Design and Optimization of a Low-Pressure Turbine for a Turbofan Jet Engine
(2026) In LUP MVKM05 20261Department of Energy Sciences
- Abstract
- This thesis presents the aerodynamic design and optimization of a three-stage low-pressure axial turbine for the RM400 turbofan engine, developed as part of the VILD project in collaboration between GKN Aerospace, Chalmers, KTH, and Lund University. The primary objective was to redesign the turbine, previously implemented with a cooled first-stage blade, into an uncooled-blade configuration capable of operating safely within the allowable temperature range, while reducing overall weight, size, and blade loading coefficient (ψ). The design process followed a structured methodology using the Concepts NREC software suite, beginning with a one-dimensional mean-line analysis and preliminary sizing in AXIAL, followed by geometry refinement,... (More)
- This thesis presents the aerodynamic design and optimization of a three-stage low-pressure axial turbine for the RM400 turbofan engine, developed as part of the VILD project in collaboration between GKN Aerospace, Chalmers, KTH, and Lund University. The primary objective was to redesign the turbine, previously implemented with a cooled first-stage blade, into an uncooled-blade configuration capable of operating safely within the allowable temperature range, while reducing overall weight, size, and blade loading coefficient (ψ). The design process followed a structured methodology using the Concepts NREC software suite, beginning with a one-dimensional mean-line analysis and preliminary sizing in AXIAL, followed by geometry refinement, loss-model selection, and blade-row optimization in redesign mode. The resulting configuration was subsequently transferred to AxCent for detailed airfoil section design, curvature-distribution refinement, and two- and three-dimensional performance evaluation using the Blade-to-Blade and Through-flow solvers. The final uncooled-blade design achieved a first-stage blade loading coefficient of 2.04, closely matching the target value of 2, and a total-to-total efficiency exceeding 90% across all three stages, comparable to the previous cooled-blade model. Compared to the earlier design, the new turbine exhibits a substantial reduction in total blade weight (approximately 76 kg versus 82 kg) and maximum blade stress (300 MPa versus 420 MPa), while the first-stage blade temperatures, though elevated due to the absence of cooling, remain within the safe operating limit of conventional blade materials. These results demonstrate that a compact, lighter, and mechanically less-stressed low-pressure turbine can be achieved without a cooling system while maintaining performance comparable to the cooled-blade baseline. (Less)
- Popular Abstract
- What enables an aircraft or a ship to generate the power needed for propulsion? Turbines are a key part of the answer. These machines transform thermal energy into mechanical power and are widely used in aircraft propulsion, marine applications, power generation, and various industrial systems. Although renewable technologies such as wind and solar power are becoming increasingly widespread, gas and steam turbines continue to play an important role in providing reliable and continuous energy. At the same time, climate change concerns and the growing cost of fuels have increased the need for more efficient and environmentally responsible turbine technologies. Modern turbines are highly complex systems, where even small modifications to... (More)
- What enables an aircraft or a ship to generate the power needed for propulsion? Turbines are a key part of the answer. These machines transform thermal energy into mechanical power and are widely used in aircraft propulsion, marine applications, power generation, and various industrial systems. Although renewable technologies such as wind and solar power are becoming increasingly widespread, gas and steam turbines continue to play an important role in providing reliable and continuous energy. At the same time, climate change concerns and the growing cost of fuels have increased the need for more efficient and environmentally responsible turbine technologies. Modern turbines are highly complex systems, where even small modifications to their design can lead to considerable improvement in performance. A key challenge in turbine design is optimizing shape and performance parameters. This thesis investigates advanced turbine design approaches and numerical simulation methods with the aim of improving turbine performance while reducing energy losses.
The Department of Energy Sciences at Lund University, in collaboration with GKN Aerospace, is working on the design of a gas turbine for a turbofan engine that is planned to enter service by 2035. One of the models studied at Lund University in 2025 was a three-stage turbine equipped with a blade cooling system. In general, gas turbines in jet engines operate at high temperatures and require blade cooling systems, particularly in the first stage. The main objective of this study was to develop a turbine model that could operate without a blade cooling system. One of the main challenges was to keep the turbine temperature low while maintaining performance parameters within an acceptable range so the turbine could meet the engine's requirements. To address this challenge, we employ a progressive design methodology. The process starts with simplified one-dimensional (1D) models, which are used to determine fundamental parameters such as mass flow rate, energy output, and the initial characteristics of each turbine stage. The preliminary design is then developed into a two-dimensional (2D) configuration, followed by detailed three-dimensional (3D) simulations to evaluate the turbine under realistic operating conditions.
The results of this study have practical significance beyond theoretical analysis, as the optimized turbine designs are developed with potential for direct implementation in industrial applications. For example, the optimized model developed in this study has a lower overall weight, which provides significant advantages, particularly in terms of manufacturing and the final cost of the turbine. Additionally, despite the reduction in turbine size and the removal of the blade cooling system, the model developed in this thesis is capable of delivering a power output comparable to that of the previous model. Moreover, although the current model operates at a higher temperature due to the removal of the blade cooling system, it has been designed to keep the resulting temperature within a safe range for gas turbine operation, which is an important result of the thesis.
Overall, this thesis presents a structured methodology for turbine design and optimization by integrating fundamental engineering concepts with numerical modeling and advanced computational methods. The results contribute to the development of a smaller and more compact turbine that delivers nearly the same power output as the cooled-blade model, while maintaining an efficiency above 90% in all three stages. It is important to mention that all results presented in this study are purely academic work and not a product of GKN Aerospace. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/student-papers/record/9251541
- author
- Geramian, Seyednavid LU
- supervisor
- organization
- course
- MVKM05 20261
- year
- 2026
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Axial Turbine Design. Meanline Analysis. Through-flow Analysis. Blade-to-Blade Analysis. AXIAL. AxCent
- publication/series
- LUP
- report number
- ISRN LUTMDN/TMHP-26/5712-SE
- ISSN
- 0282-1990
- language
- English
- id
- 9251541
- date added to LUP
- 2026-09-25 10:10:03
- date last changed
- 2026-09-25 10:10:03
@misc{9251541,
abstract = {{This thesis presents the aerodynamic design and optimization of a three-stage low-pressure axial turbine for the RM400 turbofan engine, developed as part of the VILD project in collaboration between GKN Aerospace, Chalmers, KTH, and Lund University. The primary objective was to redesign the turbine, previously implemented with a cooled first-stage blade, into an uncooled-blade configuration capable of operating safely within the allowable temperature range, while reducing overall weight, size, and blade loading coefficient (ψ). The design process followed a structured methodology using the Concepts NREC software suite, beginning with a one-dimensional mean-line analysis and preliminary sizing in AXIAL, followed by geometry refinement, loss-model selection, and blade-row optimization in redesign mode. The resulting configuration was subsequently transferred to AxCent for detailed airfoil section design, curvature-distribution refinement, and two- and three-dimensional performance evaluation using the Blade-to-Blade and Through-flow solvers. The final uncooled-blade design achieved a first-stage blade loading coefficient of 2.04, closely matching the target value of 2, and a total-to-total efficiency exceeding 90% across all three stages, comparable to the previous cooled-blade model. Compared to the earlier design, the new turbine exhibits a substantial reduction in total blade weight (approximately 76 kg versus 82 kg) and maximum blade stress (300 MPa versus 420 MPa), while the first-stage blade temperatures, though elevated due to the absence of cooling, remain within the safe operating limit of conventional blade materials. These results demonstrate that a compact, lighter, and mechanically less-stressed low-pressure turbine can be achieved without a cooling system while maintaining performance comparable to the cooled-blade baseline.}},
author = {{Geramian, Seyednavid}},
issn = {{0282-1990}},
language = {{eng}},
note = {{Student Paper}},
series = {{LUP}},
title = {{Design and Optimization of a Low-Pressure Turbine for a Turbofan Jet Engine}},
year = {{2026}},
}