Session: 12-11 Code Development

Paper Number: 82787

82787 - Developing a Scalar Flux Model Solely Based on Mean Flow Quantities for the Film Cooling Jet Flow 

Previous studies showed that RANS which based on gradient diffusion hypothesis severely under-predicts the scalar diffusion downstream the film cooling jet flow. Scalar flux models of different types have been developed throughout the years. Of particular interest are the algebraic models, which are easy to implement and has a low computational cost. Famous algebraic models include the generalized gradient diffusion hypothesis (GGDH) and the high-order generalized gradient diffusion hypothesis (HOGGDH). However, due to the dependent of the Reynolds stress, GGDH and HOGGDH may suffer from a lack of prediction, because the Bousinessqi core of the RANS results in a loss of anisotropy. The present study developed a scalar flux model by analyzing the results of a large eddy simulation (LES). In a previous study, the mechanism of the scalar transport process in the film cooling jet was revealed. Upon the mechanism revealed, this paper aims to devise a model that only depend on mean flow quantities, which includes mean velocity, turbulent kinetic energy, and some other variables. It is our purpose that the model at this stage can be comparable or surpass the ability of prediction by the GGDH and HOGGDH, and at the same time not depend on Reynolds stress. Scalar transport equation was solved with the previous LES providing the flow field quantities. The prediction of a cylindrical hole with VR=0.5 using GGDH, HOGGDH, current model were compared and analyzed.

Presenting Author: Bo Shi Gas turbine institute

Presenting Author Biography: Dr. Shi received his doctoral degree in Tsinghua University, and his main research interest lies on the flow and scalar transport problems in the gas turbine cooling.

Authors:

Bo Shi Gas turbine institute
Xueying Li gas turbine institute
Jing Ren gas turbine institute