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Projecte llegit

Títol: Optimisation of grid fins as control surfaces for booster re-entry system

Estudiants que han llegit aquest projecte:

Director/a: ALTMEYER, SEBASTIÁN ANDREAS

Departament: FIS

Títol: Optimisation of grid fins as control surfaces for booster re-entry system

Data inici oferta: 14-12-2025     Data finalització oferta: 14-07-2026


Estudis d'assignació del projecte:
    GR ENG SIS TELECOMUN
    GR ENG SIST AEROESP
    GR ENG TELEMÀTICA
Tipus: Individual
 
Lloc de realització: EETAC
 
Paraules clau:
Grid fins, Computational Fluid Dynamics (CFD), Web cross-sectional profile, Diamond profile, Local sweep, Reusable launch vehicles
 
Descripció del contingut i pla d'activitats:
The research of advanced and innovative technologies is one of the main concerns within the aerospace industry. Spacecraft re-usability is one of them, being an important aspect to diminish the huge costs and resources that a space mission implicate, minimizing also the environmental impact.

This project deals with the design and computational fluid dynamics (CFD) analysis of the aerodynamic efficiency of Grid Fins as control surfaces for rocket reentry.
The expected methodology is to first establish the theoretical background (subsonic and supersonic control surfaces). Then, design a prototype using SolidWorks to finally perform flow simulations and analysis using Ansys to validate its efficiency and obtain proper conclusions.

A parametric of key key parameters will performed in order to control the velocity with the different forces and the pitch angle with the moments. Computational fluid dynamics (CFD) simulations will be carried out in ANSYS Fluent in order to obtain the aerodynamic parameters and evaluate efficiency.
 
Overview (resum en anglès):
Grid fins are unconventional control surfaces implemented in aerospace applications, such as launch vehicle guidance and recovery, due to their exceptional stall resistance and reduced hinge moments. In contrast, their principal drawback is a severe wave drag generated in the transonic regime due to their complex grid-like geometry.

This thesis addresses the aerodynamic performance of locally swept grid fins in supersonic flow regime at Mach 2.5, aiming to optimise their current geometric design. To do so, the primary objective is to compare a configuration with a standard hexagonal web profile, against a diamond profile, theoretically identified as superior for supersonic flow, evaluating its impact on drag reduction and overall aerodynamic efficiency. The main innovation introduced by the second configuration is a variable leading edge wedge half-angle along the span of the cell, caused by the interaction of the diamond profile with local sweep.

The study employs Computational Fluid Dynamics (CFD) as the methodology to simulate the highly compressible flow around the geometries. The numerical simulations are conducted using ANSYS Fluent in steady-state mode, at 20 km altitude, across angles of attack ranging from 0º to 20º. The SST k-omega turbulence model is applied to resolve the complex shock wave structures, expansion fans, and wake interactions.

The results obtained from the CFD analysis reveal substantial differences in the aerodynamic behaviour of the two configurations. The implementation of the diamond profile combined with local sweep successfully stabilises the shock wave topology, as it generates weaker oblique shocks near the corners of the grid, reducing pressure accumulation and delaying the onset of internal flow choking. Consequently, this geometric modification results in a significant reduction in the total aerodynamic drag coefficient, while maintaining the operational benefits of the grid fin.

These findings establish the combination of local sweep with a diamond web profile as a viable aerodynamic alternative to the hexagonal standard, providing a significant improvement for the guidance and recovery of launch vehicles.

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