不同参数对含盐污水在蒸发管中流动特性影响的数值模拟分析

蒸发处理是炼化企业产生的含盐污水处理的方法之一，但是蒸发过程存在着因流动条件差异而导致传热效果不佳的问题。以降膜蒸发含盐污水为研究对象，通过数值模拟的方法分析不同参数对蒸发管传热传质效果的影响。结果表明，液体入口速度不同对蒸发管加热效果的影响是复杂的，入口速度适当增大导致轴向速度增大，虽然液体加热时间会变短，但加热效果更好；增大布膜间隙对近壁面处温度分布有积极作用，但在距管中心13.5～18.0mm范围内气相湍流强度略低，布膜间隙为1.25 mm时的温降相较于1.0 mm和1.5 mm间隙时的温降大；含盐污水盐度增大对蒸发管传热传质效果不利，特别是在近壁面处温降增大，内部湍流强度在沿径向方向距管中心0～19 mm范围内增大，近壁面处距管壁4 mm范围内速度增大。

NUMERICAL SIMULATION ANALYSIS OF INFLUENCE OF DIFFERENT PARAMETERS ON FLOW CHARACTERISTICS OF SALT-CONTAINING WASTE WATER IN EVAPORATOR PIPE

Evaporation treatment is one of methods for treatment of salt-containing waste water in refineries. However, there is a problem that the heat transfer effect is not good due to the difference of flow conditions in the evaporation process. Taking the salt-bearing wastewater of falling film evaporation as the object, the effects of different parameters on heat and mass transfer in evaporating tubes were analyzed by numerical simulation. The results showed that the effect of different liquid inlet velocities on the heating effect of the evaporative tube was complicated. The increase of inlet velocity leads to the increase of axial velocity. Although the heating time of the liquid thus became shorter, the heating effect was better. The increase of film gap had a positive effect on the temperature distribution near the wall, but the gas-phase turbulence intensity was slightly lower within 13.5-18.0 mm away from the center of the pipe. The temperature drop when the film gap was 1.25 mm was larger than that when the film gap was 1.0 mm and 1.5 mm. The increase of salinity of salt-containing sewage had adverse effects on heat and mass transfer in the evaporator tube. Especially the increase of temperature drop near the wall leads the increase of internal turbulence intensity within the range of 0-19 mm from the center of the tube in the radial direction and the increase of velocity within the range of 4 mm from the wall near the wall of the tube.