Abstract:
A comprehensive model of indoor particle deposition onto surfaces of historic interiors was developed. The model takes into account the most important deposition processes observed in historic buildings: Brownian and turbulent diffusion, gravitational settling, turbophoresis, and thermophoresis. The developed model is expressed as a function of important parameters characterizing historic interiors: the friction velocity - capturing the effect of the indoor airflow intensity, the difference between the temperature of the air and the surface, and surface roughness. In particular, a new form of the thermophoretic term was proposed to account for an important mechanism of surface soiling driven by frequent large temperature differences between indoor air and surfaces in historic buildings. The form adopted allowed the temperature gradients to be calculated down to low distances from the surfaces and showed insignificant dependence of the temperature gradient on the diameter of particles, which yielded a meaningful physical description of the process. The predictions of the developed model agreed with the outcome of the previous models, in turn correctly interpreting the experimental data. The model was used in simulating the total deposition velocity in a small-size church taken as an example of a historic building, heated in the cold period. The model adequately predicted the deposition processes and proved to be able to map magnitudes of deposition velocities for specific surface orientations. The crucial effect of the surface roughness on the deposition paths was documented.
摘要:
建立了室内颗粒沉积到历史室内表面的综合模型。该模型考虑了在历史建筑中观察到的最重要的沉积过程:布朗和湍流扩散,重力沉降,涡轮电泳,和热泳。所开发的模型表示为表征历史内部的重要参数的函数:摩擦速度-捕获室内气流强度的影响,空气和表面温度之间的差异,和表面粗糙度。特别是,提出了一种新形式的热电术语,以解释由室内空气和历史建筑表面之间频繁的大温差驱动的表面污染的重要机制。所采用的形式允许将温度梯度计算到与表面相距较低的距离,并且表明温度梯度对颗粒直径的依赖性很小。这产生了对该过程有意义的物理描述。所开发模型的预测与以前模型的结果一致,反过来正确解释实验数据。该模型用于模拟以历史建筑为例的小型教堂中的总沉积速度,在寒冷的时期加热。该模型充分预测了沉积过程,并证明能够针对特定表面方向绘制沉积速度的大小。记录了表面粗糙度对沉积路径的关键影响。