Large Eddy Simulation of Impinging Jets in a Confined Flow

Abstract

This chapter discusses a large eddy simulation (LES) of impinging jets in a confined flow. The use of impinging jets is common in the primary combustion zone, providing a region of highly recirculating flow and a stable initial combustion. This zone is considered to be one of the most challenging to model computationally. LES is applied to a representative primary combustion zone in an isothermal constant density simulation. In the uncoupled case the use of measured mean and turbulence profiles, directly providing the port boundary conditions, appears greatly improve upon the use of uniform inlet profiles resulting in a good description of the mean and turbulence fields within the combustor core. The coupled LES appears to be capable of simulating the mean port velocity profiles to an accuracy sufficient to produce a well-predicted core impingement location and strength, though it is arguable whether the uncoupled or coupled simulation gives the best overall results. Comparison of LES results with RANS data shows major improvements in the turbulence field; however both methods give a similar mean velocity distribution close to the jet inlet region. Further the chapter examines computational parameters..