bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and Pre-Test Evaluation of a Low-Pressure Compressor Test Facility for Cryogenic Hydrogen Fuel Integration
Authors: Jonsson Isak , Xisto Carlos , Lejon Marcus , Dahl Anders , Grönstedt Tomas 
Published: September 2021

Abstract
The use of hydrogen as aviation fuel is again resurfacing with unprecedented vigor. It is well known that hydrogen is a formidable heat sink and the use of heat sinks in the compression system of an aero engine may enable not only preheating of the fuel but also improve the gas turbine cycle itself. One such opportunity arises from extracting heat to the fuel as part of the compression process. This work presents the design process and pre-test evaluation of a low-speed compressor test facility dedicated to aerothermal measurements. The design has been derived from a high-speed transonic compressor developed for a large sized geared turbofan engine. The proposed pre-test evaluation methodology provides a comprehensive and affordable way to estimate facility accuracy by virtually addressing all the experimental procedures, from data acquisition to a final performance map. The evaluation of gathering compressor performance parameters via a gas-path investigation process was achieved while relying on results from numerical simulations. The pre-test evaluation details uncertainties introduced throughout this process with transducers, flow and probe specific errors, traverse discretization, and data normalization. A suitable instrumentation configuration is presented which shows that the performance parameters pressure ratio (Π) and isentropic efficiency (ηc) can be determined with uncertainties below 1% for most operating conditions and below 0.5% at design conditions.
Combustor Wall Surface Temperature and Heat Flux Measurement Using a Fiber-Coupled Long Wave Infrared Hyperspectral Sensor
Authors: Chandh Aravind , Bibik Oleksandr , Adhikari Subodh , Wu David , Lieuwen Tim , Hsu Paul , Roy Sukesh , Sikorski Ruth , Emerson Benjamin 
Published: September 2021

Abstract
In this paper, we discuss the development of a non-intrusive surface temperature sensor based on long-wavelength infrared (LWIR) hyperspectral technology. The LWIR detection enables to minimize optical interferences from hot combustion gases (emission mostly within UV-MWIR region). Utilization of hyperspectral detection allows to further improve temperature measurement accuracy and precision. The developed sensor with fiber coupling provides the required flexibility to be maneuvered around/through combustor hardware. The LWIR fiber probe is fully protected by the custom-designed water-cooled probe housing. This device is designed to sustain temperature of 2400 K at pressure of 50 bar, which enables long-term optical diagnostics inside the practical high-pressure combustion facilities where extreme thermal acoustic perturbation and intense heat fluxes are present. The housing featured a diamond window to selectively measure spectra in the LWIR region to get accurate surface temperature exclusively of the combustor wall. The probe was installed into a RQL style combustor to get surface temperature of both hot and cold side of the combustor wall. Further, pointwise heat flux estimates across the combustion liner wall was derived using the temperature measurements.
Study of Oil Film Heat Transfer in Gas Turbine Engine Bearing Chamber
Authors: Petukhov Illia , Mykhailenko Taras , Lysytsia Oleksii , Kovalov Artem 
Published: September 2021

Abstract
A clear understanding of the heat transfer processes in a gas turbine engine bearing chamber at the design stage makes it possible to properly design the lubrication and sealing systems and ensure the future bearing safe operation. The heat transfer coefficient (HTC) calculated based on the classical Newton-Richman equation is widely used to represent the heat transfer data and useful for the thermal resistance analysis. However, this approach is only formally applicable in the case of a two-phase medium. While there is a need to model a two-phase medium, setting the flow core temperature correctly in the Newton-Richman equation is an issue that is analyzed in this study.
The heat from the flow core is transferred to the boundary of the oil film on the bearing chamber walls by an adjacent air and precipitating droplets. The analysis showed that droplet deposition plays a decisive role in this process and significantly intensifies the heat transfer. The main contribution to the thermal resistance of internal heat transfer is provided by the oil film. In this regard, the study considers the issues of the bearing chamber workflow modeling allowing to determine the hydrodynamic parameters of the oil film taking into account air and oil flow rates and shaft revolutions. The study also considers a possibility to apply the thermohydraulic analogy methods for the oil film thermal resistance determination. The study presents practical recommendations for process modeling in the bearing chamber.
Optimization of a High Pressure Industrial Fan
Authors: De Jesús Rivera Edward , Besem-Cordova Fanny , Bonaccorsi Jean-Charles 
Published: September 2021

Abstract
Fans are used in industrial refineries, power generation, petrochemistry, pollution control, etc. These fans can perform in sometimes extreme, mission-critical conditions.
The design of fans has historically relied on turbomachinery affinity laws, resulting in oversized machines that are expensive to manufacture and transport.
With the increasingly lower CPU cost of fluid modeling, designers can now turn to CFD optimization to produce the necessary machine performance and flow conditions while respecting manufacturing constraints.
The objective of this study is to maximize the pressure rise across an industrial fan while respecting manufacturing constraints.
First, a 3D scan of the baseline impeller is used to create the CFD model and validated against experimental data. The baseline impeller geometry is then parameterized with 21 free parameters driving the shape of the hub, shroud, blade lean and camber.
A fully automated optimization process is conducted using Numeca’s Fine™/Design3D software, allowing for a CPU-efficient Design Of Experiment (DOE) database generation and a surrogate model using the powerful Minamo optimization kernel and data-mining tool.
The optimized impeller coupled with a CFD-aided redesigned volute showed an increase in overall pressure rise over the whole performance line, up to 24% at higher mass flow rates compared to the baseline geometry.
Thermal Barrier Coating Applied to the Structural Shroud of an Inside-Out Ceramic Turbine
Authors: Dubois P. K. , Gauvin-Verville A. , Picard B. , Plante J.-S. , Picard M. 
Published: September 2021

Abstract
Recuperated, high-temperature microturbines (&lt; 1 MW) could be a key enabler for hybrid powertrains of tomorrow’s small aircraft. To achieve competitive thermal efficiencies, turbine inlet temperature (TIT) must increase to 1550 K, well beyond conventional metallic microturbine limits. This calls for high-temperature refractory ceramics, which call for a new ceramic-specific, microturbine design like the Inside-Out Ceramic Turbine (ICT). This study focuses on the applicability of a refractory thermal barrier coating (TBC) to the internal surface of the ICT cooling ring. By cutting the heat transfer from the main flow to the structural rim-rotor, the use of a refractory TBC coating in an ICT enables higher TIT and lower cooling air mass flow.
A preliminary experimental assessment is done at room temperature on 1 mm-thick coatings of 8% yttria-stabilized zirconia (8YSZ), air plasma sprayed (APS) TBC, applied to Inconel 718 and Ti64 test coupons. Results show that the strongly orthotropic behaviour of the tested TBC fits perfectly with the deformation mechanics of the ICT configuration under load. First, large in-plane strain tolerance allows the large tangential deformation imposed by the structural shroud under centrifugal loading. Second, high out-of-plane stiffness and compressive resistance combine to support extreme compressive loads with no apparent damage to the TBC even at more than 3 times blade indentation average loading. An experimental demonstration on a small-scale prototype shows a reduction of 40% in cooling flow in a, 8-minute ICT test, with no damage to the TBC, proving the effectiveness and potential of the proposed TBC design.
Numerical Evaluation and High-Speed Rotating Test on Circular Arc Spring Dampers for Centrifugal Compressors
Authors: Takeuchi Ryota , Ishimaru Hidetsugu , Yamashita Hideaki , Inoue Takahiko , Yabui Shota , Inoue Tsuyoshi 
Published: September 2021

Abstract
A circular arc spring damper (CASD) is a recently proposed fluid-film damper that has two or more arc-shaped centering springs and dual radial clearances formed by wire electric discharge machining. CASD requires less space and weight than a conventional cage-centered squeeze film damper (SFD). It provides linear stiffness and stable damping force in rotor-bearing systems to attenuate vibration due to imbalance or to improve rotordynamic stability. The authors have been investigated the dynamic characteristics of CASD in component-level experiments. However, their performance and applicability to real machines have not been confirmed in system-level experiments. Additionally, a theoretical means of evaluation for CASD should be established to predict its dynamic coefficients, and to understand the mechanism of dynamic force generation.
In the first part of this study, a numerical evaluation method using two-way fluid-structure interaction analysis and its theoretical background is presented. Transient structural analysis and fluid-film flow analysis with a simple homogeneous cavitation model are coupled in the commercial multi-physics platform ANSYS. The accuracy of the method was validated by comparing the damping and added-mass coefficients with results from previous experiments. Furthermore, several aspects of the force generation mechanism, and the difference from conventional SFD were studied numerically.
The second part of the study addresses the application of CASD in a multi-stage centrifugal compressor. A combined 4-inch diameter, 5-Pad tilting pad journal bearing (TPJB) with 4-arc type CASD was newly designed and manufactured. To prove the applicability of the developed damper bearing, a series of rotating tests was conducted at a high-speed balancing facility with a full-scale dummy rotor with a critical speed ratio of approximately 3.1. The measured unbalance response showed a much lower amplification factor than that of the conventional TPJB without the damper, which infers a significant improvement in the stability. The measured responses agreed with the rotordynamic analysis, which uses the dynamic coefficients of CASD derived from the proposed numerical evaluation method.
Enhancing Fuel Flexibility in Solar’s® Titan™ 250 Dry Low Emissions Combustion System
Authors: Ramotowski Michael , Cramb Donald 
Published: September 2021

Abstract
Industrial gas turbines serve in a variety of markets involving wide ranging duty cycles, fuel types and quality and emission requirements. For the Oil & Gas markets, applications range from mechanical drive, compressor sets and electrical generation that may be located in developed, remote or off-shore areas requiring a backup fuel (usually a liquid fuel). Upstream applications often require the gas turbine to burn a wide Wobbe range of fuels with varying gas compositions. For Power Generation applications, flexibility in operating range and low emissions are usually required.
This paper describes Solar’s latest SoLoNOx™ (DLE) combustion system developments for the Titan 250 for both gaseous and liquid fuels with a focus on fuel type and quality, operability and emissions from both rig and engine tests. Several combustion systems will be discussed including gas only, dual fuel and a dual fuel Lean Direct Injection (LDI) system for burning lower quality liquid fuels.
Engine tests were performed with blends of reactive gases (propane and butane), inert gas (carbon dioxide) and natural gas covering a wide Wobbe range from 30 to 60 WI (MJ/Nm3). Full engine qualification testing was performed which included operability, emissions and combustion stability for both the gas only and LDI combustion systems. The LDI system is based on the dry low emissions combustion system used for gas operation and thus offers low NOx emissions on gaseous fuels with the ability to burn lower quality liquid fuels for backup operation. A dual fuel lean premixed combustion system was also fully engine qualified for natural gas and liquid fuel.
High pressure single injector rig tests using hydrogen blends with pipeline quality natural gas were also performed to qualify these fuels for engine operation in the dry low emission combustion systems with up to 30% hydrogen. The primary focus of testing was to determine overall operability, turndown, flashback risk and emissions.
Critical and Choking Mach Numbers for Organic Vapor Flows Through Turbine Cascades
Authors: aus der Wiesche Stefan , Reinker Felix , Wagner Robert , Hake Leander , Passmann Max 
Published: September 2021

Abstract
Results are presented of a theoretical and experimental study dealing with critical and choking Mach numbers of organic vapor flows through turbine cascades. A correlation was derived for predicting choking Mach numbers for organic vapor flows using an asymptotic series expansion valid for isentropic exponents close to unity. The theoretical prediction was tested employing a linear turbine cascade and a circular cylinder in a closed-loop organic vapor wind tunnel. The cascade was based on a classical transonic turbine airfoil for which perfect gas literature data were available. The cascade was manufactured by Selective Laser Melting (SLM), and a comparable low surface roughness level was established by subsequent surface finishing. Because the return of the closed-loop wind tunnel was equipped with an independent mass flow sensor and the test facility enabled stable long-term operation behavior, it was possible to obtain the choking Mach number with high accuracy. It was observed that non-perfect gas dynamics affect the critical Mach number locally, but the observed choking behavior of the turbine cascade was in good agreement with the asymptotic result for the considered dilute gas flow regime.
Performance of Unsteady Reynolds-Averaged Navier-Stokes and Hybrid Scale-Resolving Simulation Approaches in Simulating a Low-Speed Axial Compressor Rotor
Authors: Chen Xiangyi , Koppe Björn , Lange Martin , Chu Wuli , Mailach Ronald 
Published: September 2021

Abstract
Aerodynamics phenomena in compressors are highly unsteady and turbulent. Selecting a proper turbulence-modeling method is significant to reveal the complex flow mechanism in turbomachines. In the current paper, the shear stress transport (SST) model as an unsteady Reynolds-averaged Navier-Stokes (RANS) method, the scale-adaptive simulation (SAS) model, and the zonal wall-modeled large eddy simulation (zonal-LES) as two hybrid scale-resolving simulation approaches have been compared. These turbulence-modeling methods were employed to simulate a single rotor of a low-speed research compressor featuring a tip clearance of 1.3% of chord length. Comparisons were made between the simulation results and the experimental data at three operating points, and the flow fields at the design point have been specifically discussed in detail. The results show that the advantage of the zonal-LES model becomes obvious as the compressor throttles. The zonal-LES model brings a significant improvement over both the SST model and the SAS model in capturing the experimental data, especially the velocity distribution in the low-span region, as well as the loss near the endwalls. The SAS model as a scale-resolving method presents no benefits in predicting the relevant flow compared with the SST model, as the activation of the SAS source term is limited for this test case. For the loss prediction, the variation in the upper half-span region is mainly due to the different results in modeling turbulent characteristics of the tip leakage flow, whereas the mechanism behind the higher loss at the lower half-span predicted by the zonal-LES model is a consequence of the complex topology of the corner separation and the intensive mixing.
Mechanism of Circumferential Static Pressure Oscillation in a Centrifugal Compressor With Volute
Authors: Yang Ce , Su Botai , Shi Xin , Zhang Hanzhi , Wang Wenli , Yang Changmao 
Published: September 2021

Abstract
Under the action of an asymmetric volute structure, a non-uniform flow field is formed in the circumferential direction of the centrifugal compressor. During the throttling process of the compressor at different rotational speeds, the static pressure presents a double-peak distribution of two high static pressure strips, one of which is induced by the volute tongue. However, the formation mechanism of the other high static pressure strip remains unclear. In this regard, computations of the steady and unsteady flows in a centrifugal compressor with and without a volute are performed. The purpose of removing the volute is to simplify the boundary conditions at the diffuser exit, eliminate the circumferential pressure gradient distribution in the volute, and retain the circumferential local high static pressure region induced by the VT; thereafter, the circumferential static pressure distributions in the diffuser and impeller are observed. The results indicate that after eliminating the pressure gradient at the diffuser exit along the rotation direction, only local high static pressure boundary conditions can result in the formation of two high static pressure strips in the diffuser and impeller. The local high static pressure at the exit redistributes the mass flow rate at the impeller outlet, forming two regions with high airflow velocity in the diffuser; this leads to the appearance of two high static pressure strips in the circumferential direction. With the increase in the pressure amplitude of the high static pressure at the diffuser exit, the oscillation amplitude of the circumferential pressure is intensified, and the pressure peaks of the two high static pressure strips increase. However, the circumferential positions of the two static pressure peaks practically remain constant. At large mass flow rates, the pressure reduction along the circumferential direction at the diffuser exit preclude the formation of two circumferential high static pressure strips in the diffuser and impeller.
Techno-Economic Analysis of a Hydrogen Production and Storage System for the On-Site Fuel Supply of Hydrogen-Fired Gas Turbines
Authors: Bexten Thomas , Sieker Tobias , Wirsum Manfred 
Published: September 2021

Abstract
Hydrogen-fired gas turbines have the potential to play an important role in future CO2-neutral energy and industry sectors. A prerequisite for the operation of hydrogen-fired gas turbines is the availability of sufficient quantities of hydrogen. The combination of electrolysis and renewable power generation is currently considered the most relevant pathway for the large-scale production of CO2-neutral hydrogen. Regarding the fuel supply of hydrogen-fired gas turbines, this pathway is associated with various technical and economic challenges. This applies in particular to configurations in which electrolyzers and hydrogen storage capacities are installed directly at gas turbine sites to avoid hydrogen transport. Considering an exemplary system configuration, the present study extends prior model-based investigations by focusing on the economic viability of the on-site fuel supply of hydrogen-fired gas turbines. The impact of various design parameters and operational strategies is analyzed using the Levelized Cost of Hydrogen as the main economic indicator. The study reveals that the investigated on-site hydrogen production is not economically viable within the current (2019) framework of the German energy sector. Assuming the extensive availability of renewable power generation in the long-term, additional investigations indicate that on-site hydrogen production and storage systems for gas turbines could potentially become economically viable if various advantageous conditions are met. These conditions include a sufficient availability of inexpensive renewable power for the operation of electrolyzers as well as a sufficient utilization of on-site hydrogen storage capacities to justify corresponding capital expenditures.
The OP16 Gas Turbine Gen-Set for Marine Power Generation
Authors: Horvath Jan 
Published: September 2021

Abstract
Gas turbines are typically selected for propulsion or power generation on marine vessels because of their excellent power-to-weight ratio, fuel flexibility, long maintenance intervals, and reliability. These machines are operating in challenging conditions that are linked to salty and humid air, constant vessel movement, or lack of rigid foundation. This paper presents a novel gas turbine installation on the top deck of a shuttle tanker ship and its innovative integration into the vessel’s power generation system, and discusses the technical solutions that were developed to comply with the latest safety and environmental regulations.
On the Extrapolation of Rim Sealing Performance From Test Bench to Real Engine: A Numerical Survey
Authors: Da Soghe Riccardo , Bianchini Cosimo , Mazzei Lorenzo , Bonini Alessio , Innocenti Luca , Di Benedetto Daniele , Orsini Lorenzo 
Published: September 2021

Abstract
The main annulus hot gas ingress into turbine wheel-spaces is still one of the most challenging problem designers face. During the decades, several experimental test benches were developed worldwide to improve the knowledge associated to the rim seal flow physics. Even if in some cases quite complex and advanced rig configurations were proposed, limitations in the operating conditions and in the reproduction of the real engine geometries/characteristics into the rig are present.
In this paper, validated CFD computations are used to explore the impact of some experimental rigs design choices/limitations on the sealing effectiveness prediction and their ability to mimic the real engine configuration behaviour. Attention is paid on several test rig related aspects such as operating conditions, flow path configuration (blade and vane count) and accuracy in the real engine rim seal geometry reconstruction applied to the rig.
From the computations it emerges that a scaled geometry operated at lab conditions is able to mimic pretty well the real engine sealing performance when rig and engine experience the same flow path ΔCp. The ability of the rig to match the engine data is not affected by the differences in main annulus Mach number between test bench and engine.
A further result that emerges from the computation regards the fact that the Φ0 - ΔCp0.5 curve is not linear, proving that the linear extrapolation of rim sealing performance from test bench to real engine when rig and engine are characterized by different ΔCp0.5 values is not of general application and an alternative approach is given.
Finally, it is found that the impact of vane count on the rim sealing effectiveness is significant, making the extrapolation of data from rig to engine difficult.