Assessment of a confined thermal plume by PIV combined with POD analysis

2021 ◽  
Vol 188 ◽  
pp. 116590
Author(s):  
Wenhua Chen ◽  
Junjie Liu ◽  
Jiayu Li ◽  
Xilei Dai ◽  
Pan Wang ◽  
...  
Keyword(s):  
Thermal Plume ◽  
Pod Analysis

THERMAL PLUME IN A VERTICAL CANNAL: EFFECT OF THE VERTICAL SOURCE CANAL SPACING

2009 ◽  
Author(s):  
Belgacem Jouini ◽  
Mourad Bouterra ◽  
Olivier Vauquelin ◽  
Afif El Cafsi ◽  
Ali Belghith ◽  
...  
Keyword(s):  
Thermal Plume

scholarly journals Horizontal convection in a rectangular enclosure driven by a linear temperature profile

2021 ◽  
Author(s):  
Tianyong Yang ◽  
Bofu Wang ◽  
Jianzhao Wu ◽  
Zhiming Lu ◽  
Quan Zhou
Keyword(s):  
Rayleigh Number ◽  
Temperature Profile ◽  
Scaling Law ◽  
Thermal Plume ◽  
Steady Regime ◽  
Linear Temperature ◽  
Square Enclosure ◽  
Horizontal Convection ◽  
Kinetic Boundary Layer ◽  
The Mean

AbstractThe horizontal convection in a square enclosure driven by a linear temperature profile along the bottom boundary is investigated numerically by using a finite difference method. The Prandtl number is fixed at 4.38, and the Rayleigh number Ra ranges from 107 to 1011. The convective flow is steady at a relatively low Rayleigh number, and no thermal plume is observed, whereas it transits to be unsteady when the Rayleigh number increases beyond the critical value. The scaling law for the Nusselt number Nu changes from Rossby’s scaling Nu ∼ Ra1/5 in a steady regime to Nu ∼ Ra1/4 in an unsteady regime, which agrees well with the theoretically predicted results. Accordingly, the Reynolds number Re scaling varies from Re ∼ Ra3/11 to Re ∼ Ra2/5. The investigation on the mean flows shows that the thermal and kinetic boundary layer thickness and the mean temperature in the bulk zone decrease with the increasing Ra. The intensity of fluctuating velocity increases with the increasing Ra.

Computational Modeling of Particulate Pollutant Transport in a Ventilated Room in the Presence of Two Heated Breathing and Rotating Manikins

2017 ◽  
Author(s):  
Seyed Ali Keshavarz ◽  
Mazyar Salmanzadeh ◽  
Goodarz Ahmadi
Keyword(s):  
Air Quality ◽  
Computational Modeling ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Rotational Motion ◽  
Indoor Environment ◽  
Ventilation System ◽  
Thermal Plume ◽  
Displacement Ventilation ◽  
Simulation Results

Recently, attention has been given to indoor air quality due to its serious health concerns. Clearly the dispersion of pollutant is directly affected by the airflow patterns. The airflow in indoor environment is the results of a combination of several factors. In the present study, the effects of thermal plume and respiration on the indoor air quality in a ventilated cubicle were investigated using an unsteady computational modeling approach. The person-to-person contaminant transports in a ventilated room with mixing and displacement ventilation systems were studied. The effects of rotational motion of the heated manikins were also analyzed. Simulation results showed that in the cases which rotational motion was included, the human thermal plume and associated particle transport were significantly distorted. The distortion was more noticeable for the displacement ventilation system. Also it was found that the displacement ventilation system lowered the risk of person-to-person transmission in an office space in comparison with the mixing ventilation system. On the other hand the mixing system was shown to be more effective compared to the displacement ventilation in removing the particles and pollutant that entered the room through the inlet air diffuser.

scholarly journals Natural Convection From Isothermal Horizontal Cylinders

2009 ◽  
Author(s):  
Ian M. O. Gorman ◽  
Darina B. Murray ◽  
Gerard Byrne ◽  
Tim Persoons
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Separation Distance ◽  
Thermal Plume ◽  
Number Range ◽  
Vertically Aligned ◽  
Isothermal Cylinders ◽  
Horizontal Cylinders

The research described here is concerned with natural convection from isothermal cylinders, with a particular focus on the interaction between a pair of vertically aligned cylinders. Prime attention was focused on how the local heat transfer characteristics of the upper cylinder are affected due to buoyancy induced fluid flow from the lower cylinder. Tests were performed using internally heated copper cylinders with an outside diameter 30mm and a vertical separation distance between the cylinders ranging from two to three cylinder diameters. Plume interaction between the heated cylinders was investigated within a Rayleigh number range of 2×106 to 6×106. Spectral analysis of the associated heat transfer interaction is presented showing that interaction between the cylinders causes oscillation of the thermal plume. The effect of this oscillation is considered as a possible enhancement mechanism of the heat transfer performance of the upper cylinder.

Influence of Thermal Plume on Particle Inhalability of a Lying Mannequin in a Room

2021 ◽  
Author(s):  
Maryam Habibi ◽  
Mohsen Heidary ◽  
Mohammad Mehdi Tavakol ◽  
Goodarz Ahmadi
Keyword(s):  
Respiratory System ◽  
Spherical Particles ◽  
Thermal Plume ◽  
Ansys Fluent ◽  
Thermal Plumes ◽  
Micro Particles ◽  
Upward Direction ◽  
Fluent Software ◽  
Turbulence Dispersion ◽  
Aspiration Efficiency

Abstract In this study, the dispersion and deposition of particles in the respiratory system attached to a mannequin lying down inside a room were investigated numerically. The respiratory system model was prepared by processing the CT scan images of a volunteer and was attached to a mannequin lying in the middle of a room. The flow field around the mannequin and effects of the thermal plume on the particle aspiration by the mannequin model was simulated using the Ansys-Fluent software. The aspiration efficiency of spherical particles in the airway was studied with the Lagrangian particle trajectory analysis, including the turbulence dispersion effects. For validation of numerical simulations, the aspiration efficiency of the particles obtained from the numerical solution was compared with the case of a standing mannequin. The results are presented for two different modes with upward and downward thermal plumes. For the first mode, due to the strong effect of the thermal plume in the upward direction, the aspiration efficiency of midrange particles increases. However, the aspiration efficiency of large micro-particles decreases for the first mode. For the second mode, with the downward thermal plume, the aspiration efficiency of small micro-particles increases significantly.

Sign in / Sign up

Export Citation Format

Share Document