Heat Transfer Enhancement in Air Cooled Gas Turbine Blade Using Corrugated Passages.

Abstract

In this paper, an investigation of using corrugated passages instead of circular cross
section passages was achieved in conditions simulate the case in the gas turbine blade cooling
using ANSYS Fluent version (14.5) with Boundary conditions: inlet coolant air temperature of
300 K with different air flow Reynolds numbers (191000, 286000 and 382000). The
surrounding constant hot air temperatures was (1700 K). The numerical simulations was done by
solving the governing equations (Continuity, Reynolds Averaging Navier-stokes and Energy
equation) using (k-ε) model in three dimensions by using the FLUENT version (14.5). The
present case was simulated by using corrugated passage of 3 m long, internal diameter of 0.3 m,
0.01 m groove height and wall thickness of 0.01 m, was compared with circular cross section
pipe for the same length, diameter and thickness. The temperature, velocity distribution
contours, cooling air temperature distribution, the inner wall surface temperature, and thermal
performance factor at the two passages centerline are presented in this paper. The coolant air
temperature at the corrugated passage centerline was higher than that for circular one by
(12.3%), the temperature distribution for the inner wall surface for the corrugated passage is
lower than circular one by (4.88 %). The coolant air flow velocity seems to be accelerated and
decelerated through the corrugated passage, so it was shown that the thermal performance factor
along the corrugated passage is larger than 1, this is due to the fact that the corrugated walls
create turbulent conditions and increasing thermal surface area, and thus increasing heat transfer
coefficient than the circular case.