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MODELLING OF THE AIRFLOW IN THE PASSENGER COACH Cover

MODELLING OF THE AIRFLOW IN THE PASSENGER COACH

Architecture, Civil Engineering, Environment
Volume 12 (2019): Issue 4 (December 2019)
By: Izabela SARNA and  Agnieszka PALMOWSKA  
Open Access
|Jan 2020

Figures & Tables

Figure 1.

The numerical coach model – geometry

Figure 2.

The discretization grid on the side of the exterior partitions of the coach

Figure 3.

The discretization grid with inflated boundary – the crosssection

Figure 4.

a) Localization of diffusers, b) scheme of air distribution in the coach, m ˙ S – mass flow rate of air supply m ˙ S 1 – mass flow rate of air supply by lower air diffusers, m ˙ S 2 – mass flow rate of air supply by window air diffusers, m E ˙ – mass flow rate of air exhaust

Figure 5.

The comparison of distribution of air velocity in the vertical plane XY, Z = 1.804 m: a) case 1, b) case 2

Figure 6.

The comparison of the distribution of air velocity in the vertical plane YZ, X = -11.63 m: a) case 1, b) case 2

Figure 7.

The comparison of the comfort zone in the vertical plane YZ, X= -9.55 m: a) case 1, b) case 2

Figure 8.

The comparison of the distribution of air temperature in the vertical plane XY, Z = 1.804 m: a) case 1, b) case 2

Figure 9.

The comparison of the distribution of air velocity in the vertical plane YZ, X = -9.55 m: a) case 1, b) case 2

Figure 10.

The comparison of the distribution of air velocity in the vertical plane YZ, X = -11.63 m: a) theoretical distribution, b) numerical distribution for case 1, c) numerical distribution for case 2

Figure 11.

The comparison of air velocity in monitoring points for case 1 and case 2

Figure 12.

The comparison of air temperature in monitoring points for case 1 and case 2

The minimum total volume flow of fresh air for railway vehicles with air conditioning device

Exterior temperature (t em )Minimum fresh air rate equivalent to +20°C and 50% rel. hum, normal atmospheric pressure
t em < -15°C10m3/h /passenger
-15°C ≤ t em ≤ -5°C15m3/h /passenger
-5°C ≤ t em ≤ +26°C20m3/h /passenger
t em > 26°C15m3/h /passenger

Boundary condition for case 2

The element of model and kind of boundary conditionsValue of case 2
South-east wall; “Wall” with heat transfer coefficient U and sol-a ir temperature U = 1.6 w m 2 · K , t s = 53 ° C
Interior wall; “Wall”Adiabatic wall
North-west wall; “Wall” with heat tran sfer coefficient U and sol- air temperature U = 1.6 w m 2 · K , t s = 36.23 ° C
North-east wall; “Wall” with heat transfer coefficient U and sol-air temperature U = 1.6 w m 2 · K , t s = 36.42 ° C
South-east windows; “Wall” with heat tr ansfer coeffi cient U and sol-a ir temperature U = 1.6 w m 2 · K , t s = 297.5 ° C
North-west windows; “Wall” with heat transfer coeffi cient U and sol-air temperature U = 1.6 w m 2 · K , t s = 64.31 ° C
Roof; “Wall” with heat tr ansfer coefficient U and sol-air temperature U = 1.6 w m 2 · K , t s = 65 ° C
Floorboard; “Wall” wi th heat transfer coefficient U and exterior temperature U = 1.6 w m 2 · K , t s = 35 ° C
Lower diffusers; “Inlet” with mass flow rate of supply air and temperature of ventilation supply air m ˙ S 1 = 0.121 kg / s , t S 1 = 16.27 ° C
Upper diffusers; “Inlet” with mass flow rate of supply air and temperature of ventilation supply air m ˙ S 2 = 0.516 kg / s , t S 2 = 16.94 ° C
Exhaust diffusers; “Outlet” with mass flow rate of exhaust air m ˙ E = 0.032 kg / s

Parameters of outdoor air – winter conditions

Climatic zoneMinimal temperature
I-10°C
II-20°C
III-40°C

Boundary conditions for case 1

The element of model and kind of boundary conditionsValue of case 1
South-east wall; “Wall” with heat transfer coefficient U and sol-air temperature U = 2 w m 2 · K , t s = 61.8 ° C
Interior wall; “Wall”Adiabatic wall
North-west wall; “Wail” with heat teansfer coefficient U and sol-air temperature U = 2 w m 2 · K , t s = 38.3 ° C
North-east wall; “Wall” with heat transfer coefficient U and sol-air temperature U = 2 w m 2 · K , t s = 38.88 ° C
South-east windows; “Wall” with heat transfer coefficient U and sol-air temperature U = 2 w m 2 · K , t s = 157.99 ° C
North-west windows; “Wall” with drat transfer coefficient U and sol-ars temperature U = 2 w m 2 · K , t s = 48.71 ° C
Roof; “Well” with heat transfer coefficienit U and sol-air temperature U = 1.2 w m 2 · K , t s = 53.1 ° C
Floorboard; “Well” with heat transfer “coefficient U and exterior-temperature U = 1.2 w m 2 · K , t s = 35 ° C
Lower diffusers; “Inlet” with mass flow rale of supply air and temperature of ventilation supply air m ˙ S 1 = 0.121 kg / s , t S 1 = 19.4 ° C
Upper diffusers; "Inlet” with mass flow rate of supply air and temperature of ventilation supply air m ˙ S 2 = 0.516 kg / s , t S 2 = 19.9 ° C
Exhaust diffusers; “Outlet” wish mass flow rate of exhaust air m ˙ E = 0.032 kg / s

Parameters of outdoor air – summer conditions

Climatic zoneMaximum temperature, relative humidity, equivalent solar load
I40°C, 40%, 800W/m2
II35°C, 50%, 700 W/m2
III28°C, 45%, 600W/m2
DOI: https://doi.org/10.21307/acee-2019-058 | Journal eISSN: 2720-6947 | Journal ISSN: 1899-0142
Journal RSS Feed
Language: English
Page range: 125 - 133
Submitted on: Aug 7, 2019
|
Accepted on: Oct 2, 2019
|
Published on: Jan 7, 2020
Published by: Silesian University of Technology
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year
Keywords:
Airflow,
Coach,
CFD,
Heat exchange,
Ventilation
Related subjects:
Architecture and design,
Architecture,
Architects, buildings

© 2020 Izabela SARNA, Agnieszka PALMOWSKA, published by Silesian University of Technology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

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