A 2-D NUMERICAL STUDY OF THE HEAT-ISLAND EFFECT FOR BUTTON-TYPE HEAT FLUX GAGES

摘要

This study examines the errors associated with the use of button-type gages for transient heat flux measurements. A two-dimensional, conjugate numerical analysis was performed, with flow and thermal conditions that are representative of short-duration (less than 100 ms) turbine blade tests. The problem was solved using a transient conduction code for the solid and a 2D turbulent boundary layer code, STAN7, for surface heat flux calculations. The STAN7 code was qualified using recent experimental heat transfer data from a small heated calorimeter. Heat transfer coefficient (h) values computed for the gage at various test times were compared to those obtained for a surface of uniform composition. The largest difference observed between the two is greater than 30%. Epoxy surrounding the gage can reduce this error by as much as 10%, indicating the importance of gage installation details in performance assessment.