STUDY OF GAS TURBINE BLADE CONJUGATE HEAT TRANSFER TO DETERMINE BLADE TEMPERATURES

Open Access
Author:
Kane, Mangesh Ashok
Graduate Program:
Mechanical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
March 04, 2009
Committee Members:
  • Savas Yavuzkurt, Thesis Advisor
Keywords:
  • conjugate heat transfer
  • gas turbine
Abstract:
Conjugate heat transfer for turbulent flow over flat plates and turbine blades have been simulated and studied using a commercial computational fluid dynamics code FLUENT. The three two-equation turbulence models, k-ε Standard, k-ε RNG and k-ε Realizable were used. Computational grids were created using a preprocessor GAMBIT. Near wall treatment has been used for each model to resolve the flow near the solid surfaces. Experimental data for flat plate and turbine blade without film cooling was used for code validation. For the baseline case of a flat plate turbulent boundary layer, all models performed relatively similar to each other and results were within 5% and 7% of the data for skin friction coefficient and Stanton numbers, respectively. For the baseline case of a turbine blade, all models performed similar except Standard k-ε model. Results are within 3% and 5% of the data for heat transfer coefficient and surface temperatures, respectively. For above mentioned cases another approach is to use an iterative method. In this approach experimental data is used to derive a boundary condition which facilitates to solve only for conduction within the solid body and still contains the effect of conjugate heat transfer. The results were compared with the experimental data as well for three turbulence models. Results were within 5% of the data for surface temperature. Furthermore Mark-II blade which has internal cooling was simulated and studied using the same code FLUENT. This case was solved using constant wall temperature approach, Conjugate approach and the iterative method. Results for all were compared with 10% and 15% for surface temperature and Stanton number. Realizable and RNG k-ε models produced good results than the standard k-ε model. The purpose of this research is to show the advantages of the conjugate approach which is faster and more accurate to calculate the heat transfer coefficient and temperatures and where it should be used. An iterative CHT approach is developed to show its advantages over conjugate approach.