scholarly journals Modelling indoor pollutant distribution via passive scalar and virtual box approach

2021 ◽  
Vol 327 ◽  
pp. 05001
Author(s):  
George Pitchurov ◽  
Detelin Markov ◽  
Iskra Simova ◽  
Rositsa Velichkova ◽  
Peter Stankov ◽  
...  
Keyword(s):  
Mass Flux ◽  
Body Shape ◽  
Passive Scalar ◽  
Thermal Manikin ◽  
Breathing Zone ◽  
Ansys Fluent ◽  
Indoor Pollutant ◽  
Pollutant Source ◽  
Pollutant Distribution ◽  
Occupied Zone

The distribution of PM2.5 around a thermal manikin with realistic female body shape in a naturally ventilated room has been modelled. The health risk (HR) due to inhalation of the PM2.5 has been quantified by integrating the pollutants mass flux over the boundaries of a virtual box around the mannequin’s head (the breathing zone). By the same approach HR is evaluated over the boundaries of another virtual box that surrounds the manikins body and defines the occupied zone. The paper focuses on the peculiarities of creating and meshing a virtual geometry, as well as on the application of user-defined functions (UDF) for defining a pollutant source within the room using Ansys Fluent modelling package.

Improving occupational health by modelling indoor pollutant distribution

Facilities ◽  
2016 ◽  
Vol 34 (5/6) ◽  
pp. 289-301 ◽  
Author(s):  
Rui Pitarma ◽  
Miguel Lourenço ◽  
João Ramos
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Design Procedure ◽  
Distribution Patterns ◽  
Indoor Environments ◽  
Content Type ◽  
Indoor Pollutant ◽  
Pollutant Source ◽  
Pollutant Distribution

Purpose Indoor environments are characterized by several pollutant sources. Some of these can be sufficiently characterized through the prediction of the airflow and pollutant distribution patterns. The purpose of this study was to simulate, analyze and compare different locations of known pollutant source inside a ventilated room. Design/methodology/approach Computational fluid dynamics modelling approach was used to analyze the prediction of the airflow and pollutant distribution patterns for different locations of known pollutant source inside a ventilated room by mixing ventilation. Findings Distinct areas of poor air quality, perfectly identified by concentration fields, were given. The indoor air quality obtained by the different simulated conditions was analyzed and compared. Research limitations/implications Pollutant concentration was not measured in the validation experiments (qualitative validation based on the velocity fields). Practical implications Once the contaminant concentration fields are calculated based on the source location, the model is very useful to choose the best place to install any pollutant indoor equipment to preserve breathing zones. Originality/value Providing an effective indoor air quality assessment to prevent exposure risk. The results would be useful for making decisions to optimize the design procedure, such as establish the best location to install polluting equipment, occupied areas and their interdependence with ventilation systems. In addition, this tool also helps to choose the best location and correct set point adjustment for the pollutant sensors.

scholarly journals Study on the influence of pollution source location on indoor pollutant distribution under different air supply

2017 ◽  
Vol 205 ◽  
pp. 2623-2630 ◽  
Author(s):  
Shui Yu ◽  
Zhitian Yu ◽  
Xiunan Ma ◽  
Guojuan Zhang ◽  
Guohui Feng
Keyword(s):  
Source Location ◽  
Pollution Source ◽  
Air Supply ◽  
Indoor Pollutant ◽  
Pollutant Distribution

Anisotropy in the breathing zone of a thermal manikin

2007 ◽  
Vol 44 (4) ◽  
pp. 661-673 ◽  
Author(s):  
D. R. Marr ◽  
I. M. Spitzer ◽  
M. N. Glauser
Keyword(s):  
Thermal Manikin ◽  
Breathing Zone

Numerical Investigation of Heat and Mass Flux Effects on Heat Transfer Characteristics of Supercritical Water in an Upward Flow Vertical Tube

2014 ◽  
Vol 592-594 ◽  
pp. 1667-1671
Author(s):  
T. Vinoth ◽  
K. Karuppasamy ◽  
D. Santhosh Kumar ◽  
R. Dhanuskodi
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Flux ◽  
Supercritical Water ◽  
Mass Flux ◽  
Vertical Tube ◽  
Upward Flow ◽  
Heat Transfer Characteristics ◽  
Ansys Fluent ◽  
Transfer Characteristics

In the present work, the heat transfer characteristics of supercritical pressure water are numerically investigated in an upward flow vertical smooth tube. The numerical simulations are carried out by using Ansys-Fluent solver. The objective of the present work is to investigate the effect of heat flux and mass flux on heat transfer characteristics in supercritical water. In order to perform numerical simulation, experimental data of Mokryet al.[2] is considered. Various simulations were carried out for the inlet parameters of temperature 350°C, pressure 240bar; heat flux values ranging from 190 to 884kW/m2and mass flux values ranging from 498 to 1499kg/m2s. Based on the available parameters of heat flux and mass flux, they are segregated as groups with heat flux to mass flux ratios of 0.39 and 0.67. According to computational data, the heat transfer enhancement and heat transfer deterioration phenomenon of supercritical water were analyzed and based on the comparison with experimental data; their occurrence and mechanism were addressed.

scholarly journals Thermal Properties of Special New Generation Personal Protective Clothing for Firefighters-Rescuers

2021 ◽  
Vol 1 (80) ◽  
pp. 45-67
Author(s):  
Marzena Rachwał ◽  
Małgorzata Majder-Łopatka ◽  
Tomasz Węsierski ◽  
Artur Ankowski ◽  
Magdalena Młynarczyk ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Thermal Insulation ◽  
Protective Clothing ◽  
Body Shape ◽  
Thermal Protection ◽  
Thermal Manikin ◽  
Protective Equipment ◽  
Everyday Work ◽  
New Generation ◽  
Full Body

Every day, firefighters put their health and life at risk by saving people and their property not only during fires, but by being always ready during all kinds of unfortunate events. Therefore, they need special personal protective equipment, including protective clothing. The purpose of the study was to compare thermal properties of new (PROTON and SYRIUSZ) and old (US-03) personal protective clothing for firefighters. Measurements of thermal insulation (total, effective and local) were carried out using a full body shape thermal manikin Newton consisting of 34 segments, in which temperature and heat flux were controlled independently. Results of the total thermal insulation of the entire clothing reveal differences between all three models. The lowest values were noticed for the model PROTON with light and shorter jacket and the highest values of thermal insulation for the new model SYRIUSZ, indicating that this model protect the user against heat most effectively. New models of personal protective clothing for firefighters should be recommended for use in everyday work, because they are characterized by better parameters than the previous type of protective clothing, both in terms of thermal protection and mobility.

On a New Passive Scalar Equation With Variable Mass Diffusivity

2008 ◽  
Author(s):  
Fabio Gori ◽  
Andrea Boghi
Keyword(s):  
Mass Flux ◽  
Variable Mass ◽  
Mass Conservation ◽  
Passive Scalar ◽  
Conservation Equation ◽  
Average Concentration ◽  
Concentration Fluctuation ◽  
Mass Diffusivity ◽  
Coupled Solution ◽  
Mass Conservation Equation

The present work investigates the mass conservation equation of a Newtonian and non-Newtonian fluid in turbulent flow with variable mass diffusivity. The mass conservation equation is considered with the fluctuating terms in the concentration as well as in the mass diffusivity and is written for the average concentration, for the fluctuating concentration one as well as for the square of the fluctuating concentration. A new term appears in the form of product of the fluctuating mass diffusivity to the space gradient of the concentration fluctuation. This new term is interpreted and introduced in the mass conservation equation of the square of the fluctuating concentration where other new terms are also appearing. A possible physical interpretation is given to the different terms. Assuming several relations between mass diffusivity and concentration it is then possible to write expressions for the average and the fluctuating mass concentration which can be simplified on the basis of physical and mathematical considerations. Specifically, the mass flux is then expressed as the product of the derivative of the mass diffusivity to the gradient of the square of the mass fluctuation. Further considerations make possible to write a new mass conservation equation of the average concentration which include a new term which takes into account the space gradient of the mass flux. The mass conservation equation can be solved with the coupled solution of the equation of the square of the concentration fluctuation.

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