Design of internal heat transport intensifier for metal hydride storage tank

The present article deals with potential improvement of heat removal from the centre of a metal hydride tank towards the tank’s periphery while using passive heat transfer modules. Passive cooling elements are used in order to improve heat removal from the centre of a tank towards its peripheral parts. This increases the homogeneity of the thermal field in a tank’s cross-section, which is perpendicular to the longitudinal axis. Moreover, the use of such elements improves the kinetics of hydrogen absorption into an alloy, in particular by prolonging the time to an equilibrium temperature of the alloy for a particular equilibrium pressure, which may shorten the time to a tank being 100% filled with hydrogen. The article describes four different designs of internal heat transfer intensifiers, which are aimed at improving the thermal field distribution inside the tank and their theoretical impact on the thermal field, which was examined using Ansys CFX software.

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Tank Design for On-Board Hydrogen Storage in Metal Hydrides

ASME 2008 2nd International Conference on Energy Sustainability, Volume 1 ◽

10.1115/es2008-54031 ◽

2008 ◽

Cited By ~ 1

Author(s):

Karelle Couturier ◽

Farida Joppich ◽

Antje Wo¨rner ◽

Rainer Tamme

Keyword(s):

Heat Transfer ◽

Metal Hydride ◽

Storage Tank ◽

Internal Heat ◽

Transfer Model ◽

Cooling Fluid ◽

Internal Heat Exchanger ◽

Tank Design ◽

Technical Solutions ◽

Charging Dynamics

The aim of this work is to reduce the refueling time of a metal hydride storage tank by improving its design, taking in account the total volumetric and mass capacity of the tank. A heat and mass transfer model is proposed and solved to obtain the charging curve for 1 kg hydrogen in a LaNi5 reference storage tank. Compared to gas transport and reaction kinetics, heat transfer is found to limit the hydrogen charging dynamics of the storage tank. To improve the refueling time, it is found to be necessary to increase first of all the heat transfer inside the metal hydride bed, and subsequently the heat transfer from the metal hydride bed to the cooling fluid. Technical solutions such as the implementation of aluminum foam and/or internal heat exchanger tubes are investigated. By combining both solutions, the refueling time can be reduced from 400 minutes (reference tank) to 15 minutes. The tank volume still meets the DOE targets, but its mass remains a problem. Therefore, new materials with improved gravimetric capacity have to be developed. With this work it is now possible to improve the tank design for newly developed storage materials and to evaluate their potential for technical applications.

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Ceramic High-Temperature Heat-Pipes

Volume 5: Innovative Nuclear Power Plant Design and New Technology Application; Student Paper Competition ◽

10.1115/icone22-30802 ◽

2014 ◽

Cited By ~ 1

Author(s):

Peter Meisel ◽

Wolfgang Lippmann ◽

Antonio Hurtado

Keyword(s):

Heat Transfer ◽

High Temperature ◽

Heat Pipe ◽

Internal Heat ◽

Heat Removal ◽

Heat Pipes ◽

Operating Regime ◽

Working Fluid ◽

Stable Operating

Ceramic heat pipes and heat pipe based heat exchangers are tailored for automatically heat removal and heat distribution in thermally, chemically and abrasive high stressed systems. The manufacture of silicon carbide heat pipes was carried out. These were filled with sodium or zinc and sealed by laser brazing using metallic and glassy solder materials. High-temperature performance tests revealed a stable operating regime for both ceramic heat pipes with sodium and zinc as working fluid, respectively. Specifically the heat transferred by a zinc filled heat pipe of 22 mm in diameter and 750 mm in length accounted for 600 W at a temperature difference of 400 K. Notably the internal heat transfer capacity of the working fluid was even higher however, the total heat transfer was limited by the external active heat transfer area of the heat pipe. In order to evaluate the long-term stability of the heat pipes, particularly with respect to the joining seam, manufactured heat pipes are currently being tested in long-term annealing experiments at a temperature of 1000 °C under a variety of corrosive atmospheres.

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Analysis of the Heat Balance of a Metal Hydride Separator Used for the Separation of Hydrogen from Syngas

Processes ◽

10.3390/pr9020251 ◽

2021 ◽

Vol 9 (2) ◽

pp. 251

Author(s):

Tomáš Brestovič ◽

Marián Lázár ◽

Natália Jasminská ◽

Jozef Živčák ◽

Lukáš Tóth ◽

...

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Metal Hydride ◽

Heat Balance ◽

Alloy Powder ◽

Hydrogen Absorption ◽

Heat Removal ◽

Hydrogen Separation ◽

Thermal Recovery ◽

Field Homogeneity

The present article discusses the potential for hydrogen separation using a metal hydride separator, which facilitates the generation of hydrogen contained in syngas following the thermal recovery of wastes. The article provides a detailed description of the separator heat balance using analytical calculations and optimised calculations, and by applying numerical methods. The proposed concept of a separator intended for hydrogen separation from syngas offers a solution to a problem associated with the use of metal hydride alloy powders; in particular, their low thermal conductivity. In order to eliminate big temperature differences in the alloy, a heat transfer intensifier was implemented in the metal hydride alloy volume; the intensifier was made of metal and exhibited high thermal conductivity. For the purpose of comparing the thermal fields, the first stage comprised the creation of a numerical simulation of hydrogen absorption without the use of an intensifier. Subsequently, three different geometries were created for an intensifier intended to remove heat from the metal hydride alloy powder towards the separator cover, and the effects of these three geometries were analysed. The implementation of heat transfer intensifiers into the metal hydride alloy powder improved the heat removal by as much as 43.9% and increased the thermal field homogeneity by 77%. A result of the heat removal optimisation was an increase in the hydrogen absorption kinetics and the efficiency of the separator operation.

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Numerical Investigation of Heat Transfer Enhancement with Mist Injection

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.281.250 ◽

2013 ◽

Vol 281 ◽

pp. 250-253

Author(s):

Fifi N.M. Elwekeel ◽

Antar M.M. Abdala ◽

Qun Zheng

Keyword(s):

Heat Transfer ◽

Internal Heat ◽

Turbulence Models ◽

Transfer Coefficients ◽

Heat Transfer Coefficients ◽

Ribbed Channel ◽

Proper Size ◽

Ansys Cfx ◽

Sst Turbulence Model ◽

Internal Heat Transfer

In the present work, computational simulations was made using ANSYS CFX to predict the improvements of internal heat transfer in rectangular ribbed channel using different coolants. Several coolants such as air, steam, air/mist and steam/mist were investigated. The shear stress transport (SST) turbulence model is selected by comparing the predictions of different turbulence models with experimental results. The results indicate that the heat transfer coefficients enhance in ribbed channel at injection small amount of mist. The heat transfer coefficients of air/mist, steam and steam/mist increase by 1.13, 1.57 and 2.07 times than that of air, respectively. Furthermore, comparing with droplets size, the proper size is from 6 to 10 µm. which had the best enhancement performance in ribbed duct.

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Laminar Heat Transfer Behavior of a Phase Change Material Fluid in Microchannels With Staggered Pins

Journal of Heat Transfer ◽

10.1115/1.4035441 ◽

2017 ◽

Vol 139 (6) ◽

Author(s):

Satyanarayana Kondle ◽

Jorge L. Alvarado ◽

Charles Marsh

Keyword(s):

Heat Transfer ◽

Pressure Drop ◽

Phase Change ◽

Phase Change Material ◽

Single Phase ◽

Internal Heat ◽

Heat Removal ◽

Heat Transfer Fluid ◽

Change Material ◽

Phase Fluid

Microchannels have been studied extensively for a variety of heat transfer applications including electronic cooling. Many configurations of microchannels have been studied and compared for their effectiveness in terms of heat removal. Recently, the use of staggered pins in microchannels has gained considerable traction, since they can promote internal flow fluctuations that enhance internal heat transfer. Furthermore, staggered pins in microchannels have shown higher heat removal characteristics because of the continuous breaking and formation of the heat transfer fluid boundary layer. However, they also exhibit higher pressure drop because the pins act as flow obstructions. This paper presents numerical results of two characteristic staggered 100-μm pins (square and circular) in microchannels. The heat transfer performance of a single phase fluid (SPF) in microchannels with staggered pins, and the corresponding pressure drop characteristics are presented. Furthermore, a phase change material (PCM, n-eicosane) fluid was also considered by implementing the effective specific heat capacity model approach to account for the corresponding phase change process of PCM fluid. Comparisons of the heat transfer characteristics of single phase fluid and PCM fluid are presented for two different pin geometries and three different Reynolds numbers. Circular pins were found to be more effective in terms of heat transfer by exhibiting higher Nusselt number. Microchannels with circular pins were also found to have lower pressure drop compared to the square-pin microchannels.

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ОПРЕДЕЛЕНИЕ ГРАНИЧНЫХ УСЛОВИЙ ДЛЯ РАСЧЁТА ТЕРМОНАПРЯЖЕННОГО СОСТОЯНИЯ ПОРШНЯ

Aerospace technic and technology ◽

10.32620/aktt.2019.1.04 ◽

2019 ◽

pp. 39-47

Author(s):

Ван Зионг Нгуен ◽

Александр Витальевич Белогуб

Keyword(s):

Heat Transfer ◽

Thermal Properties ◽

Heat Exchange ◽

Boundary Conditions ◽

Initial Conditions ◽

Internal Heat ◽

Heat Removal ◽

Temperature Fields ◽

Working Fluid ◽

Working Process

The paper deals with the study of the influence of the working process parameters of the two-stroke opposed piston engine like D100 (20.7/2×25.4), especially the heat exchange between the working substance and the wall of the combustion chamber (CC) – cylinder and pistons on temperature and stress-strain state of the piston. To make an estimation of the effect of a working process on the boundary condition we considered the internal heat balance and specific features of gas dynamic loading of main parts of the cylinder-piston group. To calculate the temperature fields, the actual boundary conditions of non-stationary thermal loading were replaced with the equivalent steady-state ones, obtained from the condition that the amount of heat perceived by the piston surface in real and conditionally equivalent processes are equal. Equivalent parameters of heat transfer are calculated by the condition of conservation of the amount of heat passing through the walls of the CS. It was performed the validation of the calculation of equivalent heat exchange parameters. It is shown that in case of an error in specifying the initial conditions, for example, temperature per 100K, the temperature of the piston CC surface may change by 5K in the first 5 operating cycles. It is shown that the developed model of the workflow can be adjusted according to the available experimental data and used to model the boundary conditions. The authors made corrections to the dependence obtained by prof. Rosenblit, to determine the current heat transfer coefficient from the working fluid to the walls of the CC by the total heat removal for the cycle, equal to 20%. It was obtained the average coefficient of heat transfers from the working fluid to the piston and the temperature of the cycle for the nominal mode, which are 3500 W/(m2•K) and 835 K respectively. It was carried out the simulation of the thermal properties of the gap between the piston ring and the groove filled with combustion products. It is shown that the conditions of heat transfer through annular grooves and rings require clarification in modeling, which is associated with the conditions of heat transfer in the gaps, and the gap can be replaced by a gasket with appropriate thermal properties.

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