TITLE: VENTILATION IN A GAS TURBINE PLANT - A HAZARD ANALYSIS STUDY

BY: P J Phelps & D R Glynn, FLOWSOLVE. Tel: +44 181 944 0940

FOR: IVO GENERATION SERVICES / REGIONAL POWER GENERATORS LTD

• Hazard analysis study for a gas-turbine power plant.

• Accidental gas release may contact hot surfaces, resulting in an explosion.

• Ventilation provided to dilute and disperse hazardous gas releases.

• Safety requirement is that ventilation must keep critical gas concentration envelope below a defined size.

• Aim of CFD study is to assist in evaluation of alternative ventilation strategies to ensure compliance.

(1) GEOMETRY

• The next panel shows the geometry.

• Air enters through the green rectangular regions from the adjoining accessory compartment.

• Turbine casing and exhaust box are hot.

• Assumed leak location is shown.

• Model features - 3D steady, cartesian grid, ASAP, buoyancy.

(2) VELOCITY VECTORS ON VERTICAL PLANE THROUGH LEAK

The buoyant plume driven by the hot casing dominates the flow.

VELOCITY VECTORS

(3) CRITICAL CONCENTRATION CONTOUR ENVELOPE

The isosurface of gas concentration at 50% of LEL (lower explosive limit) is shown, for a given ventilation strategy.

The volume contained within this envelope is evaluated automatically by the model, for comparison with the safety requirement.

CRITICAL CONCENTRATION CONTOUR ENVELOPE

For further details see the May 1997 issue of Phoenics News.

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