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With the large-scale deployment of intermittent renewable energy, represented by wind and solar energy, the demands for flexibility in the power system are continuously increasing (Dai, H. et al., 2016; Johansson, T. et al., 2012), China relies on coal as its primary energy source (Qi, Y. et al., 2016). Thus, the implementation of a flexible transformation of the thermal power has become the most realistic and feasible choice to improve the power system flexibility (Chen, H. et al., 2021; Xiao, D. et al., 2014; Gong, S. et al., 2017; Ding, Y. et al., 2014). On this basis, in-depth research on the peak shaving technology of large-scale coal-fired units has become necessary. Grid peak shaving involves many aspects such as boilers, turbines, generators, auxiliary equipment, and transmission systems (Gu, Y. et al., 2016; Gao, Z. et al., 2021; Xue, Y. et al., 2019; Manojkumar, R. et al., 2022; Wang, J. et al., 2021). In terms of boilers, the stable combustion under low-load is a key issue, and the main solution is the development of stable combustion technology (Cheng, H. et al., 2021). Researchers have developed stable combustion technologies, including bluff bodies, ship types, pre-combustion chambers, large differential speeds, asymmetric jets, reverse blowing, and coal concentration (Zhang, H. et al., 2007; Tsumura, T. et al., 2003; Zeng, G. et al., 2017; Hu, F. et al., 2022; Wang, J. et al., 2009; Chayalakshmi, C. et al., 2009). Among them, the bluff-body stable combustion technology integrates a bluff body at the nozzle of the burner to form a recirculation zone at the nozzle outlet. This allows the fuel to ignite and burn stably under conditions of high-speed airflow. During combustion, the reflux behind the bluff body heats the fuel-air mainstream at the root of the air mass by entraining a high-temperature flue gas, thereby accelerating the exchange of momentum, mass, and energy. This is conducive to flame stability (Zhang, L. et al., 2011). However, the unburned fuel flow can only enter the recirculation zone through the boundary layer. This prevents the beneficial effect of the high-temperature recirculation zone behind the bluff body from being fully harnessed. In comparison, the slotted bluff-body stable combustion method sets a gap in the middle of the bluff body to directly introduce a small amount of fuel flow into the high-temperature recirculation zone. In this case, this fuel can be ignited first in a favorable environment before igniting the mainstream. This allows for a staged ignition mechanism in the recirculation zone and further improves the stability of combustion. At the same time, it does not destroy the basic structure of the recirculation zone behind the bluff body. (Du, Y. et al., 2006; Liao, Y. et al., 2022; Yan, Y. et al., 2019). However, there is a lack of in-depth analysis on why the slotted bluff-body combustion has good stability.