Gas Turbine Engines For Propulsion Research Articles

Phase equilibria, thermodynamic assessment, and the mechanical property of B2 phase of the Al-Ga-Ni ternary system

Ni-based alloys, known for their exceptional mechanical properties and high corrosion resistance in harsh environments, are extensively utilized in gas-turbine engines for propulsion and energy generation. Of particular interests are the L12-Ni3Al and B2-NiAl phases in Al-Ni alloy, which can be the strengthening phases for superalloy and high temperature structural materials, respectively. After Ga addition in the Al-Ni system, these promising intermetallic compounds form a continuous compositional range encompassing the L12-Ni3(Al, Ga) and B2-Ni(Al, Ga) phases. They exhibited distinct mechanical properties contingent on the ratio of Al to Ga. Additionally, Ni and Al are the commonly used substrates in the electronic package and Ga has been used as a filler material for interconnection. Hence, the Al-Ga-Ni phase equilibria are of practical importance for designing L12-Ni3(Al, Ga) and/or B2-Ni(Al, Ga) phase-dispersed Ni-based alloys as well as for evaluating interfacial reactions in the Al/Ga/Ni contacts. However, the Al-Ga-Ni ternary system remains relatively unexplored. In this study, Al-Ga-Ni isothermal sections at 600 (Ni-lean), 900, and 1000 (Ni-rich) °C were experimentally constructed based on equilibrated alloys. Additionally, a CALPHAD-type thermodynamic assessment for the Al-Ga-Ni ternary system was comprehensively performed based on all available experimental information. Furthermore, the Young's modulus and hardness of four B2-Al(Ga, Ni) compounds were determined, revealing that the addition of Ga to B2-NiAl phase would lead to a significant decrease in Young's modulus but a notable enhancement in hardness.

Correction: Gurrola Arrieta, M.d.J.; Botez, R.M. Improved Local Scale Generic Cycle Model for Aerothermodynamic Simulations of Gas Turbine Engines for Propulsion. Designs 2022, 6, 91

In the published paper [...]

Full Stage Axial Compressor Performance Modeling Incorporating the Effects of Blade Damage Due to Particle Ingestion

Abstract The damage due to particulate matter ingestion by propulsion gas turbine engines can be significant, impacting the operability and performance of plant components. Here, we focus on the axial compressor whose blades become damaged when operated in dusty/sandy environments, resulting in significant performance degradation. In this work, CFD studies are performed to model the effects of airfoil damage on the first-stage rotor blading of a GE T700–401C compressor. We use thermoplastic additive manufacturing to construct representative physical models of three damage morphologies—ballistically bent/curved leading edges, cragged erosion of leading edges, and eroded leading/tailing edges at outer span locations. The resultant damaged plastic geometries, and a baseline undamaged configuration are then optically scanned and incorporated into sublayer resolved full stage, unsteady RANS analyses. Boundary conditions are imposed that conform to damaged compressor operation protocols, and this iterative process for accommodating corrected mass flow and off-design powering is presented. The results for the three damaged and one undamaged configuration are studied in terms of compressible wave field and secondary/tip flows, spanwise performance parameter distributions and efficiency. A method to estimate the effect of rotor damage on engine SFC is presented. The code, modeling, and meshing strategies pursued here are consistent with a validation study carried out for NASA Rotor 37 — these results are briefly included, and provide confidence in the predictions of the T700 geometry studied. The results provide quantitative comparisons of, and insight into, the physical mechanisms associated with damaged compressor performance degradation.

Improved Local Scale Generic Cycle Model for Aerothermodynamic Simulations of Gas Turbine Engines for Propulsion

A local scale Aerothermodynamic Generic Cycle Model (AGCM) is proposed. The AGCM accounts for several improvements not considered in similar models, such as compressor bleed extraction for aircraft Environmental Control System (ECS), parasitic shaft power extraction, and the enthalpy of the fuel entering the combustor. The AGCM is intended for steady-state Design Point (DP) and Off-Design (OD) performance analyses. The underlying physics is presented for the DP model. The turbomachinery component maps scaling and the system of nonlinear equations necessary to define the OD model are thoroughly discussed. The AGCM is compared with an equivalent model developed in the Numerical Propulsion System Simulation (NPSS). The comparisons were performed considering a DP envisioned to approximate a General Electric CF34-8C5B1 engine. The average errors found in these comparisons for the Specific Fuel Consumption (SFC) and net thrust were −0.111% and 0.193%, respectively. Finally, the predictions of the absolute levels of performance intended for the -8C5B1 engine are compared with empirical correlations derived from a comprehensive turbofan engine database. It was found that the predictions of the AGCM are in agreement with the empirical correlations; the errors found in SFC and net thrust at cruise flight condition were −0.43% and 2.06%, respectively.

Propulsion system integration for a first-generation hydrogen civil airliner?

ABSTRACTAn unusual philosophical approach is proposed here to decarbonise larger civil aircraft that fly long ranges and consume a large fraction of civil aviation fuel. These inject an important amount of carbon emissions into the atmosphere, and holistic decarbonising solutions must consider this sector. A philosophical–analytical investigation is reported here on the feasibility of an airliner family to fly over long ranges and assist in the elimination of carbon dioxide emissions from civil aviation.Backed by state-of-the-art correlations and engine performance integration analytical tools, a family of large airliners is proposed based on the development and integration of the body of a very large two-deck four-engine airliner with the engines, wings and flight control surfaces of a very long-range twin widebody jet. The proposal is for a derivative design and not a retrofit. This derivative design may enable a swifter entry to service.The main contribution of this study is a philosophical one: a carefully evaluated aircraft family that appears to have very good potential for first-generation hydrogen-fuelled airliners using gas turbine engines for propulsion. This family offers three variants: a 380-passenger aircraft with a range of 3,300nm, a 330-passenger aircraft with a range of 4,800nm and a 230-passenger aircraft with a range of 5,500nm. The latter range is crucially important because it permits travel from anywhere in the globe to anywhere else with only one stop. The jet engine of choice is a 450kN high-bypass turbofan.

Thermodynamic Analysis of a Turboprop Engine with Intercooling and Heat Recovery

In many modern gas turbine engine ground-based power plants, used for power generation, several auxiliary systems are integrated with the main gas generator to improve the generated output power or reduce fuel consumption. Two of the most effective practices are regeneration and intercooling. The first recovers part of the enthalpy in exhaust gas to pre-heat air before introducing it into the combustion chamber. The second cools the air during compression to reduce the work, and consequently obtain more power at the output shaft. These techniques are not used in gas turbine engines for propulsion mainly due to the extra weight and size caused by the heat exchangers and more complex flow patterns that result. However, if we could overcome these difficulties by means of compact heat exchangers the same benefits obtained for the ground-based plants could be obtained for aero engines. In particular the turboprop engine seems to be the best suited to this purpose due to its smaller mass flow rate and gas path. A thermodynamic cycle analysis shows the advantages of introduction of regeneration and intercooling in a turboprop engine in terms of increased power and reduced fuel consumption.

Propulsion powered electric guns-a comparison of power system architectures

Alternative power system architectures and interface technologies for driving high-energy pulsed loads from the propulsion equipment of naval surface combatants are compared. Gas turbine mechanical and gas turbine integrated electric drive propulsion trains are considered as prime power sources. Focus is on the energy path between the ship's prime power and the pulsed load, comparing system candidates on a size, weight, and component cost basis. A capacitor-based pulse forming network (PFN) supplying an electrothermal chemical gun is utilized as the common load for all configurations. Results indicate that dedicated auxiliary generators driven from propulsion gas turbine engines are the preferred method of powering electric gun PFNs from ship drive-train equipment. Auxiliary generator-based systems are compact and lightweight over a wide power range, are equally attractive with both electric and mechanical drive trains, and demonstrate retrofit potential to the current fleet. >

Propulsion Powered Electric Guns: A Comparison of Power System Architectures

ABSTRACTAlternative power system architectures and interface technologies for driving high energy pulsed loads from the propulsion equipment of surface combatants are compared. Gas turbine mechanical and gas turbine Integrated Electric Drive (IED) propulsion trains are considered as prime power sources. Focus is on the energy path between the ship's prime power and the pulsed load, comparing system candidates on a size, weight and component cost basis. A capacitor based Pulse Forming Network (PFN) supplying an Electro‐Thermal (ET) Gun is utilized as the common load for all configurations. Results indicate that dedicated auxiliary generators driven from propulsion gas turbine engines is the preferred method of powering electric gun PFNs from ship drivetrain equipment. Auxiliary generator‐based systems are compact and lightweight over a wide power range, are equally attractive with both electric and mechanical drive trains and demonstrate retrofit potential to the current fleet.

Gas Turbine Engines in the Royal Canadian Navy Prototype Hydrofoil Vessel

The prototype hydrofoil vessel currently being designed and built for the Royal Canadian Navy employs gas turbine engines for propulsion and ancillary power. This paper describes the general arrangement and use of these engines in the hydrofoil ship and includes as background a brief description of the vessel.