外管为螺旋管及多孔填料的炼焦荒煤气显热回收套管换热器一维热计算模型

One-dimensional Heat Calculation Model of Double-pipe Heat Exchanger with Helically Coiled Tube and Porous Filler as Outer Tube for Sensible Heat Recovery of Raw Coke Oven Gas

为了实现炼焦荒煤气显热回收时上升管壁面局部温度监控以解决煤焦油析出结焦问题,基于多孔介质非热平衡理论建立了外管为螺旋管及多孔填料的炼焦荒煤气显热回收套管换热器一维稳态热计算模型,并采用有限差分法进行了数值求解。通过与三维模拟结果比较,验证了该模型的准确性。该模型既可获得所研究换热器管壁温度的局部分布特性,又可避免三维模拟复杂的建模计算过程及巨大的计算机硬件需求。与传统零维热计算模型相比,该一维热计算模型能考虑填料层轴向热耗散与吸放热两侧流体流向夹角对换热效果的影响,具有更高的精确性。该方法极大提高了对该换热器的设计能力。

In order to realize the monitoring of wall temperature of ascension tube to solve the problem of coal tar condensation and coking, a one-dimensional heat calculation model of the heat exchanger with helically coiled tube and porous filler as outer tube for sensible heat recovery of raw coke oven gas was established based on the non-thermal equilibrium theory of porous media. The solving method for this model was given with finite difference method and also verified by three dimensional simulations. This model can not only obtain the local distribution characteristic of wall temperature but also avoid the complicated modeling and calculating process of three dimensional simulations and the huge demand of computer hardware. Compared with the traditional zero-dimensional heat calculation method, the one-dimensional heat calculation method has a higher accuracy because it takes into account the influence of the axial heat dissipation of the packing layer and the flow direction angle of fluids at both sides on the heat transfer performance. This model greatly improves the capability of design on this type of heat exchanger.