Experimental Heat Transfer and Bulk Air Temperature Measurements for a Multipass Internal Cooling Model With Ribs and Bleed

Abstract

An experimental study was made to obtain heat transfer and air temperature data for a simple three-leg serpentine test section that simulates a turbine blade internal cooling passage with trip strips and bleed holes. The objectives were to investigate the interaction of ribs and various bleed conditions on internal cooling and to gain a better understanding of bulk air temperature in an internal passage. Steady-state heat transfer measurements were obtained using a transient technique with thermochromic liquid crystals. Trip strips were attached to one wall of the test section and were located either between or near the bleed holes. The bleed holes, used for film cooling, were metered to simulate the effect of external pressure on the turbine blade. Heat transfer enhancement was found to be greater for ribs near bleed holes compared to ribs between holes, and both configurations were affected slightly by bleed rates upstream. Air temperature measurements were taken at discrete locations along one leg of the model. Average bulk air temperatures were found to remain fairly constant along one leg of the model.

Experimental Study on the Influence of the Streamwise Position of Film Hole Extraction in Internal Ribbed Cooling Channels of Turbine Blades

“…A detailed view on hole placement in relation to turbulators can be found in Bunker and Bailey (2001), Heneka et al (2011), Agata et al (2012) and Klavetter et al (2016) investigating the influence of the cooling hole position relative to the turbulator and the shape of the ribs on the discharge coefficient and film cooling effectiveness. Thurman and Poinsatte (2001) and Kunze and Vogeler (2013) investigated the internal heat transfer for 90°r ibs and revealed the position of cooling holes next to the upstream rib as superior to middle and downstream position. Partial extraction of the separation region downstream of the ribs is seen as the origin of the effect.…”

Experimental Study on the Influence of the Streamwise Position of Film Hole Extraction in Internal Ribbed Cooling Channels of Turbine Blades

“…A detailed view on hole placement in relation to turbulators can be found in Bunker and Bailey (2001), Heneka et al (2011), Agata et al (2012) and Klavetter et al (2016) investigating the influence of the cooling hole position relative to the turbulator and the shape of the ribs on the discharge coefficient and film cooling effectiveness. Thurman and Poinsatte (2001) and Kunze and Vogeler (2013) investigated the internal heat transfer for 90° ribs and revealed the position of cooling holes next to the upstream rib as superior to middle and downstream position. Partial extraction of the separation region downstream of the ribs is seen as the origin of the effect.…”

Experimental and numerical investigation of convection heat transfer in a rectangular channel with angled ribs

“…Wang et al [3] presented heat transfer results for square ducts with 45°ribs. Thurman and Poinsatte [4] measured the heat transfer and bulk air temperatures in a three-pass duct with orthogonal ribs and bleed holes both located on one wall. Ligrani and Mahmood [5] presented local Nusselt numbers and friction factors for a stationary channel with an aspect ratio of angled rib turbulators inclined at 45°with perpendicular orientations on the two opposite surfaces.…”