bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flow Analysis of Various Intake Configurations of an Unmanned Aircraft Considering External Flow and Different Flight Conditions
Authors: Grois Andreas , Remiger Jonas , Stößel Marcel , Krummenauer Michael , Kozulovic Dragan 
Published: August 2024

Abstract
The importance of unmanned aircraft systems (UAS) is rapidly increasing in various fields of aerospace development. Modern military UASs require a compact full-engine integration to optimize the use of the limited installation space and to prevent radar reflections from the easily detectable fan. These goals are commonly achieved by highly bent intake ducts or by the position of the intake’s inlet section. However, an inconvenient position and an extremely compact intake shape can lead to strong flow inhomogeneities and influence the engine’s stability and performance. Previous studies at the Institute of Jet Propulsion (IJP) have focused on evaluating the flow distortions at the isolated intake duct. The effect of the external flow and the aircraft configuration was neglected. In this work, the impact of external flow on the intake aerodynamics for different aircraft intake configurations at various flight conditions, such as angles of attack or flight Mach numbers, is investigated. A generic remote carrier is used as a virtual test platform on an overall mission that covers most of the aircraft’s flight envelope. The intake systems investigated comprise strongly bent ducts and flush-intake configurations. Different flow inhomogeneities parameters allow detailed consideration of diverse aerodynamic phenomena along the intake and their impact on the Aerodynamic Interface Plane (AIP) flow. As an example, one parameter is the distorted mass flow fraction based on the average deviation from the mean total pressure. Traditional turbomachinery distortion parameters such as the DC60 or SC60 are also analyzed to allow a comparison with existing engine integration studies at the IJP and the open literature. In addition, these evaluation capabilities also enable the use of different flow distortion parameters as input to the IJP’s Engine Mission Simulation System (EMSS) to study the effects on compressor behavior and engine performance (see ASME Turbo Expo 2024 by J. Remiger). For this study, the steady-state RANS simulations of the entire remote carrier were performed using ANSYS CFX flow solver. Initial low-fidelity simulations were done using the EMSS to calculate the flight conditions and, therefore, the boundary conditions for the CFD setup. The study reveals that the external flow significantly influences the flow inhomogeneities in the intake and, therefore, cannot be neglected by evaluating an applicable flight case of a coupled aircraft and intake system. It turned out that a change in the angle of attack and the axial positioning of the intake caused a significant variation in the inflow condition. This major impact is noticeable in the distortion parameters along the intakes and leads to a sharp change in the distortion pattern at the AIP.
Numerical Investigation on the Influence of Wet Compression Aerodynamic Performance of Multi-Stage Transonic Compressor
Authors: Zhu Zihuan , Ming Lele , Zhang Xinze , Wu Yadong , Ouyang Hua 
Published: August 2024

Abstract
In this paper, the gas-liquid two-phase flow in a multistage transonic compressor was numerically simulated based on the Euler-Lagrange method. The influence of wet compression aerodynamic characteristics of the compressor was investigated under different spraying conditions (spraying rates and droplet sizes). The results indicated that the compressor choking boundary moves to a smaller flow rate after spraying. Wet compression improves efficiency of the compressor. The evaporation cooling effect of wet compression decreases total temperature ratio and increases the specific power, resulting in the promotion of the total pressure ratio. After the water droplets are injected into the compressor, due to the small rise of the airflow temperature in the first stage area, the evaporation cooling effect of droplets is weak. Negative effects of droplets lead to a decreasing in the first-stage pressure ratio after spraying. As water droplets move downstream, the gradual increase in airflow temperature enhances the evaporation cooling effect, thereby improving the compressor performance. Water droplets migrate radially inside the compressor and gather toward the blade tip area, causing the gas phase mass flow inside the compressor to be redistributed in the radial direction. Wet compression leads to an increase in the compressor twist velocity, enhancing the capability of the rotor blades to perform work on airflow.
Gas Turbine Combined Cycle System Integration with Carbon Capture Plant for Improved Value
Authors: Sammak Majed , Smith Raub , Kulkarni Parag , N. Ravi , Sholes John 
Published: August 2024

Abstract
The aim of this study is to analyze methodologies that can reduce performance impact on natural gas combined cycle (NGCC) plant when integrated with carbon capture plant (CCP) and lower the capital expenditure (CapEX) associated with carbon capture. The conventional approach of providing steam to the carbon capture reboiler for CO2 regeneration is the use of a bolt-on system, which entails an external auxiliary boiler. The study presented four promising technologies that can enhance the integration of NGCC with CCP: steam integration, exhaust gas recirculation (EGR), gas turbine improvement, and enhanced control system. The paper analyzes how EGR can decrease CCP CapEX and footprint, focusing on equipment with the most significant CapEX reductions.
The steam integration approach refers to extracting steam from various locations in the steam cycle such as the crossover between the intermediate pressure (IP) and low pressure (LP) sections of the steam turbine using a throttle and control valve.
The EGR method refers to recirculating a part of the flue gas from the stack back into the gas turbine inlet, where it is combined with ambient air. The analysis reveals that EGR contributes to an increase in the concentration of CO2 in exhaust while simultaneously decreasing the amount of flue gas directed to the CCP. This dual effect is expected to result in a reduction in both the overall CCP CapEX and its footprint. The study delves into the impact of EGR return temperature and EGR ratio on the output of gas turbine and combined cycle systems.
NGCC performance has been evaluated utilizing GE’s internal mass and heat balance tools. CCP performance and cost were assessed using commercial tools ProMax and Aspen Process Economic Analyzer.
The study demonstrates that providing steam to CCP through a steam integration solution is more effective than using a bolt-on solution. The steam integration solution has a potential to achieve up to 30% decrease in CCP CapEX compared to the bolt-on solution utilizing an auxiliary boiler. In addition, using a 30% EGR in the steam integration solution decreases the CapEx for the CCP by an additional 7%.
EGR return temperatures ranging from 27°C to 44°C at 1°C intervals are considered, alongside studied EGR ratios of 10%, 20%, 30%, and 40%. The analysis demonstrates that the output of the studied NGCC increases at all studied EGR return temperatures and EGR ratios, reaching a peak at a 35% EGR ratio before leveling off.
Investigation of Predictive Methods for Flow Resistance in Channel With Asymmetric Rib Arrangements Under Rotating Condition
Authors: Xu Yunteng , You Ruquan , Che Junxin , Li Haiwang 
Published: August 2024

Abstract
Turbine blade cooling demands vary between the leading and trailing surfaces. To achieve a refined design of blade cooling structures and maximize the utilization of cooling air, an asymmetric ribbed structure design method is proposed. The prediction of resistance is a crucial issue that urgently needs to be addressed in the design of this structures. Numerical simulation (Large Eddy Simulation) is adopted to investigate the flow characteristics and resistance properties of straight channels with asymmetric (different rib spacing) and symmetric rib arrangements, within the range of Re = 30000 and Ro = 0–0.5. The ribbed channel’s friction factor is analyzed under rotating condition. The asymmetric effects within the rotating ribbed channel and the mechanism of rotational impact on the flow are revealed, and a predictive method for the flow resistance in rotating asymmetric ribbed channels is summarized and proposed. Placing asymmetric ribs on the wall causes the airflow to shift and squeeze toward positions of lower resistance, creating a “rib-induced pushing effect” and leading to a trend of resistance between wall surfaces moving towards equilibrium development. Affected by this effect, the peak streamwise velocity shifts towards the side without ribs by 11% in single-sided ribbed channel under stationary conditions. In double-sided ribbed channels, the peak streamwise velocity increases by 13% compared to a smooth channel. Under rotational conditions, the Coriolis force effect acts in conjunction with the rib-induced propulsion effect on the airflow, resulting in regular flow within the channel. Therefore, the Coriolis force effect and ribbed-induced pushing effect are the main factors affecting the flow resistance in the rotating asymmetric rib channel, and the flow resistance coefficient in the rotating asymmetric ribbed channel can be judged according to their magnitude. In this paper, a method for predicting the flow resistance of asymmetric ribs is proposed, considering the coupled effects between wall surfaces.
Development of 1400°C (2552°F) Class Ceramic Matrix Composite Turbine Shroud and Demonstration Test With JAXA F7 Aircraft Engine
Authors: Watanabe Fumiaki , Yamanaka Shohei , Noguchi Toshihito , Hirano Hiroto , Sato Hayao , Makida Mitsumasa , Hojo Masahiro 
Published: August 2024

Abstract
Serviceable temperature for turbine components material of aircraft engines is increasingly needed to be higher in order to improve engine performance and durability. Recently SiC/SiC Ceramic Matrix Composites (CMCs) are commercialized instead of Ni-base super alloys which have been used for turbine components. The Authors developed 1400°C (2552°F) class CMC material system which consist of SiC fibers and SiC matrix and ytterbium silicate base matrix, aiming for higher temperature capability on consignment from the New Energy and Industrial Technology Development Organization (NEDO). Then they designed and manufactured high pressure turbine shrouds for aircraft engines using that 1400°C class material system, and they conducted strength tests and thermal cycle tests for turbine shroud components. After that they conducted engine tests for the CMC turbine shrouds demonstration in the actual engine environment jointly with the Japan Aerospace Exploration Agency (JAXA) in 2021. The test vehicle for this demonstration engine tests was the F7 engine which was introduced in 2019 at JAXA as the first case of a commercial transfer of the F7-10 turbofan engine which was developed by the Acquisition, Technology & Logistics Agency (ATLA) for the P-1 maritime patrol aircraft. The engine test was conducted for over 75 hours including over 35 hour hot time. After the test teardown inspection was conducted. No spallation of EBC, no recession and no wear on CMC turbine shrouds were found. As the result of the microstructure observation for cut faces of CMC turbine shrouds, no oxidation in SiC fibers, no chemical reaction in matrix, and no microcrack in matrix were found, but, some oxidation in fiber interface coating and microcrack in EBC were found. Bending strength tests with specimens cut out from CMC turbine shrouds were conducted in order to survey the degradation of material. Two types of specimens were prepared. One was the specimen cut out from the high temperature portion. The other was the specimen cut out from the high stress portion. As the result of bending test, the strength of the specimens cut out from engine tested shrouds were equivalent to the strength of the specimens cut out from unused shrouds. The CMC turbine shrouds after engine test were determined to be serviceable, therefore the developed 1400°C class CMC shrouds was proven to be sound in an actual engine environment.
Application of Ultrasound Gas Detectors in Gas Turbine Package
Authors: Sorrentino Viola , Viti Riccardo , Minotti Stefano , Tonno Giovanni , Azzini Francesco 
Published: August 2024

Abstract
A Gas Turbine (GT) usually has hot surfaces and it is installed with the fuel gas system inside a ventilated acoustic enclosure. Several connections are present in the fuel gas system and in the GT combustion chamber that could become sources of leakage. For this reason, the introduction of hydrogen as fuel for Gas Turbines requires attention in the design phase due to properties such as a large flammability range and low ignition energy. To prevent hazardous events in case of unexpected leakage, it is required to have a Gas Detection system which command an emergency shut down of the GT train. Fundamental characteristics of a gas detection system include its reliability and the response time. Since hydrogen is more reactive than conventional natural gas, the time required to detect gas leaks becomes a crucial factor. For this reason, an intervention as fast as possible is strongly recommended. Ultrasound gas detectors have these features but they regularly work in open environment and there is no evidence of their application in GT enclosures. This work describes some tests of Ultrasonic Gas Leak Detectors carried out in operating GT package. Ultrasound gas detectors were installed in several locations inside a GT enclosure and tested during different GT load conditions up to Full Speed Full Load. Hydrogen leaks have been simulated using helium as surrogate to verify GD performances. Promising results achieved from this test are shown in this paper.
Optimum Design of Scaled-Down Wind Turbines Based on Field Data
Authors: Jauregui Juan , Franco Jesus Alejandro 
Published: August 2024

Abstract
This paper presents a method for designing wind turbine-scaled models based on field data. The development of more giant wind turbines significantly contributes to power generation with renewable sources. Thus, scaling models are a crucial element in the design process of large wind turbines. The scaling process requires careful consideration of the system’s physical laws and similarity criteria. Scaling methods depend on the prototype’s operating conditions (full-size wind turbine) and the experimental conditions (scaled model dimensions and wind tunnel capabilities). The data from a field turbine is the input for creating a scaled model and testing it in a wind tunnel. However, in general, there are few field data available. The task is not straightforward since most operating conditions must be satisfied, and the similarity criteria could result in different scaled models and wind tunnel conditions. The drawback of the scaling models is their inability to reproduce all the operating conditions. The method presented here considers most of the recommended similarities, including the dynamic modeling of the system. The final scaled-model design was obtained by modifying the blade profile to reproduce similar power, pitch momentum, and trust coefficients, keeping the same twist angle as the prototype. Since the possible profiles are too large, the best approximation was obtained by comparing the coefficient curves of different blade profiles with the prototype’s curves. The curves were calculated using the BEM method. It was found that the scaled model has an entirely different design.
Thermodynamic Analysis of a Novel Transcritical CO2 Pumped Thermal Energy Storage System With a Vortex Tube Driven by Photovoltaic Thermal Collector
Authors: Chen Liangqi , Lou Juwei , Wang Bofeng , Wang Jiangfeng , Zhao Pan , Dai Yiping 
Published: August 2024

Abstract
With the growing global emphasis on the utilization of renewable energy sources, the field of energy storage has garnered significant attention. Among the various storage technologies, Pumped Thermal Energy Storage (PTES) stands out as a highly adaptable solution that is not limited by geographical boundaries. This flexibility makes PTES an attractive option for a wide range of applications, as it can be implemented in diverse settings to support the integration of renewable energy into power systems. To enhance the roundtrip efficiency of PTES, this paper proposed a PTES system based on the transcritical CO2 cycle. Furthermore, the proposed system is combined with photovoltaic thermal (PVT) collectors to improve the coefficient of performance (COP) during the energy storage process by recovering the waste heat of PVT collectors. PVT can not only improve the power efficiency of photovoltaic, but also increase the inlet temperature of compressor to reduce the energy consumption. Considering the low critical temperature (about 31°C) of CO2, the vortex tube is utilized as a condensation equipment in the proposed system to condense CO2 to liquid under ambient conditions, so that the proposed system can be more flexible in the process of application. A computational framework is developed to examine the impact of parameters on thermodynamic performance. The sensitivity analysis of key parameters such as temperature of storage tank, turbine inlet pressure and vortex tube outlet pressure are carried out to determine the energy storage characteristics of the proposed system. In addition, multi-objective optimization is performed using a genetic algorithm to achieve the optimal design performances including round-trip efficiency and average electricity growth rate of PVT.
Lean Blow-Off Behaviour of Premixed Bluff-Body Stabilized Hydrocarbon-Air Flames and Ammonia/Hydrogen/Nitrogen-Air Flames
Authors: Su Tong , Xu Boyan , Bastiaans Rob , Worth Nicholas A. 
Published: August 2024

Abstract
Ammonia blends have great potential to be utilized in gas turbine combustors as carbon-free fuels. This paper investigates and compares the lean blow-off behavior of premixed bluff-body stabilized hydrocarbon flames and ammonia/hydrogen/nitrogen flames both experimentally and numerically. Simultaneous high-speed PIV and OH-PLIF are employed to resolve temporal flame and flow field information, allowing the curvature and hydrodynamic strain rates along the flame surfaces to be calculated. OH* and NH2*, chemiluminescence images are also used to examine flame structures at the same bulk flow velocity but at four equivalence ratios which span a range of flame stability behaviour from far away from to near lean blow-off. The NH3/H2/N2 flames blow off at leaner conditions as the hydrogen volume fractions increase. A NH3/H2/N2 (70%/22.5%/7.5%) flame is slightly more resilient to lean blow-off compared with methane and propane flames at a velocity of 20 m/s despite having a significantly lower laminar flame speed. The flame structure for all fuel blends change from a ‘V-shape’ to ‘M-shape’ when approaching lean blow-off, as observed in the Abel deconvoluted OH* fields for methane and propane flames and NH2* fields for ammonia fuel blends, which can result in incomplete reactions and finally trigger the lean blow-off. However, the strong OH* intensity in the shear layer near flame root for the NH3/H2/N2 flames indicate that a robust reaction is maintained in this region for this fuel blend, increasing flame stability. The flame and recirculation zone lengths both decrease with equivalence ratio. Widely-distributed positive curvature along the flame surface of the ammonia fuel blend flames which have a Lewis number less than unity, may also enhance combustion for these flames. As blow-off is approached hydro-carbon flame fronts undergo increasing strain rates along their flame fronts, which may be due to their migration towards the inner shear layer region of the flow. In comparison the strain rates along NH3/H2/N2 flames fronts do not change significantly as blow-off is approached due to less dramatic changes to the flame shape. The faster consumption rates of hydrogen than ammonia near the flame root for the ammonia blend flames, and the lower temperature loss compared with the adiabatic temperature may also contribute to the stabilization of ammonia blends near lean blow-off.
A Physics-Informed Deep Learning Approach for HDGT Compressor Performance Simulation
Authors: Wei Manman , Jiang Xiaomo , Liu Yiyang , Ge Xin 
Published: August 2024

Abstract
Owing to the complicated structure of a heavy-duty gas turbine, its efficiency is largely impacted by the ambient and operating conditions. Real-time control and predictive maintenance based on performance model becomes a powerful method widely utilized to improve the operating efficiency of the gas turbine. However, the thermodynamic balance-based performance model is hardly applied for real-time control and predictive maintenance of the gas turbine due to its time-consuming computation. In this study, we designed a deep learning operator network (DeepONet) model to simulate the thermodynamic heat balance of axial compressor. The DeepONet is then employed to rapidly predict the efficiency and mass flow of the compressor. First, a physics-based model is built by seamlessly integrating the thermodynamic balance mechanism, structural characteristics, and operating data of the axial compressor. Then, a high-efficiency and high-precision DeepONet model is constructed with reference to the structure of the physics-based model. The yielded surrogate model is utilized to quickly predict key parameters of the compressor including its mass flow and efficiency. The accuracy and effectiveness of the proposed methodology is evaluated by comparing the prediction outputs with measured data through a case study of an axial compressor. A comparison study with conventional long short-term memory model shows that the proposed DeepONet-model provides a promising tool for performance-based smart maintenance of the compressor.
Prediction of High-Speed Hydraulic Dynamometer Safety Envelope Base on Deep Learning Neural Network
Authors: Chen Guo , Xiao Hong , Zhou Li , You Rui 
Published: August 2024

Abstract
High-speed hydraulic dynamometer is widely used for turbine component experiment in aircraft engine area. It usually works through measuring main performance parameters of turbine for verifying design method by absorbing huge shaft work which is passed from turbine. However, its water flow can generate strong turbulence phenomena between impellers in dynamometer’s case. In addition, high water temperature may generate cavitation phenomenon and cause high-frequency pressure pulsation. Both can lead to dynamometer’s performance degradation.
Artificial experience diagnosis, though not suggested, is used commonly to prevent high-speed hydraulic dynamometer from working unsteadily. This method depends on the experience of workers, which may cause fuzzy definition and lead to safety hazard.
In this paper, we propose a two-stage model of highspeed hydraulic dynamometer based on deep learning neural network. It utilizes the ideas of Transformer Model, which makes our model become more sensitive and stable. Accuracy and stability are proved by verifying actual device operation data. Based on two-stage model, we can draw work safety envelope by predicting performance parameters that delimit the safety boundary. Follow this guide workers can be able to make operation safer and stabler.