School of Mechanical Engineering, KIIT University, Bhubaneswar, Odisha, 751 024, India.
Lasers Med Sci. 2023 Apr 13;38(1):98. doi: 10.1007/s10103-023-03756-8.
The present article proposes a numerical model for a novel laser assisted cryopreservation through vitrification of biological tissue. A two-dimensional numerical model is developed considering the non-Fourier heat conduction. The Finite Volume Method is used for discretization of the governing differential equation while the Tri-diagonal Matrix Algorithm (TDMA) is used for solving the resulting discretized algebraic equation in order to obtain the temperature distribution inside the tissue domain. The existing enthalpy method is modified considering the thermal relaxation time to capture the freezing front. With the increase in thermal relaxation time value, rate of heat transfer and rise in temperature during laser heating decreases and rate of heat loss during freezing also decreases. This reduces the length up to which vitrification is achieved. So, a proper size of the tissue is to be chosen to achieve the desired freezing rate. This length may vary based on the laser parameters and the thermal relaxation time. However, the validity of the present study may be examined experimentally in real ambient conditions before application in tissue preservation.
本文提出了一种通过玻璃化冷冻来实现新型激光辅助冷冻的数值模型。考虑到非傅里叶热传导，建立了二维数值模型。对控制微分方程进行离散化时采用有限体积法，而求解所得离散化代数方程时采用三对角矩阵算法（TDMA），以获得组织域内的温度分布。通过考虑热弛豫时间来修改现有的焓法，以捕获冷冻前沿。随着热弛豫时间值的增加，激光加热过程中的传热速率和温度上升降低，冷冻过程中的热损失速率也降低。这会减少实现玻璃化的长度。因此，需要选择适当尺寸的组织来实现所需的冷冻速率。这个长度可能会根据激光参数和热弛豫时间而变化。然而，在实际应用于组织保存之前，可以在真实环境条件下进行实验来检验本研究的有效性。
