Numerical Analysis and Experimental Validation of the Jet Impingement Cooling of a Turbine-Blade Leading Edge at Different Rotation Speeds

Herein, experimental and numerical validation studies were conducted on internal channel cooling in which seven jets impinging inside a rotating semi-cylindrical channel. These studies were conducted by considering a Reynolds number of 7,500 for a jet at five rotation speeds (ranging from 0 to 200 rpm). Numerical analysis was performed using the shear stress transport (SST) k–ω turbulence model with a properly analyzed fine mesh containing eight million nodes. A test setup with required instrumentation was developed inhouse for this study. Two temperature measurement techniques, namely thermochromic liquid crystals (TLCs) and thermocouples, were adopted. Further, the target surface temperature contours were precisely analyzed by comparing the TLC temperature measurements with the numerical temperature results. The captured temperature contours indicated points of minimum-temperature regions, which corresponded to the jet impingement regions. By examining the temperature distribution along the axial centerline, a good agreement was established between the numerical results and the experimental measurements. For Reynolds number of 7,500, increasing ration speed from 0 to 250 rpm has reduced the variation in temperature between different jets. The size of inlet port to feeding duct has a strong imapact on jet formation, which led to different mass flow rate across jets. Furthermore, a small deviation between numerical and experimental data can be observed near the end side of the channel owing to the radial and lateral heat transfer losses and outlet flow restriction.