示踪气体稀释法能解决电厂大直径烟囱流场复杂导致的烟气流量测量结果误差大的问题。该方法具有可溯源性，且其测量原理与常规速度面积法不同，因此具有作为流量测量现场校准方法的潜力。为此，该文基于数值模拟方法分析示踪气体稀释法在火电厂烟囱烟气流量测量中的可行性与准确性，并在此基础上，研究示踪剂稀释比例、示踪剂注入截面对测量的影响，同时还设计不同示踪剂取样方案来评估测量的稳定性。结果表明：在约9D（D为烟囱直径）高度处，示踪剂与烟气实现充分混合；示踪剂稀释比例过高或过低均会影响示踪剂与烟气的混合效率；示踪剂在烟道处注入能有效减小流量测量误差。在负荷率80%下，采取烟囱注入时，各取样方案的误差波动范围较大，但3点取样具有较稳定且良好的测量效果，在3D、8D、12D截面上的测量误差分别仅为-3.59%、-0.69%、-1.05%；水平烟道注入时，各取样方案的流量测量误差均不超过 ± 10%，且3点取样时，在3D、8D、12D截面上的测量误差分别仅为0.98%、-0.52%、0.21%，均在 ± 1%以内。该研究证明了示踪气体稀释法在大直径烟囱烟气流量测量中的可行性与准确性。

The tracer gas dilution method can address the issue of significant measurement errors in flue gas flow caused by the complex flow field in large-diameter stacks of power plants. The method is traceable and operates on a measurement principle different from the conventional velocity-area method, making it a promising candidate for on-site calibration of flow measurements. To this end, this paper employs numerical simulation to analyze the feasibility and accuracy of the tracer gas dilution method for measuring flue gas flow in power plant stacks. On this basis, it studies the influence of the tracer gas dilution ratio and injection cross-section on measurement results. In addition, different tracer gas sampling schemes were designed to evaluate the stability of the measurements. The results demonstrate that, at a height of approximately 9D (where D is the stack diameter), the tracer gas achieves full mixing with the flue gas; both excessively high and low tracer gas dilution ratios can negatively affect the mixing efficiency; injecting the tracer gas at the flue section can effectively reduce flow measurement errors. Under 80% load rate, when the tracer gas is injected into the stack, the measurement errors vary considerably across different sampling schemes. However, the three-point sampling method demonstrates a stable and accurate performance, with measurement errors of only -3.59%, -0.69%, and -1.05% at the 3D, 8D, and 12D cross-sections, respectively. When the tracer gas is injected into the horizontal flue, the flow measurement errors for all sampling schemes remain within ±10%. Specifically, with three-point sampling, the errors at the 3D, 8D, and 12D cross-sections are 0.98%, -0.52%, and 0.21%, respectively—all within ±1%. These results demonstrate the feasibility and accuracy of the tracer gas dilution method for flue gas flow measurement in large-diameter stacks.