Analysis of a Vertical Flat Heat Pipe Using Potassium Working Fluid and a Wick of Compressed Nickel Foam

Hansen, Geir Karsten; Næss, Erling; Kristjansson, Kolbeinn Jakob

doi:10.3390/en9030170

Cited by 9 publications

(4 citation statements)

References 16 publications

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“…These systems utilize phase transition and are often used in solar collectors to keep the temperature difference low [49]. Tests in a highly corrosive environment show that with a suitable material selection, a long lifetime can be expected, and maintenance needs can be kept minimal [50].…”

Section: Economizer and Latent Heat Utilizationmentioning

confidence: 99%

Hydrogen Oxyfuel Combustion for Energy-Intensive Industries

Iplik¹,

Adendorff²,

Muren³

2022

Clean Energy Technologies - Hydrogen and Gasification Processes

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Hydrogen has been seen as a decarbonization enabler for the last few decades, and in the last couple of years, there have been many investments in its production through renewables and use in different industrial applications. It is often researched for energy storage, and combustion is an excellent alternative to recover the energy stored in hydrogen. It might be the most viable alternative, especially when it comes to energy-intensive metal and glass production processes. The utilization of hydrogen as a fuel in these processes would reduce greenhouse gas emissions significantly, considering their share in total emissions. Since these industries already benefit from oxyfuel combustion with traditional fuels for fuel savings, part of the infrastructure already exists for hydrogen oxyfuel combustion. Fuel change is expected to require some minor adjustments other than simply changing the oxidizer; however, each industry has specific points to consider. This chapter investigates metal and glass production processes based on their needs and challenges in using hydrogen oxyfuel combustion for heating. Additionally, possible exhaust gas stream improvements are suggested to recover energy and reduce emissions. Finally, safety aspects of hydrogen and oxygen use are discussed together with the community acceptance of hydrogen use.

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Section: Economizer and Latent Heat Utilizationmentioning

confidence: 99%

Hydrogen Oxyfuel Combustion for Energy-Intensive Industries

Iplik¹,

Adendorff²,

Muren³

2022

Clean Energy Technologies - Hydrogen and Gasification Processes

View full text Add to dashboard Cite

show abstract

“…The thermal resistance associated with phase change, R ph , is often neglected as it is orders of magnitude lower than the other thermal resistances shown in Figure 1 [2]. However, it should be accounted for in the simulation of heat pipes filled with alkali metal [33]. The liquid momentum equation is defined with Equation (8).…”

Section: Liquid Componentmentioning

confidence: 99%

Transient Modelling of Rotating and Stationary Cylindrical Heat Pipes: An Engineering Model

et al. 2018

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Rotating wickless and stationary capillary cylindrical heat pipes are widely used heat transfer devices. Transient behavior of such heat pipes has been investigated numerically with computational fluid dynamics and lumped parameter models. In this paper, the advantages of both methods are combined into a novel engineering model that is low in computational cost but still accurate and rich in the details it provides. The model describes the interior dynamics of the heat pipe with a 2D representation of a cylindrical heat pipe. Liquid and vapor volumes are coarsely meshed in the axial direction. The cells are allowed to change in size in the radial direction during simulation. This allows for tracking the liquid/vapor interface without having to implement fine meshing. The model includes the equations for mass, momentum and energy and is applicable to both rotating and stationary heat pipes. The predictions of the model are validated with other experimental, numerical, and analytical works having an average deviation of less than 4%. The effects of various parameters on the system are explored. The presented model is suitable for the simulation of heat pipe systems in which both the level of detail and the computational cost are crucial factors.

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“…From a literature survey, the prior work has mainly focused on the convection heat transfer within the foam filled annulus, while neglecting the thermal radiation, which may dominate the heat transfer at a high temperature. With increasing high-temperature applications [31][32][33], the radiation-convection coupled heat transfer behavior in such foam-fluid systems should be comprehensively studied. To the authors' best knowledge, the high-temperature coupled heat transfer in an open-cell foam filled annulus has not been reported in the literature.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis on the Radiation-Convection Coupled Heat Transfer in an Open-Cell Foam Filled Annulus

et al. 2018

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Forced flow and radiation-convection coupled heat transfer in an annulus filled with open-cell foam was numerically investigated at high temperatures. The Darcy-Brinkman-Forchheimer model was utilized to represent the fluid transport. The two-energy equation model was applied for the non-equilibrium heat exchange between the fluid and solid phases, while the radiation heat transfer within the foam material was solved using the P1 approximation. Two different cases of thermal boundary conditions were studied and discussed in detail, namely the inner wall with a constant heat flux while the outer wall was adiabatic (case I) and vice versa (case II). The effects of pertinent factors on the heat transfer characteristics were examined, such as the foam structural parameters and the radii ratio of the annulus. The temperature, local and average Nusselt number were predicted. The results indicate that neglecting the thermal radiation causes a large deviation in predicting the thermal performance of such foam-fluid systems. Increasing the porosity and pore diameter both promote the radiation heat transfer, while it is weakened by increasing the radii ratio. The average Nusselt number decreases as the porosity increases, while it exhibits a non-monotonic change with the pore diameter and radii ratio. Besides, case I shows a higher average Nusselt number than case II and presents an improved thermal performance.

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Analysis of a Vertical Flat Heat Pipe Using Potassium Working Fluid and a Wick of Compressed Nickel Foam

Cited by 9 publications

References 16 publications

Hydrogen Oxyfuel Combustion for Energy-Intensive Industries

Hydrogen Oxyfuel Combustion for Energy-Intensive Industries

Transient Modelling of Rotating and Stationary Cylindrical Heat Pipes: An Engineering Model

Numerical Analysis on the Radiation-Convection Coupled Heat Transfer in an Open-Cell Foam Filled Annulus

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