bluuebunny/crossref_metadata_2025 huggingface dataset:
Life Prediction for the Main Shaft of Aircraft Turbine Engine
Authors: Dunhui Liu
Published: April 2015

The life prediction of the main shaft is described herein at the following three aspects: estimation of the fatigue life, testing method of the fatigue life and determination method of the service life for the main shaft. Based on the working practice, a working block diagram of life determinating procedure for the main shaft, from which the prediction contents and steps of the fatigue life for the main shaft can be seen, is also included in this paper.

Since the factors affecting the fatigue life of hardwares are very complicated, so only the main factor can be taken into consideration in the method of prediction of the life. Therefore, in this paper it is emphasized to establish a life prediction computation program which integrates the main shaft design, testing and application, so that the computation theory of the whole life prediction can be established on the foundation of the test practice and service experience.

The life of main shaft can be predicted by calculation during the design stage. The local stress method and strain empiric formula are applicable for the prediction of the main shaft life in its elastoplastic area.
A Theoretical Analysis and Experimental Study of Flow and Heat Transfer in a Transpiration Cooled Passage
Authors: Guo-Rui Huang
Published: April 2015

In this article a theoretical analysis of the coolant flow and heat transfer in the passage for a transpiration-cooled blade was made and several mathematical expressions were led out. Various factors influenced on thermal parameters in the passage are more considered. Experimental results indicate that (1) the flow near metering orifice is not one-dimensional then it is quite important to take a correction in calculation (2) it is not appropriate to account heat transfer between the coolant and the porous shell to choice about 5 times size of the heat transfer coefficient in the turbulence tube.

This paper shows that several mathematical expressions are ready for whole heat transfer design of blades and the experimental datum are provided for the same type transpiration-cooled blade design.
Investigation Into the Cause of Failure of a Turboprop Impeller in Service
Authors: Wong H. Y.
Published: April 2015

A 2-stage centrifugal flow turboprop Dart engine failed recently in service due to the failure of the low pressure impeller. Examination by various techniques including electron microscopy based on scanning, energy dispersive analysis of x-ray and transmission electron fractography indicates that the cause was metallurgical in nature, resulting from a material manufacturing defect followed by fatigue fracture and finally by tensile rupture of the material.
Installation Requirements for Small Gas Turbine Engines
Authors: Piercy T. F. , Heathco C. E.
Published: April 2015

Allison currently has over 20,000 Model 250 small gas turbine engines operating throughout the world in a variety of turboprop and turboshaft installations. The experience base has contributed to the understanding and development of small engine installation requirements. Some of the critical interface systems will be reviewed to highlight some of the small engine considerations of engine installation design.
An Analysis of Applicability of Surge/Stall Criterion to Engineering Problems
Authors: Tang Guo-Cai , Zhang Hui-Min
Published: April 2015

A study is presented in the paper on the applicability of the surge/rotating stall criterion, or parameter B (B=U/2ωLc), to practical engineering problems. This criterion, while being of great theoretical value, appears to have some uncertainty in application to engineering compressor systems with the difficulties arising from changeable compressor characteristics and the diversity in the geometry and the time lag in different systems. Therefore, a series of calculations were conducted to show the influence of the above-mentioned factors. It is concluded from the numerical results that there exists a single critical value of parameter B for a given compressor working in possibly different systems while no identical critical value could be employed to different compressors in different systems.
Increasing Surge Margin in an Axial Flow Compressor Using “End-Bend” Airfoils
Authors: Cai Y. J. , Zhong Y. L. , Qian L. H. , He S. Z. , Pang Q. H.
Published: April 2015

This paper concentrates solely on the effect of end bend airfoil on performance of an axial flow compressor. The purpose is to reduce flow loss in the region of endwall boundary layer and to enlarge surge margin of an axial flow compressor by employing end bend airfoil on the stator blades in the last stages of the compressor. The experimental results show that surge margin is increased by 4.9–5.2 percent, efficiency by 2.6–3.2 percent at operational speed n=1.0–1.1.
Recent Developments in Vibration Monitoring and Diagnostics for Aeroderivative Gas Turbines
Authors: Adams James C.
Published: April 2015

Industrial aeroderivative gas turbines are becoming increasingly popular for use in both on-shore and off-shore installations. The characteristics of these machines — high efficiency in simple cycle operation, small size, and light weight — make them ideal for industrial applications.

As the aeroderivative gas turbine has become more widely used, the need for more reliable monitoring methods has become increasingly apparent.

Traditional velocity transducer based seismic monitoring systems have had several shortcomings when applied to aeroderivative gas turbines. One of these problems was nuisance alarms due to increasing transducer noise output. Another was not detecting increasing casing vibration because of transducer deterioration.

Overcoming these problems has required advances in transducer technology as well as changes in signal processing techniques. This paper describes the technology and techniques used in new seismic vibration monitoring systems.
Comparison of Various Fluidized Bed Combustor-Gas Turbine Systems
Authors: Fraas Arthur P.
Published: April 2015

Pressurizing a fluidized bed combustor with a gas turbine greatly improves both sulfur retention and combustion efficiency. Operating the gas turbine with a high inlet temperature (e.g. 900°C) would yield a thermal efficiency about four points higher than for an atmospheric furnace, but 40 y of experience have failed to solve problems with flyash erosion and deposits. Extensive experience such as that with fluidized bed catalytic cracking units indicates that the gas turbine blade erosion and deposit problems can be handled by dropping the turbine inlet temperature below 400°C where the turbine delivers just enough power to drive the compressor. The resulting thermal efficiency is about half a point higher than for an atmospheric bed, and the capital cost of the FBC-related components is about 40% lower.

While a closed-cycle helium gas turbine might be used rather than a steam cycle, the thermal efficiency would be about four points lower and the capital cost of the FBC-related components would be roughly twice that for the corresponding steam plant.
The Development of Integrated Coal-Gasification Power Plants With Clean Combustion in Germany
Authors: Finckh H. H. , Mueller R.
Published: April 2015

As advances are made in flue-gas clean-up systems, such as electrostatic precipitators, wet and dry desulfurization techniques and deNOX catalysers, the environmental impact of conventional steam turbine power plants fired with pulverized coal can be reduced at great expense in the form of additional capital investment and lowered station efficiency. The clean fuel gas obtainable from various coal-gasification processes, however, can be used to generate electricity with excellent efficiency and low-pollution emissions in low-cost unfired combined-cycle power plants of modular design. These are termed GUD power plants from the German designation “Gas und Dampf” meaning gas and steam. The overall efficiency is appreciably enhanced by closely integrating the gas-production process with the power generating cycle. Such an integrated coal-gasification combined-cycle installation should thus allow China to exploit its vast coal reserves for electrical energy production in both the most economical and environmentally acceptable way.
Evaporation Histories of Fuel Sprays Injected Across a Flowing Air Stream
Authors: Chin J. S. , Freeman W. G. , Lefebvre A. H.
Published: April 2015

For systems featuring cross-stream injection of fuel into flowing air, a calculation procedure is presented which allows the fraction of fuel evaporated to be estimated rapidly as a function of downstream distance from the plane of fuel injection. The method takes into account the effects on evaporation length of variations in ambient air pressure, temperature, and velocity, as well as changes in fuel spray characteristics such as mean drop size and drop-size distribution. Calculations carried out at typical gas turbine combustor operating conditions indicate that the main factors influencing the length required to achieve any given degree of fuel evaporation are air temperature and velocity, and the mean drop size of the spray.
Gas Turbine Heat Recovery Systems Predicting Fired Performance
Authors: Pasha Akber
Published: April 2015

Heat recovery systems generate steam by extracting heat from the gas turbine exhaust. This steam is used either in a steam turbine to generate power or as a heating and drying medium in a process. Most of the time it is a combination of both. Because of the cogeneration criteria and because of the independent power and process equipment, the HRS can no longer depend on gas turbine exhaust alone to produce the needed steam. Some sort of induct auxiliary firing is employed to satisfy the steam demand. The HRS, therefore, is needed to operate satisfactorily at various ambients and loads and at fired and unfired conditions. The design of the HRS should take into consideration all of these unfired and fired conditions so that the HRS operation can be stable over the operating range.

There are numerous design parameters which affect the design and operational stability of the HRS and all these need to be reviewed at each operating condition for the design to be satisfactory. This paper presents charts and graphs which predict the probable values of these design parameters under various operating conditions. By utilizing these, the HRS user can establish the stability of the HRS performance over the operating range based on the specified design point parameters. If there is undesirable performance at a certain point, then either the operating condition or the design parameters can be changed. An HRS user can, by using these charts, be able to specify more realistic design parameters without a lengthly analysis by the HRS manufacturer which costs both money and time.
Cogeneration Combined Cycle Achievements by the Dow Chemical Company in the Conservation of Energy
Authors: Zanyk J. P.
Published: April 2015

A review of the development and use of the gas turbine generator unit in The Dow Chemical Company for the cogeneration of steam and electric power energy for Dow’s major chemical complex. This review highlights the success and problems of Dow Chemical’s most recently constructed power plant at its Texas Division in Freeport, Texas. A review of Dow’s experience and developed technology to provide a reliable cogenerating plant.
Unstable Flows in the Vaneless Diffuser of a Centrifugal Compressor at Low Flow Rates
Authors: Mizuki S. , Park C. W. , Deckker B. E. L.
Published: April 2015

Time-averaged and time-dependent velocity distributions have been measured in the the vaneless diffuser of an experimental compressor. Changes in these distributions have been identified with the onset of rotating stall and fully developed stall. At very small flow rates, an approach to equilibrium has been observed. Frequency spectra analyses have revealed the existence of low frequency disturbance waves which, together with the large adverse pressure gradient prevailing in the diffuser, could lead to selective wave amplification and surging.
Measurement of Swirling Flow Field Using the Single Slanted Hot-Wire Technique
Authors: Shin H. W. , Hu Z. A.
Published: April 2015

This paper presents the use of a single slanted hot wire to measure the three velocity components of a swirling flow field. In its usage, the hot wire probe has been calibrated in a subsonic air jet for both speed and direction. It was then used to measure the swirling flow field associated with the presence of an inlet model. Using Hybrid Method, the final velocity components are obtained via the solution of a set of simultaneous nonlinear equations given the voltage readings at three orientations of the hot wire probe at a point in the flow field. The distortions of total pressure and velooity were also measured in the same inlet model.
Theoretical Analysis and Experimental Research of Three-Dimensional Flow of Centrifugal Impeller
Authors: Renyong Tu , Lu He , Yanling Wang
Published: April 2015

The quasi-orthogonal surface method of calculation of three-dimensional flow of references (1, 2, 3) is extended to take account of the influences of upstream and downstream flow and to include various losses in the impeller. By this method, the three-dimensional flow distribution of two impellers were calculated and the results were compared with experimental data. It was found that the calculation results of the present method which takes account of the gradient of entropy and the upstream and downstream conditions are in closer agreement with the experimental results than the previous method.
Numerical Study of a Dump Diffuser Flow Field in a Short Annular Combustor
Authors: Zhiben Hu , Guangshi Hua
Published: April 2015

A computer program for solving the two-dimensional steady flow field of the dump diffuser is made based on the streamtube method and SIMPLE (Semi–Implicit Method for Pressure linked Equations) algorithm. Some concrete measures or improvements are developed to treat the irregularly shaped calculation domain, the inlet distribution of k and ε to use the variable relaxation factors. The flow field in a short dump diffuser model with pre–diffuser and blind flame tube is calculated with the program. The calculated results agree well with the experimental data.
The Behaviour of Creep-Fatigue Interactions in GH36 Superalloy
Authors: Zouxiang Duan , Youlian Ning , Jinrui He
Published: April 2015

In this paper, the behaviour of creep-fatigue interactions in GH36 superalloy at 650°C is determined and a number of strainrange-life relationships of is given. Strain Energy Partitioning Approach (SEP), developed previously by the present authors, is applied to predict high-temperature, low-cycle fatigue life for this superalloy by comparison with Strainrange Partitioning method (SRP).
A Check on the Energy Method of Predicting Blade Transonic Stall Flutter
Authors: Li He , Sheng Zhou
Published: April 2015

An improved structural dynamic model of an oscillating blade in two degrees of freedom is combined with an unsteady aerodynamic model for the transonic flow about a cascade with separation resulting a coupled system. The system is solved in an iterative way between the two models. As a check on the current energy methods, the stall flutter boundaries for two real rotors are predicted by using the present method and the results are compared with the experiments and those predicted by using an energy method.
An Actuator-Disk Model for Predicting Stall Flutter of Steam Turbines
Authors: Yang X. D. , Tang Z. M. , Zhou S.
Published: April 2015

A deforming actuator disk model for predicting stall flutter of the last stage in steam turbines is presented in this paper, which is transplanted from predicting stall flutter of axial-flow fans and compressors of aero-engines. The onset of stall flutter in steam turbines has been predicted by means of this method. Some comparisons between predictions and experimental results are presented.
Numerical Solution of Transonic Stream Function Equation on S1 Stream Surface in Cascade
Authors: Yaonan Hua , Wenquan Wu
Published: April 2015

A method is presented in this paper for calculating transonic flow field in turbomachinery cascades. With respect to non-orthogoanl curvilinear coordinates, the stream function equation governing fluid flow was established. Using the Artificial Compressibility Method, the discretization of the partial differential equation was carried out by use of the standard central difference formula. The set of linear algebraic equations obtained is solved by means of the Direct Matrix Method. In order to overcome the non-uniqueness of density in transonic flow in the stream function method, the velocities at grid nodes are first obtained by integrating the momentum equation and then the densities are determined from the energy equation.

Application of this method to some transonic cascade-flow with supersonic or subsonic inlet velocity shows that the solution obtained is in fair agreement with experimental data.
Experimental Investigations on Extremely High-Loaded Axial-Flow Stages
Authors: Brodersen Soenke
Published: April 2015

For several years investigations have been carried out at the Pfleiderer-Institute for Fluid Flow Engines at the Technical University of Brunswick (West-Germany) to estimate the boundary of aerodynamic load of axial-flow stages. The results presented here are comparisons of different bladings designed at various flow coefficients at hub/tip ratios 0.70 and 0.55 with an alternating increase in pressure rise parameter up to a notable overloading. The diffusion factor is applied as a criterion of load. At different blade heights boundary values of diffusion factor at design point are given. In these investigations the carpet plots for estimating the performance of axial-flow stages, as reported by Lieblein et.al., were checked and gave the result, that they are applicable even at extremely high-loaded axial-flow stages.
Particulate Flow Solutions Through Centrifugal Impeller With Two Splitters
Authors: Elfeki Salah , Tabakoff Widen
Published: April 2015

Centrifugal impeller with splitters is one of the design techniques used in small engines. Many such engines are operating in different environmental conditions. One of which is where the atmosphere is polluted by small solid particles. Engines operating in such particulate environment are exposed to erosion and performance deterioration.

In this paper the flow field through an impeller with two different size splitters is presented. The mean streamline pattern in the meridional plane was estimated by the computer code ‘MERDIL’, and an improved panel method was used to calculate the blade-to-blade flow solution. In addition, the particle trajectories were calculated by direct integration of the particle equations of motion. Particle collisions with the blade, hub and casing surfaces were determined. The data obtained from this analysis can be applied for calculating the erosion and performance deterioration in turbomachinery with such impellers.
Operation and Control of Space-Based Solar Energy Power Plants With CCGT Using Helium as a Working Medium
Authors: Sutsch A.
Published: April 2015

The features of a Space-based Solar Energy Power Plant for electric power generation with a closed cycle gas turbine running on Helium are discussed. The system is intended for generating both electricity and process heat for industrial manufacturing processes in a large space station. A system overview for operation and control of such a plant is presented.
Tepco 2000 MW Combined Cycle Power Plant Construction Progress and Start-Up
Authors: Tomlinson Leroy O. , Kojima T.
Published: April 2015

Tokyo Electric Power Company is completing the construction of the first 1,000 MW group in the world’s largest, 2000 MW, combined cycle power plant. The 165 MW single shaft combined cycle systems are being started sequentially. A description of the construction progress, start-up and initial operation of the first 165 MW combined cycle system and the planned completion of the station are presented.
An Experimental Investigation of the Three-Dimensional Flow Within Large Scale Turbine Cascades
Authors: Jílek Jaromír
Published: April 2015

A detailed experimental investigation of the three-dimensional subsonic flow was carried out in a typical nozzle and impulse configuration of plane turbine cascades with a chord length 0.5 m. Flow parameters were measured within the passage and behind the cascade using a five-hole probe. Pressure distribution measurements and flow visualization were made on blade surfaces and side walls. Flow measurements were taken in endwall and airfoil boundary layers for both types of cascades. The influence of the aspect ratio, the inlet side wall boundary layer and the position of traversing planes on aerodynamic characteristics and losses is discussed.
Combustion Instability of a Gas Turbine Combustor up to 50-Atmosphere Condition
Authors: Tamaru T. , Shimodaira K. , Kurosawa Y. , Kuyama T.
Published: April 2015

Combustion instabilities or blow-off phenomena at high pressure conditions were investigated on practical can-type combustion chambers. An air loading parameter, ma/VP2 at constant inlet temperature, was used to evaluate the allowable air flow rate in the combustion chamber. It was found that the pressure dependency of the parameter was not adequate for the high pressure conditions. It is revealed that the blow-off velocity in the flame holding region is related to the maximum laminar burning velocity corresponding to the pressure and temperature and that the velocity in the primary zone must be a very small value at high pressure condition.
Inverse Design of Composite Turbine Blade Circular Coolant Flow Passages
Authors: Chiang Ting-Lung , Dulikravich George S.
Published: April 2015

An inverse design and optimization method is developed to determine the proper size and location of the circular shaped holes (coolant flow passages) in a composite turbine blade. The temperature distributions specified on the outer blade surface and on the surfaces of the inner holes can be prescribed a priori. In addition, heat flux distribution on the outer blade surface can be prescribed and iteratively enforced using optimization procedures. The prescribed heat flux distribution on the outer surface is iteratively approached by using the Sequential Unconstrained Minimization Technique (SUMT) to adjust the sizes and locations of the initially guessed circular holes. During each optimization iteration, a two-dimensional heat conduction equation is solved using direct Boundary Element Method (BEM) with linear temperature singularity distribution. For manufacturing purposes the additional constraints are enforced assuring the minimal prescribed blade wall thickness and spacing between the walls of two neighboring holes. The method is applicable to both single material (homogeneous) and coated (composite) turbine blades. Three different cases were tested to prove the feasibility and the accuracy of the method.
Power Level Influence on Architecture of Small Helicopter Turboshaft Engines
Authors: Giraud M.
Published: April 2015

In the field of helicopter turboshaft engines, TURBOMECA is present in the range of 400 to 1 600 kW with four new engines, all under development. Naturally all these engines, born of a same general philosophy, have a pronounced ≪family likeness≫ from the general mechanical and aerodynamic point of view.
Mass Balancing of Hollow Fan Blades
Authors: Kielb Robert E.
Published: April 2015

This paper uses a typical section model to analytically investigate the effect of mass balancing as applied to hollow, supersonic fan blades. A procedure to determine the best configuration of an internal balancing mass to provide flutter alleviation is developed. This procedure is applied to a typical supersonic shroudless fan blade which is unstable in both the solid configuration and when it is hollow with no balancing mass. The addition of an optimized balancing mass is shown to stabilize the blade at the design condition.
Limitations of Thermocouples Used in Hot Zones in Gas Turbines
Authors: Van Den Andel J.
Published: April 2015

Thermocouples are extensively used for controlling as well as safeguarding gas turbines. Some thermocouples have found their way into environments where their life expectancy could not be fulfilled. The literature provides very little information on thermocouple used beyond 3000 hours and yet in gas turbines, 30 000 h expectancy is not uncommon. In the hottest zones, deterioration takes place in spite of special precautions in shielding. A test was developed to find troubles which could not be revealed by calibration or other means of testing. Thermocouples thus identified had lives of less than half the design value and restrictions have been placed on the time span a thermocouple is considered useful. The paper follows a practical approach to a practical problem.
Interactive Cycle Analysis
Authors: Anderson B. A. , Trenkamp P. J.
Published: April 2015

A new Interactive Cycle System has been developed by General Electric’s Aircraft Engine Business Group for the cycle analysis and performance optimization of conceptual and preliminary engine designs. This paper will explore some of the considerations in moving from a large, well-known, batch, detailed design, modeling system to a low-cost, flexible, responsive, user-friendly, interactive cycle analysis system. The resulting system utilizes menu screens for user input and data review, a modular program structure with stacking of modules to achieve the desired engine configuration, a library of component characteristics augmented by parametric component map generators, and an interpretive reader to permit real-time logic creation without the need for compiling.
Experiments and Performance Evaluation of a Transonic Axial Flow Turbine With Variable Nozzle
Authors: Takagi Toshiyuki
Published: April 2015

To examine extensively the overall performance of a single-stage transonic turbine under high-loading conditions, aerodynamic experiments were conducted over a wide range of stage pressure ratios up to 4.16. The measured performance is estimated by means of a mean-line prediction method with two loss systems and is discussed with radial variations and surface pressure distributions. The results show that airflow characteristics, loss systems and choking Mach numbers play an important role in evaluating the performance when choking occurs at either row.
Gas Turbine Uses Coal Fuel With Indirect Heat Transfer via Circulating Ceramic Beads
Authors: Jahnig C. E.
Published: April 2015

This paper defines a gas turbine power system in which the heat from coal combustion is transferred to a clean working gas by contact with a recirculated stream of hot ceramic beads. The beads are first heated by direct contact in a pressurized coal combustion zone and then the hot beads are separated, freed of coal ash and contacted directly with a pressurized gas such as air going to a gas turbine. Separate zones are used for combustion and for contact with the clean gas to be heated, and these two zones are kept separated by an intermediate column of beads at each transfer point. Similar technology is well known and used commercially in the petroleum industry, for example, in catalytic cracking of oil to make gasoline.

Hot clean gas from the operation is used to generate power in an expander, while the products from coal combustion are handled by conventional methods for environmental control. The system offers the simplicity and efficiency typical of gas turbines and avoids the large use of water typical of steam power systems. Low investment is expected, together with minimal environmental impact.
Influence of Free Stream Turbulence and Blade Pressure Gradient on Boundary Layer and Loss Behaviour of Turbine Cascades
Authors: Hoheisel H. , Kiock R. , Lichtfuß H. J. , Fottner L.
Published: April 2015

The optimization of the blade surface velocity distribution is promising a reduction of turbine cascade losses. Theoretical and experimental investigations on three turbine cascades with the same blade loading show the important influence of the blade pressure gradient and the free stream turbulence on the loss behaviour. The results presented demonstrate that it is the boundary layer transition behaviour that determines the losses on turbine cascades. An enormous effort in measuring technique is required in order to define the location of transition from cascade experiments very accurately.
Stall Cell Development in an Axial Compressor
Authors: Jackson Andrew D.
Published: April 2015

An experimental investigation of stall inception and stall cell development in a single stage axial compressor is described. The stall inception was found to be naturally non-random: by artificially perturbing the flow the inception could be accurately fixed at a known location in the compressor. The stall cell was first detected behind the rotor at a small distance from the tip. The stall cell grew very rapidly in circumferential extent, but slowly in radial extent. After reaching the hub the cell decreased in size before reaching full development as a single full span rotating stall cell. Relationships between various parameters of the stall cell growth are presented. The growth is explained in terms of the cell blockage, and the mechanism for multiple stall inception is discussed.
Infrared Thermometry for Control and Monitoring of Industrial Gas Turbines
Authors: Kirby P. J. , Zachary R. E. , Ruiz F.
Published: April 2015

Infrared thermometry is potentially a valuable technique for more efficient and reliable operation of gas turbines. Work is described in which single waveband and ratio techniques have been used to provide contamination-tolerant average rotor temperature for engine control, and a high resolution thermal “fingerprint” for engine health monitoring. Also described is an installation method eliminating exposure of the instrument to the turbine environment and facilitating on-line maintenance. It is believed that these developments provide a practical basis for permanent on-site monitoring and control.
Instrumentation and Control Principles for Large Combined Cycles
Authors: Geney Jean-Noël , Garret Bernard
Published: April 2015

The combined cycle plant is the most attractive of all possible power or steam production means. Besides the process and the general operation which slightly differ from those of a conventional plant, the instrumentation and control fundamentals are particular because of the combined cycles process and type of operation. After a brief review of the largepower combined cycle plants operation, this paper will present the particularities of the instrumentation and control system and components.
Operation of the CT7 Turboprop Engine as an Auxiliary Power Unit (APU)
Authors: Stewart J. D.
Published: April 2015

In response to the need of the new generation of commuter airliners, General Electric has developed the CT7 Turboprop engine so that it may be used as an Auxiliary Power Unit (APU) in addition to its normal mission as a prime propulsion unit. The General Electric CT7 Turboprop is a 1700 shaft horsepower class engine (Figure 1) developed for the new generation of 30+ passenger commuter and executive aircraft(1). Beyond this, the CT7 engine now offers the airlines a self-contained APU system to provide bleed air for the Environmental Control System (ECS) and electrical power for the aircraft during ground operation. This negates the need for a separate on-board APU with its extra cost, weight and fuel consumption and also eliminates the requirements for ground power units at the airlines’ operational terminals. The development of the engine as an APU generated a new set of technical requirements for the design and development and necessitated the development of special certification requirements as this was a new and unique operating condition for an aircraft prime propulsion system. A propeller brake had to be developed to lock the propeller and power turbine system and the engine had to be designed to operate at or near idle while producing large amounts of bleed air and electrical power. This development program was successfully completed in mid-1985 with the certification of the aircraft to operate with the CT7 Turboprop engine running as an APU.
Excitation of Blade Vibration by Flow Instability in Centrifugal Compressors
Authors: Haupt U. , Abdelhamid A. N. , Kaemmer N. , Rautenberg M.
Published: April 2015

Experiments were conducted to investigate the interactions between blade vibrations and self-excited flow oscillations in a high performance centrifugal compressor system. Unsteady pressure fluctuations and dynamic stress levels were measured during compressor operation near choke, in self-excited oscillating flow conditions and near surge for four different speed lines. The unsteady pressure field for every operating condition was determined from the simultaneous recording of the output of twelve dynamic pressure transducers which were successively positioned in two peripheral and one meridional planes. Corresponding blade vibration data were collected using an eight channel telemetry system transmitting the outputs of semi-conductor strain gages located on different blades. Analysis of the measurements showed that the unsteady pressure field due to self-excited flow oscillations can be characterized by multiples of rotating and non-rotating pressure patterns at different frequencies. The blade vibration signals clearly demonstrated the excitation of the blade by each of the different unsteady pressure patterns and the frequencies of the unsteady flow field demonstrates the complexity of this flow phenomena and the need to understand the mechanism of its occurrence in order to avoid blade resonance excitation and failure during compressor operation.
Development of Ultrasonic Tests for Super Ceramics
Authors: Stockman A. J. , Patel N. D. , Van Den Andel J. , Nicholson P. S. , Mathieu P.
Published: April 2015

Critical flaw sizes in ceramic turbine parts are very small, especially for dynamic applications. Detection of these small (< 30 μm) internal flaws are almost exclusively in the realm of ultrasonics, wherein 30 to 100 MHz test frequencies are required. Satisfactory transducers for this purpose are not available from commercial suppliers. These devices are now being developed and will be discussed together with problems of signal strength, focussing, penetration and defect signal characterization in ceramics containing both real and artificial defects.
Oil Free Compression on a Natural Gas Pipeline
Authors: Cataford G. F. , Lancee R. P.
Published: April 2015

Oil entrainment in the natural gas stream together with maintenance associated with oil systems have been long standing problems in booster compressors on a natural gas pipeline system. The use of dry gas shaft seals and active magnetic bearings will effectively eliminate the use of oil systems in gas compression. The paper will deal with the history of TransCanada PipeLines’ past experiences with oil eliminating devices, the theory of dry gas seals and magnetic bearings, the effects on rotor dynamics of magnetic bearings and the recent installation of a set of seals and bearings in a booster compressor unit, in service on the TransCanada PipeLines system.
Engine Condition Monitoring at KLM Royal Dutch Airlines
Authors: Adamse Peter H. C.
Published: April 2015

Engine Condition Monitoring (ECM) for an airline is a basic need to make its engine operation as economic as possible.

This paper describes the ECM development at KLM-Royal Dutch Airlines.

The objectives and philosophy of the systems are discussed, as well as the current and future functions and the use in the airline organisation.
AGT101 Advanced Gas Turbine Technology Update
Authors: Boyd G. L. , Kidwell J. R. , Kreiner D. M.
Published: April 2015

The Garrett/Ford Advanced Gas Turbine Technology Development Program, designated AGT101, has made significant progress during 1985 encompassing ceramic engine and ceramic component testing. Engine testing has included full speed operation to 100,000 rpm and 1149C (2100F) turbine inlet temperature, initial baseline performance mapping and ceramic combustor start and steady state operation. Over 380 hours of test time have been accumulated on four development engines. High temperature foil bearing coatings have passed rig test and a thick precious metal foil coating selected for engine evaluation.

Ceramic structures have been successfully rig tested at 1371C (2500F) for over 27 hours. Interface compatibility testing conducted during these runs indicate RBSN-to-RBSN or SASC-to-SASC result in “sticking” — however, RBSN-to-SASC in either planar or line contact show no evidence of sticking. Ceramic combustor rig tests have demonstrated acceptable lightoffs using either a conventional ignitor or a commercially available glow plug. Operation to 1371C (2500F) combustor discharge temperatures have also been demonstrated. Ceramic turbine rotor fabrication efforts have continued at ACC and Ford. Kyocera and NGK-Locke also have been working on the rotor. Several rotors have been received and are currently undergoing final machining and qualification tests. Testing of the all-ceramic AGT101 engine is currently scheduled for late 1985.
Performance of Two Transonic Axial Compressor Rotors Incorporating Inlet Counterswirl
Authors: Law C. Herbert , Wennerstrom Arthur J.
Published: April 2015

A single-stage axial-flow compressor which incorporates rotor inlet counterswirl to improve stage performance is discussed. Results for two rotor configurations are presented, including design and experimental test data. In this compressor design, inlet guide vanes were used to add counterswirl to the inlet of the rotor. The magnitude of the counterswirl was radially distributed to maximize the overall stage efficiency by minimizing the rotor combined losses (diffusion losses and shock losses). The shock losses were minimized by simultaneously optimizing the rotor blade section geometry, through-blade static pressure distribution, and leading edge aerodynamic/geometric shock sweep angles. Results from both the design and experimental performance analyses are presented and comparisons are made between the experimental data and the analyses and between the performances of both rotor designs. The computation of the flow field for both rotor designs and for the analysis of both tests was performed in an identical fashion using an axisymmetric, streamline-curvature-type code. Results presented include tip section blade-to-blade static pressure distributions and rotor through-blade and exit distributions of various aerodynamic parameters. The performance of this compressor stage represents a significant improvement in axial compressor performance compared to previous attempts to use rotor inlet counterswirl and to current, more conventional, state-of-the-art axial compressors operating under similar conditions.
On the Shear-Stress Integral of Turbulent Boundary Layers
Authors: Pfeil H. , Göing M.
Published: April 2015

The paper presents an integral method to predict turbulent boundary layer behaviour in two-dimensional, incompressible flow. The method is based on the momentum and moment-of-momentum integral equations and a friction law. By means of the compiled data of the 1968-Stanford-Conference, the results show that the integral of the turbulent shear-stress across the boundary layer, which appears in the moment-of-momentum integral equation, can be described by only two basic assumptions for all cases of flow.
Fabrication of High-Alumina Ceramic Fixtures for Jet Engine Repair Applications
Authors: Kuo S. C. , Wood M.
Published: April 2015

A new concept of utilizing a castable high-alumina ceramic, instead of machined steel or graphite, to make low-cost non-outgassing jet engine repair fixtures is presented in this paper. The desirable thermophysical and mechanical properties for the fixture material developed are summarized, and a process developed to produce the ceramic fixtures of different configurations and sizes is described. Each of the major production steps is identified in a production flow chart. Specifically, the methods to make the appropriate molds needed for casting the fixture, and the procedures for mixing, casting, curing, drying and sintering the ceramic fixtures are explained in detail. Crack problems and their controls throughout the production process particularly relevant to fixture geometry are discussed in reference to the several prototype fixtures fabricated. Preliminary test results for these fixtures mated with engine stators in a high-temperature furnace are reviewed. Potentials for this fixture material and production processes for other manufacturing applications are also discussed.
Energy Recovery With Turbo Expanders
Authors: Cleveland Anthony
Published: April 2015

In the oil, gas and petrochemical industry, there are many instances where energy is under-utilized, if not actually wasted.

In many cases it may be possible to recover some of this energy and obtain useful work, thereby improving plant efficiency and the economics of the operation.

The turbo expander is a simple device that can make a significant contribution to the recovery of energy in all kinds of plants.

This paper considers some ways in which turbo expanders may be used and looks in detail at an application in the gas industry where the energy lost in pressure reduction may be recovered and used to assist in reducing operating costs. The design criteria for such turbo expanders are discussed and areas for future development are proposed.

The paper concludes that there are significant gains to be made in the recovery of waste energy and that the turbo expander can play a major role in this activity.
Theoretical and Experimental Investigation for Some Basic Physical Phenomena of Centrifugal Compressors
Authors: Qinghuan Wang
Published: April 2015

Based on a series of theoretical and experimental investigation, this paper presents several fundamental views on some basic physical phenomena of centrifugal compressors, such as choking flow, surge characteristics, matching of impeller and diffuser, the position of high-efficiency region on the performance map, etc. A prototype centrifugal compressor for a marine turbocharger series has been designed according to the principles discussed in this paper. It was a great success and has been put into production.
A Study of Radially Curved Mixed-Flow Vaneless Diffusers
Authors: Niizeki Yoshiki , Sakai Toshimichi
Published: April 2015

The flow pattern and performance of radially-curved mixed-flow vaneless diffusers were examined. From the experimental results the correlation between the inlet flow angle, the radius of curvature of the radially curved test section and diffuser performance was clarified. Favorable inner flow with higher diffuser performance were obtained in the case of diffusers having small pressure gradient normal to the diffuser walls. From this concept, a method to give an optimum configuration of the radially curved diffuser was established.
Ultrasonic Characterization of Ceramics
Authors: Slavin Michael J. , Gruber Jeffrey J.
Published: March 2015

This paper discusses ultrasonic nondestructive evaluation (NDE) methods that are useful for ceramic characterization. These methods are: ultrasonic velocity measurements, velocity and defect C-scans and attenuation measurements. The way in which the ultrasonic measurements are influenced by the ceramic’s structure and properties is examined. The ultrasonic techniques discussed in this paper are routinely used as part of an inspection/quality control procedure of ceramics for armor and heat engine applications. Sintered beta silicon carbide (β-SiC), sintered alpha silicon carbide (α-SiC) and hot pressed titanium diboride (TiB2) have been well characterized by these techniques. Elastic modulus values as determined from velocity measurements agree very well with values measured from flexural tests. Correlations between the velocity C-scans, elastic properties and densities have also been determined. The limitations and potential of each of the ultrasonic techniques are discussed.
Real Gas Properties and Space Shuttle Main Engine Fuel Turbine Performance Prediction
Authors: Harloff G. J.
Published: March 2015

Real gas thermodynamic and transport properties are presented over a range of temperatures and pressures for the SSME fuel turbine. Computed air equivalent turbine performance is presented.
Computer Predictions of Erosion Damage in Gas Turbines
Authors: El-Sayed A. F. Abdel Azim , Brown A.
Published: March 2015

In this article an iterative procedure is presented for estimating erosion in axial gas turbine blades. The procedure is applied to a two stage turbine and the erosion is estimated for a 12,000 hour engine running time. The effect of the erosion on engine performance is estimated through changes in pressure coefficient distribution around a blade section.
A Model to Determine the Behaviour of a Pressure Measurement Equipment During Non-Static Operations of Gasturbine Engines
Authors: Lemmer K.-U. , Hass J.
Published: March 2015

For some time there have existed different approaches and models by various authors to describe the behaviour of gasturbines during the transition between different operating points. A problem that has not been solved satisfactorily so far is the verification of these models with the help of exact data. Quite often one notices that the instruments do not react properly to the processs they are measuring: there is a time lag and the measured values become distorted by the measuring facility.

This paper is a contribution to the adjustments on gasturbine engines during non-static operations. A mathematical model has been developed to determine the influence of the different components on the measuring chain, which consist of a pressure measuring transducer with high natural frequency on a semiconductor base, a hose pipe and a pressure probe. This model has been verified by pressure measurements with a calibrating device. The final part is the discussion of the pressure values, which were measured on a gasturbine engine during the transition between different operating points and adjusted with the help of the mathematical model for the measuring chain.
A Reheat Gas Turbine Oilfield Cogeneration System, Fueled With Heavy Crude Oil, Which Produces Very Low NOx Emissions
Authors: Moreno Frederick E. , Divirgilio Philip J.
Published: March 2015

A gas turbine cogeneration system is described that offers fuel flexibility plus substantially reduced NOx emissions without water injection or selective catalytic reduction (SCR). The entirely new turbine design developed by TurboEnergy Systems permits boiler repowering and other cogeneration applications. The first application will be in the California heavy oilfields; the system will be retrofitted to an existing 50 million btu/hr oilfield steam generator used in thermally enhanced oil recovery. The turbine, rated at 1250 kw (site output), was sized to match the combustion air flow requirements of the steam generator. A reheated design was selected to maximize power output from the limited airflow available and to maximize the exhaust temperature for cogeneration and industrial process applications. The oilfield cogeneration system being developed includes a new heavy oil burner for the steam generator which will be fired on the high temperature exhaust from the turbine. The system will also provide low NOx emissions, below the tightest projected standards in Kern County, which has a large concentration of heavy oilfields. Both the turbine and the steam generator burner will burn heavy (API 13 gravity) crude oil. The paper describes the overall system, its interface with the existing process, the design techniques used, and presents performance projections. Field testing will begin at a site near Bakersfield, California, starting in early to mid-1987.