Dipasquale, Daniele

Preferred name

Dipasquale, Daniele

Alternative Name

Dipasquale, D.

Main Affiliation

International Academy of Aviation Industry

daniele.di@kmitl.ac.th

Now showing 1 - 6 of 6

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Topology Optimization of an aircraft engine gearbox
(2021-08-12)
Wattananaphakaseam, Nuz
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Sittisang, Natthasit
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Phengsalae, Napat
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Dipasquale, Daniele
Topology Optimization (TO) is a mathematical method extensively employed to optimize material layout within the design space, for a given set of boundary conditions with the goal of maximizing the performance of the system. This process takes a three-dimensional design space and whittles material away within it to achieve the most efficient design. Currently, engineers use this mathematical approach at a concept level of a design process, leading to results which are often fine-tuned for manufacturability. In some cases, the optimized geometry can be directly manufactured using additive manufacturing, indeed, TO is a key part of design for additive manufacturing. This work aims to apply TO in order to minimize the mass of an engine gearbox while maintaining an acceptable mechanical performance when compared to the original design. Numerical simulations are carried out by means of CAD and FEM software in order to improve the design of an aircraft gearbox composed of four gears, therefore, irrelevant parts of material are removed in the design space to meet the goal of minimizing the mass of the gearbox. The application of TO allows to obtain a better, lighter, and more efficient design of the gearbox by keeping its mechanical performance unchanged.
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EFFECTS OF VANE TRAILING EDGE DETERIORATION ON FLOW PHENOMENA: A CFD SIMULATION OF BROKEN SCENARIOS
(2023-01-01)
Thammachote, Benyapa
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Premyothin, Jitlada
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Tanpradit, Ditthaphat
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Wongsatanawarid, Atikorn
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Dipasquale, Daniele
To achieve high thermal and propulsive efficiencies from an aircraft powerplant using an air-breathing system, the turbine inlet temperature (TIT), a critical design-limit variable, must rise. However, the increment of the TIT is limited by the survivability of the turbine material. Beyond the safety zone of the material, the operation can end in failure. For this reason, the turbine nozzle guide vane (NGV) is a critical component of gas turbine engines because it must operate in hot gas environments. Due to the constraints of effective cooling and the thinnest possible shape of the trailing edge (TE), this region can be suddenly or gradually deteriorated by cracks when the turbine is in long-term operation. This situation can have a seriously negative effect on the engine's performance because the flow field and heat phenomena are different from the usual conditions. Therefore, the problem of vane TE damage is very challenging, and sustainable solutions require a thorough understanding of flow physics and heat transfer mechanisms. A three-dimensional CFD simulation with the SST k-ω turbulence model is used in this work to investigate flow phenomena at the vane trailing edge while subjected to damage effects. The profile of the Mark II vane is used to create vane boundaries in the computational domain. The computational mesh is generated by ICEM and 18 layers are added to the vane surface to capture the flow in the boundary layer. The minimum quality of the mesh is 0.2 and y+ is less than 4.5. The FLUENT software is used as the solver, with second order upwind discretization. Under the compressible flow model, air is used as the burned gas. Broken scenarios in both the streamwise and spanwise directions are presented in a very simplistic manner, with a short, shallow cutback expanding into a long, deep one, namely, 0.1 cm x 1 cm to 0.3 cm x 3 cm. The convergence of the numerical results is considered by the residual of the governing equations. Boundary conditions are set to be the same as experimental data reported by NASA so that numerical results in terms of the pressure distribution along the vane midspan can be validated. The results predicted by the SST k-w turbulence model can provide an acceptable agreement with the experiment. For subsequent simulations, numerical results involving turbulent flow, such as turbulent viscosity, turbulent kinetic energy, vorticity, and streamlines, are compared, and discussed. The findings show that vane TE damage has a significant impact on fluid in motion, particularly the phenomenon of turbulent viscosity. This suggests that heat convection is disrupted.
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Investigation of cooling performances of a non-film-cooled turbine vane coated with a thermal barrier coating using conjugate heat transfer
(2018-04-01)
Prapamonthon, Prasert
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Yooyen, Soemsak
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Sleesongsom, Suwin
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Dipasquale, Daniele
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Xu, Huazhao
The aim of this paper is to numerically investigate cooling performances of a non-film-cooled turbine vane coated with a thermal barrier coating (TBC) at two turbulence intensities (Tu = 8.3% and 16.6%). Computational fluid dynamics (CFD) with conjugate heat transfer (CHT) analysis is used to predict the surface heat transfer coefficient, overall and TBC effectiveness, as well as internal and average temperatures under a condition of a NASA report provided by Hylton et al. [NASA CR-168015]. The following interesting phenomena are observed: (1) At each Tu, the TBC slightly dampens the heat transfer coefficient in general, and results in the quantitative increment of overall cooling effectiveness about 16-20%, but about 8% at the trailing edge (TE). (2) The protective ability of the TBC increases with Tu in many regions, that is, the leading edge (LE) and its neighborhoods on the suction side (SS), as well as the region from the LE to the front of the TE on the pressure side (PS), because the TBC causes the lower enhancement of the heat transfer coefficient in general at the higher Tu. (3) Considering the internal and average temperatures of the vane coated with two different TBCs, although the vane with the lower thermal conductivity protects more effectively, its role in the TE region reduces more significantly. (4) For both TBCs, the increment of Tu has a relatively small effect on the reduction of the average temperature of the vane.
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Optical performance evaluation of the high spatial resolution imaging camera of BepiColombo space mission
(2021-09-01)
Dipasquale, Daniele
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Debei, Stefano
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Cremonese, Gabriele
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Capaccioni, Fabrizio
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Palumbo, Pasquale
Thermo-elastic analyses of the High spatial Resolution Imaging Camera (HRIC), which is mounted on Mercury Planetary Orbiter BepiColombo Integrated Observatory SYStem suit (SIMBIO-SYS) of BepiColombo space mission, are carried out in order to evaluate the effect of thermo-elastic deformations on the optical performance experienced by the camera at the worst thermal scenario of Mercury space environment. In particular, the optical performance is evaluated in terms of the pointing error of the camera and the potential presence of optical aberrations.
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Numerical Study on Flow Physics of Damaged Vane Trailing Edge
(2024-01-01)
Thammachote, B.
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Premyothin, J.
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Khumhaeng, S.
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Tanpradit, D.
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Dipasquale, D.
According to practical applications in gas turbines, the turbine's nozzle guide vane (NGV) is the first downstream component of the combustor that experiences high thermal loads from burned gases. This situation can severely damage the vane material, particularly the trailing edge (TE). This is because of the limitation of TE thickness and the difficulty of effective cooling in that region. Moreover, the deterioration of the TE surface leads to vane fatalities and has a negative impact on turbine performance because the flow field is unfavorably changed during the operation. This paper aims to numerically study the flow physics of a damaged vane TE using a 3D steady-flow CFD simulation with the SST k-turbulence model. Under the assumptions of ideal gas and compressible flow, air is used as the burned gas. To simplify the vane damage shape, the broken pattern at the TE is given in a long cutback geometry in the simulation. Numerical results in terms of turbulent kinetic energy (TKE), vorticity magnitude, turbulent viscosity, and streamlines are compared and discussed. The interesting findings show that with the inclusion of the damaged TE, the TKE and turbulent viscosity in the broken region increase dramatically on both the midspan and vertical planes. Furthermore, an increment in the vortex size is observed on the midspan plane. However, the vortex centers along the broken region disappear and are replaced by smooth streamlines.
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A Stress Tensor-based Failure Criterion for Ordinary State-based Peridynamic Models
(2022-01-01)
Dipasquale, Daniele
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Sarego, Giulia
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Prapamonthon, Prasert
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Yooyen, Soemsak
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Shojaei, Arman
Peridynamics is a recent nonlocal theory of continuum mechanics that is suitable to describe fracture problems in solid mechanics. In this paper, a new failure criterion based on the stress field is developed by adopting the damage correspondence model in the ordinary state-based peridynamic theory. The proposed stress tensor-based failure criterion is capable of predicting more accurately crack propagation in the mixed mode I-II fracture problems different from other failure criteria in peridynamics. The effectiveness of the proposed model is demonstrated by performing several examples of mixed-mode dynamic fracture in brittle materials.

Dipasquale, Daniele

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