电厂烟气脱碳用文丘里射流器气液两相试验与数值模拟

Experiment and numerical simulation of gas-liquid flow in Venturi jet for the decarbonization of power plant flue gas

以电厂烟气氨法脱碳用文丘里射流器为研究对象,设计并加工实验室用小型文丘里射流器,以水-空气为介质,测定了不同液体流量条件下的吸气量与压降,并作为数值模拟结果对比值。采用欧拉多相流模型、标准k-ε湍流模型对文丘里气液射流器内部流场进行数值模拟,经网格无关性检验,所用模型能较好预测试验结果,其中吸气量值最大偏差为0.96%,压降值最大偏差为1.26%;数值模拟结果表明,文丘里射流器的负压区主要出现在喉管和扩散段前端,文丘里射流器的扩散段存在明显的气液分层情况,气液两相流线和湍动能模拟均表明扩散段近壁面区域存在环形涡旋区,涡旋区域的速度梯度较大。

The Venturi jet is the key reactor for the ammonia decarbonization of the power plant flue gas.A lab scale Venturi jet was designed and manufactured.For the water-air system,the gas suction flow rate and the pressure drop under different liquid flow conditions were measured as a comparison for the numerical simulation results.The Euler Multiphase Flow Model and the Standard k-εTurbulence Model were used to numerically simulate the internal flow field of the Venturi gas-liquid jet.After the grid independence test,the model used can better predict the experimental results,among which the deviation for the gas suction flow rate is 0.96%,and the maximum deviation of the pressure drop value is 1.26%.The numerical simulation results show that the negative pressure area of the Venturi jet mainly occurs at the front of the throat and the diffusion section.An obvious gas-liquid separation existed in the diffusion section of the Venturi jet.The streamline and turbulent kinetic energy show that there is an annular vortex region near the wall of the diffusion section,and the velocity gradient in the vortex region is large.