Detailed Heat Transfer Measurements of Various Rib Turbulator Shapes at Very High Reynolds Numbers Using Steady-state Liquid Crystal Thermography

In order to protect gas turbine blades from hot gases exiting the combustor, several intricate external and internal cooling concepts are employed. High pressure stage gas turbine blades feature serpentine passages where rib turbulators are installed to enhance heat transfer between the relatively colder air bled off from the compressor and the hot internal walls. Most of the prior studies have been restricted to Reynolds number of 90000 and several studies have been carried out to determine geometrically optimized parameters for achieving high levels of heat transfer in this range of Reynolds number. However, for land-based power generation gas turbines, the Reynolds numbers are significantly high and vary between 105 and 106. Present study is targeted towards these high Reynolds numbers where traditional rib turbulator shapes and prescribed optimum geometrical parameters have been investigated experimentally. A steady-state liquid crystal thermography technique is employed for measurement of detailed heat transfer coefficient. Five different rib configurations, viz., 45 deg., V-shaped, inverse V-shaped, W-shaped and M-shaped have been investigated for Reynolds numbers ranging from 150,000 to 400,000. The ribs were installed on two opposite walls of a straight duct with aspect ratio of unity. For very high Reynolds numbers, the heat transfer enhancement levels for different rib shapes varied between 1.3 and 1.7 and the thermal hydraulic performance was found to be less than unity.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2018

Author dc:creator

• Zhang, Mingyang

Chair dc:contributor.committeechair

• Ekkad, Srinath V.

Committee members dc:contributor.committeemember

• Qiao, Rui
• Pitchumani, Ranga

• High Reynolds number
• rib turbulators
• thermal hydraulic performance

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:13765

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/81859