PIV methods for quantifying human thermal plumes in a cabin environment without ventilation

Due to the fast development of high-speed rail (HSR) around the world, high-speed trains (HSTs) are becoming a strong competitor against airliners in terms of long-distance travel. Compared with airliner cabins, HST cabins have much larger window sizes. When the big windows provide better lighting and view of the scenery, they also have significant effects on the thermal conditions in the cabins due to the solar radiation through them. This study presents a numerical study on the solar radiation on the thermal comfort in a typical HST cabin. The effect of solar radiation was discussed in terms of airflow pattern, temperature distribution and thermal comfort indices. Parametric studies with seven different daytime hours were carried out. The effect of using the roller curtain was also studied. The overall cabin air temperature, especially near passengers, was found to have significantly increased by solar radiation. Passengers sitting next to windows were recorded to have an obvious thermal comfort variation at different hours of the day. To improve the passengers’ comfort and reduce energy consumption during hot weather, the use of a curtain could effectively reduce the solar radiation effect in the cabin environment.

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Inverse design of aircraft cabin environment using computational fluid dynamics-based proper orthogonal decomposition method

Indoor and Built Environment ◽

10.1177/1420326x17718053 ◽

2017 ◽

Vol 27 (10) ◽

pp. 1379-1391 ◽

Cited By ~ 4

Author(s):

Jihong Wang ◽

Tengfei (Tim) Zhang ◽

Hongbiao Zhou ◽

Shugang Wang

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Proper Orthogonal Decomposition ◽

Flow Fields ◽

Orthogonal Decomposition ◽

Inverse Design ◽

Air Supply ◽

Spatial Modes ◽

Cabin Environment ◽

Proper Orthogonal

To design a comfortable aircraft cabin environment, designers conventionally follow an iterative guess-and-correction procedure to determine the air-supply parameters. The conventional method has an extremely low efficiency but does not guarantee an optimal design. This investigation proposed an inverse design method based on a proper orthogonal decomposition of the thermo-flow data provided by full computational fluid dynamics simulations. The orthogonal spatial modes of the thermo-flow fields and corresponding coefficients were firstly extracted. Then, a thermo-flow field was expressed into a linear combination of the spatial modes with their coefficients. The coefficients for each spatial mode are functions of air-supply parameters, which can be interpolated. With a quick map of the cause–effect relationship between the air-supply parameters and the exhibited thermo-flow fields, the optimal air-supply parameters were determined from specific design targets. By setting the percentage of dissatisfied and the predicted mean vote as design targets, the proposed method was implemented for inverse determination of air-supply parameters in two aircraft cabins. The results show that the inverse design using computational fluid dynamics-based proper orthogonal decomposition method is viable. Most of computing time lies in the construction of data samples of thermo-flow fields, while the proper orthogonal decomposition analysis and data interpolation is efficient.

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Role of thermal plumes on particle dispersion in a turbulent Rayleigh-Bénard cell

Journal of Physics Conference Series ◽

10.1088/1742-6596/318/5/052011 ◽

2011 ◽

Vol 318 (5) ◽

pp. 052011

Author(s):

V Lavezzo ◽

H J H Clercx ◽

F Toschi

Keyword(s):

Particle Dispersion ◽

Thermal Plumes ◽

Rayleigh Benard

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

10.1115/fedsm2021-65652 ◽

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.

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