Integration of Secondary Airflow Modeling Into Synergetic Cycle Calculation of F Class Industrial Gas Turbine

Abstract

Industrial gas turbines are complex systems, and their proper analysis requires specific knowledge of the different components interacting with each other. One of the challenges is to accurately predict the overall performance of the system. To do so, a performance analysis tool can be used but it needs to rely on representative characteristics from the different elements. One of the key items required for the performance derivation is the understanding of the total cooling and leakage air (TCLA) and its distribution within the machine. A secondary air flow (SAF) tool is used to evaluate TCLA, but it needs to be “connected” with the overall performance model. The source locations of the SAF system are relatively straightforward to handle, but the sink (or dump) locations occurring in the turbine section require a detailed understanding of the pressure distribution within the flowpath. As a matter of fact, a change in SAF distribution to the turbine yields a change in turbine work output and load distribution that needs to be captured in the overall engine performance assessment. Furthermore, a change in turbine inlet boundary conditions also yields a change in pressure values for the SAF system. For these reasons, an accurate performance modeling of a gas turbine requires a so-called Synergy Loop to converge the overall boundary conditions of all its interacting modules and sub-models. This paper will describe the method used to integrate different commercial and in-house software to complete the Synergy Loop. The authors will also describe the different iteration steps possible between the specific components and the recommended iteration loop sequence for fast convergence.