Ingenieurbüro für angewandte Strömungsmechanik


CFD in Power Plants

Exhaust Gas Washer / Dryer

A uniform velocity profile is essential for ensure that the dryer will work efficiently. The construction constraints however make it very difficult t fulfill this requirement.

Simulations help determine the deviation from the ideal situation before actually installing the apparatus. Optimisations can also be investigated to gauranty that everything is installed right the first time.

Courtesy of Munters Euroform GmbH.

Geometry and grid

Velocity distribution [m/s]

Boiler House Ventilation

A boiler ventilation systems might implement mechanical components such as fans to force cooling air through the boiler house. A more effective and reliable method is the use of natural convection (natural ventilation). The design of such a system is based on key conditions:

  • Black case
  • Summer case
  • Winter case

CFD simulations enable an exact determination of the neutral level and the required vent areas below and above the neutral level.

The example given here shows the 50°C isosurface for the black case. The colours displayed on the isosurface show the pressure distribution.

The stream lines show the flow regime. Eddies which might lead to hot spots can be located and avoided.

Courtesy of AeroTech Europe GmbH

Streamlines and 50°C isosurface

Boiler / Erosion Problems

Ash and soot particles flow with the exhaust gas around the heat exchangers (transparent blocks in image) of a boiler. The slit between the heat exchanger and the outer boiler walls causes an acceleration of both the gases and the particles flowing through them. The particle inertia leads to high concentrations at a certain position which lead to tube erosion. Finally the boiler fails and vapour production is lost.

The CFD investigations conducted were able to explain the reason for the encountered problems and were used for the reengineering of the boiler. Since then no damage has been reported.

Optimised particle distribution

Coal Combustion

Power = 350 MW

Particle size ca. 22 mm
Water content = 1,4%
Ash content =32,6%
Coal contant =65,9%
Volatile content =8,73%

Hydrogen = 2,1%
Carbon = 60,3%
Oxygen = 2,45%
Nitrogen = 1,12%
Sulphur = 1,43%

Swirl number of primary inlet = 2
Swirl number of secondary inlet = 1

The pictures show the burner configuration, the swirling flow coming into the combustion chamber and the isosurface 1600°C. The concentration of ash is plotted on the isosurface.

Bioler geometry

Swirl flow

1200°C isosurface and ash distirbution

Exhaust Gas Emission

This example shows the exhaust gas emission when considering a stably stratified atmosphere. The wind direction is given by the vectors displayed.

The isosurface displays the position of 3% exhaust gas concentration. The volume within the isosurface has a large exhaust gas concentration. The pressure distribution is plotted on the isosurface. Hotter colours indicate higher pressure values. Thus the pressure near the chimney is higher than further away from it.

Courtesy of RW-TÜV Anlagentechnik GmbH.

Flue gas emission
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