scholarly journals Mechanical Behaviour of Inconel 718 Thin-Walled Laser Welded Components for Aircraft Engines

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Enrico Lertora ◽  
Chiara Mandolfino ◽  
Carla Gambaro
Keyword(s):  
Inconel 718 ◽  
Gas Turbines ◽  
Shape Control ◽  
Postweld Heat Treatment ◽  
Fatigue Behaviour ◽  
High Energy ◽  
Parent Material ◽  
High Energy Density ◽  
Welding Parameters ◽  
Technical Specifications

Nickel alloys are very important in many aerospace applications, especially to manufacture gas turbines and aero engine components, where high strength and temperature resistance are necessary. These kinds of alloys have to be welded with high energy density processes, in order to preserve their high mechanical properties. In this work, CO2laser overlap joints between Inconel 718 sheets of limited thickness in the absence of postweld heat treatment were made. The main application of this kind of joint is the manufacturing of a helicopter engine component. In particular the aim was to obtain a specific cross section geometry, necessary to overcome the mechanical stresses found in these working conditions without failure. Static and dynamic tests were performed to assess the welds and the parent material fatigue life behaviour. Furthermore, the life trend was identified. This research pointed out that a full joint shape control is possible by choosing proper welding parameters and that the laser beam process allows the maintenance of high tensile strength and ductility of Inconel 718 but caused many liquation microcracks in the heat affected zone (HAZ). In spite of these microcracks, the fatigue behaviour of the overlap welds complies with the technical specifications required by the application.

Fast Pyrolysis Oil for Power Generation

2006 ◽  
Author(s):  
David Chiaramonti ◽  
Anja Oasmaa ◽  
Yrjo¨ Solantausta
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbines ◽  
Large Scale ◽  
Fast Pyrolysis ◽  
High Energy ◽  
High Energy Density ◽  
Current Status ◽  
Pyrolysis Oil

Biomass fast-pyrolysis oil (PO) is a liquid biofuel derived from lignocellulosic biomass: it offers several advantages compared to the direct us of solid bio fuels, such as high energy density, storability and transportability typical of liquid fuels, possibility to use the fuel in engines and turbines, easier downscaling of plants (which is a very important aspect for decentralized energy generation schemes). In addition, PO is the lowest cost biofuel, thus offering the possibility to penetrate also the large scale power generation market. Biomass POs have been studied and applications tested for many years, either for heat generation in medium-scale boilers or power generation. The present works reviews and analyses the most relevant experiences carried out so far and published results in power production from biomass PO. Power generation systems (PGS) which are here examined are gas turbines, diesel engines, stirling engines, as well as co-firing applications in large scale power plants (coal or natural gas plants). The main techniques for upgrading this biofuel and their impact on technologies are also shortly introduced and considered. The current status of development for each PO-based power generation option is discussed. This review work showed that long term demonstration (either technical or economical) is however still needed, even for the most developed technologies (use of PO in modified gas turbines and cofiring in natural gas stations): projects are on going to achieve long term demonstration.

scholarly journals Experimental Evaluation and Characterization of Electron Beam Welding of 2219 AL-Alloy

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Mohamed Sobih ◽  
Zuhair Elseddig ◽  
Khalid Almazy ◽  
Mohamed Sallam
Keyword(s):  
Electron Beam ◽  
Aluminum Alloys ◽  
Weld Joint ◽  
Electron Beam Welding ◽  
High Energy ◽  
High Energy Density ◽  
Welding Parameters ◽  
Deep Penetration ◽  
Al Alloy ◽  
Aircraft Industry

Aiming to reduce the weight of components, thus allowing a profit in terms of energy saving, automotive industry as well as aircraft industry extensively uses aluminum alloys. The most widely used joining technology in aircraft industry is riveting, while welding seems to be used in the car industry in the case of aluminum alloys. However, welding technology is characterized by many defects, such as gas porosity; oxide inclusions; solidification cracking (hot tearing); and reduced strength in both the weld and the heat affected zones which could limit its development. Many techniques are used for aluminum alloys welding, among them is electron beam welding (EBW), which has unique advantages over other traditional fusion welding methods due to high-energy density, deep penetration, large depth-to-width ratio, and small heat affected zone. The welding parameters that yield to optimal weld joint have been previously obtained. These optimal parameters were validated by welding a specimen using these parameters. To evaluate this optimal weld joint, complete, microstructural observations and characterization have been carried out using scanning electron microscopy, optical microscopy, and energy dispersive X-ray analysis. This evaluation leads to description and quantification of the solidification process within this weld joint.

Design and Testing of a Micromix Combustor With Recuperative Wall Cooling for a Hydrogen Fuelled μ-Scale Gas Turbine

2010 ◽  
Author(s):  
A. E. Robinson ◽  
H. H.-W. Funke ◽  
P. Hendrick ◽  
R. Wagemakers
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Mass Flow ◽  
Gas Turbines ◽  
High Energy ◽  
High Energy Density ◽  
Energy Output ◽  
Experimental Investigations ◽  
Small Scale ◽  
Micro Scale

For more than a decade up to now there is an ongoing interest in small gas turbines downsized to micro-scale. With their high energy density they offer a great potential as a substitute for today’s unwieldy accumulators, found in a variety of applications like laptops, small tools etc. But micro-scale gas turbines could not only be used for generating electricity, they could also produce thrust for powering small unmanned aerial vehicles (UAVs) or similar devices. Beneath all the great design challenges with the rotating parts of the turbomachinery at this small scale, another crucial item is in fact the combustion chamber needed for a safe and reliable operation. With the so called regular micromix burning principle for hydrogen successfully downscaled in an initial combustion chamber prototype of 10 kW energy output, this paper describes a new design attempt aimed at the integration possibilities in a μ-scale gas turbine. For manufacturing the combustion chamber completely out of stainless steel components, a recuperative wall cooling was introduced to keep the temperatures in an acceptable range. Also a new way of an integrated ignition was developed. The detailed description of the prototype’s design is followed by an in depth report about the test results. The experimental investigations comprise a set of mass flow variations, coupled with a variation of the equivalence ratio for each mass flow at different inlet temperatures and pressures. With the data obtained by an exhaust gas analysis, a full characterisation concerning combustion efficiency and stability of the prototype chamber is possible. Furthermore the data show a full compliance with the expected operating requirements of the designated μ-scale gas turbine.

scholarly journals Effect of Layer-Wise Varying Parameters on the Microstructure and Soundness of Selective Laser Melted INCONEL 718 Alloy

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2165 ◽  
Author(s):  
Xiang Wang ◽  
Jinwu Kang ◽  
Tianjiao Wang ◽  
Pengyue Wu ◽  
Tao Feng ◽  
...  
Keyword(s):  
Energy Density ◽  
Inconel 718 ◽  
Laser Energy ◽  
Scanning Speed ◽  
High Energy ◽  
High Energy Density ◽  
Inconel 718 Alloy ◽  
Melt Pool ◽  
Columnar Grains ◽  
Melt Pool Size

Selective laser melting (SLM) is a promising powder bed fusion additive manufacturing technique for metal part fabrication. In this paper, varying scanning speed in the range of 500 mm/s to 1900 mm/s, and laser power in the range of 100 W to 200 W, were realized from layer to layer in a cycle of 56 layers in a single cuboid Inconel 718 alloy specimen through SLM. Layer-wise variation of microstructure and porosity were acquired, showing the layer-wise controlling capability of microstructural soundness. The melt pool size and soundness are closely linked with the energy input. High energy density led to sound regions with larger, orderly stacked melt pools and columnar grains, while low energy density resulted in porous regions with smaller, mismatched melt pools, un-melted powder, and equiaxed grains with finer dendrites. With the increase of laser energy density, the specimen shifts from porous region to sound region within several layers.

New Insights From Conceptual Design of an Additive Manufactured 300 W Micro Gas Turbine Towards UAV Applications

2020 ◽  
Author(s):  
Lukas Badum ◽  
Boris Leizeronok ◽  
Beni Cukurel
Keyword(s):  
Heat Transfer ◽  
Energy Density ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Energy ◽  
High Energy Density ◽  
Heat Transfer Analysis ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Micro Gas Turbine

Abstract Owing to high energy density of hydrocarbon fuels, ultra-micro gas turbines with power outputs below 1 kW have potential as battery replacement in drones. To overcome the obstacles observed in previous works on gas turbines of this scale, novel gas turbine architecture is proposed based on conventional roller bearing technology that operates at up to 500,000 RPM and additively manufactured monolithic rotor in cantilevered configuration, equipped with internal cooling blades. The optimum turbomachinery design is elaborated using diabatic cycle calculation, coupled with turbomachinery meanline design. This approach provides new insights on interdependencies of heat transfer, component efficiency and system electric efficiency. Thereby, reduced design pressure ratio of 2.5 with 1200 K turbine inlet temperature is identified as most suitable for 300 W electric power output. In following, material properties and design constraints for the monolithic rotor are obtained from available additive manufacturing technologies. Rotordynamic simulations are then conducted for four available materials using simplified rotor model. CFD simulations are conducted to quantify compressor efficiency and conjugate heat transfer analysis is performed to assess the benefit of internal cooling cavity and vanes for different rotor materials. It is demonstrated that the cavity flow absorbs large heat flux from turbine to compressor, thus cooling the rotor structure and improving the diabatic cycle efficiency. Finally, results of this conceptual study show that ultra-micro gas turbine with electric efficiency of up to 5% is feasible, while energy density is increased by factor of 3.6, compared to lithium-ion batteries.

Numerical and Experimental Investigation of a Micromix Combustor for a Hydrogen Fuelled µ-Scale Gas Turbine

2009 ◽  
Author(s):  
A. E. Robinson ◽  
H. H.-W. Funke ◽  
R. Wagemakers ◽  
J. Grossen ◽  
W. Bosschaerts ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Mass Flow ◽  
Gas Turbines ◽  
Ambient Pressure ◽  
High Energy ◽  
High Energy Density ◽  
Design Parameters ◽  
Small Scale ◽  
Symmetric Model ◽  
Cfd Model

This last decade has shown an increased interest in the downsizing of gas turbines to micro-scale. Their potential for high energy density makes them extremely attractive for small scale high power units as alternative to traditional unwieldy accumulators or as thrust systems in small robots and unmanned aerial vehicles (UAVs). Beneath great challenges with the rotating parts at this small scale, another crucial item is in fact the combustion chamber needed for a safe and reliable operation. This paper presents a study to an alternative approach in μ-scale hydrogen combustion. The burning principle is based upon the so-called inverse micromix injection. In this non-premixed design, hydrogen fuel is introduced through a porous metal and injected in the axial direction into the combustion chamber. A CFD-model has been implemented to parameterise the different geometrical aspects of the combustion chamber and is set up as a 2D axis-symmetric model to allow for a rapid optimisation of the parameters. The flow calculations are done with a commercial CFD-software. The final optimised geometry showed stable combustion, a well suited temperature profile and acceptable wall temperatures. An overview on the influence of the critical design parameters for the different geometries is presented. Experimental investigations comprise a set of mass flow variations coupled with a variation of the equivalence ratio for each mass flow but always at ambient pressure conditions. With the data obtained by an exhaust gas analysis, a full characterisation concerning combustion efficiency and stability of the burning principle is possible. Combined with the wall temperature measurements, these results lead to a further validation of the CFD model.

Study of Metallurgical and Mechanical Behavior of Laser Butt-Welded Dissimilar Joint of Inconel and Stainless Steel

2019 ◽  
Author(s):  
Sanjib Jaypuria ◽  
Santosh Kumar Gupta ◽  
Sulthan Suresh-Fazeela ◽  
Dilip Kumar Pratihar ◽  
Debalay Chakrabarti ◽  
...  
Keyword(s):  
Laser Welding ◽  
Welding Speed ◽  
Inconel 718 ◽  
Electron Beam Welding ◽  
High Energy ◽  
High Energy Density ◽  
Laser Source ◽  
Laves Phases ◽  
Xrd Phase Analysis ◽  
Welding Processes

Abstract High energy density welding processes like laser and electron beam welding are capable of welding dissimilar plates with much ease due to high power density and low heat input in spite of the varying thermos-physical properties of the used alloys. The present work is aimed to check the feasibility of joint prepared with laser welding of SS 316L and Inconel 718 plates. The experiments are designed to study the effect of welding speed on the mechanical and metallurgical behavior of the joints without any offset to joint line. The formation of laves phases is confirmed by energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) phase analysis. These laves phase are micro-segregation of Nb, Fe, C and Cr, which is because of high temperature in a small area of fusion zone (FZ) due to intense heat of laser source. Micro-segregation of different elements has led to micro-fissures, which is detrimental for the joints operating at elevated temperature. Cooling rate and peak temperature during welding play the significant role in obtaining a sound quality joint. The present work gives an insight on feasibility of laser welded joint of SS 316L and Inconel 718 with suitable selection of welding speed during laser welding.

Microstructure Study on Fe/Cr Based Alloys Added with Yttrium Oxide (Y2O3) Prepared via Ultrasonic Technique for Solid Oxide Fuel Cell (SOFC) Application

2014 ◽  
Vol 493 ◽  
pp. 651-655 ◽  
Author(s):  
Dafit Feriyanto ◽  
Maizlinda Izwana Idris ◽  
Darwin Sebayang ◽  
Ashraf Bin Otman ◽  
Pudji Untoro
Keyword(s):  
Yttrium Oxide ◽  
Ultrasonic Treatment ◽  
High Efficiency ◽  
High Energy ◽  
Parent Material ◽  
Solid Oxide ◽  
High Energy Density ◽  
Second Phase ◽  
Oxide Fuel ◽  
Higher Temperature

Solid oxide fuel cells (SOFC) are the current research having several potential to obtain high efficiency, high energy–density power generation which operated at relatively higher temperature. Yttrium oxide (Y2O3)contributions at high temperature are accelerating to the development oxide layer of FeCr alloy. The aim of this research is to investigate the microstructure of Fe/Cr added with Y2O3acting as a reactive element. The purpose is to improve macrostructure of Fe/Cr powders which can be applied at steel industry. In this study the mixing process of Fe/Cr and Y2O3powder was conducted via ultrasonic treatment at a frequency of 22 kHz, and at two different holding time of 2.5 h and 3.5 h. The particle size of chromium (Cr) can be reduced by ultrasonic treatment at from 60µm to 30µm through threshing the cluster of Cr particle. It shows that the ultrasonic vibration effectively removes oxides and other contaminates on a surface coating. Therefore, homogeneity of the parent material, segregation, and uniform distribution of second phase were increased.

New Insights From Conceptual Design of an Additive Manufactured 300 W Micro Gas Turbine Towards UAV Applications

2020 ◽  
Author(s):  
L. Badum ◽  
B. Leizeronok ◽  
B. Cukurel
Keyword(s):  
Heat Transfer ◽  
Energy Density ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Energy ◽  
High Energy Density ◽  
Heat Transfer Analysis ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Micro Gas Turbine

Abstract Owing to the high energy density of hydrocarbon fuels, ultra-micro gas turbines with power outputs below 1 kW have clear potential as battery replacement in drones. However, previous works on gas turbines of this scale revealed severe challenges due to air bearing failures, heat transfer from turbine to compressor, rotordynamic instability and manufacturing limitations. To overcome these obstacles, a novel gas turbine architecture is proposed based on conventional roller bearing technology that operates at up to 500,000 RPM and an additively manufactured monolithic rotor in cantilevered configuration, equipped with internal cooling blades. The optimum turbomachinery design is elaborated using diabatic cycle calculation, coupled with turbomachinery meanline design code. This approach provides new insights on the interdependencies of heat transfer, component efficiency and system electric efficiency. Thereby, a reduced design pressure ratio of 2.5 with 1200 K turbine inlet temperature is identified as most suitable for 300 W electric power output. In following, a review of available additive manufacturing technologies yields material properties, surface roughness and design constraints for the monolithic rotor. Rotordynamic simulations are then conducted for four available materials using a simplified rotor model to identify valid permanent magnet dimensions that would avoid operation close to bending modes. To complete the baseline engine architecture, a novel radial inflow combustor concept is proposed based on porous inert media combustion. CFD simulations are conducted to quantify compressor efficiency and conjugate heat transfer analysis of the monolithic rotor is performed to assess the benefit of the internal cooling cavity and vanes for different rotor materials. It is demonstrated that the cavity flow absorbs large amount of heat flux from turbine to compressor, thus cooling the rotor structure and improving the diabatic cycle efficiency. Finally, the results of this conceptual study show that ultra-micro gas turbine with electric efficiency of up to 5% is feasible, while energy density is increased by factor of 3.6, compared to lithium-ion batteries.

Design and Testing of a Micromix Combustor With Recuperative Wall Cooling for a Hydrogen Fueled μ-Scale Gas Turbine

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
A. E. Robinson ◽  
H. H.-W. Funke ◽  
P. Hendrick ◽  
R. Wagemakers
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Mass Flow ◽  
Gas Turbines ◽  
High Energy ◽  
Gas Analysis ◽  
High Energy Density ◽  
Energy Output ◽  
Experimental Investigations ◽  
Small Scale

For more than 1 decade up to now, there is an ongoing interest in small gas turbines downsized to microscale. With their high energy density, they offer a great potential as a substitute for today’s unwieldy accumulators found in a variety of applications such as laptops, small tools, etc. But microscale gas turbines could not only be used for generating electricity, they could also produce thrust for powering small unmanned aerial vehicles or similar devices. Beneath all the great design challenges with the rotating parts of the turbomachinery at this small scale, another crucial item is in fact the combustion chamber needed for a safe and reliable operation. With the so-called regular micromix burning principle for hydrogen successfully downscaled in an initial combustion chamber prototype of 10 kW energy output, this paper describes a new design attempt aimed at the integration possibilities in a μ-scale gas turbine. For manufacturing the combustion chamber completely out of stainless steel components, a recuperative wall cooling was introduced to keep the temperatures in an acceptable range. Also a new way of an integrated ignition was developed. The detailed description of the prototype’s design is followed by an in depth report about the test results. The experimental investigations comprise a set of mass flow variations, coupled with a variation of the equivalence ratio for each mass flow at different inlet temperatures and pressures. With the data obtained by an exhaust gas analysis, a full characterization concerning combustion efficiency and stability of the prototype chamber is possible. Furthermore, the data show full compliance with the expected operating requirements of the designated μ-scale gas turbine.

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