火管式废热锅炉管板冷却室内流动、传热与热应力研究

Fluid Flow, Heat Transfer, and Thermal Stress in Tube Sheet Cooling Chamber of Fire Tube Waster Heat Boiler

通过对火管式废热锅炉管板冷却室建立三维流动、传热模型,考察了冷却室侧面和顶端进水的优劣,探究了工艺参数对冷却室传热的影响。结果表明:侧面进水较顶端进水室内近壁区存在更多湍流漩涡、强化传热效果显著;合成气进口温度对热应力影响显著,温度从1373增加到1623 K,热应力增幅45.4%;进气负荷对传热影响有限,负荷从70%增至120%,热应力增幅18.2%;提高冷却水进口温度可降低管壁热应力,水温从430增至520 K,热应力降幅11.4%;降低合成气进口温度、升高冷却水进口温度对维持装置长周期运行很有意义。

Three dimensional flow and heat transfer models were established to study tube sheet cooling chamber of fire tube waste heat boilers. The advantages and disadvantages of two cooling water inlets(lateral and downward inlets) were discussed, and effects of process parameters on the heat transfer of cooling chamber were investigated. Simulation results show that the lateral water inlet generates more eddies near the tube wall, intensifies turbulence, and enhances heat transfer when comparing to those of the downward water inlet. The thermal stress increased by 45.4% when the temperature of syngas flow increased from 1373 to 1623 K, while the syngas flow rate has less effect on heat transfer(thermal stress increased by 18.2% when the syngas flow rate increased from 70% to 120%). The thermal stress of the tube wall can be decreased by increasing the inlet temperature of cooling water(it decreased by 11.4% when the temperature increased from 430 to 520 K). Therefore, reduce of syngas flow temperature and increase of cooling water temperature can help to maintain equipment long-term operation.