封闭漫射灰腔内辐射模型的应用

Application of Diffuse Gray Enclosure Radiation Theory to Thermal Operation of Reheating Furnace

在满足计算精度的基础上，提出计算量相对较小的高温燃烧室辐射传热模型，可供工程实际应用．模型以高温传热中辐射占主导地位为前提，引入封闭漫射灰腔内辐射理论，将辐射换热空间离散成有限个独立封闭换热灰体腔，在灰体腔内部进行辐射计算，灰体腔之间的辐射换热通过假想面进行．辐射全交换面积仍然采用区域法的积分思想，但是只计算封闭灰腔内部各单元的交换面积及相邻区域对假想面的交换面积，因此计算量相对区域法小得多．模型采用能量平衡方法，直接建立热源、吸收性介质及吸热物质之间的函数关系．实例计算结果表明，该模型能真实反映加热炉燃烧室内的传热效果，计算机时少。

On the premise of satisfying the calculation precision, this paper built a radiation heat transfer model of combustion chamber, which took less time than the prevalent methods, such as Zone Method, Monte Carlo, Heat Flux Method. According to the dominant function of radiation heat transfer in high temperature chamber, this model adopted the diffuse gray enclosure radiation theory and divided heat transfer space into independent diffuse gray enclosures. Radiation exchange occurred in the internal of each diffuse gray enclosure. The radiation exchange among enclosures took place across the imaged surface. Total radiation exchange area was calculated with the method of integration, which was the same as Zone Method. Because only the exchange area of elements in each enclosure and the exchange area between the imaged surface and enclosure were calculated, the model was simpler than Zone Method. By the method of energy balance, this model built the functional relationship among fuel, gaseous medium of absorbility, heated materials. The modeling result shows that the model can reflect true temperature distribution of the furnace and predict the effect of the variations of energy consumed and productivity on the heating quality.