Interior air flow simulation in railway rolling stock

Author(s):  
T Berlitz ◽  
G Matschke

For the thermal comfort of passengers in modern trains thermodynamic parameters such as pressure, temperature and relative humidity are important, but also technical features such as location, velocity and direction of the air supplied to the compartment must not be neglected. By applying computational fluid dynamics (CFD) to the simulation of the interior air flow, time- and cost effectiveness can be increased significantly: in an early development phase, where influencing the design and the concept is still possible with low additional effort, air conditioning can be optimized in a very cost- and time-effective way. Thus, by exceeding the normative requirements the passenger's needs are met more closely and more easily. After validation of the method and numerical model by full-scale measurements, a powerful and sound tool for parameter variations and the design and construction of air-conditioning facilities is obtained. The interior air flow in the first-class compartment of a regional train was simulated numerically. Thermodynamic and aerodynamic parameters were measured in a full-scale test train for the validation. The results show the ability of CFD to deal with parameter variations and the prediction of thermal comfort. Benefits and drawbacks and the limits of the application of CFD have been worked out.

2013 ◽  
Vol 773 ◽  
pp. 883-888 ◽  
Author(s):  
Hamid Nawaz ◽  
Yan Sheng Yuan

The focus of this work is to simulate and optimize thermal comfort in a ship air-conditioning system by evaluating the performance of different types of air supply outlets. Thermal comfort analyses were performed in Solidworks Flow Simulation software by changing the number, type and position of air supply outlets and the comfort was optimized by evaluating the values of temperature, velocity, PMV (Predicted mean vote) & PPD (Predicted Percentage Dissatisfied). It was concluded from the results obtained from different analyses that air supply outlet is a vital part in any type of HVAC (Heating ventilation & air conditioning) system design, as its number, type and position has significant effect on the air distribution and thermal comfort in a subject space. It was also deduced that improper selection of air supply outlet can result in room air stagnation, unacceptable temperature gradients, and undesirable velocities in the occupied zone that may lead to occupant discomfort. Through this work the importance and effectiveness of CFD (computational fluid dynamics) design tools, in the design & optimization of HVAC systems has been evaluated and it was concluded that CFD design software like Solidworks flow simulation provide an excellent provision to validate different aspects of HVAC design before actual construction.


2019 ◽  
Vol 111 ◽  
pp. 01079
Author(s):  
Hikari Sakakibara ◽  
Takashi Akimoto ◽  
Hitomi Igarashi ◽  
Shunsuke Nakamura ◽  
Madoka Kimura

The “Strategic Energy Plan” implemented by the Cabinet of Japan in 2014 strives for zero energy building design for typical new construction by 2030. The present study focuses on a ductless and variable air conditioning system, using the Coanda effect, with the aim of reducing fan power, and saving of resources by reducing the space between the ceiling. In this study, we examined the air blowing method and evaluated thermal comfort using computational fluid dynamics as well as subjective perception of coolness in a midsize office. A draft zone was reduced by extending the interval between conditioned air outlets. However, if the extension of throw length was excessive, hot space would be formed near the air outlets, and there would be a risk of impacting thermal comfort. Moreover, we confirmed that the thermal comfort was generally favourable. In particular, perceived thermal comfort was better at the position in the office where the air flow landed on the upper body of the subjects. On the other hand, it decreased when the influence of the air flow was small, and at the point where air flow landed on the lower body of the subjects.


2011 ◽  
Vol 213 ◽  
pp. 260-266
Author(s):  
Jun Wang ◽  
Hai Xia Wang

Simulation with CFD and local test are two main methods in study on air flow in large space building. This paper tests and simulates thermal comfort and air distribution of existing air- conditioning mode of some exhibition center. Through comparison and analysis on existing and simulated air-conditioning pattern, draw a conclusion that it’s feasible to simulate thermal comfort and air distribution of air-conditioning. And the research is important to guide energy efficiency and design optimization of air-conditioning system in large space building.


Author(s):  
Hesham S. A. Munem ◽  
ElSayed K. Abou El Kassem ◽  
Essam E. Khalil

Although there are still a number of squash arenas that are not air-conditioned or heated; Air conditioning of squash courts has become a trend when design and establishing new squash courts as well as other sporting arena. The current paper numerically investigates the influence of location and number of air conditioning supply and extracts openings on air flow properties in spectators’ area within a squash area. The present work focuses on predicting air flow patterns and thermal behaviour through investigating of the air flow regimes and moisture content inside the spectators’ area. Furthermore, the work investigates the heat transfer behaviour through analysing temperature and relative humidity profiles within the area. Moreover, carbon dioxide dispersion is investigated in order to recommend design features that aid to achieve the thermal comfort environment inside the studied area. The present investigation made use of Computational Fluid Dynamics (CFD) simulation techniques as embedded in the commercially available code (FLUENT 6.2).


2004 ◽  
Vol 69 (575) ◽  
pp. 75-82 ◽  
Author(s):  
Sueg-jae LEE ◽  
Shin-ichi TANABE ◽  
Tatsuo NOBE

2019 ◽  
pp. 53-65
Author(s):  
Renata Domingos ◽  
Emeli Guarda ◽  
Elaise Gabriel ◽  
João Sanches

In the last decades, many studies have shown ample evidence that the existence of trees and vegetation around buildings can contribute to reduce the demand for energy by cooling and heating. The use of green areas in the urban environment as an effective strategy in reducing the cooling load of buildings has attracted much attention, though there is a lack of quantitative actions to apply the general idea to a specific building or location. Due to the large-scale construction of high buildings, large amounts of solar radiation are reflected and stored in the canyons of the streets. This causes higher air temperature and surface temperature in city areas compared to the rural environment and, consequently, deteriorates the urban heat island effect. The constant high temperatures lead to more air conditioning demand time, which results in a significant increase in building energy consumption. In general, the shade of the trees reduces the building energy demand for air conditioning, reducing solar radiation on the walls and roofs. The increase of urban green spaces has been extensively accepted as effective in mitigating the effects of heat island and reducing energy use in buildings. However, by influencing temperatures, especially extreme, it is likely that trees also affect human health, an important economic variable of interest. Since human behavior has a major influence on maintaining environmental quality, today's urban problems such as air and water pollution, floods, excessive noise, cause serious damage to the physical and mental health of the population. By minimizing these problems, vegetation (especially trees) is generally known to provide a range of ecosystem services such as rainwater reduction, air pollution mitigation, noise reduction, etc. This study focuses on the functions of temperature regulation, improvement of external thermal comfort and cooling energy reduction, so it aims to evaluate the influence of trees on the energy consumption of a house in the mid-western Brazil, located at latitude 15 ° S, in the center of South America. The methodology adopted was computer simulation, analyzing two scenarios that deal with issues such as the influence of vegetation and tree shade on the energy consumption of a building. In this way, the methodological procedures were divided into three stages: climatic contextualization of the study region; definition of a basic dwelling, of the thermophysical properties; computational simulation for quantification of energy consumption for the four facade orientations. The results show that the façades orientated to north, east and south, without the insertion of arboreal shading, obtained higher values of annual energy consumption. With the adoption of shading, the facades obtained a consumption reduction of around 7,4%. It is concluded that shading vegetation can bring significant climatic contribution to the interior of built environments and, consequently, reduction in energy consumption, promoting improvements in the thermal comfort conditions of users.


1994 ◽  
Vol 1 (1) ◽  
pp. 77-83
Author(s):  
Yoshiji Moro ◽  
Tomoo Fujita ◽  
Takeshi Kanno ◽  
Akira Kobayashi

2019 ◽  
Vol 18 (1) ◽  
pp. 76-80 ◽  
Author(s):  
Kichul Kim ◽  
Pil-Ju Park ◽  
Soomi Eo ◽  
Seungmi Kwon ◽  
Kwangrae Kim ◽  
...  

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