为研究电磁场对换热表面析晶污垢的抑垢情况,该研究以电磁水处理动态试验台为依托通过一系列变工况的试验,获取了不同磁场强度、流速和入口温度下碳酸钙污垢热阻热阻曲线,又通过电磁场、流场及温度场之间的正交分析得出了各因素对析晶污垢生长的具体影响.结果表明,试验磁感应强度范围内污垢热阻随磁感应强度的增大呈减小趋势;不加磁场湍流状态下,流速越大污垢热阻越小;磁场与流速共同作用可以强化阻垢效果.随着入口温度的增加,热阻渐近值先增大后减小,在入口温度为30℃时出现极大值;电磁场处理产生的热阻减小的效果要大于入口温度增加引起的热阻增加的效果.通过正交分析,得出了影响污垢生长的主次因素由强到弱依次为磁感应强度、流速、入口温度.同时计算出了该试验台在试验工况下的最优运行工况,在入口温度30℃,流速0.4 m/s,磁感应强度20 mT情况下抑垢效果最好.研究结果可为工业循环水除垢抑垢提供一定的参考.

为研究管式换热器表面不同磁感应强度对析晶污垢的影响,并比较不同磁感应强度下水质参数的变化.通过实验研究的方式,得出在0 T、0.01 T、0.02 T下污垢热阻及水质参数(pH、电导率、溶解氧、OD值)的变化情况.结果表明,随磁感应强度的增大,污垢热阻值减小;水质参数值逐渐增大;对比水质参数与热阻,得出不同水质参数下对热阻的影响.对热阻及水质参数值进行多项式拟合,通过多元线性回归,得出基于Kern-Seaton模型和各参量的污垢热阻表达式.

The absorbance values of specific configuration solutions under different magnetic treatment conditions are studied using the UV method based on the circulating dynamic simulation experiment platform for the anti‐scaling of electromagnetics. Additionally, the relationship between the absorbance value and solution concentration is determined. Moreover, the nucleation rate of CaCO 3 is calculated using the absorbance value. The influence of the specific magnetic field on nucleating rate is analyzed. Subsequently, the magnetic memory effect and time of CO 3 −2 and water are studied. Results show that the magnetic treatment changes the nucleation rate of CaCO 3 and the critical oversaturation of the solution by acting on CO 3 −2 . This treatment also can promote the dissolution of CaCO 3 in water by changing the properties of water. These two aspects all exert memory effects; however, their respective memory times are different. Moreover, the results show that the magnetic treatment can reduce the critical oversaturation of the CaCO 3 solution and accelerate the nucleation rate. Furthermore, the memory time of the magnetic field acting on CO 3 −2 and the properties of water are 45 min and 78 h, respectively.

The correlations of various parameters were compared to study the influence of the flow parameters and structural parameters of the vortex generators on the crystallization fouling.Through numerical simulation,the change of the fouling resistance at different inlet velocity,wall temperature and working fluid concentration for different corrugated long,array pitch and radius were obtained.According to the principle of Grey correlation,the relationship between three flow parameters,three structural parameters and fouling resistance were analyzed.The influence of two flow parameters on fouling resistance is higher than the influence of the structure parameters,however the correlation between fouling resistance and corrugated long is stronger than that with concentration.

为研究矩形通道内部流动阻力与颗粒污垢间的关系,通过改变涡流发生器的布局方式,改变通道内部压降,研究涡流发生器对流阻和污垢热阻的影响,进而实现流阻与污垢热阻的关联研究.通过实验得出,在布置区间改变过程中,污垢热阻渐近值与结垢前后的压降差呈同相变化.在改变交错方式过程中,污垢热阻渐近值随压降的增加而减小.

通过数值模拟的方法,研究半球型涡流发生器的结构参数变化对析晶污垢沉积过程的影响.考察了球窝半径、球凸半径、球窝与球凸圆心距以及布局对污垢热阻的影响.结果表明,经过模拟得出球凸半径变化对污垢热阻的影响高于球窝交化产生的影响.球窝前置时对污垢热阻的影响大于球凸前置时的影响.圆心距对污垢热阻的影响呈现波动变化的趋势.

为了研究运行工况对强化管内析晶污垢的影响.采用数值模拟方法研究了强化管内CaSO4析晶污垢的沉积过程.主要分析了两种强化管内CaSO4溶液的速度和壁面温度对污垢热阻的影响.结果表明,随着速度的增大污垢热阻值逐渐减小;随着壁面温度的增大污垢热阻值也是逐渐减小.综合对比两种强化换热管可知,内肋管的污垢热阻值小于缩放管的热阻值,即内肋管抑垢效果好于缩放管.