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Technical Paper

The Volvo Heavy Truck Gas Turbine VT300

2005-11-01
2005-01-3504
Renewed interest in a gas turbine as an alternative driveline for heavy trucks within Volvo, driven by the demands for lower emissions, resulted in a pre-study during 1990-1992 and the development and testing of a demonstrator engine between 1993 and 2000. To achieve the demanding goals for efficiency and emissions, the engine was designed as a recuperated and intercooled two shaft powerplant with a low-emission combustor. Following a comprehensive aerodynamic and concept study, engine components were rig tested and the engine mechanical design was finalized. Two engines were built and tested in a rig and in a truck. Very low exhaust emissions were demonstrated during rig testing, with NOx as low as 0,22 g/kWh in a 13-mode test. The efficiency goal of 42 % was not reached, but given more development time the measured efficiency of 38,6 % can most certainly be improved. Still, it will be the fuel consumption that is the major disadvantage compared to a diesel engine.
Technical Paper

High Efficiency Vehicular Gas Turbines

2005-09-07
2005-01-3461
Recuperated intercooled gas turbine cycles offer efficiencies in the 40% and higher range at medium to high loads. Although these cycles offer better low-load efficiency than other gas turbine cycles, the idle and low-load fuel consumption are still not good enough for satisfactory vehicle operation. In addition, response time to sudden demands for power is slow. The multi-pressure gas turbine allows the combustion air to enter the cycle at a different point, reducing the mass flow and the rating of the gas turbine for efficient operation at low power. Yet, the full power of the gas turbine is available quickly for acceleration or hill climbing.
Journal Article

An Agent Based Approach for Multi-Objective Optimization in Production Scheduling for Turbine Engine Blade Manufacturing

2014-09-16
2014-01-2230
Abstract With the development of many new technologies in aircraft manufacturing area and the increasing competition of the global market, aircraft manufacturing enterprises have to reduce their production time and increase the cost-efficiency, with the consideration of high speed response to the changes inside enterprises or in the environment. Production scheduling is a significant process in manufacturing, especially for complicated part or component processing. This paper proposes an agent based multi-objective optimization approach for production scheduling based on Genetic Algorithms. It aims to minimize the total production cost and simultaneously reducing the emission released during production, and the delivery time and equipment constraints are satisfied as well. The new approach is tested in a virtual plant for turbine blade manufacturing.
Technical Paper

Noise Characteristics of a Micro Gas Turbine for Use in a Serial Hybrid Concept

2014-06-30
2014-01-2066
Abstract The development of energy-efficient and lightweight vehicles is a major challenge for researchers and engineers in the automotive industry, with one solution being the use of micro gas turbines in serial hybrid vehicles. Among other advantages, the use of a micro gas turbine instead of a reciprocating engine enables a high reliability and low emissions. What makes the concept of using a gas turbine even more interesting are its special NVH characteristics, which are quite different from those of a reciprocating engine. Besides the fact that a gas turbine in general produces less noise and vibration than a diesel engine of the same power, the characteristic noise spectrum is also very different. In this paper, the noise characteristics of a micro gas turbine are compared to those typical for a common reciprocating engine and the sources of the noise are considered.
Technical Paper

Turboelectric Distributed Propulsion Protection System Design Trades

2014-09-16
2014-01-2141
Abstract The Turboelectric Distributed Propulsion (TeDP) concept uses gas turbine engines as prime movers for generators whose electrical power is used to drive motors and propulsors. For this NASA N3-X study, the motors, generators, and DC transmission lines are superconducting, and the power electronics and circuit breakers are cryogenic to maximize efficiency and increase power density of all associated components. Some of the protection challenges of a superconducting DC network are discussed such as low natural damping, superconducting and quenched states, and fast fault response time. For a given TeDP electrical system architecture with fixed power ratings, solid-state circuit breakers combined with superconducting fault-current limiters are examined with current-source control to limit and interrupt the fault current.
Technical Paper

Development of Installed Propulsion Performance Model for Efficient Supersonic Air Vehicle Design

2014-09-16
2014-01-2133
Abstract For the design process of the class of aircraft known as an efficient supersonic air vehicle, particular attention must be paid to the propulsion system design as a whole including installation effects integrated into a vehicle performance model. The propulsion system assumed for the efficient supersonic air vehicle considered in this paper is a three-stream variable cycle engine. A computational model has been built with the Numerical Propulsion System Simulation (NPSS) software to analyze this engine. This engine model was based on the generic adaptive turbine engine model developed at the turbine engines division of the US Air Force Research Laboratory. Along with this variable cycle NPSS model, a three-ramp external compression inlet model meant for conceptual design has been developed. This model will be used to capture inlet installation effects, including those attributable to angle of attack changes at supersonic Mach numbers.
Technical Paper

Development of an Exhaust Driven Turbine-Generator Integrated Gas Energy Recovery System (TIGERS®)

2014-04-01
2014-01-1873
Abstract This paper describes the design and development steps taken to realise a functioning Turbo-generator Integrated Gas Energy Recovery System (TIGERS®). The main areas covered focus on simulation, machine design, control system development and validation. The mechanical design for this application is particularly challenging for a number of reasons. The turbine is capable of rotating the shaft at speeds greater than its critical rotating limit. Rolling element grease filled bearings are used to allow application flexibility; these have an operating temperature limit of 200°C. The exhaust gas can reach temperatures greater than 900°C in spark ignition applications, whereas the turbine upper functional limit is 850°C. The power electronics are integrally mounted in the machine and have a maximum thermal operating limit of 120°C.
Journal Article

An Assessment of the Influence of Gas Turbine Lubricant Thermal Oxidation Test Method Parameters Towards the Development of a New Engine Representative Laboratory Test Method

2013-12-20
2013-01-9004
In the development of a more accurate laboratory scale method, the ability to replicate the thermal oxidative degradation mechanisms seen in gas turbine lubricants, is an essential requirement. This work describes an investigation into the influence of key reaction parameters and the equipment set up upon extent and mechanism of oil degradation. The air flow rate through the equipment was found to be critical to both degradation rate and extent of volatilization loss from the system. As these volatile species can participate in further reactions, it is important that the extent to which they are allowed to leave the test system is matched, where possible, to the conditions in the gas turbine. The presence of metal specimens was shown to have a small influence on the rate of degradation of the lubricant. Loss of metal from the copper and silver specimens due to the mild corrosive effect of the lubricant was seen.
Technical Paper

Analysis of Global Dynamics of Rotating Systems like Jet Engines, with Special Emphasis on Harmonic Analysis in the Presence of Bearing with Clearances

2013-09-17
2013-01-2120
The paper presents first a description of the methods used for the analysis of global dynamics of rotating systems like jet engines but also auxiliary power units. Different methodologies are described so to model rotating parts using beam, but also Fourier multi-harmonic, three dimensional models or to take into account cyclic symmetry and multistage cyclic symmetry concepts. Advantages and disadvantages of the different model types are discussed and compared. The coupling of the rotating parts with casings and stators is then discussed both in the inertial frame and in the rotating frame. The effect on global dynamics of bearing and other linking devices is taken into account for different type of analysis from critical speed analysis, to harmonic and transient analysis. The effect of gears and gear boxes coupling different rotors (like it is the case for auxiliary power units in a jet engine) is then discussed and appropriate methods described so to model this coupling effect.
Technical Paper

Evaluation of Downstream Dilution Techniques for the Sampling of Turbine Engine Particulate Matter

2013-09-17
2013-01-2130
Measurement of turbine engine particulate matter (PM) requires diligent handling of the sample to maintain integrity and minimize any alteration due to sampling or transport artifacts. PM sample dilution at the probe tip is a common and widely used technique to condition the sample in order to reduce PM losses and potentially “freeze” chemical reactions that may occur throughout the sampling train to the instruments. Diluting the PM sample at a location downstream in the sample line is preferred by engine manufacturers as probes used for gas emissions can be used for PM; however, implications on PM characteristics and comparisons against probe-tip dilution are unknown. The present study compares the characteristics of turbine engine PM diluted at the probe tip and at a location downstream in the sampling train. Downstream dilution was accomplished by injecting nitrogen through a commercial ejector (operated both as a diluter and pump) and a through simple concentric tube arrangement.
Journal Article

Blade Tip Clearance Sensors for Use in Engine Health Monitoring Applications

2013-09-17
2013-01-2145
Blade tip clearance is a key design parameter for gas turbine designers. This parameter is often measured during engine testing and development phases as part of design validation but has yet to be utilized during normal engine fleet operation. Although blade tip clearance measurements are often mentioned for fleet operation in the context of active clearance control, the use of blade tip clearance measurements can provide an additional benefit for engine health monitoring. This paper explores the use of blade tip clearance sensors for engine condition monitoring of hot section blades. Blade tip clearance, especially in the first stage turbine, has an impact on exhaust gas temperature. The use of tip clearance measurements can provide supplementary information to traditional EGT measurements by providing a direct measurement of wear on the blade tips.
Technical Paper

Compressor Airfoil Protective Coating for Turbine Engine Fuel Efficiency

2013-09-17
2013-01-2187
Small media ingestion has been known to cause erosion and result in corrosion to compressor components of gas turbine engines. Compressor degradation negatively impacts fuel consumption, engine performance, reliability, and maintenance costs. Power losses in the compressor section are often unrecoverable without increasing fuel consumption; therefore, protecting the compressor from excessive erosion/corrosion may extend the life of an engine, and reduce fuel, maintenance costs, and emissions. A study was conducted to investigate the effect of a new compressor blade and vane erosion/corrosion resistant coating on two Rolls-Royce T56-A7-B engines. The study included a comprehensive sand ingestion test that compared the performance and hardware condition of uncoated and coated compressor airfoils before, during, and after sand ingestion of 135 pounds of sand mixture.
Technical Paper

Impact of Heat Exchanger Location on Engine Performance

2012-10-22
2012-01-2168
Recent turbine engine numerical modeling developments have significantly improved the capability to accomplish integrated system-level analyses of aircraft thermal, power, propulsion, and vehicle systems. Combining desired aircraft performance with thermal management challenges of modern aircraft, which include increased heat loads from components such as avionics and more-electric accessories, as well as maintaining engine components at specified operating temperatures, demands we look for solutions that maximize heat sink capacity while minimizing adverse impacts on engine and aircraft performance. Development of optimized aircraft thermal management architectures requires the capability to directly analyze the impact of thermal management components, such as heat exchangers, on engine performance. This paper presents a process to evaluate the impact of heat exchanger design and performance characteristics (e.g., volume and pressure drops) on engine performance.
Journal Article

From Fordsons to Jets: A Designer's Journey

2012-10-22
2012-01-2155
The remarkable evolution of the gas turbine engine has made the world much smaller and provided power for worldwide use. I often think of growing up in a farm environment, being fascinated with machinery and then having the opportunity to take part in the design and development of the world's most complex product. I worked with brilliant engineers and experienced the transition from slide rules and “hand calculation” methods to computers and more precise finite element modeling. Perhaps this story will present insight for current and future design engineers who create the manufactured products used by mankind.
Technical Paper

Refinements to Mechanical Health Monitoring Algorithms

2012-10-22
2012-01-2096
This paper discusses recent improvements made by Honeywell's Condition-Based Maintenance (CBM) Center of Excellence (COE) to Mechanical Health Management (MHM) algorithms. The Honeywell approach fuses Condition Indicators (CIs) from vibration monitoring and oil debris monitoring. This paper focuses on using MHM algorithms for monitoring gas turbine engines. First an overview is given that explains the general MHM approach, and then specific examples of how the algorithms are being refined are presented. One of the improvements discussed involves how to detect a fault earlier in the fault progression, while continuing to avoid false alarms. The second improvement discussed is how to make end of life thresholds more robust: rather than relying solely on the cumulative mass of oil debris, the end of life indication is supplemented with indicators that consider the rate of debris generation.
Technical Paper

Sensory Prognostics and Management System (SPMS)

2012-10-22
2012-01-2095
The Sensory Prognostics and Management Systems (SPMS) program sponsored by the Federal Aviation Administration and Boeing developed and evaluated designs to integrate advanced diagnostic and prognostic (i.e., Integrated Vehicle Health Management (IVHM) or Health Management (HM)) capabilities onto commercial airplanes. The objective of the program was to propose an advanced HM system appropriate for legacy and new aircraft and examine the technical requirements and their ramifications on the current infrastructure and regulatory guidance. The program approach was to determine the attractive and feasible HM applications, the technologies that are required to cost effectively implement these applications, the technical and certification challenges, and the system level and business consequences of such a system.
Journal Article

Numerical and Experimental Investigation of the Piezoelectric Flapping Wing Micro-Air-Vehicles Propulsion

2012-10-20
2012-01-2245
The flapping flight is advantageous for its superior maneuverability and much more aerodynamically efficiency for the small size UAV when compared to the conventional steady-state aerodynamics solution. Especially, it is appropriate for the Micro-air-vehicle (MAV) propulsion system, where the flapping wings can generate the required thrust. This paper investigated such solution, based on the piezoelectric patches, which are attached to the flexible plates, in combination with an appropriate amplification mechanisms. The numerical and experimental flow analyses have been carried out for the piezoelectric flapping plate, in order to characterize the fluid structure interaction induced by the swinging movement of the oscillating plate.
Technical Paper

CFD Analysis of Supercooled Large Droplets in Turbofan Engines

2011-06-13
2011-38-0080
The study of Supercooled Large Droplets (SLD) has received greater attention in the Aviation industry since the ATR-72 accident in 1994, which was attributed to SLD. This type of icing cloud usually consists of droplets of up to a millimeter in diameter and mean volumetric diameter (MVD) greater than 40 microns1. The analyses of the ice accretion process with SLD have focused mainly on the wing and stabilizers, particularly on the leading edges where accretion can occur beyond the ice protected areas. There are several numerical and empirical models to predict the mass and shapes of ice accreted from SLD, but there are few published papers that focus on SLD accretion within aircraft turbofan engines2, 3, 4, 5, 6, 7, 8, 9. SLD droplets have higher inertia than conventional icing droplets, which leads to their trajectories being less influenced by the aerodynamic forces. However, large droplets are more likely to breakup than smaller droplets when subjected to highly shear flows.
Technical Paper

Development of a Unique Icing Spray System for a New Facility for Certification of Large Turbofan Engines

2011-06-13
2011-38-0099
The Global Aerospace Centre for Icing and Environmental Research (GLACIER) facility has been constructed in Thompson, Manitoba, Canada. This project involves the construction and operation of a facility which will provide icing certification tests for large gas turbine engines, as well as performance, endurance and other gas turbine engine qualification testing. MDS Aero Support, in partnership with the National Research Council of Canada (NRC), Pratt and Whitney Canada, and Rolls Royce Canada, has developed a globally unique outdoor engine test and certification facility. The prime purpose of this facility is for icing certification of aviation gas turbine engines, initially for Rolls-Royce and Pratt & Whitney, two of the three largest gas turbine manufacturers in the world.
Technical Paper

Gas Turbine Generator Sets for Hybrid Vehicles

1992-02-01
920441
A gas turbine-driven generator set is being developed as a range extender for a major automobile manufacturer's hybrid electric vehicle. The 24 kW continuous rating is sufficient to propel the automobile at maximum legal speed in the United States. For hill climbing and passing, 30 kW is available. A circumferential recuperator increases efficiency to 30% on unleaded gasoline. There is no gearbox since the permanent magnet generator is mounted on the gas turbine shaft. There is no lubrication system as the rotor group shaft runs on air bearings. The complete generator set with recuperator weighs 36 kg (80 lb). The OEM price will be under $1,000 in automotive quantities. Production units will have catalytic combustion to reduce emissions to less than those of an electric utility power plant. California regulatory authorities have indicated that this could permit a hybrid vehicle to be classed as “zero emission”.
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