A MULTI-TIMESCALE APPROACH FOR THE PREDICTION OF TEMPERATURES IN A GAS TURBINE COMBUSTOR LINER

The desire for increased engine efficiencies is driving higher firing temperatures. But this increases the risk for hot spots in solid components which can lead to durability issues. These may not be discovered until late in the design process through expensive and time consuming thermal paint tests. Historically, conjugate heat transfer simulations to predict solid temperatures have been done with steady RANS. However, Large Eddy Simulation (LES) is now being used in the early design process for gas turbine engines to account for the multiphysics of reacting flows. Incorporating the solid into these simulations poses a new challenge: the physical response time of the solid components can be orders of magnitude larger than the reacting gas phase. Running a fully coupled unsteady conjugate heat transfer analysis is therefore not tractable, but the high fidelity of the LES reacting solution is still desired. The objective of this paper is to demonstrate a multi-timescale simulation approach for conjugate heat transfer (CHT) in Simcenter STAR-CCM+ 2019.3. The combustor is solved using LES, including all relevant physics, while steady state conduction is determined in the metal liner and thermal barrier coating. Time averaged boundary conditions are transferred from the combustor to the solids, and temperature is returned through multiple exchanges until the solid temperatures reach a stable solution. A simplified case is used to verify the approach, and then results from a test combustor are compared against data. The investigation compares results obtained with PISO and SIMPLE numerical schemes.