TY - JOUR
T1 - A novel multi-dimensional model for solidification process with supercooling
AU - Uzan, Avihai Yosef
AU - Kozak, Yoram
AU - Korin, Yosef
AU - Harary, Itay
AU - Mehling, Harald
AU - Ziskind, Gennady
N1 - Funding Information:
This research was partially sponsored by the European Union , under Partnership Agreement INNOSTORAGE-PIRSES-GA-2013-610692 (Use of innovative thermal energy storage for marked energy savings and significant lowering of CO 2 emissions).
Funding Information:
This publication is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 657466 (INPATH-TES).
Publisher Copyright:
© 2016 Elsevier Ltd
PY - 2017/3/1
Y1 - 2017/3/1
N2 - It is well known that many materials do not solidify at their nominal phase-change temperature. Rather, nucleation occurs in them at a lower temperature. This phenomenon is usually termed “supercooling” or “subcooling” in the literature. Understanding, prediction and, if possible, prevention, or at least reduction, of supercooling are very important specifically to latent heat thermal energy storage (LHTES) systems, because the temperature differences in them must be small in order to achieve higher efficiency. In the present study, a novel mathematical model of solidification with supercooling and heat transfer is developed. For the first time, it is multidimensional in space. The model encompasses all possible stages of the process, namely, single-phase liquid cooling from the initial state to the nucleation temperature, kinetic nucleation accompanied by a rapid temperature rise to the nominal phase-change temperature, regular solidification and finally cooling of the solid phase. The kinetic solidification speed, based on the activation energy, is temperature- and, as a result, time-dependent. The model ensures a smooth, physically meaningful transition from the kinetic to regular solidification. Local and overall energy balance preservation at all stages of the process is ensured. The model is based on the enthalpy formulation, resolved using an in-house numerical code based on finite volumes. For the single phase cooling, it is validated using the well-known solutions from the literature. The model is then compared to experimental results of solidification of supercooled gallium in a vertical cylindrical mold. Accordingly, heat transfer in the mold is also included. It is shown that the model reflects the experimental results fairly well, in particular when predicting temperatures at various locations inside the material. Also, physically sound solidification patterns are obtained.
AB - It is well known that many materials do not solidify at their nominal phase-change temperature. Rather, nucleation occurs in them at a lower temperature. This phenomenon is usually termed “supercooling” or “subcooling” in the literature. Understanding, prediction and, if possible, prevention, or at least reduction, of supercooling are very important specifically to latent heat thermal energy storage (LHTES) systems, because the temperature differences in them must be small in order to achieve higher efficiency. In the present study, a novel mathematical model of solidification with supercooling and heat transfer is developed. For the first time, it is multidimensional in space. The model encompasses all possible stages of the process, namely, single-phase liquid cooling from the initial state to the nucleation temperature, kinetic nucleation accompanied by a rapid temperature rise to the nominal phase-change temperature, regular solidification and finally cooling of the solid phase. The kinetic solidification speed, based on the activation energy, is temperature- and, as a result, time-dependent. The model ensures a smooth, physically meaningful transition from the kinetic to regular solidification. Local and overall energy balance preservation at all stages of the process is ensured. The model is based on the enthalpy formulation, resolved using an in-house numerical code based on finite volumes. For the single phase cooling, it is validated using the well-known solutions from the literature. The model is then compared to experimental results of solidification of supercooled gallium in a vertical cylindrical mold. Accordingly, heat transfer in the mold is also included. It is shown that the model reflects the experimental results fairly well, in particular when predicting temperatures at various locations inside the material. Also, physically sound solidification patterns are obtained.
KW - Enthalpy method
KW - Multidimensional
KW - Numerical modeling
KW - Solidification
KW - Supercooling (subcooling)
UR - http://www.scopus.com/inward/record.url?scp=84992154160&partnerID=8YFLogxK
U2 - 10.1016/j.ijheatmasstransfer.2016.10.046
DO - 10.1016/j.ijheatmasstransfer.2016.10.046
M3 - Article
AN - SCOPUS:84992154160
SN - 0017-9310
VL - 106
SP - 91
EP - 102
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
ER -