Effects of ultrahigh permittivity ceramic on water freezing by high voltage electric field-assisted freezing system

Abstract

• High voltage electric field-assisted freezing (HVEFF) on water sample was studied. • Ultra-high permittivity ceramic (UHPC) was used for the 1 st time in the freezing. • Decreasing percentage of supercooling degree was 90.3% under UHPC-HVEFF at 9 kV. • UHPC greatly improved water freezing performance when integrated to HVEFF. • UHPC possessed potentials for enlarging the sample-treating capacity of HVEFF. To investigate the effect of ultra-high permittivity ceramic (UHPC) on water freezing, a UHPC-based high voltage electric field-assisted freezing system (UHPC-HVEFF) and a low permittivity acrylic-based high voltage electric field-assisted freezing system (LPA-HVEFF) were developed. The freezing behaviours of water under UHPC-HVEFF and LPA-HVEFF at 0, 3, 6, 9 kV were comparatively studied. Hierarchical cluster analysis (HCA) was used to visualize the difference between UHPC-HVEFF and LPA-HVEFF. COMSOL was used to simulate the distribution of electric field strength in the water sample under HVEF. It was found that the decreasing percentage of the supercooling degree of the water reached 34.9%, 89.2% and 90.3% under UHPC-HVEFF at 3, 6 and 9 kV, respectively, whereas those were only 2.40%, 10.4% and 24.6% under LPA-HVEFF at 3, 6 and 9 kV, respectively. Results from the simulation indicated that the electric field strength in the water under UHPC-HVEFF was on average 11.7-7.5 times that of LPA-HVEFF, thus contributing to the high freezing efficiency of UHPC-HVEFF. This study indicated that UHPC possessed great potential to increase the sample-treating capacity of HVEF-assisted freezing system.