Measurement of indoor ²²²Rn concentration and interpretation of distribution patterns are important for inhalation dosimetry in occupational and residential areas. Experimental determination of ²²²Rn concentration distribution and estimation of inhalation doses depend on the underlying aspects such as calibration of the detectors, accuracy of the techniques etc. Therefore, ²²²Rn concentration distribution needs to be very well understood in a closed domain for the controlled studies. In the recent times, Computational fluid dynamics (CFD) technique has gained a lot of attention for the prediction and visualization of indoor ²²²Rn concentration profiles and their mixing ability in the domain. The present study aims to simulate the effect of forced mixing on the ²²²Rn concentration profile in a 22 m³ experimental chamber. This chamber is designed for carrying out the controlled experiments, calibration and inter-comparison studies of various types of ²²²Rn detectors. Effect of different parameters such as time, flow rates, fan-off and fan-on conditions have been studied on the transient response, extent of the air mixing patterns and subsequently on ²²²Rn concentration profile in the chamber. Further, Non uniformity index (NUI) is introduced as a measure of the uniformity of the distribution in the closed domain. NUI is estimated for different cases in order to efficiently interpret the effect of above mentioned parameters on ²²²Rn profile in the chamber. This study will be useful to represent the turbulent conditions in real indoor domains and occupational facilities as U-mines during calibration and inter-comparison exercises of different ²²²Rn detectors.

室内²²² Rn浓度的测量和分布模式的解释对于职业和住宅区的吸入剂量测定很重要。²²² Rn浓度分布的实验确定和吸入剂量的估算取决于基本方面，例如检测器的校准，技术的准确性等。因此，对于封闭对照研究，需要在封闭域中很好地理解²²² Rn浓度分布。近年来，计算流体力学（CFD）技术在室内²²²的预测和可视化方面引起了广泛关注。Rn浓度分布及其在域中的混合能力。本研究旨在模拟强制混合对22 m ³实验室内²²² Rn浓度分布的影响。该腔室设计用于执行各种类型的²²² Rn探测器的受控实验，校准和比对研究。研究了不同参数（例如时间，流量，风扇关闭和风扇开启条件）对瞬态响应，空气混合模式的范围以及随后对^222的影响腔室中的Rn浓度曲线。此外，引入非均匀性指数（NUI）作为封闭域中分布均匀性的度量。为了有效地解释上述参数对腔室中²²² Rn轮廓的影响，需要针对不同情况估算NUI 。这项研究将有助于在不同²²² Rn探测器的校准和比对练习中，将真实的室内区域和职业设施中的湍流状况表示为U型地雷。