Session: 11-14-01 Heat Transfer in Gas Turbines

Paper Number: 69405

Start Time: Wednesday, 01:00 PM

69405 - Performance Analysis of a Gas Turbine Disk Containing Rotating Heat Pipes 

In the face of the future worsening thermal environment, the turbine disk as a key component of aeroengine works under extremely increasing thermal load. The combination of high temperature heat pipes with a turbine disk is an effective method to control thermal load and corresponding stress level. Radially rotating high temperature heat pipes are used in the heat pipe turbine disk. Heat pipes are placed circumferentially in the turbine disk and extended from the hub to the rim. The heat pipe is filled with liquid alkali metal as the working fluid, such as sodium. The high temperature of the rim and the low temperature of the hub create conditions for the heat pipe to be applied to the turbine disk. In the evaporation section, the working fluid absorbs heat and undergoes a phase change to form vapor. The vapor flows to the condensation section under pressure. In the condensation section, the vapor releases latent heat to condense into liquid. Under the centrifugal force, the liquid is pressed back to the evaporation section and the cycle starts again. Therefore, heat pipes with high thermal conductivity enable rapidly transfer heat from the rim of the disk to the hub, and reduce the radial temperature gradient of the turbine disk, thereby reducing the thermal stress of the disk. In this study, the influence of temperature and stress distribution variations caused by two different shapes of heat pipes are evaluated using thermomechanical finite element simulation. Results show that although the considered two shapes of heat pipes have little effect on the temperature change at the rim, the special shape heat pipe turbine disk with a connecting ring at the bottom(SSHPTD) has the advantage over cylindrical heat pipe turbine disk(CHPTD) in stress level decrease at the hub. This is mainly because the heat pipe turbine disk with a connecting ring at the bottom has a lower rotating circumferential stress component, and its thermal circumferential stress component is also slightly lower than that of a cylindrical heat pipe turbine disk. Besides, it is found that the heat pipe works as a notch and causes harmful notch stress at the end of the heat pipe condenser. The notch stress can be effectively controlled by adjusting the length of heat pipes and other geometrical parameters. Specially, when the length of the heat pipe is less than a certain critical value, the maximum stress will not be affected by the heat pipe.

Presenting Author: Wanqiu Lu Beihang University

Authors:

Wanqiu Lu Beihang University
Shuiting Ding Beihang University
Guo Li Beihang University