Abstract A new approximate method of optimum heating cylindrical pressure elements weakened by openings was proposed. Optimum variations in fluid temperature when heating the pressure component were determined from the condition that the total circumferential stress at the edge of the opening, resulting from the thermal load and pressure is equal to the allowable stress. The allowable stress is determined from the Wohler fatigue diagram for a given number of start-ups and shutdowns of a power unit from the cold state. Optimum temperature changes are difficult to estimate at the beginning of the heating, using both exact analytical and numerical methods. In case of analytical methods, this is due to the very slow convergence of a series for near-zero time in the exact solution. In this paper, the optimum temperature changes of the fluid at the beginning of heating were determined using the heat balance integral method (HBIM). This method makes it possible to determine with high accuracy the temperature of the fluid for times close to zero, i.e., at the beginning of the heating process. In the second stage of heating, the optimum fluid temperature was determined on the assumption of a quasi-steady temperature field in the pressure element. The problem analysed in the article is important to increase flexibility of boilers and steam units. By optimising the heating up of the boiler during boiler start-up, the start-up time of the boiler and the whole unit can be significantly shortened and the power unit can be quickly connected to the power system.

中文翻译：

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加热带开口的厚壁部件时确定最佳流体温度的新方法

摘要 提出了一种新的近似优化加热开孔弱化圆柱压力元件的方法。加热压力元件时流体温度的最佳变化是根据以下条件确定的，即由热负荷和压力引起的开口边缘处的总周向应力等于容许应力。允许应力由 Wohler 疲劳图确定，其中功率单元从冷态启动和停机给定次数。使用精确的分析和数值方法很难在加热开始时估计最佳温度变化。在分析方法的情况下，这是由于精确解中接近零时间的级数收敛非常缓慢。在本文中，使用热平衡积分法（HBIM）确定加热开始时流体的最佳温度变化。这种方法可以在接近零的时间，即在加热过程开始时，高精度地确定流体的温度。在加热的第二阶段，最佳流体温度是根据压力元件中准稳态温度场的假设确定的。文章中分析的问题对于提高锅炉和蒸汽机组的灵活性很重要。通过优化锅炉启动时的锅炉升温，可显着缩短锅炉及整机启动时间，使机组快速接入电力系统。这种方法可以在接近零的时间，即在加热过程开始时，高精度地确定流体的温度。在加热的第二阶段，最佳流体温度是根据压力元件中准稳态温度场的假设确定的。文章中分析的问题对于提高锅炉和蒸汽机组的灵活性很重要。通过优化锅炉启动时的锅炉升温，可显着缩短锅炉及整机启动时间，使机组快速接入电力系统。该方法可以在接近零的时间（即在加热过程开始时）以高精度确定流体的温度。在加热的第二阶段，最佳流体温度是根据压力元件中准稳态温度场的假设确定的。文章中分析的问题对于提高锅炉和蒸汽机组的灵活性很重要。通过优化锅炉启动时的锅炉升温，可显着缩短锅炉及整机启动时间，使机组快速接入电力系统。最佳流体温度是根据压力元件中准稳态温度场的假设确定的。文章中分析的问题对于提高锅炉和蒸汽机组的灵活性很重要。通过优化锅炉启动时的锅炉升温，可显着缩短锅炉及整机启动时间，使机组快速接入电力系统。最佳流体温度是根据压力元件中准稳态温度场的假设确定的。文章中分析的问题对于提高锅炉和蒸汽机组的灵活性很重要。通过优化锅炉启动时的锅炉升温，可显着缩短锅炉及整机启动时间，使机组快速接入电力系统。