【摘要】 皮肤低温外科手术中的一个关键问题是对体表受冷刀作用后组织温度场的准确预测和调控 ,而生物组织内真实血管的空间分布会对这一相变传热过程产生重要的影响。本文将常温情况下建立的Weinbaum Jiji生物传热方程拓展应用于该问题的分析 ,由此考察血管空间分布结构对皮肤相变传热过程的影响 ,以一维问题为例 ,采用变时间步长的数值计算方法得到了体表受冷刀作用下的组织冻结温度变化情况。作为对比 ,本文还求解了经典Pennes生物传热方程及普通导热方程的相应相变传热问题。三类方程的比较表明在相同冷冻和物性条件下 ,血管空间分布效应会对一定部位的组织瞬态温度响应产生很大影响 ,这提示了在低温外科手术中预示相变过程时考虑血管传热机制的重要性。文中还考察了相变温度和大血管入口速度对温度预示的影响情况。就作者所知 ,本文是考虑血管分布效应后对皮肤低温相变传热进行分析的首次尝试。更多还原

【Abstract】 One of the most critical issues in skin cryosurgery is to accurately predict and control tissue temperature field during the phase change heat transfer process,which is significantly inflluenced by local vascular geometry and blood flowing conditions.The well known Weinbaum\|Jiji(W\|J) bioheat transfer equation for normal temperature was applied in this paper to investigate vasculature effects to skin freezing problem.The finite difference method with variable time step was applied to solve one\|dimensional W\|J equation,as well as the traditional Pennes equation, and the pure heat conduction equation under phase change.Predictive results from these three heat transfer models were compared,and it was found that,for the same freezing conditions,existence of local vascular geometry and blood flowing conditions greatly influenced the transient temperature response,which is critical for a successful cryosurgery.This means the importance of considering the vasculature for cryosurgery temperature prediction.Besides,influence of the phase change point due to non\|ideal tissue material to the temperature prediction was analyzed numerically.Parameter study on W\|J equation shows that the effective vascular heat conduction term has far larger influence than that of the convection term for temperature prediction.The present study is likely the first attempt to study the skin phase change problem by incorporating vasculature and blood flowing conditions.更多还原