TY - JOUR
T1 - Combined close-contact and convective melting in a vertical cylindrical enclosure
AU - Shockner, T.
AU - Ziskind, G.
N1 - Funding Information: The authors are grateful to Dr. Yoram Kozak of Tel-Aviv University for his generous advice concerning the modeling approach. Publisher Copyright: © 2021
PY - 2021/10/1
Y1 - 2021/10/1
N2 - The use of phase change materials (PCM) for latent heat thermal energy storage (LHTES) is receiving considerable amount of attention in recent years. Experimental findings have demonstrated that the so-called ‘close contact melting’ (CCM) enhances heat transfer during the melting process remarkably. Yet, the commercially-available numerical schemes are not suitable for the modeling of CCM. Therefore, in this study a new numerical model for combined convective and close-contact melting in an axisymmetric cylindrical geometry is devised. A full set of the governing conservation equations is solved using finite differencing framework, integrated with an advanced immersed boundary method for the fluid-solid interaction and enthalpy formulation for the phase change process into an original in-house code. First, the model is validated carefully for each physical phenomenon with known benchmarks. Then, a numerical study is conducted to elucidate the melting process in a vertical cylindrical enclosure heated isothermally from the bottom and side wall. Twelve study cases are considered in order to reveal the transient phase-change sequence dependence on the aspect ratio and the excess temperature. Detailed data on the flow and temperature fields are obtained. The overall results are generalized using a dimensional analysis, which includes the Fourier, Stefan and Archimedes numbers and the enclosure aspect ratio. A correlation for the melt fraction, suitable for all cases studied, is suggested.
AB - The use of phase change materials (PCM) for latent heat thermal energy storage (LHTES) is receiving considerable amount of attention in recent years. Experimental findings have demonstrated that the so-called ‘close contact melting’ (CCM) enhances heat transfer during the melting process remarkably. Yet, the commercially-available numerical schemes are not suitable for the modeling of CCM. Therefore, in this study a new numerical model for combined convective and close-contact melting in an axisymmetric cylindrical geometry is devised. A full set of the governing conservation equations is solved using finite differencing framework, integrated with an advanced immersed boundary method for the fluid-solid interaction and enthalpy formulation for the phase change process into an original in-house code. First, the model is validated carefully for each physical phenomenon with known benchmarks. Then, a numerical study is conducted to elucidate the melting process in a vertical cylindrical enclosure heated isothermally from the bottom and side wall. Twelve study cases are considered in order to reveal the transient phase-change sequence dependence on the aspect ratio and the excess temperature. Detailed data on the flow and temperature fields are obtained. The overall results are generalized using a dimensional analysis, which includes the Fourier, Stefan and Archimedes numbers and the enclosure aspect ratio. A correlation for the melt fraction, suitable for all cases studied, is suggested.
KW - Close-contact melting
KW - Dimensional analysis
KW - Numerical modeling
KW - Phase change material
KW - Vertical tube
UR - http://www.scopus.com/inward/record.url?scp=85108798017&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.ijheatmasstransfer.2021.121492
DO - https://doi.org/10.1016/j.ijheatmasstransfer.2021.121492
M3 - Article
SN - 0017-9310
VL - 177
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
M1 - 121492
ER -