Heat transfer and pressure distributions on a gas turbine blade tip

Heat transfer coefficient and static pressure distributions are experimenta lly investigated on a gas turbine blade tip in a five-bladed stationary lin ear cascade. The blade is a two-dimensional model of a first-stage gas turb ine rotor blade with a blade tip profile of a GE-E-3 aircraft gas turbine e ngine rotor blade. The flow condition in the test cascade corresponds to an overall pressure ratio of 1.32 and exit Reynolds number based on axial cho rd of 1.1 x 10(6). The middle 3-blade has a variable tip gap clearance. All measurements are made at three different tip gap clearances of about 1, 1. 5, and 2.5 percent of the blade span. Heat transfer measurements are also m ade at two different turbulence intensity levels of 6.1 and 9.7 percent at the cascade inlet. Static pressure measurements are made in the midspan and the near-tip regions as well as on the shroud surface, opposite the blade tip surface. Detailed heat transfer coefficient distributions on the plane tip surface are measured using a transient liquid crystal technique. Result s show various regions of high and low heat transfer coefficient distributi ons. Tip clearance has a significant influence on local tip heat transfer c oefficient distribution. Heat transfer coefficient also increases about 15- 20 percent along the leakage flow path at higher turbulence intensity level of 9.7 over 6.1 percent. [S0889-504X(00)00404-9].