Wake-induced unsteady stagnation-region heat transfer measurements

Conference · Sat Jan 01 04:00:00 EST 1994 · Journal of Turbomachinery; (United States)

OSTI ID:5130569

Magari, P J; LaGraff, L E ^[1]

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1. Syracuse Univ., NY (United States). Dept. of Mechanical and Aerospace Engineering

An experimental investigation of wake-induced unsteady heat transfer in the stagnation region of a cylinder was conducted. The objective of the study was to create a quasi-steady representation of the stator/rotor interaction in a gas turbine using two stationary cylinders in crossflow. In this simulation, a larger cylinder, representing the leading-edge region of a rotor blade, was immersed in the wake of a smaller cylinder, representing the trailing-edge region of a stator vane. Time-averaged and time-resolved heat transfer results were obtained over a wide range of Reynolds number at two Mach number: one incompressible and one transonic. The tests were conducted at Reynolds numbers, Mach numbers, and gas-to-wall temperature ratios characteristic of turbine engine conditions in an isentropic compression-heated transient wind tunnel (LICH tube). The augmentation of the heat transfer in the stagnation region due to wake unsteadiness was documented by comparison with isolated cylinder tests. It was found that the time-averaged heat transfer rate at the stagnation line, expressed in terms of the Frossling number (Nu/[radical]RE), reached a maximum independent of the Reynolds number. The power spectra and cross-correlation of the heat transfer signals in the stagnation region revealed the importance of large vortical structures shed from upstream wake generator. These structures caused large positive and negative excursions about the mean heat transfer rate in the stagnation region.

• OSTI ID: 5130569
• Report Number(s): CONF-920602--
• Conference Information: Journal Name: Journal of Turbomachinery; (United States) Journal Volume: 116:1
• Country of Publication: United States
• Language: English

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