Circulating fluidized bed (CFB) boilers offer a technically viable and environmentally friendly means for the clean and efficient utilization of solid fuels. However, the complex gas–solid two-phase flow processes within them have hindered a thorough resolution of prediction issues related to coupled combustion, heat transfer, and pollutant generation characteristics. To address the deficiencies in scientific research, meet the practical operational needs of CFB boilers, and comply with new carbon emission policies, conducting full-scale field tests on large-scale CFB boilers is needed, so that the complex gas–solid flow, combustion, and heat transfer mechanisms in the furnace can be comprehended. In this paper, issues related to large-scale CFB boilers, including the uniformity of air distribution, secondary air injection range, spatial distribution of oxygen consumption and combustion reactions, distribution of pollutant generation, hydrodynamic and heat transfer characteristics, coal feeding distribution characteristics, coal diffusion characteristics under thermal operating conditions, and engineering research on anti-wear technology, are reviewed. By integrating practical engineering applications, the basic methods and measurement techniques used in full-scale field tests for large-scale CFB boilers are summarized, providing a practical reference for conducting engineering tests with large-scale CFB boilers.

Clamp-on ultrasonic flowmeters serve as an important tool for on-site testing of gas flow meters. However, its accuracy is significantly affected by the actual flow field, thus limiting its application scenarios. To address this issue, this study focuses on typical industrial disturbance structures and obtains the evolution and distribution of non-ideal flow fields downstream of disturbances through experiments and numerical simulations, as well as their effects on velocity and flow measurement errors. The results indicate that when traditional reflection or diagonal measurements were used in the downstream of disturbances, the flow deviation was largely dependent on the installation position and angle of the clamp-on ultrasonic flowmeter. This introduced significant uncertainty and bias, rendering it impossible to correct measurement results through quantitative coefficients. Utilizing a dual-channel measurement method can enhance measurement accuracy. When two sets of sensors perpendicular to each other were used to combine the reflection measurement path, the deviation fluctuation downstream of disturbances can be effectively controlled within the range of ±2%, irrespective of the installation angle. This measurement approach significantly reduced the distance limitations on the distance of the straight pipe section during the use of clamp-on ultrasonic flowmeters.