水冷壁气流床气化炉渣层热应力数值模拟方法的改进

固态渣层能够保护气流床气化炉的水冷壁，防止其受到高温合成气直接辐射以及液态熔渣的侵蚀。本文提出一种数值模拟渣层热应力的改进方法，并应用该改进方法对降温阶段渣层热应力的变化进行模拟研究。在渣层热应力的数值模拟研究中，经常假定水冷壁渣层的热应力变化基于一个固定的参考温度（比如环境温度25℃）。然而对于降温阶段的水冷壁气流床气化炉，一个固定的参考温度值并不能表征渣层"无应力"的初始状态，在此基础上计算将会得到一个不合理的渣层应力分布结果。针对该问题，提出了一种改进方法：将水冷壁渣层分割为多个子计算域，每个子计算域内单独设置参考温度，以此实现在整个水冷壁渣层上施加一个近似为降温初始时刻的参考温度分布，从而使渣层在降温初始时刻处于"无应力"状态。同时，对前人文献中的三维水冷壁渣层结构在降温过程中的热应力变化情况进行计算，以此测试改进方法的准确性，改进方法得到的模拟结果与其他参考文献得到的渣层热应力变化趋势一致。

An improvement on numerical modeling for thermal stress analysis of slag layer in a membrane wall entrained-flow gasifier

Solid slag layer can protect membrane wall from syngas radiation and liquid slag erosion. The work presented here aims to provide an improvement of numerical modeling for thermal stress analysis of slag layer and accurately represent the change of thermal stress during the cooling process. In the former studies, the numerical modeling for thermal stress analysis of slag layer often assumes that the change of thermal stress of the computational domain was based on a constant reference temperature (ambient temperature 25℃ is in common use). However, a single reference temperature cannot present the initial temperature distribution of the computational domain with a stress balance state of the cooling process, and will acquire an incorrect thermal stress distribution. Therefore, an improvement has been proposed:cutting the whole computational domain into some subdivisions and applying a reference temperature distribution on the subdivisions, in order to acquire a stress balance state at the beginning of the cooling process. 3D numerical model of previous literature was recalculated to test the validity of the improvement. Result showed a similarly trend with reference article on a membrane wall entrained-flow gasifier.