TY - JOUR
T1 - Effect of turbulent Prandtl number on the computation of film-cooling effectiveness
AU - Liu, Cun Liang
AU - Zhu, Hui Ren
AU - Bai, Jiang Tao
PY - 2008/12
Y1 - 2008/12
N2 - This paper presents a method to improve the accuracy of computed film cooling effectiveness spanwise distribution. The effect of turbulent Prandtl number in the flow field outside the near-wall region on the computation is studied. Realizable k s(-) ε model with a one-equation model in near-wall region is employed. The results show that the variation of turbulent Prandtl number has great influence on the computation. Reducing turbulent Prandtl number increases film cooling effectiveness of the whole spanwise region remarkably under large blowing ratios. Under small blowing ratios, the reduction of turbulent Prandtl number decreases the cooling effectiveness of the center region, and increases the effectiveness of the lateral region off the centerline. Compared with the single value turbulent Prandtl number computation the agreement between computation and measured results is improved notably with varied one in different spanwise regions. A new laterally varying turbulent Prandtl number (LV-Prt) model dependent on lateral location and blowing ratio has been suggested. Computation accuracy is improved greatly by LV-Prt model. Compared with the TLVA-Pr model of Lakehal [D. Lakehal, Near-wall modeling of turbulent convective heat transport in film cooling of turbine blades with the aid of direct numerical simulation data, ASME J. Turbomach. 124 (2002) 485-498] which provides the best results in the calculated cases LV-Prt model is an effective way to improve computation accuracy in the frame of the traditional isotropic turbulence models. More work on the information of the turbulent Prandtl number has to be done for the further development of the LV-Prt model.
AB - This paper presents a method to improve the accuracy of computed film cooling effectiveness spanwise distribution. The effect of turbulent Prandtl number in the flow field outside the near-wall region on the computation is studied. Realizable k s(-) ε model with a one-equation model in near-wall region is employed. The results show that the variation of turbulent Prandtl number has great influence on the computation. Reducing turbulent Prandtl number increases film cooling effectiveness of the whole spanwise region remarkably under large blowing ratios. Under small blowing ratios, the reduction of turbulent Prandtl number decreases the cooling effectiveness of the center region, and increases the effectiveness of the lateral region off the centerline. Compared with the single value turbulent Prandtl number computation the agreement between computation and measured results is improved notably with varied one in different spanwise regions. A new laterally varying turbulent Prandtl number (LV-Prt) model dependent on lateral location and blowing ratio has been suggested. Computation accuracy is improved greatly by LV-Prt model. Compared with the TLVA-Pr model of Lakehal [D. Lakehal, Near-wall modeling of turbulent convective heat transport in film cooling of turbine blades with the aid of direct numerical simulation data, ASME J. Turbomach. 124 (2002) 485-498] which provides the best results in the calculated cases LV-Prt model is an effective way to improve computation accuracy in the frame of the traditional isotropic turbulence models. More work on the information of the turbulent Prandtl number has to be done for the further development of the LV-Prt model.
KW - Film cooling effectiveness
KW - Numerical simulation accuracy
KW - Spanwise distribution
KW - Turbulent Prandtl number
UR - https://www.scopus.com/pages/publications/55549133937
U2 - 10.1016/j.ijheatmasstransfer.2008.04.039
DO - 10.1016/j.ijheatmasstransfer.2008.04.039
M3 - 文章
AN - SCOPUS:55549133937
SN - 0017-9310
VL - 51
SP - 6208
EP - 6218
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
IS - 25-26
ER -