Conjugate heat transfer of impingement cooling using conical nozzles with different schemes in a film-cooled blade leading-edge

Fawzy, Hamza; Zheng, Qun; Jiang, Yuting; Lin, Aqiang; Ahmad, Naseem

doi:10.1016/j.applthermaleng.2020.115491

Cited by 27 publications

(7 citation statements)

References 34 publications

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“…For the forced convection simulation, based on the inlet values for the fan airflow, Reynolds number is in the turbulent range (3000-12,000); therefore, the k-ε turbulence model has been used for the fluid flow and the heat transfer phenomenon. The turbulent kinetic energy k and the dissipation rate ω are obtained from the following equations [59]:…”

Section: Conjugate Convective Heat Transfer Simulationmentioning

confidence: 99%

Combining Digital Twin and Machine Learning for the Fused Filament Fabrication Process

Butt

Mohaghegh

2022

Metals

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In this work, the feasibility of applying a digital twin combined with machine learning algorithms (convolutional neural network and random forest classifier) to predict the performance of PLA (polylactic acid or polylactide) parts is being investigated. These parts are printed using a low-cost desktop 3D printer based on the principle of fused filament fabrication. A digital twin of the extruder assembly has been created in this work. This is the component responsible for melting the thermoplastic material and depositing it on the print bed. The extruder assembly digital twin has been separated into three simulations, i.e., conjugate convective heat transfer, multiphase material melting, and non-Newtonian microchannel. The functionality of the physical extruder is controlled by a PID/PWM circuit, which has also been modelled within the digital twin to control the virtual extruder’s operation. The digital twin simulations were validated through experimentation and showed a good agreement. After validation, a variety of parts were printed using PLA at four different extrusion temperatures (180 °C, 190 °C, 200 °C, 210 °C) and ten different extrusion rates (ranging from 70% to 160%). Measurements of the surface roughness, hardness, and tensile strength of the printed parts were recorded. To predict the performance of the printed parts using the digital twin, a correlation was established between the temperature profile of the non-Newtonian microchannel simulation and the experimental results using the machine learning algorithms. To achieve this objective, a reduced order model (ROM) of the extruder assembly digital twin was developed to generate a training database. The database generated by the ROM (simulation results) was used as the input for the machine learning algorithms and experimental data were used as target values (classified into three categories) to establish the correlation between the digital twin output and performance of the physically printed parts. The results show that the random forest classifier has a higher accuracy compared to the convolutional neural network in categorising the printed parts based on the numerical simulations and experimental data.

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Section: Conjugate Convective Heat Transfer Simulationmentioning

confidence: 99%

Combining Digital Twin and Machine Learning for the Fused Filament Fabrication Process

Butt

Mohaghegh

2022

Metals

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“…Another important industry in which CHT is of great interest is transportation, whether to improve the cooling of blades in aero engines [15,16], or in the automotive in-dustry either for conventional internal combustion engines [17,18] or, for example, cooling of battery packs for electrical vehicles [19].…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Conjugate Heat Transfer and Natural Convection Using the Lattice-Boltzmann Method for Realistic Thermophysical Properties

Landl

Prieler

Monaco

et al. 2023

Fluids

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To enable the lattice-Boltzmann method (LBM) to account for temporally constant but spatially varying thermophysical properties, modifications must be made. Recently, many methods have emerged that can account for conjugate heat transfer (CHT). However, there still is a lack of information on the possible physical property range regarding realistic properties. Therefore, two test cases were investigated to gain further insight. First, a differentially heated cavity filled with blocks was used to investigate the influence of CHT on the error and stability of the LBM simulations. Reference finite volume method (FVM) simulations were carried out to estimate the error. It was found that a range between 0.5 to 1.5 is recommended for the fluid relaxation time to balance computational effort, stability, and accuracy. In addition, realistic thermophysical properties of fluids and solids were selected to test whether the lattice-Boltzmann method is suitable for simulating relevant industry-related applications. For a stable simulation, a mesh with 64 times more lattices was needed for the most extreme test case. The second test case was an insulated cavity with a heating pad as the local heat source, which was investigated in terms of the accuracy of a transient simulation and compared to a FVM simulation. It was found that the fluid-phase relaxation time mainly determines the error and that large thermal relaxation times for the solid improve accuracy. Observed deviations from the FVM reference simulations ranged from approximately 20% to below 1%, depending on collision operator and combination of relaxation times. For processes with a large temperature spread, the temporally constant thermophysical properties of the LBM are the primary constraint.

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“…Furthermore, as the blowing ratio increases, the benefits of using sister holes become more significant. In a few studies, FC has been used with impingement cooling to maximize coolant utilization following impingement (Immarigeon and Hassan, 2006;Liu et al, 2014;Fawzy et al, 2020;Youn et al, 2021). A real gas turbine's cooling system involves both convection and conduction heat transfer.…”

Section: Introductionmentioning

confidence: 99%

“…The study also involved varying Biot numbers (ranging from 0.013 to 3.162) to analyze their impact on the overall cooling performance. All simulations were conducted under normal temperature ranges (not actual turbine conditions) and low speeds to demonstrate conceptual designs that can be further validated through experiments (Jung et al , 2017; Nowak and Wróblewski, 2011; Panda and Prasad, 2014; Wang et al , 2015; Kazemi Kelishami and Lakzian, 2017; Fawzy et al , 2020; Singh et al , 2021a, 2021b). The temperature ratio considered for the simulations ranged from 0.67 to 0.95 (Jung et al , 2017; Jaiswal et al , 2021).…”

Section: Introductionmentioning

confidence: 99%

Mini-channel embedded film cooled flat plate: conjugate heat transfer analysis and enhancement study

Jaiswal,

Sinha Mahapatra

2023

HFF

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Purpose Maintaining the turbine blade’s temperature within the safety limit is challenging in high-pressure turbines. This paper aims to numerically present the conjugate heat transfer analysis of a novel approach to mini-channel embedded film-cooled flat plate. Design/methodology/approach Numerical simulations were performed at a steady state using SST k – ω turbulence model. Impingement and film cooling are classical approaches generally adopted for turbine blade analysis. The existing film cooling techniques were compared with the proposed design, where a mini-channel was constructed inside the solid plate. The impact of the blowing ratio (M), Biot number (Bi) and temperature ratio (TR) on overall cooling performance was also studied. Findings Overall cooling effectiveness was always shown to be higher for mini-channel embedded film-cooled plates. The effectiveness increases with increasing the blowing ratio from M = 0.3 to 0.7, then decreases with increasing blowing ratio (M = 1 and 1.4) due to lift-off conditions. The mini-channel embedded plate resulted in an approximately 21% increase in area-weighted average overall effectiveness at a blowing ratio of 0.7 and Bi = 1.605. The lower uniform temperature was also found for all blowing ratios at a low Biot number, where conduction heat transfer significantly impacts total cooling effectiveness. Originality/value To the best of the authors’ knowledge, this study presents a novel approach to improve the cooling performances of a film-cooled flat plate with better cooling uniformity by using embedded mini-channels. Despite the widespread application of microchannels and mini-channels in thermal and fluid flow analysis, the application of mini-channels for blade cooling is not explored in detail.

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Conjugate heat transfer of impingement cooling using conical nozzles with different schemes in a film-cooled blade leading-edge

Cited by 27 publications

References 34 publications

Combining Digital Twin and Machine Learning for the Fused Filament Fabrication Process

Combining Digital Twin and Machine Learning for the Fused Filament Fabrication Process

Numerical Investigation of Conjugate Heat Transfer and Natural Convection Using the Lattice-Boltzmann Method for Realistic Thermophysical Properties

Mini-channel embedded film cooled flat plate: conjugate heat transfer analysis and enhancement study

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