Urbanization, characterized by a significant increase in population density and infrastructure development, brings with it a host of challenges. As cities expand, the complexity of their metro spaces escalates, often becoming a primary mode of transportation for a large number of people. This necessitates robust safety measures, a key component of which is understanding the behavior of smoke during a fire incident.

Computational Fluid Dynamics (CFD) serves as an indispensable tool in this regard. 

A study found that the dispersion distance of smoke for a fire in the tail car of a subway train is 83 m, which is  56.60% greater than that for a fire in the head car. 

This necessitates the importance of location-specific safety measures in metro spaces. Let us explore the intricacies of CFD models, their real-world applications, and how they contribute to the development of effective safety measures.

Basics on Smoke Analysis for Metro

Before going into advanced knowledge, it is important to understand the basics.

Differences Between Fire Behavior in Open and Enclosed Spaces

Fire and smoke behave differently in enclosed spaces compared to open ones. In an enclosed space, such as a metro station, the smoke rising from the fire becomes trapped by the ceiling and then spreads in all directions to form an ever-deepening layer over the entire room space. The smoke will pass through any holes or gaps in the walls, ceiling, and floor into other parts of the building.

Depending on the dimensions of the scenario, the type of fuel, and the ventilation conditions, the fire passes through different stages after ignition. 

In open spaces, fires can spread more easily as they are burning in an open environment. However, in enclosed spaces, the lack of physical separations (e.g., walls, floors) can allow smoke and hot gases to move unimpeded to locations far removed from the fire source.

Introduction to CFD and Its Application in Fire and Smoke Simulations

CFD is a revolutionary approach for smoke analysis for metro that employs computational simulations to analyze and predict the behavior of fluids, including smoke, within a given space. These predict smoke movement in buildings with the advent of performance-based codes and are increasingly used in fire safety engineering.

For instance, Autodesk CFD software  is used as a design analysis tool for fire and smoke simulation in buildings. It helps define fire source and smoke generation and explore results visualization and extraction tools. 

Types of Models Used to Simulate Fires: Zone Models and Field Models for Smoke Analysis for Metro

Fire models are categorized as zone models and field models.

• Zone models divide the fire environment into regions: flame, plume, hot gas layer, and ambient. They are simpler and outperform field models in terms of computational time and cost efficiency.

• Field models, on the other hand, excel in accuracy. They are used to perform the calculations required to simulate the free-stream flow of the fluid and the interaction of the fluid with surfaces defined by boundary conditions.

Advantages of Using CFD Models for Complex Geometries in  Smoke Analysis for Metro

CFD models offer several advantages when used for complex geometries:

1. Increased accuracy: CFD simulations provide detailed and accurate information. For example, in HVAC system design, CFD can accurately predict airflow, temperature distribution, and contaminant distribution in a room, which is difficult to measure in physical experiments.

2. Enhanced understanding: CFD simulations offer a deeper understanding of the flow behavior. For instance, in the automotive industry, engineers use CFD to study the airflow around vehicles, helping them understand how different designs can affect vehicle performance.

3. Virtual prototyping: CFD allows for virtual prototyping. For example, in the design of a new car model, engineers can use CFD to test and optimize aerodynamics, cooling, and other aspects before building a physical prototype.

4. Improved safety: CFD simulations can evaluate safety and predict potential hazards. For instance, in building design, CFD can simulate smoke dispersion during a fire, helping architects design more effective evacuation routes.

Mechartes: Leading the Way in Smoke Analysis for Metro Spaces Using CFD

Mechartes is a leader in the field of CFD  and its application in simulating smoke dispersion in enclosed metro spaces. Our decade-spanning expertise lies in evaluating the effectiveness of smoke exhaust systems in complex buildings like airports, malls, museums, and auditoriums.

We leverage CFD consultancy to bolster fire safety in large structures. Our work in CFD, FEA, HVAC analysis, Piping Analysis, and Acoustic Analysis has positioned us as a renowned firm in the industry. We are committed to enhancing safety and efficiency in large structures with our CFD modeling services.

Mechartes: Expertise in Smoke Analysis for Metro Spaces

Here is a case study exploring Mechartes’ experience with smoke analysis for metro:

Goal:

• Design a safe and effective smoke ventilation system for metro stations and car parks using CFD modeling.

• Ensure the system complies with all relevant fire safety standards, such as NFPA 130.

Methodology:

• Fire Scenario Modeling:

  • Simulate diverse fire scenarios in metro stations and car parks using advanced CFD software like ANSYS Fluent.

  • Consider fires of varying sizes and locations to capture a comprehensive range of potential incidents.

• Smoke Analysis:

  • Analyze smoke movement and behavior within the simulated fire scenarios using CFD simulations.

  • Evaluate the efficacy of various smoke exhaust configurations in controlling smoke spread and ensuring safe evacuation.

• CFD Simulations:

  • Conduct comprehensive CFD simulations to assess the performance of different smoke exhaust configurations.

  • Analyze key parameters like smoke flow patterns, temperature distribution, and smoke concentration levels in case of a fire.

• Standards Compliance:

  • Analyze the CFD simulation results to ensure adherence to all applicable fire safety standards, such as NFPA 130.

  • Identify areas for improvement within the smoke ventilation system through this analysis.

Results:

• The system effectively removes smoke from stations and car parks during fire emergencies, facilitating the safe evacuation of passengers and personnel.

• The simulations identified potential areas for improvement, including increasing the capacity of smoke exhaust fans.

To learn more about the case study, click here.

Final Note

Understanding the complexities of smoke behavior in such environments is vital, considering the significant impact of urbanization on metro spaces. Mechartes, as a front-running organization in CFD applications, exemplifies the importance of utilizing advanced simulations to design effective smoke ventilation systems.

For more information on our services and to explore how Mechartes can contribute to your safety and efficiency goals, contact us today!