽  
Measurement Systems ◽  
Temperature Measurement System

In 1999, ITP (Industria de Turbopropulsores, S.A.) launched a wide on-going research program focusing on new technologies to provide significant improvements in Low Pressure Turbines cost and weight. As consequence of the new technologies the experience limits are exceeded and new unknown concepts, like high stage loading turbines, must be explored and then a wide experimental work is required for validation purposes. Cold flow single stage rigs in high-speed facilities were selected by ITP as main vehicle to carry out the experimental validation. Single stage Low Pressure Turbine rigs have low-pressure ratio and power consumption, therefore efficiency predictions based on temperature drop require high accuracy thermocouple measurement systems (precision uncertainties lower than ±50 mK), if small efficiency variations must be captured. In this paper, a detailed uncertainty analysis is introduced and a temperature measurement system that allows achieving such high measurement accuracy is evaluated and described. Type T thermocouples are proposed for use in the range 0°C to 80°C, which are individually calibrated. The procedure followed for this calibration is presented and how is possible to achieve a precision of 30 mK. It is also shown as conventional UTR based on metal plates can behave as good as thermal baths in terms of temperature uniformity and errors, with the adequate isolation and temperature reference calibration. The conventional data recording and voltage measurement systems are experimentally evaluated, and they are found as main source of temperature errors. Although following some recommendations the precision of those systems can be improved, it is experimentally probed and therefore suggested the use of high accuracy voltmeter with a commutation unit to reduce significantly the temperature uncertainty. Finally a miniature Kiel Shroud is proposed and aerodynamically characterised in a high-speed facility. Mach, Reynolds number, yaw, blockage and manufacturing tolerance impact on recovery factor can be inferred from those results.

Turbines and Structures for Ultra-High Pressure Ratio Aero-Engines

2016 ◽  
Author(s):  
Anders Lundbladh ◽  
Ralf von der Bank ◽  
Richard Avellán ◽  
Stefan Forsman ◽  
Stefan Donnerhack ◽  
...  
Keyword(s):  
High Pressure ◽  
Direct Reduction ◽  
Pressure Ratio ◽  
Weight Ratio ◽  
Performance Improvements ◽  
High Pressure Ratio ◽  
Ultra High Pressure ◽  
Component Efficiency ◽  
Aero Engines ◽  
Emission Core

This paper describes the research carried out in the European Commission co-funded project LEMCOTEC (Low Emission Core Engine Technology) on aerodynamics for turbines and structures for compressors, combustors and turbines. The aim is to significantly contribute to the reduction of the environmental footprint of aviation with regard to emissions from aero engines. The LEMCOTEC turbine and structure technologies are directed primarily to act as enablers for higher thermal efficiency arising from increased overall pressure ratio. Thus the work is supporting increased operating temperatures, reduced core deformation, reduced cooling flows and increased performance to weight ratio, in addition to direct reduction of flow losses and associated component efficiency increases. The article details the targets for performance improvements, the validation of the technologies and how they, together with LEMCOTEC’s improved technologies on compressors and combustors, relate to the goal of building ultra-high pressure ratio engines.

A Generalized Procedure to Estimate Matching of Power Turbine With Aeroderivative Gas Generator at High Speed Settings

2005 ◽  
Author(s):  
Inam U. Haq
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Pressure Ratio ◽  
Gas Generator ◽  
High Pressure Turbine ◽  
Data Manipulation ◽  
Turbine Inlet ◽  
Engine Design ◽  
Power Turbine ◽  
Set Up

This paper encapsulates generalized considerations of power turbine matching with aeroderivative gas generator at high power settings. A computation route is set up to estimate the magnitude of the desired parameters from design point knowledge of a gas generator. Then, a method is delineated to verify matching of power turbine inlet nozzle area with exhaust of gas generator by measuring tangible tested parameters. Data manipulation revealed that there exists a favorable correlation between pressure ratio of high pressure turbine and gas generator speed that may directly reflect the influence of physical area change of power turbine inlet nozzle area. A practical example is presented to demonstrate the procedure. From engine design to retirement, the generalized considerations may be applied on several occasions where question of matching may become important and require explanation for performance and financial justifications. Some generalized rules of matching are condensed and their applications are suggested.

Performance Analysis of Refrigerants R1234yf Single Stage Compression Cycle with a Throttle Valve and an Expander

2013 ◽  
Vol 753-755 ◽  
pp. 2790-2793
Author(s):  
Jing Rui Tian ◽  
Hong Li Wang ◽  
Gui Jun Xue ◽  
Qing Hua Zhang
Keyword(s):  
High Pressure ◽  
Performance Analysis ◽  
Pressure Ratio ◽  
Single Stage ◽  
Cycle Performance ◽  
Outlet Temperature ◽  
Throttle Valve ◽  
Compression Cycle ◽  
Increasing Trend ◽  
Better Than

In range of high pressure, the performance of single stage cycle with an expander (SCE) is better than the cycle with a throttling valve (SCV). With increasing of the evaporating temperature or decreasing outlet temperature of condenser, the performance of the two cycles is an increasing trend. With increasing of pressure ratio, the performances of all cycles are decreased. Under the same comparison conditions, expander cycle performance superior to the throttle valve performance.

scholarly journals High Pressure Ratio Intercooled Turboprop Study

1992 ◽  
Author(s):  
C. Rodgers
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Waste Heat ◽  
Pressure Ratio ◽  
Weight Ratio ◽  
Unmanned Aircraft ◽  
High Pressure Ratio ◽  
Rotary Engines ◽  
Component Efficiency ◽  
Long Endurance

High altitude long endurance unmanned aircraft impose unique contraints on candidate engine propulsion systems and types. Piston, rotary and gas turbine engines have been proposed for such special applications. Of prime importance is the requirement for maximum thermal efficiency (minimum specific fuel consumption) with minimum waste heat rejection. Engine weight, although secondary to fuel economy, must be evaluated when comparing various engine candidates. Weight can be minimized by either high degrees of turbocharging with the piston and rotary engines, or by the high power density capabilities of the gas turbine. The design characteristics and features of a conceptual high pressure ratio intercooled turboprop are discussed. The intended application would be for long endurance aircraft flying at an altitude of 60,000 ft. (18,300 m). It is estimated that such a turboprop would be capable of thermal efficiencies exceeding 40% with current state-of-the-art component efficiency levels and an overall compressor pressure ratio of 66.0. Projected Power (at altitude) to weight ratio is comparable to that of competitive piston and rotary engines.

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