Architecture & Engineering
Proceed with the confidence of flawlessly engineered designs for the built environment.
- Air pollution control systems
- Combustion systems
- Water and wastewater equipment and systems
- Explosion modeling
- Structural consequence modeling
- Draft loss optimization
- Fire safety designs
- Tunnel & Subway ventilation systems
- Thermal comfort (HVAC) studies
- Clean room design
- Indoor air quality (IAQ) studies
- Dispersion of pollutants
Water & Wastewater Systems
There are many applications for simulation across the spectrum of water and wastewater equipment and systems. Water storage, treatment and disinfection are frequently modeled with Computational Fluid Dynamics (CFD). Identifying the existence of (and eliminating) short circuiting are obligatory requirements for potable water distribution networks. CFD modeling is also used to analyze and optimize mixing in service reservoirs, clarifiers, and digesters. Poor mixing can result in stagnant areas which can lead to bacteriological failure in the network. Spillway and dropshaft discharges are dramatic events that can also be accurately simulated with CFD. From ensuring that multiple flows mix within a single sump, to analyzing grit settlement and aeration, CFD is now routinely used to assess the efficiency of water and wastewater treatment systems.
Fire & Smoke modelling
Smoke modelling is a technique for simulating the way smoke will behave in the event of a fire. In certain types of structures, such as a shopping center or a building with an atrium, smoke modelling is likely to be required as part of the standard design process. In others, it might be used as part of a fire engineering justification for a building. CFD analysis allows us to accurately calculate the growth of a fire, smoke development and smoke dispersion into a building, atrium or other inhabited space. Because the studies are transient in nature, fire and smoke modeling can be used in conjunction with predicted egress times to demonstrate the safety of a building’s design for its occupants. Additionally, information from the study allows engineers to "right-size" the smoke mitigation system and its ductwork. A significant reduction in air handling requirements is often achieved through the use of CFD models as compared to other techniques, and the results are acceptable proof of design for fire marshals and code officials.
Clean Room and Laboratory Design
The use of CFD in the clean room industry allows users to gain insight into their designs with regard to flow patterns and flow fields, particulate dispersion characteristics, airborne chemical contaminates, and temperature uniformity. Better airborne particulate control and more energy-efficient clean room operation is made possible when the clean areas are evaluated using CFD. Clean rooms and laboratories are some of the most energy intensive spaces of any buildings and engineers historically have overdesigned the mechanical systems servicing the spaces with safety in mind. CFD now provides a systematic methodology to accurately assess both the ventilation performance of clean rooms and laboratories and the containment/energy efficiency of fume hoods that may reside in those spaces.
Tunnel and Subway Ventilation
Tunnels, subways and other underground roadways may require ventilation for a variety of reasons – for example to ensure an adequate air quality, to control the spread of smoke in case of fire, or to reduce temperatures to acceptable limits. The function of the ventilation relates to the type of tunnel in question. Vehicular tunnels (road, rail and metro) generally require high air quality during normal operation and smoke control in case of fire, while cable tunnels require cooling, smoke control and a certain amount of air exchange. Mine tunnels and station tunnels also require adequate ventilation for physiological, cooling and smoke control requirements. The use of CFD as a tool to predict airflows in tunnel systems is rapidly gaining world-wide acceptance by health and safety executives, railway authorities, civil engineering contractors and engineering consultants. When CFD is rationally applied by experts for the design of an emergency ventilation system, substantial civil, mechanical and electrical cost savings can be made, while simultaneously offering a high degree of safety to underground passengers. This is due to the deeper insights that CFD offers us with respect to smoke movement and the effect of imposed ventilation.
Air Pollution Control Systems
One of the foremost applications of Computational Fluid Dynamics (CFD) modeling over the past two decades has been in the area of optimizing Air Pollution Control (APC) systems used to reduce emissions from fossil fuel fired stationary sources such as power plants and steel mills. CFD analyses enable engineers to proactively decide on what approaches to take during each step of APC engineering design. For example, knowing the continuum concentration distributions of reactants and pollutants, the temperature profiles, and the velocity patterns within these systems are critical to ensuring performance. Flue Gas Desulphurization (FGD) systems, Selective Catalytic Reduction (SCR) systems, and particulate removal systems such as fabric filters and Electro-Static Precipitator (ESP) systems all depend on optimized fluid dynamics fore efficient operation. If flow or distribution profiles are highly skewed, engineers can perform CFD analyses to assess required counter-measures such as improved flow distribution devices or the addition of static mixers.
The figure on the right demonstrates the effective distribution of a chemical reagent, in this case Ammonia, in flue gas upstream of a Selective Catalytic Reduction (SCR) system. Flue gas is moving from left-to-right in the figure, from the solid-fuel combustion chamber and into the SCR system catalyst bed at the bottom of the figure. At the catalyst bed, Ammonia and Nitrogen Oxides take part in a surface reaction resulting in the reduction of nitrogen oxides and production of water vapor. In order for this reaction to achieve an efficiency of greater than 90%, Ammonia and Nitrogen Oxides must be equally distributed, demonstrating a coefficient of variation of less than 5%, at the entrance to the catalyst bed. Likewise, flue gas velocities must be uniform and demonstrate a coefficient of variation of less than 10% across the face of the catalyst bed. CFD modeling is used to determine the number and location of ammonia injection points, as well as downstream flow distribution equipment (turning vanes and perforated plates) as well as static mixers that are needed to achieve this level of reagent and flow uniformity.
Combustion technology underpins almost every facet of our modern life. Electricity is generated by the combustion of coal, oil, gas and increasingly biomass. Cars, trains, planes and even lawnmowers are powered by engines that burn gasoline, diesel or natural gas. Industry uses gas-fired heaters in many processes to generate heat for applications as diverse as glass manufacture to calcination.
CFD models of combustion can answer many more questions than simple thermodynamics, including:
- Where will reactions take place and where is heat being released?
- What is the distribution of temperature and chemical species?
- What is the heat flux to walls, refractories, boiler tubes and other critical structures?
- What are the exit concentrations of pollutants such as NOx, SOx and soot?
- What modifications are required to a plant to change fuel, such as moving from burning pulverised coal to a mixture of coal, wood chips, organic waste, biomass or shredded paper?
- Will a newly designed burner be stable or will it be subject to flashback? What will be the metal temperatures?
This knowledge allows engineers to implement intelligent modifications of combustion systems via simple procedures. Combustion is a broad topic and careful consideration of your CFD modelling approach is required for any given application, including key considerations of project timeframes, available hardware, and appropriate models and algorithms.
System Pressure Losses
With the rising costs of energy and emissions, engineers have increased focus on designing, or redesigning, flue gas systems with minimal energy losses in mind. In this regards, a common source of energy inefficiency is in the lack of appropriate flow control measures within flue gas and ductwork systems. Whether it be poorly or un-vaned ductwork elbows, expansions or contractions, excessive ductwork internal obstructions, or needless flow conditioning equipment such as perforated plates and screens, CFD is being used to assess the energy efficiency of current designs and optimize future designs for energy efficiency. The picture on the left demonstrates the flow of flue gas through a ductwork system downstream of a coal-fired, electricity producing boiler, produced in such a CFD modeling study. In addition to energy concerns, such modeling informs engineers as to locations of flow maldistributions that can cause poor performance in the form of accelerated erosion of internal members and poorly performing process equipment.
Atmospheric dispersion modelling
Computational modeling is now used in assessing a wide range of air quality issues relating to the built environment. These assessments often support occupational health and safety studies in an attempt to reduce associated environmental impacts. Such assessments include dust collection design reviews, temperature rise studies and exhaust and fume dispersion modelling. A typical example of this capability is in the design and assessment of stacks and resulting mitigation measures to reduce emissions and their impact on the environment.
Accurate dispersion simulations consider factors such as topography, solar load, humidity, buoyancy, building effects and atmospheric stability. A high degree of competence is therefore required to select the most appropriate model, to specify appropriate input data and most importantly to evaluate the results. Our simulation services assist designers in making quick and data-based decisions. This saves potential re-construction costs, improves performance and minimizes risks during operations.