An experimental study of heat-transfer and pressure-drop of leading-edge coolant channel with effusion in a gas turbine stator blade

Abstract

The present experimental study investigated the heat transfer and pressure drop performances of the isosceles trapezoidal channel cooled by the impinging jet-row with and without effusion Three effusion conditions by allocating the effusion holes as (I) one-row (II) two-row (III) three-row along the channel apex wall the apex and one sidewall and the apex and two sidewalls At each effusion condition the discharged ratio between the exhausted mass flow rate from channel tip and the total supplied airflow rate was controlled at 0% (fully closed condition) 5% 10% and fully open condition At each effusion and tip-discharged condition the steady-state infrared thermography method was used to detect the full-field heat transfer data for the channel apex wall and two channel sidewalls The measurements of heat transfer rate Fanning friction coefficient and thermal performance factor at each effusion and tip-discharge condition were carried out at channel Reynolds number of 5000 7500 10000 12500 and 15000 As the effusion from the bottom-sealed channel considerably suppressed the crossflow effect and the flow confinement the heat transfer performances were improved from those detected from the non-effusion channel Among the test channels with different effusion row numbers the channel with three rows of effusion holes exhibited the best heat transfer performance Unlike the significant heat transfer impact caused by the effusion holes the adjustment of the tip-discharged ratio showed lesser effect on the heat transfer performance But the decrease of tip-discharge ratio still improved the overall heat transfer performance Due to relaxation of the confinement effect by effusion the Fanning friction coefficients of the channels were reduced by effusion Combining the heat transfer enhancement and the reduction of channel pressure drop by effusion the thermal performance factors of the effusion channels were elevated from the non-effusion channel references

Date of Award	2020
Original language	English
Supervisor	Shyy-Woei Chang (Supervisor)