为提高沥青搅拌设备烘干筒传热效率,降低烘干筒散热损失,对烘干筒内部料帘区和火焰区的传热过程与方式进行了分析。在综合考虑火焰、烟气、烘干筒筒壁与骨料之间的辐射、对流和接触热交换过程的基础上,提出了烘干筒一维轴向传热数学模型,并结合已有研究成果给出了各传热系数的计算公式和辐射网络模型,同时采用4阶龙格-库塔方法对烘干筒传热过程进行了数值计算,并以4000型搅拌设备烘干筒为试验对象进行了计算和验证。结果表明:火焰区烘干筒表面温度最高约300℃,料帘区的温度在30℃~170℃范围内;在料帘区前半段,试验与数值计算结果相差4.86%,变化规律基本一致;随温度增加,两者差值变大,最大差值出现在火焰区,约为19.5%,但仍基本满足工程计算的需要,此时计算的烘干筒表面热损失约占总热量的3%;研究结果可为烘干筒结构优化和节能提供依据。
Abstract
To improve the heat transfer efficiency and reduce the heat loss of drying drum for the asphalt mixing plant, the heat transfer process and mode in internal particle curtain area and fire area of drying drum were analyzed. On the basis of considering the heat radiation, convection and contact transfer process between fire, smoke, drying drum wall and aggregate, the one-dimension axial heat transfer mathematical model of drying drum was proposed. Combining with the calculation formulae of the heat transfer coefficient and the radiation network models of existing researches, fourth order Runge-Kutta method was adopted on calculation of the heat transfer process of drying drum, and the model was calculated and verified by drying drum for 4000 type mixing plant. The results show that the highest surface temperature in fire area is about 300 ℃, and the temperature in particle curtain area is in the range of 30 ℃ to 170 ℃. In the first half of particle curtain area, the D-values between experiment result and calculation result is 4.86% and have the basically same change law. With temperature increasing, the D-value grows. The maximum D-value exists in the fire area, which is about 19.5%. But the model still satisfies with the requirements of engineering calculation. The calculated heat loss on the surface of drying drum accounts for about 3% of the total heat. The results provide the basis for structure optimization and energy conservation of drying drum.
关键词
机械工程 /
传热过程 /
数值计算 /
一维轴向模型 /
热损失 /
烘干筒
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Key words
mechanical engineering /
heat transfer /
numerical calculation /
one-dimension axial model /
heat loss /
drying drum
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中图分类号：
U415.522
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脚注
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基金
国家自然科学基金项目(51408046);中央高校基本科研业务费专项资金项目(G20132251008)
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