三维湍流回流气相和煤粉燃烧辐射传热离散坐标模型和热流模型比较

Comparison of Two Radiative Heat Transfer Models in Three Dimension Turbulent Gas and Coal Particle Combustion

:针对空腔内纯三维辐射传热和大速差射流燃烧室内三维湍流回流气体燃烧和煤粉燃烧 ,对其中辐射传热分别采用离散坐标模型和热流模型进行了分析与比较。模拟结果表明 ,两种模型所得到的温度分布在趋势上类似 ,而在定量上有差别。对纯辐射传热模拟 ,与区域法的精确数据对比表明 ,离散坐标模型的结果更合理。对燃烧的模拟结果是 ,离散坐标模型所得的气体温度要高于热流模型的相应值 ,亦即热流法低估了气体温度和壁面热流。二者所得到的速度场差别不大 ,计算时间大体相仿。这表明 ,今后四角喷燃炉内流动和煤粉燃烧的模拟应当采用离散坐标辐射传热模型。

Two radiative heat transfer models,the discrete ordinate (DO) model and the FLUX model,were both applied in a chamber and a large velocity slip combustor.The results of the two models show that they are the same in quality but differ in details.For the case of the chamber,it is used to verify the two models.Compared with thosed of the zone method,the results of the DO model show that the DO model is more accurate while the FLUX model gives relatively large deviations.For the case of the combustor,the combustion results show that the predicted temperature of the DO model is higher than that of the FLUX model.There is little difference in the velocity fields and the time both models require is almost equal.All these show that the DO model should be used more in future in flow and combustion simulation.