Effect of microscale mass transport and phase change on numerical prediction of freezing in biological tissues
Effect of microscale mass transport and phase change on numerical prediction of freezing in biological tissues
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DOI：
10.1115/1.1445134
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发表时间：
2002-04-01
影响因子：
--
通讯作者：
Bischof, JC
中科院分区：
文献类型：
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作者：
Devireddy, RV;Smith, DJ;Bischof, JC
建立了生物组织冷冻过程中微尺度热质输运的数值模型。传热问题是制定在一个一般的一维坐标系（carbohydrate，圆柱形或球形），并使用有限控制体积离散。对于域中的每个控制体积，潜热释放由在那里发生的细胞水运输和细胞内冰形成过程（耦合的热/生物物理方法）确定。将耦合模型应用于两个具有不同几何形状和边界条件的低温生物冻结问题。水的温度依赖的热性质和生物物理性质的两个生物组织，正常大鼠肝脏和Dunning AT-1大鼠前列腺肿瘤组织被用来模拟微观和宏观尺度的冷冻过程。耦合的热/生物物理模型的一个主要优点是其独特的能力，预测在冷冻过程中的组织域内的各个位置的宏观尺度的热响应和微观尺度的生物物理响应，同时。将由耦合模型预测的热历史与标准非线性方法模型的预测进行比较，其中潜热释放的温度依赖性A（T）是从水-NaCl相图调整的显式函数，并且相变不受微尺度生物物理过程的速率限制（即，非耦合方法）。两种模型的结果非常相似，这表明在冷冻过程中所选择的生物组织中发生的微尺度生物物理过程对相变发生的速率几乎没有限制。额外的模拟表明，预测的宏观热历史结果没有显着影响（
A numerical model incorporating the microscale heat and mass transport in biological tissue during freezing is developed. The heat transfer problem is formulated in a general one-dimensional coordinate system (cartesian, cylindrical or spherical), and a finite control volume discretization is used. The latent heat release,for each control volume in the domain is determined by the cellular water transport and intracellular ice formation processes occurring there (a coupled thermal/biophysical approach). The coupled model is applied to two cryobiological freezing problems, with different geometry and boundary conditions. The temperature dependent thermal properties of water and the biophysical properties of two biological tissues, normal rat liver and Dunning AT-1 rat prostate tumor tissue are used to simulate both the micro and macroscale freezing processes. A major advantage of the coupled thermal/biophysical model is its unique ability to predict both the macroscale thermal response and the microscale biophysical response at various locations within the tissue domain during a freezing process, simultaneously. Thermal histories predicted by the coupled model are compared to predictions of a standard enthalpy-method model in which the temperature dependence of the latent heat release, A(T) is an explicit function adapted from the water-NaCl phase diagram, and phase change is not rate-limited by microscale biophysical processes (i.e., an uncoupled approach). The results for both models are very similar; this suggests that the microscale biophysical processes which occur in the chosen biological tissues during freezing do little to limit the rate at which phase change occurs. Additional simulations suggest that the predicted macroscale thermal history results are not significantly affected (