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Numerical Investigation of Heat Conduction in a Rectangular Composite Plate with Sinusoidal Heat Input from Top Wall
Published in Satyajit Chakrabarti, Ayan Kumar Panja, Amartya Mukherjee, Arun Kr. Bar, Intelligent Electrical Systems: A Step towards Smarter Earth, 2021
Debarghya Kar, Sumanta Banerjee
The primary objective of the present work is to conduct a simulation study of 2D steady-state heat conduction in a rectangular plate composed of two sections, each with a different (constant) value of thermal conductivity k. The individual sections are assumed to be homogeneous and isotropic. There is no internal heat generation. Perfect thermal contact is assumed at the interface so that the contact resistance is neglected. The schematic of the rectangular plate, with appropriate thermal boundary conditions, is depicted in Figure 7.1(a). The lengths of the horizontal edge and the vertical edge of the plate are W and H, respectively. The thermal boundary conditions (Dirichlet-type) are also specified. The two sections are visually demarcated by distinct hatchings.
One-Dimensional Steady-State Heat Conduction
Published in Yaman Yener, Sadık Kakaç, Heat Conduction, 2018
where we have assumed perfect thermal contact between the fuel rod and the cladding, and the interface temperature is denoted by Tw. Generally, we do not expect to achieve perfect thermal contact. In some fuel element designs, in fact, there is usually a space between the fuel rod and the cladding which may, for example, be filled with helium. In addition, the surface temperature of the cladding, Ts, is assumed to be given. By solving Eqs. (3.89) and (3.90) with the boundary conditions (3.91) we obtain () Tw−Ts=q′L2πk2lnr2r1
One-Dimensional Steady-State Heat Conduction
Published in Sadık Kakaç, Yaman Yener, Carolina P. Naveira-Cotta, Heat Conduction, 2018
Sadık Kakaç, Yaman Yener, Carolina P. Naveira-Cotta
where we have assumed perfect thermal contact between the fuel rod and the cladding, and the interface temperature is denoted by Tw. Generally, we do not expect to achieve perfect thermal contact. In some fuel element designs, in fact, there is usually a space between the fuel rod and the cladding which may, for example, be filled with helium. In addition, the surface temperature of the cladding, Ts, is assumed to be given. By solving Eqs. (3.89) and (3.90) with the boundary conditions (3.91) we obtain
Viscoelastic simulation and optimisation of the polymer flow through the hot-end during filament-based material extrusion additive manufacturing
Published in Virtual and Physical Prototyping, 2022
Marcin P. Serdeczny, Raphaël Comminal, Md. Tusher Mollah, David B. Pedersen, Jon Spangenberg
Similar to other manufacturing processes, the complexity of MEX can be modelled using multi-physics Computational Fluid Dynamics (CFD) simulations (Jabbari et al. 2018). Go et al. (2017) investigated numerically the throughput limits that are related to the heat and mass exchange inside the flow channel. It was found that the maximum hot-end throughput is limited by the heat transfer and insufficient melting of the solid filament at the high flow rates. The flow and heating of an amorphous polymer were also modelled by Pigeonneau et al. (2020). It was concluded that the polymer had a perfect thermal contact with the liquefier’s walls based on the comparison of the modelling results with the measured polymer temperature by Peng et al. (2018). On the other hand, Phan et al. (2018) reported that the outlet temperature of the polymer falls dramatically at high flow rates and argued that this could be due to a thermal resistance at the channel walls. Furthermore, in a CFD model presented by Serdeczny et al. (2020b), the inclusion of the thermal resistance at the channel wall improved the predictions of the filament feeding force, when compared with the measurements. In the same work, the CFD simulations were shown to capture the feeding force fluctuations that occur at the high flow rates and limit the maximum hot-end throughput. However, in some cases, discrepancies between the modelling results and experimental measurements were reported and attributed to the simplified rheological behaviour of the polymer in the numerical model.
Transient thermal performance of multilayer thermal protection systems doped with phase change materials
Published in Numerical Heat Transfer, Part A: Applications, 2023
Wen-Zhen Fang, Yu-Qing Tang, Wen-Quan Tao
First, we study on the thermal performance of the TPS in perfect thermal contact and put our attention on the temperature at the back surface of the TPS. Figure 9 shows the thermal performances of TPSs with different layer thicknesses δp. It can be seen that the TPS with δp = 0.035 m has the worst thermal insulation performance before t = 4000 s, and the optimal thickness of δp depends on the service time that the TPS is required to withstand. The TPS with δp = 0.02 m has the best thermal insulation performance at t = 2500 s, while the TPSs with δp= 0.025 m and δp= 0.03 m are the best at t = 3000 s and t = 4000 s, respectively. For a longer service time, a thicker layer of SiO2 aerogel doped with the PCM is required to provide a sufficient amount of the latent heat. Compared to the TPS in the layout A, the TPS in the layout B has a lower temperature at the back surface because it can utilize a greater proportion of the PCM and take more benefits from the latent heat. The melting information of the TPS with different layer thicknesses δp is presented in Table 4. It shows that all the PCM doped in the TPS can be fully utilized before t = 4000 s, except the case of the TPS with δp= 0.035 m. While the PCM doped in those TPSs with δp thinner than the 0.02 m and 0.03 m can be completely utilized before the moment of t = 2500 s and t = 3000 s, respectively. As a result, the optimal thickness of layer of the SiO2 aerogel doped with the PCM increases with the service time.
A survey of design methods for material extrusion polymer 3D printing
Published in Virtual and Physical Prototyping, 2020
Jiaqi Huang, Qian Chen, Hao Jiang, Bin Zou, Lei Li, Jikai Liu, Huangchao Yu
For ABS filament extrusion, D’Amico and Peterson (2018) presented an adaptable FEA model with sufficiently small time scales, which is capable of simulating heat transfer in 3D and capturing the details of rapid cooling. In this model, a few simplifications were made for the trade-off between accuracy and computing time, such as invariant material properties with temperature, neglect of material flow and perfect thermal contact between layers, nozzle and build plate. Zhou and Hsieh (2017) developed a 3D finite element model using birth and death elements and validated the thermal model with an infrared thermography imaging measurement.