In order to optimize the temperature field uniformity of Rossini gas calorimeter to minimize the measurement uncertainty, 3D transient numerical simulation was carried out for temperature field of Rossini gas calorimeter based on MRF model and standard k-ε turbulence model, and the influence of rotational speed and the combustion chamber height on unsteady temperature field in calorimeter vessel was also obtained, especially the influence on heat transfer between combustion chamber and heat transfer medium. Meanwhile, the best installation location of temperature sensor was also determined. The results indicate that rotational speed of 420 r/min can be regarded as the optimal rotational speed of stirrer paddle, the heat transfer between combustion chamber wall surface and heat transfer medium is maximum at this time, the standard deviation of the temperature at the monitoring point of heat transfer medium is within 1.5 mK. Reduction of the height of the combustion chamber can improve the temperature homogeneity of the heat transfer medium. At the heating stage, the standard deviation of temperature at the monitoring points is reduced from 26 mK to 7.5 mK when the combustion chamber height is reduced from 180 mm to 140 mm. The optimum installation position of the temperature sensor is 25 mm to the bottom of shell, on the equidistant line of the symmetry axis of combustion chamber and guide cylinder.%为优化Rossini型气体热量计温度场均匀性以减小测量不确定度,采用多重参考系法(MRF)和标准k-ε湍流模型对Rossini型气体热量计的温度场进行三维瞬态数值模拟,分别得到搅拌器转速尧燃烧室高度对量热容器内非稳态温度场的影响,特别是对燃烧室与吸热介质之间热传递的影响以及对吸热介质温度均匀性的影响,同时确定温度传感器的最佳安装位置.结果表明:搅拌器桨叶最佳转速为420 r/min,这时燃烧室壁面与吸热介质之间的传热效率最大,并且吸热介质内监测点温度的标准偏差保持在1.5 mK以内.燃烧室高度减小可以提高吸热介质的温度均匀性,加热阶段中,燃烧室高度从180 mm降低到140 mm时,监测点温度的标准偏差从26 mK降低到7.5 mK.温度传感器的最佳安装位置在燃烧室对称轴及导流筒对称轴的等距线上离壳体底部25 mm处.
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