Gas Turbine Compartment Ventilation System

The configuration of the compartment ventilation system is an important requirement in the gas turbine industry. The purpose of heating and ventilation system is to keep the turbine compartment within a fixed temperature envelope for at least personnel safety, equipment protection and reduction of turbine distortion by maintaining circumferentially uniform temperature distribution. The ventilation system also provides capability to detect and dilute the leaks by continually purging potential gas build up areas. Displacement ventilation is commonly used for the above considerations. The current GE approach is to perform CFD analysis to quantify the ventilation fan flow rate and arrive at fan static pressure head through simplified 1-D calculations. A detailed CFD geometric model is developed by including the entire turbine, piping, major support structure, all components with stringent temperature limits, ventilation inlets and outlets, enclosure roof and walls to verify the flow field. The fan static pressure head for various ambient conditions is obtained through 1-D calculations using the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) duct-fitting database. The goal of this work is: (1) accurate modeling of the components within the enclosure for better prediction of component temperatures; (2) consideration of solar radiation; and (3) integration of the 1-Dimensional Flowmaster models and 3-Dimensional CFD results to improve the predictions from One-Dimensional model.