“…In order to compare the CFD results with other studies, Visnuprasad et al 23 and Zhuo et al 8 assumed ACH = 4.3 h −1 in the open-door scenario and the average indoor radon concentrations in their studies were reported to be 29 and 15 Bq m -3 , respectively, while in this study it was simulated to be 20 Bq m −3 , the results of which are given in Table 1 . The average indoor radon concentration reported by Rabi et al 12 was 49 Bq m −3 which assumed that ACH = 1 h −1 , in the closed-door scenario, while in this study the corresponding value was around 70 Bq m −3 . Figure 5 Velocity distribution in the modelled test room in both scenarios at 2 different ventilation rates.…”
Section: Resultsmentioning
confidence: 46%
“…For instance, Zhou et al applied the finite difference method to derive discrete equations before linking them to the commercial FU-JITSU/a-FLOW code to study the concentrations and their distributions of 222 Rn and 220 Rn as well as their progenies in a model room 8 . Rabi et al implemented a 222 Rn distribution inside a typical Moroccan room using Fortran software 12 . Chauhan et al and Agarwal et al in this regard also used the software Fluidyn MP based on the Finite Volume Method (FVM) 11 , 14 .…”
Based on the European Union Basic Safety Standards to protect people against exposure to ionizing radiation, establishing and addressing the reference levels for indoor radon concentrations is necessary. Therefore, the indoor radon concentration should be monitored and control in dwelling and workplaces. However, proper ventilation and sustainability are the major factors that influence how healthy the environment in a building is for its occupants. In this paper, the indoor radon distribution in a typical naturally ventilated room under two scenarios (when the door is closed and open) using the computational fluid dynamics (CFD) technique was studied. The CFD code ANSYS Fluent 2020 R1 based on the finite volume method was employed before the simulation results were compared with analytical calculations as well as passive and active measurements. The average radon concentration from the CFD simulation was found to be between 70.21 and 66.25 Bq m−3 under closed and open-door conditions, respectively, at the desired ventilation rate of 1 ACH (Air Changes per Hour). Moreover, the highest concentrations of radon were measured close to the floor and the lowest values were recorded near to the inlet, resulting in the airflow velocity profile. The simulation results were in good agreement with the maxima of 19% and 7% compared to analytical calculations at different indoor air velocities in the open- and closed-door scenarios, respectively. The measured radon concentrations obtained by the active measurements also fitted well with the CFD results, for example, with a relative standard deviation of around 7% and 2% when measured by AlphaGUARD and RAD7 monitors at a height of 1.0 m above the ground in the open-door scenario. From the simulation results, the effective dose received by an individual from the indoor air of the workplace was also calculated.
“…In order to compare the CFD results with other studies, Visnuprasad et al 23 and Zhuo et al 8 assumed ACH = 4.3 h −1 in the open-door scenario and the average indoor radon concentrations in their studies were reported to be 29 and 15 Bq m -3 , respectively, while in this study it was simulated to be 20 Bq m −3 , the results of which are given in Table 1 . The average indoor radon concentration reported by Rabi et al 12 was 49 Bq m −3 which assumed that ACH = 1 h −1 , in the closed-door scenario, while in this study the corresponding value was around 70 Bq m −3 . Figure 5 Velocity distribution in the modelled test room in both scenarios at 2 different ventilation rates.…”
Section: Resultsmentioning
confidence: 46%
“…For instance, Zhou et al applied the finite difference method to derive discrete equations before linking them to the commercial FU-JITSU/a-FLOW code to study the concentrations and their distributions of 222 Rn and 220 Rn as well as their progenies in a model room 8 . Rabi et al implemented a 222 Rn distribution inside a typical Moroccan room using Fortran software 12 . Chauhan et al and Agarwal et al in this regard also used the software Fluidyn MP based on the Finite Volume Method (FVM) 11 , 14 .…”
Based on the European Union Basic Safety Standards to protect people against exposure to ionizing radiation, establishing and addressing the reference levels for indoor radon concentrations is necessary. Therefore, the indoor radon concentration should be monitored and control in dwelling and workplaces. However, proper ventilation and sustainability are the major factors that influence how healthy the environment in a building is for its occupants. In this paper, the indoor radon distribution in a typical naturally ventilated room under two scenarios (when the door is closed and open) using the computational fluid dynamics (CFD) technique was studied. The CFD code ANSYS Fluent 2020 R1 based on the finite volume method was employed before the simulation results were compared with analytical calculations as well as passive and active measurements. The average radon concentration from the CFD simulation was found to be between 70.21 and 66.25 Bq m−3 under closed and open-door conditions, respectively, at the desired ventilation rate of 1 ACH (Air Changes per Hour). Moreover, the highest concentrations of radon were measured close to the floor and the lowest values were recorded near to the inlet, resulting in the airflow velocity profile. The simulation results were in good agreement with the maxima of 19% and 7% compared to analytical calculations at different indoor air velocities in the open- and closed-door scenarios, respectively. The measured radon concentrations obtained by the active measurements also fitted well with the CFD results, for example, with a relative standard deviation of around 7% and 2% when measured by AlphaGUARD and RAD7 monitors at a height of 1.0 m above the ground in the open-door scenario. From the simulation results, the effective dose received by an individual from the indoor air of the workplace was also calculated.
“…The distribution of the activity concentration of 220 Rn inside the chamber can be accurately predicted and simulated by using the computational fluid dynamics (CFD) technique. In previous studies, CFD software was employed as a powerful analytical tool for studying the distributions of 222 Rn and 220 Rn inside dwellings 4,21,[25][26][27][28][29][30][31] . For example, Agarwal et al used CFD to assess the 220 Rn distribution in confined volumes in the presence of a forced flow, such as the delay volume used as a mitigation device 21,30 .…”
Section: Development Of a Thoron Calibration Chamber Based On Computa...mentioning
Recently, interest in measuring the concentration of 220Rn in air has increased greatly following the development of standards and the calibration of monitoring instruments. In this study, a 220Rn calibration chamber was designed and developed at the Institute of Radiochemistry and Radioecology (RRI) based on the computational fluid dynamics (CFD) method implemented in ANSYS Fluent 2020 R1 code at the University of Pannonia in Hungary. The behavior of 220Rn and its spatial distribution inside the 220Rn calibration chamber at RRI were investigated at different flow rates. The 220Rn concentration was close to homogeneous under higher flow regimes due to thorough mixing of the gas inside the chamber. Predictions based on CFD simulations were compared with experimentally measured transmission factors (Cout/Cin). The spatial distribution of 220Rn was dependent on the flow rate and the positions of the inlet and outlet. Our results clearly demonstrate the suitability of the 220Rn calibration chamber at RRI for calibrating monitoring instruments. Furthermore, the CFD-based predictions were in good agreement with the results obtained at higher flow rates using experimental and analytical models according to the relative deviation, with a maximum of approximately 9%.
“…The equilibrium factor between radon and its descendants is a dimensionless parameter and is defined as follows [10]: F = ".$"%. & '".%$(.…”
Section: The Equilibrium Factormentioning
confidence: 99%
“…Regional doses, weighted with factors assigned for the partition of radiation detriment, are summed to give a value of committed equivalent dose for the thoracic H Q j and extrathoracic H R j regions. According to the ICRP 66 [12], we have the following equations: H Q j = A SS H SS j + A TT H TT j + A /U H /U j (9) and H R j = A R $ H R $ j + A R V H R V j (10) where H SS j , H TT j and H /U j are the equivalent doses in the BB, bb and AI tissues of the thoracic region, respectively; H R $ j and H R V j are the equivalent doses in the ET 1 and ET 2 tissues of the extrathoracic region, respectively; A BB = 0.333, A TT = 0.333 and A AI = 0.333 are the weighting factors for the partition of radiation detriment for the BB, bb and AI tissues of the thoracic region, respectively, and A R $ = 0.001 and A R V = 1 are the weighting factors for the partition of radiation detriment for the ET 1 and ET 2 extrathoracic regions [12]. The annual effective dose (mSv y -1 h -1 exposure) due to radon decay products inside the Hammam was evaluated by using the following equation:…”
Section: Determination Of Annual Committed Equivalent Dosesmentioning
Radon and its descendants are the main causes of lung cancer in non-smokers. Therefore, the study of the behavior of radon and its descendants in indoor air is of the highest importance, in ordre to limit the risk of radiation dose due to inhalation of indoor air by members of the public. This article focuses to study the effect of meteorological parameters on the concentration and distribution of radon and its descendants inside a traditional Hammam by using CFD simulation. The results of modeling are qualitative and show that the concentration and distribution of radon and its descendants decrease when the ventilation rate increases, as well as, as the temperature increases; however, it increases with the increase relative humidity. Moreover, the committed equivalent doses due to 218 Po and 214 Po radon short-lived progeny were evaluated in different tissues of the respiratory tract of the members of the public from the inhalation of air inside the traditional Hammam. The influence of the activity of 218 Po and 214 Po and mass of the tissue on the committed equivalent doses per hour of exposure was investigated. The annual effective dose due to radon short-lived progeny from the inhalation of air inside the traditional Hammam by the members of the public was investigated.
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