bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micro Gas Turbine Firing Ammonia
Authors: Iki Norihiko , Kurata Osamu , Matsunuma Takayuki , Inoue Takahiro , Tsujimura Taku , Furutani Hirohide , Kobayashi Hideaki , Hayakawa Akihiro , Arakawa Yoshiyuki , Ichikawa Akinori 
Published: September 2016

A demonstration test with the aim to show the potential of ammonia-fired power plant is planned using a micro gas turbine. 50kW class turbine system firing kerosene is selected as a base model. A standard combustor is replaced by a prototype combustor which enables a bi fuel supply of kerosene and ammonia gas. Diffusion combustion is employed in the prototype combustor due to its flame stability. Demonstration test firing ammonia gas was achieved using a new facility of large amount of ammonia supply. The gas turbine started firing kerosene and increased its electric power output. After achievement of stable power output, ammonia gas was started to be supplied and its flow rate increased gradually.
41.8kW power output was achieved by firing ammonia gas only. Ammonia gas supply increases NOx in the exhaust gas dramatically. However post-combustion clean-up of the exhaust gas via Selective Catalytic Reduction can reduce NOx successfully.
Natural Cooling Affecting the Restart of Micro Gas Turbine
Authors: Tisarev Andrei , Falaleev Sergey , Koch Christian , Nagorski Matthias , Staudacher Stephan 
Published: September 2016

The research into natural cooling of a shutdown gas turbine engine is necessary to understand the factors reducing the engine components life by restart. The additional unbalance, bearing overheating and clearance changes are phenomena, which can appear during cooldown and engine restart. In this work, experimental and numerical research for a micro GTE cooldown were conducted.
Numerical conjugate flow & heat-transfer model of the whole engine was created for these purposes. The calculated temperature distribution at an operating point was used as a starting point of the cooldown time. Cooldown calculation included two phases: run-down and natural cooling. The numerical investigation was supported by experimental measurements, which were obtained using a micro gas turbine test rig.
From the results obtained it can be concluded that the allowed time before the restart must generally be based on individual factors such as bearings temperature, the displacement of turbine wheels centers of gravity etc. These factors attain their peak values at different time points after the engine shutdown.
The Exergy Optimization Analysis of 700°C HUSC Steam Turbine Using a Echelon Cycle System
Authors: Yi Xiaolan , Fan Shiwang , Li Haitao , Yang Jiandao , Chen Tao , Yang Hong 
Published: September 2016

700°C HUSC technology is considered as the next generation of more efficiently coal-fired power generation technology, the heat rate of which can be reduced by more than 8% on the basis of current ultra-supercritical units. That means there is a huge energy saving benefits. With the main steam / reheat steam temperature increasing from 600°C / 620 °C to 700°C/ 720°C, the temperature of extraction steam increases dramatically, especially the first extraction stage after reheater, the temperature of which will increase to 630 ∼ 650 °C. That means a substantial increase in the cost of the initial investment because of the nickel-based material being used in extraction pipe and heaters. With EC system, the extraction steam temperature is reduced sharply because the high temperature extraction steam is moved from the main turbine to a small parallel extraction turbine and the steam source of the small extraction turbine is from the cold reheater. So the highest extraction steam temperature will not exceed 500 °C, and the high temperature risk of heat recovery system will be eliminated completely.
In this paper, exergy theory is introduced to analyze the cycle efficiency of the new thermodynamic system and the conventional one. In order to obtain a better 700 °C high ultra-supercritical thermodynamic system solution, GA method is used to optimize the regenerative system parameters to lower the overall heat consumption. The exergy theory is also used to analyze the reason why optimal solution can bring economic benefits. Finally, the feasibility of the entire system project will be analyzed.
Design for Additive Manufacturing: Internal Channel Optimization
Authors: Pietropaoli M. , Ahlfeld R. , Montomoli F. , Ciani A. , D’Ercole M. 
Published: September 2016

The new possibilities offered by Additive Manufacturing (AM) can be exploited in gas turbines to produce a new generation of complex and efficient internal coolant systems. The flexibility offered by this new manufacturing method needs a paradigm shift in the design approach and a possible solution is offered by Topology Optimization.
The overall goal of this work is to propose an innovative method to design internal channels in gas turbines that that fully exploit AM capabilities. The present work contains a new application of a Fluid Topology sedimentation method to optimize the internal coolant geometries with minimal pressure losses while maximizing the heat exchange. The domain is considered as a porous medium with variable porosity: the solution is represented by the final solid distribution that constitutes the optimised structure. In this work the governing equations for an incompressible flow in a porous medium are considered together with a conjugate heat transfer equation that includes porosity dependent thermal diffusivity. An adjoint optimisation approach with steepest descent method is used to build the optimisation algorithm.
The simulations are carried out on two different geometries: a U-Bend and a straight duct. For the U-Bend a series of splitter is automatically generated by the code, minimizing the stagnation pressure losses. In the straight duct the impact of different porosity dependant thermal diffusivity is analysed to achieve high thermal exchange. The results show “rib like” structures that enhance the heat transfer.
Application of Film Cooling to an Unshrouded HP Turbine Casing
Authors: Collins Matthew , Chana Kamaljit , Povey Thomas 
Published: September 2016

In this paper we describe the design, modelling and experimental testing of a film cooling scheme employed on an unshrouded HP rotor casing.
The casing region has high thermal loads at both low and high frequency, with the flow being dominated by the potential field of the rotor and over-tip leakage flows. Increasingly high turbine entry temperatures necessitate internal and film cooling of the casing to ensure satisfactory service life and performance. There are, however, very few published studies presenting CFD and experimental data for cooled rotor casings.
Experimental testing was performed on a film cooled rotor casing in the Oxford Turbine Research Facility (OTRF) — a rotating transonic facility of engine scale. Unsteady CFD of a HP rotor blade row with a film cooled casing was performed with a domain utilizing a sliding interface in the tip gap.
Specific advances in validation data and understanding include:
1. A discussion of the challenges faced in the design of a casing film cooling scheme. We show that the seemingly hostile film cooling environment can be managed with the use of holes shaped to utilize acoustic pressure wave reflections.
2. Time resolved and time averaged predictions of adiabatic film effectiveness on the rotor casing are presented. Mechanisms for interaction of the coolant with the rotor tip are proposed and discussed.
3. Acoustic effects due to the passing of the rotor are demonstrated on a 3D CFD geometry, supporting conclusions drawn by Collins and Povey [1] on the importance of this effect in a casing film cooling system.
4. Time-resolved and time-mean measurements of TAW and η’ taken using a high density array of thin film heat flux gauges are presented and compared to CFD predictions for the casing region (−30 % to +125 % CAX).
Transient Performance Analysis of an Industrial Gas Turbine Operating on Low-Calorific Fuels
Authors: Singh Vrishika , Axelsson Lars-Uno , Visser W. P. J. 
Published: September 2016

The demand for more environmentally friendly and economic power production has led to an increasing interest to utilize alternative fuels. In the past, several investigations focusing on the effect of low-calorific fuels on the combustion process and steady-state performance have been published. However, it is also important to consider the transient behavior of the gas turbine when operating on non-conventional fuels. The alternative fuels contain very often a large amount of dilutants resulting in a low energy density. Therefore a higher fuel flow rate is required, which can impact the dynamic behavior of the gas turbine.
This paper will present an investigation of the transient behavior of the all-radial OP16 gas turbine. The OP16 is an industrial gas turbine rated at 1.9 MW, which has the capability to burn a wide range of fuels including ultra-low-calorific gaseous fuels. The transient behavior is simulated using the commercial software GSP including the recently added thermal network modeling functionality. The steady-state and transient performance model is thoroughly validated using real engine test data.
The developed model is used to simulate and analyze the physical behavior of the gas turbine when performing load sheds. From the simulations it is found that the energy density of the fuel has a noticeable effect of the rotor over-speed and must be considered when designing the fuel control.
Reducing Solid Particle Erosion on Steam Turbine Stages
Authors: Chen Tie , Singh Gurnam , Millington Peter , Haller Brian 
Published: September 2016

Solid Particle Erosion (SPE) damage can be found on steam turbine stages. These solid particles are caused by the exfoliation of iron oxides formed on the inner surfaces of both boiler tubes and steam pipes which are exposed to elevated temperature. They can damage both fixed and Moving Blades, as well as both outer extension ring and tip seals. Severe SPE damages can be expensive for the utility industry due to reduced efficiency and lost power generation, as well as increased costs of repair or replacement of eroded components. Thus it is very important to understand this phenomenon and propose cost effective solutions to reduce the damage.
This study investigates the effects of SPE damage using particle trajectory calculations. This investigation confirms that “Bounce Back” is the dominant cause for the SPE damage on both Fixed Blade trailing edge and Moving Blade leading edge. The particles do not accelerate at same speed as steam, therefore they travel much slower when they hit the Moving Blade leading edge. Then they are thrown back towards the Fixed Blade to hit the trailing edge. Due to strong centrifugal forces, the particles are also thrown radically outwards and damage both outer extension ring and tip seals.
Based on these enhanced understandings, a practical solution is proposed to reduce SPE damage. It is predicted to have negligible impact on the stage performance. Evidence from the latest inspection demonstrates that this solution is very effective in reducing SPE damage to the Fixed Blade trailing edge.
Influence of the Blade-Spoke Connection Point on the Aerodynamic Performance of Darrieus Wind Turbines
Authors: Bianchini Alessandro , Balduzzi Francesco , Ferrara Giovanni , Ferrari Lorenzo 
Published: September 2016

The assessment of robust CFD techniques is casting new light on the aerodynamics of airfoils rotating around an axis orthogonal to flow direction, with particular reference to flow curvature effects and stall mechanisms. In particular, Darrieus wind turbines’ designers are taking profit from these new discovers to improve the aerodynamic design of the rotors, in view of an increase of the overall efficiency and a reduction of the structural stresses on the blades.
A controversial design parameter for Darrieus turbines, especially in case of small-size rotors, is represented by the location of the blade-spoke connection along the chord.
The most common solution is indeed to place the connection at approximately airfoil’s quarter chord, i.e. where the pressure center is commonly located for low incidence angles. In some cases, however, the blade is connected at middle chord due to symmetry or aesthetic reasons. In some small turbines, innovative designs have even disregarded this parameter. Even if one can argue that the blade connection point is about to have some aerodynamic effects on the turbine’s performance, the real impact of this important design parameter is often not fully understood.
The present study makes use of extensive CFD simulations on a literature case study, using a NACA 0021 airfoil, to assess the influence of the blade-spoke connection point. In particular, the differences in terms of power coefficient curve of the turbine, optimal tip-speed ratio, torque profiles and stresses on the connection are analyzed and discussed. Detailed flow analyses are also shown for azimuthal positions of particular interest. Results on the selected case study showed that the middle-chord blade-spoke connection point seems to guarantee a higher performance of the rotor, even if additional solicitation is applied to the connection itself. It is further shown that the same performance can indeed be obtained with the airfoil attached at quarter chord and properly pitched. By doing so, the stresses are contained and the performance is maximized.
Rigid Mode Vibration Control and Dynamic Behavior of Hybrid Foil-Magnetic Bearing (HFMB) Turbo Blower
Authors: Jeong Sena , Kim Jungwan , Jeon Doyoung , Lee Yong Bok 
Published: September 2016

In this study, experimental and analytical analyses of the vibration stability of a 225 kW class turbo blower with a hybrid foil-magnetic bearing (HFMB) were performed. First, critical speed and unbalance vibration responses were examined as part of the rotordynamic research. Then, an experimental double-suction turbo blower with an HFMB was built. The turbo blower consisted of an impeller at each end and a permanent magnet motor in the center. Its shaft diameter was 71.5 mm, its total length was 693 mm, and the weight of the rotor was 17.8 kg. The air foil bearing (AFB) utilized was 50 mm long and had a 0.7 aspect ratio. The results of analyses indicate that rigid mode (conical mode) occurred close to 8,036 rpm, and the results of natural frequency analysis and dynamic behavior prediction of the rotor-bearing system were similar to those obtained experimentally. However, in the experiments conducted, excessive vibration and rotor motion instability occurred in the range 12,000–15,000 rpm, which resulted from insufficient dynamic pressure caused by the length of the foil bearing being too short. Consequently, as the rotor speed increased, excessive rotor motion attributable to aerodynamic and bearing instability became evident.
This study therefore focused on improving rotordynamic performance by rectifying rigid mode unstable vibration at low speed, 20,000 rpm, and asynchronous vibration due to aerodynamic instability by using HFMB with vibration control. Although the normal operating speed is 39,000 rpm, the experiments were conducted at 20,000 rpm. The experimental results obtained were compared for each bearing type (AFB and HFMB) to improve the performance of the vibration in the low speed region.
The experimental results show that the HFMB technology results in superior vibration stability for unbalance vibration and aerodynamic instability in the range 12,000–15,000 rpm (200–250 Hz). The remarkable vibration reduction achieved from vibration control of the hybrid foil-magnetic rotor-bearing system show that oil-free turbomachinery can achieve excellent performance.
Integration and Optimization of Coal Gasification Systems With a Near-Zero Emissions Supercritical Carbon Dioxide Power Cycle
Authors: Lu Xijia , Forrest Brock , Martin Scott , Fetvedt Jeremy , McGroddy Michael , Freed David 
Published: September 2016

The Allam Cycle is a semi-closed, recuperated, oxy-fuel, supercritical carbon dioxide (sCO2) Brayton power cycle, offering advantages over simple cycle and combined cycle arrangements. The Allam Cycle uniquely combines oxy-combustion with a substantially elevated operating pressure, high sCO2 recirculation flow, high gross turbine efficiency, and inventive low- and high-grade heat recuperation. As a result, the core Allam Cycle meets or exceeds the achievable net efficiencies of existing high efficiency combined cycle plants not equipped for carbon capture, while capturing substantially all CO2 emissions at purities and pressures necessary for downstream CO2 reuse and/or sequestration. Additionally, with minor alterations, the core cycle can operate with a variety of organic fuels. A 50MWt natural gas-fired demonstration of the core cycle is currently under development by 8 Rivers, NET Power, CB&I, Exelon, and Toshiba.
This paper addresses the coal syngas-fired variant of the Allam Cycle system, extending beyond high-level feasibility analyses conducted in previous studies. The paper explores in detail the unique considerations, possible hurdles, and advantages of integrating a commercially-available coal gasifier with the Allam Cycle. In particular, the paper analyzes five (5) primary technical optimizations that drive the Allam Cycle’s advantages in efficiency and cost over conventional baselines. These include: (1) a simpler overall process, requiring fewer critical integration points while still providing for efficient high- and low-grade heat recuperation; (2) high efficiencies regardless of coal rank and type used — further, the efficiency drop when using low-rank coal in an Allam Cycle arrangement is smaller than IGCC arrangements; (3) high efficiencies regardless of syngas composition (such as H2:CO ratio), particularly when compared to gasification in the chemical industry and IGCC with carbon capture and sequestration; (4) the ability to utilize a singular, cost-effective post-combustion SOX/NOX removal mechanism; and (5) considerable water savings versus IGCC and SCPC baselines, with the ability to run substantially water free with only minor impacts to overall efficiency.
Retracted: “Design and Testing Process for a 7kW Radial Inflow Refrigerant Turbine at the University of Queensland” [ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition, Volume 8: Microturbines, Turbochargers and Small Turbomachines; Steam Turbines, Seoul, South Korea, June 13–17, 2016, Conference Sponsors: International Gas Turbine Institute, ISBN: 978-0-7918-4986-6, Copyright © 2016 by ASME. Paper No. GT2016-58111, pp. V008T23A036; 11 pages; doi:10.1115/GT2016-58111]
Authors: ASME  
Published: September 2016

The above referenced paper has been removed from publication. December 5, 2016.
Copyright © 2016 by ASME
Bacteriome and Mycobiome Interactions Underscore Microbial Dysbiosis in Familial Crohn’s Disease
Authors: Hoarau G. , Mukherjee P. K. , Gower-Rousseau C. , Hager C. , Chandra J. , Retuerto M. A. , Neut C. , Vermeire S. , Clemente J. , Colombel J. F. , Fujioka H. , Poulain D. , Sendid B. , Ghannoum M. A. 
Published: September 2016

ABSTRACT

Crohn’s disease (CD) results from a complex interplay between host genetic factors and endogenous microbial communities. In the current study, we used Ion Torrent sequencing to characterize the gut bacterial microbiota (bacteriome) and fungal community (mycobiome) in patients with CD and their nondiseased first-degree relatives (NCDR) in 9 familial clusters living in northern France-Belgium and in healthy individuals from 4 families living in the same area (non-CD unrelated [NCDU]). Principal component, diversity, and abundance analyses were conducted, and CD-associated inter- and intrakingdom microbial correlations were determined. Significant microbial interactions were identified and validated using single- and mixed-species biofilms. CD and NCDR groups clustered together in the mycobiome but not in the bacteriome. Microbiotas of familial (CD and NCDR) samples were distinct from those of nonfamilial (NCDU) samples. The abundance of
Serratia marcescens
and
Escherichia coli
was elevated in CD patients, while that of beneficial bacteria was decreased. The abundance of the fungus
Candida tropicalis
was significantly higher in CD than in NCDR (
P
= 0.003) samples and positively correlated with levels of anti-
Saccharomyces cerevisiae
antibodies (ASCA). The abundance of
C. tropicalis
was positively correlated with
S. marcescens
and
E. coli
, suggesting that these organisms interact in the gut. The mass and thickness of triple-species (
C. tropicalis
plus
S. marcescens
plus
E. coli
) biofilm were significantly greater than those of single- and double-species biofilms.
C. tropicalis
biofilms comprised blastospores, while double- and triple-species biofilms were enriched in hyphae.
S. marcescens
used fimbriae to coaggregate or attach with
C. tropicalis
/
E. coli
, while
E. coli
was closely apposed with
C. tropicalis
. Specific interkingdom microbial interactions may be key determinants in CD.

IMPORTANCE
Here, we characterized the gut bacterial microbiota (bacteriome) and fungal community (mycobiome) in multiplex families with CD and healthy relatives and defined the microbial interactions leading to dysbiosis in CD. We identified fungal (
Candida tropicalis
) and bacterial (
Serratia marcescens
and
Escherichia coli
) species that are associated with CD dysbiosis. Additionally, we found that the level of anti-
Saccharomyces cerevisiae
antibodies (ASCA; a known CD biomarker) was associated with the abundance of
C. tropicalis
. We also identified positive interkingdom correlations between
C. tropicalis
,
E. coli
, and
S. marcescens
in CD patients and validated these correlations using
in vitro
biofilms. These results provide insight into the roles of bacteria and fungi in CD and may lead to the development of novel treatment approaches and diagnostic assays.