M2 hattı şişli istasyonu platform ayırıcı kapıların ısıl konfora ve hava hareketlerine etkisinin incelenmesi
Effects of psds on thermal comfort and air flow on the M2 line of the sisli subway station
Yazar: OĞUZ BÜYÜKŞİRİN
Danışman: PROF. DR. MESUT GÜR
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Makine Mühendisliği Ana Bilim Dalı / Isı-Akışkan Bilim Dalı
Derece: Yüksek Lisans, 2014
Konu: Makine Mühendisliği = Mechanical Engineering
Dizin: İstanbul metrosu = Istanbul metro

Özet:
Günümüzde  demiryolu taşımacılığı, insanların hızlı ulaşım araçlarını tercih etmeleri nedeniyle önem kazanmıştır. Bu sebeble demiryolu taşımacılığını daha iyi hale getirmek için iyileştirme ve geliştirme projeleri hızlanmıştır. Özellikle yer altı raylı taşıma sistemleri günümüzde oldukça revaçtadır. Yoğun karayolu trafiği nedeniyle  en çok tercih edilen şehir içi toplu taşıma aracı haline gelmiştir. 
Metro sistemlerinin temel olarak tercih edilme sebepleri arasında hız, konfor ve güvenlik faktörleri sayılabilir. Metroların gelişiminde konfor ve güvenlik özelliklerini iyileştirebilmek için istasyon ile ray hattını birbirinden ayıran platform ayırıcı kapı sistemleri (PAK) uygulamaları da günümüzde yaygınlaşmaya başlamıştır. Platform ayırıcı kapı sistemlerinin birincil görevi , ray hattına yolcuların düşmesini ve itilmesini önlemektir. Konfor şartlarına etkiside bu yüksek lisans tezinin araştırma konusudur.
Yapılan  yüksek lisans tez çalışması kapsamında İstanbul'da bulunan M2 Yenikapı – Hacıosman Metro Hattı'na ait Şişli-Mecidiyeköy İstasyonu'na platform ayırıcı kapı sistemi uygulanması halinde yolcu ısıl konforunun ne şekilde etkileneceği ve istasyondaki hava hareketleri incelenmiş olup. İstasyona en uygun platform ayırıcı kapı sistemi tipi önerisi yapılmıştır. Çalışmaya başlamadan önce platform ayırıcı kapı sistemlerinin dünya çapındaki uygulamalarını araştırmak gerektiği kanaatine varılmış ve kaynak araştırması yapılmıştır. Daha sonra bu kaynak araştırmalarının neticesinde  yaygın olarak kullanılan kapı sistemlerinin tipleri ve özellikleri incelenmiştir. Bunları takiben Şişli İstasyonu'na ait ısıl kazançlar standartlar çerçevesinde hesaplanmıştır. Bu aşamadan sonra istasyon SolidWorks programında üç boyutlu ve bire bir olarak çizilmiş ve HAD (Hesaplamalı Akışkanlan Dinamiği) analizi için uygun parametreler ile hesaplanan ısıl kazanç verileri sınır koşulları olarak girilerek modellenmiştir.Belirli mühendislik kabulleri çerçevesinde başlangıç koşulları belirlenmiş ve programa tanıtılmıştır. Modelin zamana bağlı olarak çözümlenmesi Autodesk Simulation CFD (CFDesign) HAD analiz programı ile gerçekleştirilmiştir. 
Analizler platform ayırıcı kapı olmayan ve farklı platform ayırıcı kapı tiplerinin olduğu durumlar için ve farklı dış ortam sıcaklıkları ve farklı işletme koşulları için tekrarlanmış ve tren piston etkisinin havalandırma üzerindeki etkisinin her durum için ne seviyede olduğu incelenmiştir. 
Çalışmanın sonucunda elde edilen hava hareketleri ve sıcaklık sonuçlarına göre istasyona uygulanabilecek en uygun PAK tipine karar verilmiş ve önerilerde bulunulmuştur.

Abstract:
Today, subway transportation has gained popularity based on people opting for faster vehicles (people's need to travel faster). Therefore, projects to better advance railroad transportation have gained substantial momentum. Today, subway systems, especially, have become the most preferred method of transportation as they eliminate the hassle of dealing with heavy highway traffic.
Among the many factors, speed, comfort and safety are the main reasons why subway systems are chosen by the masses (preferred way of transportation for people).  To improve the safety and thermal comfort features of subways, platform screen doors (PSDs), which help to separate the station from the railway, are being installed.  The main purpose of the PSDs is to prevent passengers from falling or being thrown onto the tracks. The subject of this thesis is the impact of the PSDs on thermal comfort conditions.
During this study, we examined  how thermal comfort was affected by installing PSDs at the Sisli station for M2 Yenikapi-Haciosman Subway Line.  We also studied the thermal currents in the station to determine and advise on the best PSDs for the subway station.  Prior to starting the project, we decided it would be beneficial to study PSD applications around the world and did extensive research on the subject matter.  After completing the research, we identified the commonly used PSDs and their features (specifications).  Later, we measured the thermal output data against the standards at the Sisli station.  Following this process, we did 3D and 1-1 drawings of the Sisli station using the SolidWorks sofware. Thermal output values were calculated by using the appropriate parameters used for computational fluid dynamics; and were modeled and entered as boundary conditions. Initial conditions were identified based on accepted engineering principles and were entered into the software. The transient solutions of the model were conducted at Autodesk Simulation CFD (CFDesign) software.
Analyses were conducted at stations that had no PSDs and at stations with different types of PSDs under various temperatures and various working conditions, and the levels of the effects of train piston on air ventilation under each condition were observed and measured.
The best PSD type to be applied to a subway station was determined based on the data obtained studying the air currents and temperature results obtained during this study. In this study, we examined the types and sizes of PSDs that were being considered for installation at the Sisli Metro Station, by using thermodynamics as well as CFD (computational fluid dynamics) analysis and their impact on thermal comfort.

The Autodesk Simulation CFD (CFDesign) software was used for the CFD analysis.This software is solving partial differential equations by using finite element method.This numerical method is applicable in multi-physics problems that is why we prefer this method in our own problem .In our model the major partial differential equations are Navier-Stokes and Energy equations. 
Partial differential equations arise in the mathematical modelling of many physical,
chemical and biological phenomena and many diverse subject areas such as fluid dynamics, electromagnetism, material science, astrophysics, economy, financial
modelling, etc. Frequently these equations under consideration are so complicated
that finding their solutions in closed form or by solely analytical means (e.g.by Laplace and Fourier transform methods, or in the form of a power series) is either
impossible or impracticable, and one has to resort to seeking numerical approximations to the unknown analytical solution.
These are the determining factors  to seek  a particular class of numerical techniques for the approximate solution of partial differential equations: finite element methods. They were proposed in a seminal work of Richard Courant1, in 1943; unfortunately, the importance of this article was not recognised at the time and the idea was forgotten.In the early 1950's the method was rediscovered by engineers, but the mathematical analysis of finite element approximations began much later, in the 1960's, the first important results being due to Milos Zlamal in 1968. Since then finite elementmethods have been developed into one of the most general and powerful class oftechniques for the numerical solution of partial differential equations and are widely used in engineering design and analysis.
In finite elements method the most crucial point is the mathematical aspects such as stability, accuracy, reliability and adaptivity. In order to provide these terms the optimum number of finite elements has to be obtained. To obtain the optimum number of finite elements steady state solutions were conducted and we reached the desired number. Thermodynamics analysis was also done in order to ensure our limits based on our approximations.
Thermodynamic analysis was done when there were no PSDs and also when the PSDs were completely closed.  The number of passengers and subway schedules were taken into consideration in creating the thermodyonamic model.  When fully closed PSDs are used, it was observed that the station temperature increased.  In other words, it had an affect on the  thermal comfort conditions in the station.  
The CFD analysis was done using a a station thermodynamic model that was develeoped exclusively for this analysis.  Outside temperature, 4 or 8 subway carts, and subway schedules were used as parameters for the model.  The mathematical model was created by using a CFD Transient Solver.  Therefore, all air flows were calculated and distributions are shown based on temperature, air velocity and pressure values during times when the train arrives at the station, while it is stopped, and when it departs the station. 
It is determined that generally PSD effect is important.
1- When fully closed PSDs are selected, the station is fairly isolated from the movement of the train and it's thermal comfort conditions change.   In other words, additional design work is needed to achieve the station's thermal comfort standards. 
2-  Fully open PSD system is affected by the movement of the train itself.
3- 2.4 meter,semi-Open PSDs are more suitable for thermal comfort levels, however, an additional analysis should be done to understand how these doors function during emergencies.  A formal decision can then be made after completion of the analysis. 
According to the research findings, when no PSDs are used, it was observed that air velocity reached 3-3.5 meter/second (m/s) which is well below the standard limit of 5 m/s.
However, under the same circumstances, it was observed that to maintain thermal comfort conditions, the pressure ranges were at critical levels at the metro station. Based on these studies, by installing the PSDs at the Sisli Subway Station, it is possible to achieve the passenger comfort conditions stated in the ASHRAE standards as well as to increase safety levels for passengers.  Given the results obtained by analyzing the impact of various PSDs on thermal comfort and outside temperatures, even though the effect of  the 1.5 meter PSD system showed different results for air velocity, graphical analysis showed that the PSD system caused a significant drop in pressure change values and made it possible to reach the optimum pressure range that achieved the comfort condition standard.
The piston affect of the train is blocked when the full size PSD is used.This type of PSD blocks the air movement on the platform where the passengers wait .  This situation restricts the air flow inside the subway station.  Also, it was determined that any increase in temperatures around the subway station would make it uncomfrotable for waiting passengers.
Also, when the air was pushed out of the shafts by the piston affect of the train, it was noted that the the air velocity in the shafts reached and exceeded the critical level (11-13 m/s). 
To install a full size PSD system, the air ventilation system at the station has to be reevaluated to determine the right capacity to achieve passenger comfort standards. 
At the conclusion of the study, it was determined that the most suitable PSD model is 2.4 meters in height.  Having a PSD 2.4 m in height, would allow the heat from the train to dissipate over a greater area and would allow improved air circulation.  Also, a 2.4 m. PSD is recommended as the most suitable PSD as it also provides the best means of achieving the thermal comfort standards.