Abstract：
In this study, a computational fluid dynamics (CFD) model was developed to predict all relevant phenomena occurring during a moist heat sterilization process at a high level of temporal and spatial resolution. The developed CFD model was used to simulate the distribution of, for example, pressure, temperature, and residual air within a large-scale industrial steam autoclave (multiphase flow models), which was not published until now. Moreover, the thermodynamic behavior and distribution of fluids and temperatures inside the sterilization load were simulated and were verified with measurements. Based on the obtained sterilization temperature profiles in connection with the sterilization environment (e.g., non-condensable gases, natural convection), bacterial inactivation could be simulated. A complete moist heat sterilization process was simulated, including all relevant phenomena inside an autoclave chamber and a Peritoneal Dialysis Bag System (PDBS), which represents a complex sterilization item. To verify the simulation results, simulated pressures and temperatures were compared with measurement data for both the autoclave chamber and the PDBS. The results show that the simulated and measured values were in excellent accordance. By using the novel CFD model, the distribution of steam and residual air inside the autoclave chamber, as well as the natural convection inside the sterilization load, could be precisely predicted. To predict the inactivation of Geobacillus stearothermophilus inside different moist heat environments, the CFD model was extended with bacterial inactivation kinetics based on measurement data. The simulation results clearly indicate that our developed CFD model can be used to predict the inactivation kinetics of bacteria, depending on the sterilization temperature profile of the sterilization process as well as the moist heat sterilization environment, and to resolve the kinetics in time and space. Therefore, the developed CFD model represents a powerful tool that might be used in the future to predict, for example, \"worst case\" locations for any given autoclave and sterilization load or any other relevant process parameter, enabling the operator to develop an effective sterilization process.
摘要：
在这项研究中,开发了计算流体动力学（CFD）模型，以在较高的时间和空间分辨率下预测湿热灭菌过程中发生的所有相关现象。建立的CFD模型被用来模拟分布，例如,压力,温度,和大型工业蒸汽高压釜中的残余空气（多相流模型），直到现在才出版。此外，模拟了灭菌负荷内流体和温度的热力学行为和分布，并通过测量进行了验证。基于获得的与灭菌环境相关的灭菌温度曲线(例如，不可冷凝的气体，自然对流)，可以模拟细菌灭活。模拟了一个完整的湿热灭菌过程，包括高压灭菌器腔和腹膜透析袋系统（PDBS）内的所有相关现象，这代表了一个复杂的灭菌项目。为了验证仿真结果，将模拟压力和温度与高压灭菌器室和PDBS的测量数据进行比较。结果表明,模拟值与实测值吻合良好。通过使用新颖的CFD模型，蒸汽和剩余空气在高压灭菌器室内的分布，以及灭菌负载内的自然对流，可以准确预测。预测嗜热脂肪地芽孢杆菌在不同湿热环境下的失活情况,基于测量数据,用细菌灭活动力学扩展了CFD模型.模拟结果清楚地表明，我们开发的CFD模型可用于预测细菌的失活动力学，根据灭菌过程的灭菌温度曲线以及湿热灭菌环境，并解析时间和空间上的动力学。因此,开发的CFD模型代表了未来可能用来预测的强大工具，例如,任何给定高压灭菌器和灭菌负荷或任何其他相关工艺参数的“最坏情况”位置，使操作者能够开发有效的灭菌过程。
