  Latent heat thermal energy storage (LHTES) has been recommended as an
effective technology to the thermal management system of space exploration for
its excellent ability of storing thermal energy. However, it is well known that
the low thermal conductivity of phase change material (PCM) seriously weakens
the heat charging and discharging rates of LHTES system. In present study, the
electrohydrodynamic (EHD), which is a popular active heat transfer enhancement
technology, is introduced to enhance the PCM melting in a shell-tube LHTES
system under microgravity. In our numerical simulations, we mainly focus on the
combined effects of the electric Rayleigh number $T$ and the eccentricity
$\Gamma$ on the melting performance under microgravity. Based on the numerical
results, it is found that in contrast to the case without the electric field,
the presence of the electric field causes the heat transfer efficiency and
melting behavior of LHTES system to be enhanced significantly. In addition, our
results indicates that the EHD technique always shows a good performance in
accelerating the melting process even under microgravity, and specially, the
maximum time saving in some cases is more than $90\%$. Furthermore, we note
that although the concentric annulus is always the optimal configuration under
no-gravity condition, the optimal eccentric position of the internal tube
strongly depends on the electric Rayleigh number if the gravity effects are
taken into account.
