Rogers V C, Nielson K K
Rogers and Associates Engineering Corporation, Salt Lake City, UT 84110-0330.
Health Phys. 1991 Jun;60(6):807-15. doi: 10.1097/00004032-199106000-00006.
Radon generation and transport in porous materials involve solid, liquid, and gas phases in the processes of emanation, diffusion, advection, absorption, and adsorption. Oversimplifications, such as representing moist soil systems by air-phase emanation and transport models, cause theoretical inconsistencies and biases in resulting calculations. Detailed Rn rate balance equations for solid, liquid, and gas phases were analyzed and combined using phase equilibrium constants to derive a single diffusive-advective rate balance equation in the traditional form. The emanation, diffusion, and permeability coefficients in the new equation have expanded definitions and interpretations to include Rn phase transfer. Radon adsorption was characterized by an exponential moisture dependence, and diffusion and permeability constants utilized previous moisture relationships. Correct boundary and interface conditions were defined, and the unified theoretical approach was applied to field data from a diffusion-dominated system and to laboratory data from an advection-dominated system. Measured 222Rn fluxes and concentrations validated the modeled values within the measurement variability in both applications.
多孔材料中氡的产生和传输在析出、扩散、平流、吸收和吸附过程中涉及固相、液相和气相。一些过度简化的做法，比如用气相析出和传输模型来表示潮湿土壤系统，会导致理论上的不一致以及计算结果出现偏差。分析了固相、液相和气相详细的氡速率平衡方程，并利用相平衡常数将它们结合起来，以传统形式推导出一个单一的扩散 - 平流速率平衡方程。新方程中的析出、扩散和渗透系数有了扩展的定义和解释，以纳入氡的相转移。氡吸附的特征是对湿度呈指数依赖关系，扩散和渗透常数采用了先前的湿度关系。定义了正确的边界和界面条件，并将统一的理论方法应用于来自扩散主导系统的现场数据以及来自平流主导系统的实验室数据。在这两种应用中，实测的222Rn通量和浓度在测量误差范围内验证了模型值。
