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Heat Conduction
Published in Greg F. Naterer, Advanced Heat Transfer, 2018
The thermal contact resistance is influenced by several factors, including contact pressure, interstitial materials, surface roughness, cleanliness, and surface deformations. As the contact pressure increases, the thermal resistance becomes smaller since the contact surface area between the adjoining materials is larger. Most thermal contact resistance correlations are made as a function of contact pressure since this is the most significant factor. Another factor is interstitial gaps, due to rough surfaces in contact, which influence heat flows through the gases/fluids filling these gaps. Also, surface features such as roughness, waviness, and flatness may be significant factors. Furthermore, surface cleanliness and the presence of dust particles can also affect the thermal resistance.
Motor Cooling
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
Each type of thermal interface material may display different levels of efficiency for reducing the thermal contact resistance, depending on the nature of the contacting materials, contact conditions (e.g., applied contact pressure, temperature), morphological and crystallographic characteristics of the mating surfaces (e.g., surface roughness, hardness, and wettability), and the process parameters for the thermal interface material application technique.
An improved interface temperature distribution in shallow hot mix asphalt patch repair using dynamic heating
Published in International Journal of Pavement Engineering, 2020
Juliana Byzyka, Mujib Rahman, Denis Albert Chamberlain
The inverse of thermal contact resistance is thermal contact conductance. Thermal contact conductance can be calculated by the ratio of the conductivity of the material over its thickness and it is expressed in W/m2 K. The higher the thermal conductance, the lower the thermal resistance at the interface. Thermal conductance is influenced by the characteristics of the two surfaces in contact such as surface deformation, surface cleanliness, surface roughness, waviness and flatness (Gilmore 2002), the contact pressure between the two bodies and any conducting fluid (fluids or gases) in the voids spaces of the bodies’ interface (Cooper et al. 1969).
The thermal contact resistance of a steel-ceramic interface with oxide intermediates
Published in Cogent Engineering, 2020
Jussi Silvonen, Erkki Levänen, Mikko Uusitalo
In practical applications, thermal expansion mismatch can cause unexpected gaps between the layers in a construction and thus increase the thermal resistance in the vicinity of the joint. Thermal contact resistance is highly dependent on the quality of the contact, such as the roughness and flatness of the opposing surfaces. Refractory castables are typically cast on top of their metal counterpart, thus adopting the shape of the metal, so the contact between a castable and its metal counterpart is initially good.
Solar photovoltaic thermal system: a comprehensive review on recent design and development, applications and future prospects in research
Published in International Journal of Ambient Energy, 2022
Disha Dewangan, Jasinta Poonam Ekka, T. V. Arjunan
Several challenges are faced in developing a new design of the PV/T system for enhancing thermal and electrical energy. Some of them are listed below: In heat pipe PV/T collectors due to high contact thermal resistance between the condenser and manifold and low heat transfer area between the evaporator and absorber plate. The heat exchange is reduced because of the low heat transfer coefficient in natural convection.Due to the non-uniform temperature distribution on the PV cell surface, there is a probability of degradation of the module.There is a significant drop in pressure and difficulty in designing and installing fins below the PV modules.The first and foremost concern about nanofluids is their chemical stability under a high-temperature range. Higher production cost affects the use on a large scale, such as in industrial applications.Increase in pumping power due to the high viscous nanofluids.Continuous heating and cooling of PCM PV/T will reduce PCM’s life cycle, and it gets disintegrated.More research and development activities should be focused on improving electrical and thermal output, reliability and reducing cost.A more experimental investigation is to be carried out to study nanofluids thermophysical and optical parameters for use in PV/T systems. A study can also be performed on the different types of surfactants used in nanofluid to identify the most suitable, which can withstand high-temperature range.Most research on heat pipe-based PV/T systems is oriented toward using integrated and loop-type heat pipes PV/T systems. Very little work was reported on the pulsating type of heat pipe.To reduce thermal contact resistance.Finding new cost-effective materials for TEG to maintain the high-temperature gradient and improve good contact between two sides of TEG.