MODELLING OF THE AIRFLOW IN THE PASSENGER COACH

Exterior temperature (t _em )	Minimum fresh air rate equivalent to +20°C and 50% rel. hum, normal atmospheric pressure
t _em < -15°C	10m³/h /passenger
-15°C ≤ t _em ≤ -5°C	15m³/h /passenger
-5°C ≤ t _em ≤ +26°C	20m³/h /passenger
t _em > 26°C	15m³/h /passenger

**The numerical coach model – geometry**

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

**The discretization grid with inflated boundary – the crosssection**

a) Localization of diffusers, b) scheme of air distribution in the coach, ${\dot{m}}_{S}$ – mass flow rate of air supply ${\dot{m}}_{S 1}$ – mass flow rate of air supply by lower air diffusers, ${\dot{m}}_{S 2}$ – mass flow rate of air supply by window air diffusers, $\dot{m_{E}}$ – mass flow rate of air exhaust

Table 4.

Boundary conditions for case 1

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

Table 5.

Boundary condition for case 2

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

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

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

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

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

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

**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**

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

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

References

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DOI: https://doi.org/10.21307/acee-2019-058 | Journal eISSN: 2720-6947 (formerly 1899-0142) | Journal ISSN: 1899-0142

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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.

Volume 12 (2019): Issue 4 (December 2019)

MODELLING OF THE AIRFLOW IN THE PASSENGER COACH

Figures & Tables

Table 1.

Table 2.

Table 3.

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Table 4.

Table 5.

Figure 5.

Figure 6.

Figure 7.

Figure 8.

Figure 9.

Figure 10.

Figure 11.

Figure 12.

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