Measurement of effective thermal conductivity of LaNi5 powder packed bed

Measurement and the improvement of effective thermal conductivity for a metal hydride bed – a review

“…At the same time, the low thermal conductivity material was filled around the specimen between the guard plate and the cooling plate to limit the lateral heat loss. At present, GHP used for the measurement of the effective thermal conductivity of hydride powder bed was only found in 2021, that Kim et al 30 used a designed miniaturized GHP apparatus to measure the effective thermal conductivity of LaNi 5 packed bed. The measurement results showed that under vacuum condition, the effective thermal conductivity of LaNi 5 packed bed with particle size less than 50 μm was only 0.0128 W (m −1 K −1 ).…”

“…It is worth pointing out that helium gas has a similar molecular size and thermal conductivity compared to hydrogen gas, thus it is particularly widely used as a comparative gas for the effective thermal conductivity measurement. 28–30…”

“…At the same time, it should be noted that the distribution of different particle sizes may lead to changes in porosity and affect the effective thermal conductivity. 29,30…”

“…It is worth pointing out that helium gas has a similar molecular size and thermal conductivity compared to hydrogen gas, thus it is particularly widely used as a comparative gas for the effective thermal conductivity measurement. [28][29][30] In 1980, Suda et al 31 discovered that the effective thermal conductivity of the TiMn 1.5 powder bed changed with hydrogen pressure, and pointed out that it was the result of a strict relationship with the mean free path of the gas. In 1986 and 1990, Nagel 21 and Sun 22 divided the inuence of pressure into three sections and explained the properties of uids.…”

“…At the same time, it should be noted that the distribution of different particle sizes may lead to changes in porosity and affect the effective thermal conductivity. 29,30 Solovey et al 44 studied the effective thermal conductivity of LaNi 4.6 Al 0.4 compacts with the particle size of 70 mm and 70-200 mm, and the results show that the effective thermal conductivity were 9.6 and 17.6 W (m À1 K À1 ) under the hydrogen pressure of 0.11 MPa, respectively. The MmNi 4.15 Fe 0.85 compact prepared in the same form also has the same trend that the effective thermal conductivity increases with the increasing particle size.…”