Based on the gas analysis error of a single position

the influence law of the fuel-air ratio error between gas analysis and flow measurement on the testing precision of combustion efficiency and exhaust emission was founded for the current sampling mode of primary combustor

afterburner and gas turbine engine. The data were valid for primary combustor test by swing mode when fuel-air ratio error was less than 5.1% between flow measurement and gas analysis; meanwhile

the error of combustion efficiency was less than 0.5% and sampling density was considered enough. The error of fuel-air ratio of flow measurement to gas analysis was large due to less sampling density in afterburner and gas turbine engine

the precision of combustion efficiency was also affected by fuel-air ratio and the volume fraction of CO. It indicates that enough sampling density for gas analysis is necessary for high test precision.