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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-469-4

ISBN Online: 978-1-56700-470-0

Second Thermal and Fluids Engineering Conference
April, 2-5, 2017, Las Vegas, NV, USA

THIN FILM EVAPORATION OF LIQUID NITROGEN ON A MICRO STRUCTURED SURFACE

Get access (open in a dialog) pages 2807-2813
DOI: 10.1615/TFEC2017.mst.017617

Abstract

Vitrification is one of the most effective methods for cell cryopreservation. An ultra-fast cooling rate is beneficial to improve the vitrification level of the extra- and intra-cellular solution and decrease the concentration of cryoprotectant. This article focuses on the evaporation characteristics of liquid nitrogen on a micro structured surface (MSS) etched into the frozen carrier surface. Three main parameters, the heat flux, the total heat resistance and the evaporation heat transfer coefficient of the liquid nitrogen, were investigated in the dangerous temperature zone (0°C ~ - 60°C) using a lumped capacitance method. The experimental work verified the feasibility of fast freezing based on liquid nitrogen thin film evaporation. The heat transfer characteristics of the frozen carrier were experimentally measured and analyzed. It was found that the frozen carrier and the fast cooling technology designed in this study can acquire a high average cooling rate of 9.04 × 104 °C/min in the 0°C ~ - 60°C temperature zone. Two types of frozen carriers, an etched micro structure on the surface (MSS) and a plain surface, were compared: both carriers showed optimal heat transfer performance at a pressure of 10.3kPa, but the carrier with etched MSS achieved 44% higher average cooling rate than the one with plain surface.