燃气采暖热水炉冷凝换热器数值模拟  

Numerical Simulation of Condensing Heat Exchanger of Gas Heating and Hot Water Combi-boiler

作　　者：梁展程 LIANG Zhancheng

机构地区：[1]广东万和热能科技有限公司,广东佛山528325

出　　处：《煤气与热力》2019年第8期32-35,J0043,J0044,共6页Gas & Heat

摘　　要：针对燃气采暖热水炉的冷凝换热器(管壳式换热器,烟气走壳程,水走管程,换热管采用波纹管),采用Fluent软件模拟不同烟气进气角下冷凝换热器烟气温度场、传热系数、进出口烟气压力降,根据模拟结果分析最佳烟气进气角。在建立几何模型时,冷凝换热器外壳内壁面考虑两种情况,一种为平面内壁,另一种为波纹内壁(以下分别称为平面内壁换热器、波纹内壁换热器)。两种换热器烟气入口右侧(远离出口侧)均存在烟气滞留区。由于波纹对换热管与外壳间隙实现了填充,波纹内壁换热器不会出现平面内壁换热器的烟气短路情况(部分进口烟气未经换热管与管内冷水换热,就流向烟气出口)。波纹内壁换热器出口烟气温度明显低于平面内壁换热器,说明波纹内壁换热器的换热性能更优。两种换热器的传热系数均随烟气进气角的增大而增大。相同烟气进气角条件下,波纹内壁换热器的传热系数大于平面内壁换热器。两种换热器烟气压力降均随烟气进气角的增大而增大。相同烟气进气角条件下,平面内壁换热器的烟气压力降小于波纹内壁换热器。平面内壁换热器、波纹内壁换热器的最佳烟气进气角分别为15°、30°。For condensing heat exchanger of gas heating and hot water combi-boiler(shell and tube heat exchanger,flue gas shell,water tube,corrugated heat exchange tube),Fluent software is used to simulate the flue gas temperature field,heat transfer coefficient,inlet and outlet flue gas pressure drop of condensing heat exchanger under different flue gas inlet angles,and according to the simulation results,the best flue gas inlet angle is analyzed.When establishing the geometric model,two cases are considered on the inner wall of the condensation heat exchanger shell,one is the plane inner wall,the other is the corrugated inner wall(hereinafter referred to as the plane inner wall heat exchanger,the corrugated inner wall heat exchanger).There are flue gas retention zones on the right side of the two heat exchanger flue gas inlets(away from the outlet side).Since the corrugation fills the gap between the heat exchange tube and the shell,the corrugated inner wall heat exchanger does not have the flue gas short circuit of the heat exchanger with plane inner wall(part of the inlet flue gas does not exchange heat with the cold water in the tube,and flows to the flue gas outlet).The flue gas temperature at the outlet of the corrugated inner wall heat exchanger is significantly lower than that of the plane inner wall exchanger,indicating that the heat transfer performance of the corrugated inner wall heat exchanger is better.The heat transfer coefficients of the two heat exchangers increase with the increase of flue gas inlet angles.Under the condition of the same flue gas inlet angle,the heat transfer coefficient of the corrugated inner wall exchanger is greater than that of the plane inner wall exchanger.The pressure drop of the two heat exchangers increases with the increase of the increase of flue gas inlet angles.Under the condition of the same flue gas inlet angle,the pressure drop of the plane inner wall heat exchanger is less than that of the corrugated inner wall exchanger.The optimum flue gas inlet angles of the plane inn

关 键 词：燃气采暖热水炉 冷凝式换热器 传热系数 烟气压力降 烟气进气角 

分 类 号：TU996.75[建筑科学—供热、供燃气、通风及空调工程]