Parallelized, Automated, Predictive, Imprint Cooling Model for Combustor Liners

Abstract

A novel parallelized, automated, predictive imprint cooling model (PAPRICO) was developed for modeling and simulation of combustor liners using a Reynolds averaged Navier-Stokes (RANS) approach. The methodology involves removing the film and effusion cooling jet geometry from the liner while retaining the cooling hole imprints on the liner. The PAPRICO can operate under two modalities, viz., two-sided and one-sided. For the two-sided PAPRICO model, the imprints are kept on the plenum and combustor sides of the liner. For the one-sided PAPRICO model, the imprints are retained only on the combustor side of the liner and there is no need for a plenum. Consequently, the one-sided PAPRICO significantly reduces the size of the mesh when compared with a mesh that resolves the film and effusion cooling holes. The PAPRICO model neither needs a priori knowledge of the cooling flow rates through various combustor liner regions nor specific mesh partitioning. The PAPRICO model uses the one-dimensional adiabatic, calorifically perfect, total energy equation. The total temperature, total pressure, jet angle, jet orientation, and discharge coefficient are needed to determine the imprint mass flow rate, momentum, enthalpy, turbulent kinetic energy, and eddy dissipation rate. These physical quantities are included in the governing equations as volumetric source terms in cells adjacent to the liner on the combustor side. Additionally, the two-sided PAPRICO model integrates the volumetric sources to calculate their corresponding volumetric sinks in the cells adjacent to the liner on the plenum side. The PAPRICO model user-defined subroutines were written in C programming language and linked to the ANSYS Fluent. A Fluent graphical user interface panel was also developed in Scheme language to effectively and conveniently form effusion cooling regions based on jet angle, jet orientation, pattern, and discharge coefficient. The PAPRICO algorithm automatically identifies and computes the jet area, jet diameter, jet centroid, and jet count per cooling region from an arbitrarily partitioned mesh. Jets with concentric patterns, containing multiple jet orientations, can be conveniently grouped into a single imprint zone. A referee combustor liner was simulated using PAPRICO under non-reacting flow conditions. The PAPRICO results were compared with the non-reacting flow results of a resolved geometry containing 1504 cooling jets (with multiple jet sizes, orientations and angles) and 7 dilution jets. The PAPRICO results were also compared with the non-reacting numerical results of the referee combustor liner with prescribed mass and enthalpy source terms. The numerical results were also compared with experimental measurements of mass flow rates through the referee combustor liner. The numerical results clearly conclude that PAPRICO can qualitatively and quantitatively emulate the local turbulent flow field with only one third of the mesh of that which resolves the effusion cooling jets. The simulations with prescribed mass and enthalpy sources fail to emulate the local turbulent flow field. The PAPRICO model can predict the relative flow rates through the various regions in the liner based on comparisons with measurements.