bluuebunny/crossref_metadata_2025 huggingface dataset:
Exergy Analysis for Air Separation Process Under Off-Design Conditions
Authors: Yao Li , Tong Lige , Zhang Aijing , Xie Yunfei , Shen Jianbiao , Li Huazhi , Wang Li , Li Shiqi
Published: February 2015

An air separation unit (ASU) represents the largest overall energy consumption (about 15–20%) in a steel production facility. Therefore, improving the operating efficiency of an ASU is an effective way to achieve energy savings and emission reductions. The exergy calculation program for an air separation process is developed, and the detailed exergy calculations and analysis for an actual ASU with capacity of 40,000 Nm3/h in service at Tangshan Tangsteel Gas Co. Ltd. are performed. The results show that the molar exergy contained in oxygen is the largest among all gaseous products, liquid argon contains the largest molar exergy among all liquid products, and liquid products of the same type have larger exergy values than their gaseous equivalents. In a same condition scenario (same environmental condition, same air feed mass flow at rated load operation of the expander), increasing liquids production is an effective way to enhance the process efficiency, especially by increasing liquid argon production at the rated load operation of the expander. The object efficiency of the process from the cleaning unit to production in an actual 40,000 m3/h ASU is 46.84%, while the simple efficiency of the cold box of the ASU is 64.31%. The largest amount of exergy loss is caused by the air compressor (AC), the packed-type air cooling tower (PACT), and the molecular sieve (MS) purifier. The cryogenic ASU itself is well operated from an exergetic viewpoint. On the basis of exergy analysis conducted, this study provides a reference for the improvement of the ASU analyzed and provides a reference for ASUs in general.
Three-Dimensional Flow in a Highly Loaded Single-Stage Transonic Fan
Authors: Bryce J. D. , Cherrett M. A. , Lyes P. A.
Published: February 2015

Tests have been conducted at DRA Pyestock on a single-stage transonic fan which has a very high level of aerodynamic loading at the hub. The objective of the tests was to survey the flow field in detail, with emphasis on studying the 3D viscous aspects of the flow. The test module was highly instrumented. Detailed flow traversing was provided at rotor and stator exit, and replaceable stator cassettes allowed various types of on-blade instrumentation to be fitted.

The test rig and instrumentation are described and detailed flow measurements, taken at peak efficiency operation on the design speed characteristic, are presented. These measurements, which are supplemented by flow visualisation results, indicate the presence of a severe endwall corner stall in the stator hub flow field. The fan was modelled using the DRA S1-S2 method and these results are also discussed.
Computed Tomography Evaluation of Metal-Matrix Composites for Aeropropulsion Engine Applications
Authors: Yancey R. N. , Baaklini G. Y.
Published: February 2015

Computed tomography (CT) is a powerful evaluation tool for advanced propulsion engine materials and components. CT uses X-rays to nondestructively produce images of 2-D slices or planes through an object. This paper will present data from CT investigations of metal-matrix composite (MMC) ring, rod, and coupon structures. Moderate resolution CT data identified density variations within reinforced sections which was correlated with fiber packing densities. Also, some composite lay-up features were also imaged. High-resolution CT data provided information on fiber spacing and distribution. Correlation with other NDE techniques and destructive analysis was good. CT proved to provide valuable information on the internal state of these metal-matrix composite components. Use of CT during process development of MMC’s and the components made from MMC’s is encouraged given the results of this study.
Condensation in Jet Engine Intake Ducts During Stationary Operation
Authors: Young John B.
Published: February 2015

The paper describes an analysis of the condensation of moist air in very long intake ducts of jet engines during stationary operation. Problems arising from such condensation include fan overspeed and increased stagnation pressure loss in the intake duct.

The analysis demonstrates that, for moderate values of relative humidity, homogeneous condensation will occur in an outer annulus adjacent to the intake cowling if the local flow Mach number attains values of about 1.0. In the central region of the intake duct, where design Mach numbers of 0.8 may be attained, homogeneous condensation is unlikely to occur except, possibly, when the relative humidity is close to 100% and the ambient temperature very high. However, if the intake duct is very long, significant heterogeneous condensation on foreign particles present in the atmosphere is possible. The concentration of foreign nuclei required for this type of condensation is comparable to the likely levels of contamination at many industrial test sites.

The effects of condensation on engine test results are twofold. Firstly, condensation is a thermodynamically irreversible process and results in an increase of entropy and hence loss of total pressure in the intake duct. Uncorrected measurements using Pitot probes may not record this loss correctly. Secondly, the mass and energy transfer between the phases during the condensation process has a tendency to accelerate the flow approaching the engine, an effect which may be counteracted by a reduction in mass flowrate in order to maintain the static pressure constant. These conclusions are in agreement with experimental results obtained on-site during the testing of a jet engine fitted with a very long intake duct.
Detailed Flow Measurements and Predictions for a Three-Stage Transonic Fan
Authors: Calvert W. John , Stapleton Andrew W.
Published: February 2015

Detailed flow measurements were taken at DRA Pyestock on a Rolls-Royce three-stage transonic research fan using advanced laser transit velocimetry and holography techniques to supplement the fixed pressure and temperature instrumentation. The results have been compared with predictions using the DRA S1-S2 quasi-3D flow calculation system at a range of speeds. The agreement was generally encouraging, both for the overall performance and for details of the internal flow such as positions of shock waves. Taken together with the computational efficiency of the calculations and previous experience on single-stage transonic fans and core compressors, this establishes the S1-S2 system as a viable design tool for future multistage transonic fans.
Thermal Diffusivity Imaging of Ceramic Composites
Authors: Cramer K. Elliott , Winfree William P. , Generazio Edward R. , Bhatt Ramakrishna , Fox Dennis S. , Eckel Andrew J.
Published: February 2015

Strong, tough, high temperature ceramic matrix composites are currently being developed for application in advanced heat engines. One of the most promising of these new materials is a SiC fiber-reinforced silicon nitride ceramic matrix composite (SiCf/Si3N4). The interfacial shear strength in such composites is dependant on the integrity of the fiber’s carbon coating at the fiber-matrix interface. The integrity of the carbon rich interface can be significantly reduced if the carbon is oxidized. Since the thermal diffusivity of the fiber is greater than that of the matrix material, the removal of carbon increases the contact resistance at the interface reducing the thermal diffusivity of the composite. Therefore thermal diffusivity images can be used to characterize the progression of carbon depletion and degradation of the composite. A new thermal imaging technique has been developed to provide rapid large area measurements of the thermal diffusivity perpendicular to the fiber direction in these composites. Results of diffusivity measurements will be presented for a series of SiCf/Si3N4 (reaction bonded silicon nitride) composite samples heat-treated under various conditions. Additionally, the ability of this technique to characterize damage in both ceramic and other high temperature composites will be shown.
Effect of Rotary Inertia and Gyroscopic Moments on Dynamics of Two Spool Aeroengine Rotor
Authors: Gupta K. , Kumar R. , Tiwari M. , Prakash O.
Published: February 2015

The main objective of the paper is to study the effect of rotary inertia and gyroscopic moments due to lumped masses on the dynamics of two spool aeroengine rotors. Since the rotary inertia effect is well established, the thrust of the paper is on the effect of gyroscopic moments. Quantitative as well as qualitative aspects are studied. Effect of gyroscopics and rotary inertia on rotor critical speeds and unbalance response are studied for several rotors with particular reference to relative LP and HP rotor speeds. A two spool rig which resembles an actual aeroengine has been designed and built. Experiments have been conducted on two configurations of the rig in order to verify the theoretical results obtained by a formulation developed using the method of extended transfer matrices, for the two spool rotor with two intershaft bearings. A reasonably good correlation between the theoretical and experimental results is observed.
Next Generation 2 MW Turboshaft and Turboprop Engines
Authors: Vogt Robert L. , Sehra Arun
Published: February 2015

Textron Lycoming of Stratford, Connecticut is incorporating the latest in advanced technology into turboshaft and turboprop engines for near term commercial service. The level of cold section technology being incorporated is the already demonstrated next generation of axi-centrifugal compressor beyond that which was developed for the U.S. Army T800, 0.9 MW turboshaft engine in the late 1980s. The compressor evolution is given special emphasis. The hot section technology is a robust, simplified, low cost, commercial endurance derate of the tri-service; US Army, US Navy, US Air Force and Textron Lycoming joint core engine [1] now on test. The new 2 MW commercial engine has substantially reduced fuel consumption, is lighter, and is smaller than today’s best engines. Engineering development is now underway and certification is slated to be completed in 1996.
Repairable Gas Turbine Electrical Cable Assemblies
Authors: DiCicco William
Published: February 2015

Often electrical cable assemblies are required to operate under hostile environmental conditions which lead to the need for periodic maintenance. Several designs have been introduced, however many address repairability while sacrificing environmental suitability.

A repairable cable assembly has been designed which addresses both the environmental aspects of applications and ease of repair. The technique can be applied to the two basic types of shielded cable, the conduit type and the braided outer jacket type. The repairable design feature provides excellent shielding from EMI/RFI, is waterproof, and can be pushed back for easy access to the back of connectors to facilitate replacement of contacts.
The Modelling of Flow in the Volute and Vanes of a High Pressure Radial Inflow Turbine
Authors: Lobo M. , Elder R. L.
Published: February 2015

The flow in a vaned volute of a radial inflow turbine is analysed using PHOENICS, a very general three-dimensional viscous CFD code based on finite-volume pressure-correction techniques for solving the Navier-Stokes equations. The study involves two physically complementary but mathematically very different problems — flow modelling in the vaneless section of the volute and flow modelling in the vanes. Each of these problems is considered in turn — and each presents characteristic hurdles. Particular attention is paid to grid-generation and the process is carried out alongside the flow computation, the grids being modified in such a way so as to facilitate convergence and accuracy.

Numerical results are presented in the form of vector plots for purposes of general description and tables for comparison with experiment. Agreement with experiment is good. However experimental results, for comparison are available only in the vanes. In the vaneless section of the volute, the converged solution depicts some interesting secondary flow features — in regions inaccesible to the current experimental measurements.
Investigation of Flow in a Radial Turbine Using Laser Anemometry
Authors: Zaidi Sohail Hamid , Elder Robin L.
Published: February 2015

A lightweight, high pressure radial inflow turbine was tested and laser anemometry used to measure the flow at various positions within the nozzle guide vanes, immediately upstream of the rotor and at two axial stations downstream of the rotor.

The laser anemometry results indicated flow conditions within the nozzle vanes which were largely two dimensional (blade-to-blade with little hub to shroud variation) except at the vane outlet. Unsteadiness due to rotor blade passing effects were detected at the nozzle guide vane trailing edge but had almost entirely decayed at the vane throat. The results also indicate significant variations in flow conditions across the pitch of the nozzles suggesting incidence variations on the rotor of approaching 30 degrees. The laser anemometry results downstream of the turbine show a swirling flow characterised by a turbulent inner core region, a ‘centre annulus’ region of uniform velocity and flow direction and an outer flow region with a similar flow direction but velocity which increases rapidly towards the outer wall. The blade passing unsteadiness (blade-to-blade) is hardly noticeable some 50mm downstream of the rotor trailing edge.
The Turbine Components Development for the 100 kW Automotive Ceramic Gas Turbine
Authors: Nakazawa Norio , Inaba Shizuo , Izumi Takao , Munekiyo Masayuki , Sasaki Shoji , Fujimori Kokichi
Published: February 2015

Based on the specifications of a 100 kW single shaft automotive CGT, the aerodynamic design and the basic structure design of the radial turbine components, and the detailed design of each part were carried out. When designing, attaching great importance to the problems (brittleness and difficulty in manufacturing) unique to ceramic materials is required. The life was estimated with a strength reliability designing tool.

The aerodynamic characteristics were evaluated by testing metallic models, and the level of the intermediate target efficiency was achieved. The turbine rotor and the stationary structure parts were manufactured, and the strength reliability was evaluated with single and combined parts respectively. A peripheral speed of 830 m/s (113% of the rated value) with a turbine inlet temperature of 1200°C was obtained for the rotor hot-spin burst test.

The aerodynamic characteristics and the strength reliability shall be improved by repeating trial manufacture and test evaluation of ceramic parts.
Measurement of Residual Stresses in Metal Matrix Composites
Authors: Wright P. K.
Published: February 2015

Metal matrix composites (MMC) are expected to develop internal residual stresses on cooling from fabrication due to the large thermal expansion mismatch between reinforcing fibers and the matrix. This work was undertaken to experimentally measure these residual stresses and compare them with analytical calculations in order to clearly establish their levels and dependence on material parameters.

Two techniques for residual stress measurement were investigated: 1) Xray diffraction (sin2 psi method) and 2) neutron diffraction. Both techniques gave results in good agreement with analytical predictions for several systems (SCS-6/Ti-24Al-11Nb, W/NiAl, and Al2O3NiAl). The results obtained showed a dependence of residual stresses on thermal expansion coefficients, elastic moduli, volume fraction fibers, and matrix yield strengths. The fibers showed compressive stress states, and the matrix, tension. Average stresses were higher in the fiber direction than transverse to fibers.
Numerical Modelling of Entropy Generation and Transport in the Blade-Tip Gap Layer of a Radial Impeller
Authors: Brizuela E. A.
Published: February 2015

Entropy generation in the blade-tip gap layer of a radial impeller is studied by means of simple physical models solved numerically. It is shown that entropy is generated in two regions, i.e., near the shroud wall and at the fluid boundary between the gap layer and the impeller, in comparable amounts. Entropy generated near the shroud wall is carried by the flow in the gap, either upstream to the impeller inlet or downstream to the discharge. Most of the entropy generated at the fluid boundary is incorporated into the bulk flow in the channel. Operating conditions for minimal entropy generation within the tip gap are identified.
Buoyancy-Affected Flow and Heat Transfer in Asymmetrically-Heated Rotating Cavities
Authors: Long C. A. , Morse A. P. , Zafiropoulos N.
Published: February 2015

Finite-volume predictions are presented for the convective heat transfer rates in a rotating cavity, formed by two co-rotating plane discs and a peripheral shroud, and subjected to a radial outflow of cooling air. The heating of the discs is asymmetric, the air entering the cavity through a central hole in the cooler (upstream) disc. The predicted Nusselt number distributions for each disc are compared with unpublished data from the University of Sussex for dimensionless mass-flow rates in the range 2800 ≤ Cw ≤ 14000 and rotational Reynolds numbers, Reθ, up to 5.2 × 106. A single-grid elliptic procedure was used with turbulent transport represented via a low Reynolds number k-ε model and the turbulence Prandtl number concept. In comparing the predicted and measured convective heat fluxes, it is important to consider the radiative heat exchange between the discs. This is estimated using a conventional view-factor approach based on black-body emission.

Under conditions of asymmetric heating, rotationally-induced buoyancy forces can exert significant effect on the flow structure, the induced motion tending to oppose that imposed by the radial outflow. Indeed, flow visualisation studies have revealed that, as the rotational Reynolds number is increased (for a fixed value of Cw), the flow in the source region initially becomes oscillatory in nature, leading eventually to the onset of chaotic flow in which the usual Ekman layer structure does not persist in all angular planes. The extent to which the effects of such flow behaviour can be captured by the steady, axisymmetric calculation approach used here is questionable, but it is found that the turbulence model (used previously for the prediction of heat transfer in symmetrically-heated cavities) still leads to good (±10%) predictive accuracy for the heated (downstream) disc. However, the predicted Nusselt numbers for the cooler (upstream) disc generally show little accord with experimental data, often signifying heat flow into the disc instead of vice-versa. It is concluded that the modelling of the turbulent heat transport across the core region of the flow is erroneous, especially at high rotational Reynolds numbers: this is attributed to overestimated turbulence energy production in that region due to the action of the radial-circumferential component of shear stress (vw). Adoption of an algebraic-stress model for this shear stress is partly successful in removing the discrepancies between prediction and experiment.
Leading Edge Separation Bubbles on Turbomachine Blades
Authors: Walraevens R. E. , Cumpsty N. A.
Published: February 2015

Results are presented for separation bubbles of the type which can form near the leading edges of thin compressor or turbine blades. These often occur when the incidence is such that the stagnation point is not on the nose of the aerofoil. Tests were carried out at low speed on a single aerofoil to simulate the range of conditions found on compressor blades. Both circular and elliptic shapes of leading edge were tested. Results are presented for a range of incidence, Reynolds number and turbulence intensity and scale.

The principal quantitative measurements presented are the pressure distributions in the leading edge and bubble region, as well as the boundary layer properties at a fixed distance downstream where most of the flows had reattached. Reynolds number was found to have a comparatively small influence, but a raised level of freestream turbulence has a striking effect, shortening or eliminating the bubble and increasing the magnitude of the suction spike. Increased freestream turbulence also reduces the boundary layer thickness and shape parameter after the bubble. Some explanations of the processes are outlined.
Euler Solutions for Transonic Oscillating Cascade Flows Using Dynamic Triangular Meshes
Authors: Hwang C. J. , Yang S. Y.
Published: February 2015

The modified total-variation-diminishing scheme and an improved dynamic triangular mesh algorithm are presented to investigate the transonic oscillating cascade flows. In a Cartesian coordinate system, the unsteady Euler equations are solved. To validate the accuracy of the present approach, transonic flow around single NACA 0012 airfoil pitching harmonically about the quarter chord is computed first. The calculated instantaneous pressure coefficient distributions during a cycle of motion compare well with the related numerical and experimental data. To further evaluate the present approach involving nonzero interblade phase angle, the calculations of transonic flow around oscillating cascade of two unstaggered NACA 0006 blades with interblade phase angle equal to 180 deg are performed. From the instantaneous pressure coefficient distributions and time history of lift coefficient, the present approach, where a simple spatial treatment is utilized on the periodic boundaries, gives satisfactory results. By using the above solution procedure, transonic flows around oscillating cascade of four biconvex blades with different oscillation amplitudes, reduced frequencies and interblade phase angles are investigated. From the distributions of magnitude and phase angle of the dynamic pressure difference coefficient, the present numerical results show better agreement with the experimental data than those from the linearized theory in most of the cases. For every quarter of one cycle, the pressure contours repeat and proceed one pitch distance in the upward or downward direction for interblade phase angle equal to −90 deg or 90 deg, respectively. The unsteady pressure wave and shock behaviors are observed. From the lift coefficient distributions, it is further confirmed that the oscillation amplitude, interblade phase angle and reduced frequency all have significant effects on the transonic oscillating cascade flows.
Comparison of Experimental and Theoretical Results for Unsteady Transonic Cascade Flow at Design and Off-Design Conditions
Authors: Carstens V. , Bölcs A. , Körbacher H.
Published: February 2015

This paper presents experimental and theoretical results for turbine cascades performing harmonic oscillations in transonic flow at design and off-design conditions. The experimental investigations were performed in an annular test facility where unsteady blade pressures were measured in two different test cascades, one operating at the nominal inlet flow angle, the other at an incidence angle exceeding the normal value by more than 20 degrees. The corresponding theoretical results were computed with a 2D Euler code which makes use of flux vector splitting in combination with a time-dependent grid generation.

The present data were all obtained for tuned bending modes where the blades performed heaving oscillations with the same frequency and amplitude, but with a constant interblade phase angle. For the cascade operating at design conditions, the steady flow was purely subsonic. The other test cascade was run in transonic flow, and a normal shock appeared on the rear part of the blade’s suction surface.

It was found that measured unsteady pressure and damping coefficients are well reproduced by the computed results for the first test cascade. In the case of steady off-design flow (the second test cascade), significant differences between experimental and theoretical results are observed.
Inviscid-Viscous Interaction Method for 3D Inverse Design of Centrifugal Impellers
Authors: Zangeneh M.
Published: February 2015

A 3D inverse design method for the design of the blade geometry of centrifugal compressor impellers is presented. In this method the blade shape is computed for a specified circulation distribution, normal (or tangential) thickness distribution and meridional geometry. As the blade shapes are computed by using an inviscid slip (or flow tangency) condition, the viscous effects are introduced indirectly by using a viscous/inviscid procedure. The 3D Navier-Stokes solver developed by Dawes is used as the viscous method. Two different approaches are described for incorporating the viscous effects into the inviscid design method. One method is based on the introduction of an aerodynamic blockage distribution throughout the meridional geometry. While in the other approach a vorticity term directly related to the entropy gradients in the machine is introduced.

The method is applied to redesign the blade geometry of Eckardt’s 30° backswept impeller as well as a generic high pressure ratio (transonic) impeller. The results indicate that the entropy gradient approach can fairly accurately represent the viscous effects in the machine.
A Three-Dimensional Navier-Stokes Calculation Applied to an Axial Compressor Rotor and Stator
Authors: Dring Robert P. , VanSeters Ricky J. , Zacharias Robert M.
Published: February 2015

The objective of this paper is to apply a three-dimensional Navier-Stokes calculation to the second stage rotor and stator of a large scale compressor and to compare the computed results with measured data. The comparisons include: (1) airfoil and endwall surface streamlines, (2) radial-circumferential distributions of exit total pressure, (3) spanwise distributions of circumferentially averaged inlet and exit flow quantities, and (4) fullspan airfoil pressure distributions. This assessment demonstrates that the computational state-of-the-art has advanced to a point where calculations such as this can be applied with reasonable confidence in both design and analysis situations.
Pressure and Temperature Distortion Testing of a Two-Stage Centrifugal Compressor
Authors: Cousins W. T. , Dalton K. K. , Andersen T. T. , Bobula G. A.
Published: February 2015

Altitude pressure and temperature inlet distortion testing of the two-stage centrifugal compressor in the T800-LHT-800 engine is described. The test setup and the testing techniques are reviewed and the results of the test are presented.

The generation of classical 180 degree patterns of both pressure and temperature distortion is discussed. Temperature distortion was created using a hydrogen burner system while pressure distortion was created in the classical manner, using screens. Results of both individual and combined temperature and pressure distortions in both opposed and concurrent patterns are shown.
Numerical Analysis of the 3D Swirling Flow in Centrifugal Compressor Volutes
Authors: Ayder E. , Van den Braembussche R.
Published: February 2015

The improvement of centrifugal compressor performance and the control of the radial forces acting on the impeller due to the circumferential variation of the static pressure caused by the volute require a good understanding of the flow mechanisms and an accurate prediction of the flow pattern inside the volute. A 3D volute calculation method has been developed for this purpose.

The volute is discretized by means of hexahedral elements. A cell vertex finite volume approach is used in combination with a time marching procedure. The numerical procedure makes use of a central space discretization and a four step Runge-Kutta time stepping scheme. The artificial dissipation used in the solver is based on the fourth order differences of the conservative variables. Implicit residual smoothing improves the convergence rate. The loss model implemented in the code accounts for the losses due to internal shear and friction losses on the walls.

A comparison of the calculated and measured results inside a volute with elliptical cross sectional shape reveals that the modified Euler solver accurately predicts the velocity and pressure distribution inside and upstream of the volute.
The Increased Use of Gas Turbines as Commercial Marine Engines
Authors: Brady C. O. , Luck D. L.
Published: February 2015

Over the last three decades, aeroderivative gas turbines have become established naval ship propulsion engines but use in the commercial marine field has been more limited. Today, aeroderivative gas turbines are being increasingly utilized as commercial marine engines. The primary reasons for the increased use of gas turbines is discussed and several recent GE aeroderivative gas turbine commercial marine applications are described with particular aspects of the gas turbine engine installations detailed. Finally, the potential for future commercial marine aeroderivative gas turbine applications is presented.
Experimental Investigation of GTE-115 Combustor With Premixed Burner Unit
Authors: Sokolov K. Y. , Tumanovsky A. G. , Gutnik M. N. , Mechanikov A. I. , Reshitko V. P. , Grinshtein M. I.
Published: February 2015

The results of experimental investigation of basic parameters of one-burner, 1/18 sector of a full-scale annular combustor of the “Turboatom” GTE-115 gas turbine unit are presented. Specifics of fuel burnup, formation of toxic pollutants in premixed combustion using a pilot diffusion burner are presented. Generalised dependences of combustor characteristics vs flow parameters and optimized algorithm of combustor loading are illustrated.
A New High-Efficiency Heavy-Duty Combustion Turbine 701F
Authors: Fukue I. , Aoki S. , Aoyama K. , Umemura S. , Merola A. , Noceto M. , Rosso M.
Published: February 2015

The 701F is a high temperature 50Hz industrial grade 220 MW size engine based on a scaling of the 501F 150MW class 60Hz machine, and incorporates a higher compressor pressure ratio to increase the thermal efficiency. The prototype engine is under a two-year performance and reliability verification testing program at MHI’s Yokohama Plant and was initially fired in June of 1992.

This paper describes the 701F design features design changes made from 501F. The associated performance and reliability verification test program will also be presented.
Effect of Wind Tunnel Acoustic Modes on Linear Oscillating Cascade Aerodynamics
Authors: Buffum Daniel H. , Fleeter Sanford
Published: February 2015

The aerodynamics of a biconvex airfoil cascade oscillating in torsion is investigated using the unsteady aerodynamic influence coefficient technique. For subsonic flow and reduced frequencies as large as 0.9, airfoil surface unsteady pressures resulting from oscillation of one of the airfoils are measured using flush-mounted high-frequency-response pressure transducers. The influence coefficient data are examined in detail and then used to predict the unsteady aerodynamics of a cascade oscillating at various interblade phase angles. These results are correlated with experimental data obtained in the traveling-wave mode of oscillation and linearized analysis predictions. It is found that the unsteady pressure disturbances created by an oscillating airfoil excite wind tunnel acoustic modes which have detrimental effects on the experimental results. Acoustic treatment is proposed to rectify this problem.
A Method for the Calculation of the Tip Clearance Flow Effects in Axial Flow Compressors: Part II — Calculation Procedure
Authors: Nikolos I. K. , Douvikas D. I. , Papailiou K. D.
Published: February 2015

An algorithm was set up for the implementation of the tip clearance models, described in Part I, in a secondary flow calculation method. A complete theoretical procedure was, thus, developed, which calculates the circumferentially averaged flow quantities and their radial variation due to the tip clearance effects.

The calculation takes place in successive planes, where a Poisson equation is solved in order to provide the kinematic field. The self induced velocity is used for the positioning of the leakage vortex and a diffusion model is adopted for the vorticity distribution.

The calculated pressure deficit due to the vortex presence is used, through an iterative procedure, in order to modify the pressure difference in the tip region. The method of implementation and the corresponding algorithm are described in this part of the paper and calculation results are compared to experimental ones for cascades and single rotors. The agreement between theory and experiment is good.
Package Design of the RLM 1600 Gas Turbine
Authors: Samson Martin T.
Published: February 2015

The LM 1600 Gas Turbine has proven to be an excellent engine when packaged in compliance with GE’s design recommendations. A packaging approach has been developed by European Gas Turbines which maintains a standardized core-engine installation for the package, while still retaining the capability to be easily reconfigured for inlet and exhaust duct routings, underbase designs and driven-equipment options. This paper presents an overview of the design goals of the package along with specific examples of their execution. Graphics of the package features and build sequence are included along with some current applications.
The Investigation of the Travelling Wave Resonance of Driven Helical Gear
Authors: Qiu Shijun , Xu Min
Published: February 2015

The main vibration type gearing in modern aeroengine transmission is the travelling wave vibration which is divided into two kinds: the forward travelling wave vibration and the backward travelling wave vibration. If the frequency of vibration exciting force, which comes from the meshing of a set of helical gears, is the same as the frequency of travelling wave resonance, the dangerous resonant vibration will take place. However both of forward and backward travelling wave resonance can not be excited as easily. The results of an aeroengine transmission test indicate that forward travelling wave resonant vibrations are more easily excited to the driven helical gear and more dangerous.

The work done by the component force, which is generated because of the angle of travelling wave vibration, on the driven helical gear, work done on the forward travelling wave vibration is positive and the backward travelling wave vibration is negative. In other words, for backward travelling wave vibration the induced force acts as a damping force, but for forward travelling wave vibration the induced force acts as a self–exciting force. Therefore it is more dangerous to driven helical gear when forward travelling wave vibration appears.
Woodsdale: A Unique Peak Generating Plant
Authors: Carey Robert P. , Cassell Carl C.
Published: February 2015

The Cincinnati Gas & Electric Company (CG&E) has recently completed construction of the first block of units at their Woodsdale Generating Station, near Trenton, Ohio. The first block of six indoor simple cycle combustion turbine-generators are in commercial operation, with additional space allocated for six more units to be constructed as their peak electric load requires. Woodsdale Generating Station, ultimately having a peaking capacity of 960 MW, has several features unique to a peaking plant. The units are fueled with natural gas or propane, with fuel switchover capability. NOx emission control is achieved with water injection, produced by a water treatment system consisting of filtration, reverse osmosis, and demineralizers. The station also includes a central control room, black start unit, office and maintenance facilities, compressed air system, and computer-monitored gas detectors throughout. The plant staffing, operating history, and lessons learned during the first several months of service are presented.
Predictions of the Pressure Losses in 2D and 3D Model Pump Diffusers
Authors: Little A. R. , Manners A. P.
Published: February 2015

Two methods of evaluating the loss of mechanical energy in CFD predictions are described. It is shown that the difference between the two methods is a good measure of grid dependence for the prediction of the flows in 2D plane and annular model dump diffusers. The additional loss of mechanical energy due to sector end walls is investigated for 3D plane and annular model dump diffusers over a range of sector widths. The results show a strong dependence on the size of the boundary layer on the sector end walls at the inlet to the pre–diffuser. With no boundary layer on the sector end walls, the measured loss on the central symmetry plane is within 15% of the of the underlying 2D loss for pre–diffuser inlet width to height ratios of greater than 10:1. The deviation from the underlying 2D loss increases with the size of the boundary layer on the sector end walls.
Design of Closed-Cycle Helium Turbine Nuclear Power Plants
Authors: Yan Xing L. , Lidsky Lawrence M.
Published: February 2015

This paper describes the design of two closed-cycle helium turbine electric power plants using a modular high temperature gas-cooled reactor (MGR) as heat source. The MGR-GT utilizes a direct cycle with the turbine in the primary coolant loop while the MGR-GTI uses an intermediate heat exchanger. Both plants are based on current technologies and offer busbar efficiencies in excess of 45% at generating costs competitive with other nuclear or fossil systems. The MGR-GTI indirect cycle faces less technical challenge and is easier to license under current technical and institutional realities, whereas the MGR-GT direct cycle is better able to accommodate future developments in fuel and materials and is an ultimate design capable of capturing the full economic potential through further design simplicity. The two designs thus provide an evolutionary path for the commercialization of MGR gas turbine technology.
The Effect of Wake-Passing and Free-Stream Turbulence on Laminar Gas Turbine Blade Boundary Layers
Authors: Greenblatt David
Published: February 2015

A computational procedure has been developed which accounts for the combined time-mean effect of wake-passing and free-stream turbulence on laminar turbine blade boundary layers. The procedure has the advantage of being computationally efficient as well as providing a realistic model of the unsteady nature of the flow. The procedure yielded the parameter TuReD/σD/2 for characterizing the time-mean flow in the leading edge region and the parameter Γ≡2T~u2σx/γ for describing the flow downstream of the stagnation point. A provisional comparison with stagnation flow experimental data showed that the procedure may be more general than initially expected.
Detailed Measurements of Local Heat Transfer Coefficient and Adiabatic Wall Temperature Beneath an Array of Impinging Jets
Authors: Van Treuren Kenneth W. , Wang Zuolan , Ireland Peter T. , Jones Terry V.
Published: February 2015

A transient method of measuring the local heat transfer under an array of impinging jets has been developed. The use of a temperature sensitive coating consisting of three encapsulated thermochromic liquid crystal materials has allowed the calculation of both the local adiabatic wall temperature and the local heat transfer coefficient over the complete surface of the target plate. The influence of the temperature of the plate through which the impingement gas flows on the target plate heat transfer has been quantified. Results are presented for a single inline array configuration over a range of jet Reynolds numbers.
Development of Quasi-Three Dimensional Turbulence Model for Film Cooling on Flat Plate
Authors: Maeng Joo Sung , Lee Jong Shin
Published: February 2015

The present paper describes predictions of Full Coverage Film Cooling. The calculations have been performed by a quasi-three dimensional model that account for the basically three dimensional nature of the flow. The quasi-three dimensional model are solved by finite analytic method, modified simpler algorithm and body fitted coordinate systems. The turbulent stresses and heat fluxes are obtained from the low Reynolds K-ε turbulence model. The results are given for flows over flat plates for different injection angles, relative spacings, blowing rates and injection temperatures.
Application of State-of-the-Art Power Plant (SOAPP) Workstation for Combustion Turbine Emissions Control
Authors: Perry Philip A. , Van Laar James A. , Touchton George , Pace Stanley E.
Published: February 2015

The Electric Power Research Institute (EPRI) has been conducting a broad research and development effort over the last ten years to provide better designs and materials for fossil fuel power plants. To facilitate transferring this advanced design and technology knowledge to the power industry for the next generation of power plants, EPRI and Sargent & Lundy (S&L) are creating the State-of-the-Art Power Plant (SOAPP) Workstation. The SOAPP Workstation will be available to the industry as a powerful tool that can be used to screen advanced technologies for appropriateness to specific sites; obtain design guidelines for advanced technologies; and generate site-specific conceptual designs, including conceptual design drawings, heat balances, cost estimates, and schedules.

The technology transfer components of this project are a series of individual software modules that will be integrated into the SOAPP Workstation. This paper discusses two software modules that have recently been developed for combustion turbine power plant emission control. The Combustion Turbine Nitrogen Oxides (NOx) Combustor Control Strategies technology module presents state-of-the-art technologies that are commercially available to reduce NOx emissions during combustion, including water injection, steam injection, and dry low NOx combustors. The second technology module, Combustion Turbine Postcombustion NOx/CO Control Strategies, examines selective catalytic reduction (SCR) and carbon monoxide (CO) oxidation technologies for reducing postcombustion NOx and CO emissions. These two technology modules, operating within the SOAPP Workstation, will allow appropriate decisions to be made concerning combustion turbine emission control.
A Review of the Full Capabilities of Blade Path Thermocouples
Authors: Wisch Howard H.
Published: February 2015

Thermocouples have been installed in gas turbine exhaust gas paths for decades for control functions. Since the late 1970s, such thermocouples have also been used for combustion monitoring. The purposes for these thermocouples and the use of the information they provide are sometimes misunderstood. When properly situated and incorporated into a control system, these devices provide data that can ensure a properly operating combustion system, prevent catastrophic hot parts failures, extend component life, and increase availability. Although the use of blade path thermocouples for combustion monitoring has generally been associated with later model gas turbines using cannular combustors, their advantages can also be realized by the modification of older cannular gas turbines as well as turbines with annular or silo combustors. This paper reviews the concept and summarizes the benefits of blade path monitoring and the use of the temperature information obtained. A recommendation is made for the retrofit of older engines and the enhanced instrumentation of some later frames.
Flow Analysis in a Spiral Inducer Impeller
Authors: Howard J. H. G. , Hutchinson B. R. , Broberg R. B.
Published: February 2015

The flow within an axial-flow spiral inducer impeller is complex and three-dimensional. The long but tightly-spiralled passages give rise to secondary flow fields strongly influenced by the blade walls. Flow analysis in such an impeller is carried out by a three-dimensional viscous flow code and compared with previously published LDV measurements. Due to the extreme blade angles of the inducer, an unconventional meshing strategy is required in order to prevent high mesh non-orthogonality. Details of that strategy are provided. Tip clearance modelling was not incorporated in this first stage of investigation. Despite this, the flow analysis reveals the pattern of development of the secondary flow field along the length of the high solidity passage consistent with the LDV data but in much greater detail than was possible with the limited capability of the measurement system. Predicted flow patterns upstream suggest preconditions for the initiation of the observed induction of upstream flow swirl at reduced flow rates.
Application of Probabilistic Methods to the Structural Analysis of Liquid Rocket Engine Components
Authors: Newell J. F. , Rajagopal K. R.
Published: February 2015

Probabilistic Design Analysis (PDA) methodology and related tools are evolving in conjunction with the needs and requirements for designs that are robust with quantified reliability and risk. The implementation of these methodologies through a concurrent engineering process is ideal for integrating the results in a quantified manner. Each critical element of the analysis is given an observable input and relationship to the objective of the robustness and desired results. Several rocket engine components have been case studies of PDA as it has evolved toward this risk–based approach. These hardware components include a turbine blade, LOX post (Liquid Oxygen injector element), transfer duct, system ducting, and combustion chamber liner hardware. The methodology evolution in loads, structural response, damage assessment, reliability, and risk analyses is discussed in the context of the PDA of these components. The current areas of research and approach to structural risk and certification methodologies for minimizing development costs and testing are addressed.
Navier-Stokes Computations for Turbulent Flow Predictions in Transonic Turbine Cascade Using a Zonal Approach
Authors: Yeuan J. J. , Hamed A. , Tabakoff W.
Published: February 2015

Numerical results are presented for viscous flow through a transonic turbine cascade using different turbulence models and H-type grids. The explicit Navier-Stokes solver used in the solution was developed with an option of conservative zonal approach for interpolation across the periodic boundaries with minimum numerical errors. This approach allows the use of a grid that is more orthogonal and less skewed which leads to higher accuracy in the prediction of turbine blade performance. The results obtained with an algebraic and two equation turbulence models, and with two types of H grids are compared at two different flow conditions.
Fuel Control of Gas Turbines by Programmable Logic Controllers
Authors: King Dan A.
Published: February 2015

NOVA Corporation of Alberta has developed a programmable logic controller based gas turbine fuel control system for natural gas compressor set applications. The system carries out all necessary fuel control functions and was integrated into the existing programmable logic controller used for sequencing and shutdown. The system has been successfully implemented on several different aero derivative gas turbines to date. This paper discusses the development of the system, its performance and advantages over standalone hardware-based fuel control systems typically used in the application.