ABSTRACT In this study, thermomechanical and creep analyses of boiler tubes are performed and a procedure for cost-based optimization of boiler tube geometries is presented. First, analytical thermal convection and conduction heat transfer under ultra-supercritical (USC) and advanced ultra-supercritical (A-USC) conditions as well as numerical evolution of creep stresses in the boiler tube are obtained. Subsequently, the results are used to calculate the thermal efficiency and creep lifetime of austenitic stainless steel Super 304H and Ni-based alloy Nimonic alloy 80A. The geometric parameters of the boiler tube are then optimized to minimize the total cost related to the boiler tubes including capital investment and operational costs. Comparing with the conventional approach which assumes a fixed creep lifetime for simplicity, the present results also showed that creep lifetime assessment is important and should be included in the optimization. This optimization procedure can also be applied to other boiler tube materials under various operating conditions of thermal power plants.

中文翻译：

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蠕变寿命对热电厂锅炉管几何优化的影响

摘要 在这项研究中，进行了锅炉管的热机械和蠕变分析，并提出了基于成本的锅炉管几何优化程序。首先，获得了超超临界（USC）和先进超超临界（A-USC）条件下的分析热对流和传导传热以及锅炉管蠕变应力的数值演化。随后，将结果用于计算奥氏体不锈钢 Super 304H 和 Ni 基合金 Nimonic 合金 80A 的热效率和蠕变寿命。然后优化锅炉管的几何参数以最小化与锅炉管相关的总成本，包括资本投资和运营成本。与为简单起见假设固定蠕变寿命的传统方法相比，目前的结果还表明蠕变寿命评估很重要，应该包括在优化中。这种优化程序也可以应用于火力发电厂各种运行条件下的其他锅炉管材料。